1. How are similar electrodes rated? Is one "better" than another? More stable for instance?

    • Electrodes don’t have a current rating system because the decision of which electrode depends on budget, patient demographics, and, most of all, a simple issue of personal preference in most situations. If you compare electrodes, you have a few differences, such as different types of metal. Electrode options include gold, silver or silver/chloride, tin, platinum and more. Now these metal types are often just on the outside of the electrodes--for example a Gold Cup is typically an electrode made of silver with a plating of gold on top of the silver base. Many folks think a gold electrode is 100% gold and this is not the case. The purpose of the metal is to conduct, and each lab may decide which metal produces the best data for their service. Gold is usually preferred for PSG because it has been shown to enhance the slower frequencies better which is important for PSG labs. EEG and Epilepsy labs have a preference for silver metals because they accentuate the faster frequencies. I will admit that I have used many different types of metals and I have difficulty telling the difference in data results.

      Beyond the metal, there are differences in the way the “cup” shape is made. A “stamped” style electrode typically has a bigger cup capacity and is a thinner thickness versus the “casted” style which is a thicker metal cup with a smaller cup capacity in some cases. Both collect data and it’s a preference as to which is preferred.Some casted styles have a thinner “rim” that touches the patient than a stamped, so some folks prefer a casted for skin integrity issues.

      Other differences are the way lead wires are made. Some are made of copper, some of tinsel and other materials. That is what makes different lead wires “feel” different between manufacturers. Different strategies are used due to cost and artifact management.

      And, then you have the transition to the use of fully disposable EEG electrodes which are electrodes made of a base of plastic and covered by silver, silver/silver chloride, or other materials. So, the summary to the above answer is that is up to each individual as data can support the advantages of each different type of lead, but whether that benefit translates to a usable benefit for your lab is a question only you can answer. To compare, I would recommend calling manufacturers and asking for samples for comparison purposes and do your own head to head comparison. Because remember, you can use different leads from different manufacturers, however, I would avoid mixing metals on the same patient or differing types of conductive paste. But, the same metal type with the same past or gel will be a solid comparison.

    • You would assume this would be a fairly easy question to answer, but it’s not. It’s all dependent on what signals you are recording. For example epilepsy and EEG folks look for high amplitude fast frequencies and that is not the same data that a PSG technologists would be looking to obtain. And, the above question of type of signal could be handled by scientific data analysis of metal type and manufacturing styles; but even more importantly, what your preference for the tangible “feel” of the electrode. It’s a very subjective answer. And there is no concrete and definitive answer to your question. But, with that said, there are a few statements that have been widely acceptable for decades. I'm not saying each point is completely correct but arguably the below statements have been generally accepted. --Casted cup electrodes are more durable than stamped.

      --But, stamped electrodes have larger “domes” for holding conductive paste than casted styles.

      --Casted are more expensive than stamped.

      --Gold electrodes record better PSG data than silver because they accentuate the slower frequencies.

      --Silver leads are better for EEG and epilepsy studies for the reason mentioned above.

      --Chlorided silver electrodes record EEG data better than unchlorided silver electrodes

      --Tin is better than either gold or silver because it conducts more efficiently and is less costly

      --ECG pads are better for recording peripheral data like legs than cup electrodes

      Now, you add all the new products of flat electrodes, disposable EEG cups, and more, and your question gets even harder to answer. My recommendation: call around and ask for samples of gold, silver, silver chloride, stamped versions, casted versions , flat versions, disposable cups, and any other electrode type you want to consider. Then, I recommend you apply a few electrodes of each type to the same patient. Make up a montage and record the data and see how it looks. This will help you decide which electrode is the best for what part of the patient’s body and for your application technique. So the answer really is that all electrodes regardless of manufacturing style (stamped or casted) or metal type (gold, tin, silver, silver/silver chloride) conduct the electrical signals from our patients in the form of EEG, EMG and other data. So which is best, truly is answered per each individual’s preference until a day arrives when one electrode type can prove its dominance over the rest. Oh, and lastly, the lead wire attached to the electrode is whole other conversation--same argument regarding which lead wire is best.

  2. We run a pediatric sleep lab and our leads can take quite a beating. What draw backs are there to the disposable leads vs reusable? Also what is the difference in using "cup" leads and flat leads? I asked two vendors at a recent conference and they couldn't tell me.

    • Great question. Reusable EEG Electrodes and Disposable EEG Electrodes are more alike than they are different. Both electrode types typically use the same type of lead wire and connectors. The only difference is the “cup” itself.

      A reusable EEG Cup is a reliable and accepted product for quality testing and disposables are still proving themselves regarding their quality of recording compared to a reusable. I would recommend doing a “head to head” comparison of reusable electrode versus disposable electrodes literally on the same patient. For instance, use reusables on the right and disposables on the left and compare directly. This is the most reliable way to compare quality of each lead type for your individual patient demographic and application style. This will answer the top priority question…does a disposable record as well as a reusable? Now, advantages of reusables are they typically are made of 99.9% silver and coated with either silver/silver chloride or plated with gold. Because of the robust metal that is used the reusable EEG electrode can last months. My experience is reusable EEG electrodes last an average of 5 months…some longer and some shorter. The life of the product is most definitely the benefit of a reusable electrode. This benefit of long product life can also be a cost savings as well in certain situations. Disposable cups may not have that advantage but they have their own benefits to offer. Regarding material of the disposable cup, the cup part is typically made of a plastic that is coated with a silver/silver chloride coating. They are designed to record equally as well as a reusable. They are not as durable as a reusable cup but they don’t need to be because they are designed for a single patient. But, they do not have a Gold option--only silver at this point. This can be a negative for some services who use Gold. But, the ability to “reuse” an electrode can be the negative as well. There is no guarantee how long a reusable will last--it could break 30 days after being used and depending on your warranty this can be costly. Also, the reusable electrode requires strict compliance with cleaning and disinfecting protocols to ensure the electrode is safe for repeat use across multiple patients. If the skin of the patient is abraded, meaning if you use a Q-Tip, for example, with NuPrep or any other prep that is designed to lightly abrade the skin, that electrode falls under the criteria of a Semi-Critical item and requires specific disinfecting protocols. Most commercially available disinfecting solutions such as Cidex or others meet this criteria, but an electrode cannot be used without full compliance to the recommended cleaning directions of these products. And, this can lead to higher labor costs to clean and disinfect a reusable electrode. Even if you have staff spending 20 minutes to clean and disinfect reusable electrodes--this is money and cost for the department or service that MUST be considered when a cost comparison is being done between reusables and disposables. The general impression is typically that reusables are less expensive than disposables. However, disposables have cost benefits even though many people do not look at the full investment to a service to appreciate the cost savings. For example, the direct cost of disposables versus reusables will no doubt show a cost savings to the reusable product. But, it’s not just the direct purchase cost that should be considered. Costs of additional inventory, chemicals for cleaning and disinfecting and as mentioned above the cost of labor, even what seems to be a small amount of labor, can add up quickly. So, costs, historically, have leaned towards reusables, but now a service should run analysis and decide of that is true to for their situations. Quality can be comparable or identical, but again should be individually compared. Reusables offer a Gold option and Disposables currently do not. Disposables arguably offer the best risk management option due to elimination of cross contamination risks because they are not reused. So, long answer for your question is there are pros and cons to both. And, both should be openly considered in your service. You may even find that your service can efficiently and cost effectively use a combination of both reusable and disposables which could be a definite benefit for a pediatric facility that can deal with many other risks of fluids, electrode contaminations, etc. The second part of your question about the cup design versus the flat electrode design. The “cup” itself is designed to hold the conductive paste--a storage spot basically. The problem with the cup design is that our paste begins to melt or dissipate away as soon as we put the lead on the patient due to the patient’s body heat. When the paste begins to “melt” out of the cup, the surface area of the cup no longer has consistent contact with the conductive material and this will lead to pops and other artifact issues as the testing goes on.

      Flat electrodes whether disposable self adhesive stickies or reusable flat electrodes can better retain the consistency of the conductive material in contact with the electrode. So, the flat lead should allow for more consistent recording quality for a longer periods of time. But, again, this should be tested per facility to compare the options. Some flat electrodes take some time to “get used to” and may require slight adjustments in application techniques. Additionally, some flat electrodes are significantly more comfortable for the patient and have shown to cause less skin irritations than some cup designs.

      Cup designed electrodes can be maximized for their potential with a good covering placed over the cup to help keep the paste in place longer; but the flat designs offer patient comfort and some skin benefits as well. And especially with pediatrics the comfort and skin integrity issue is probably more prominent than in an adult facility. I hope that helps. I am happy to answer any other questions.

  3. My sleep techs (all RPSGTs) tell me that it is rarely possible to reach an impedance of 10 kOhms in all the EEG and EOG electrodes, let alone the 5kOhms that is recommended by AASM. Ours is a pediatric lab, but the impedance problem occurs in infants through adolescents. The signals appear physiologic, and when they don't, the techs make the appropriate electrode replacement or adjustment. Should I expect better impedances?

    • The easy answer would be to say “yes” you should expect better. But, being a technologist that has worked in pediatric facilities for over 10 years, I can tell you that this question does not have an easy answer. Your patient load varies with skin integrity and other issues that affect impedances. There are a few tips you can use to help your impedances get to the 5K level, at least part of the time.

      First, check with your equipment manufacturer and ask them how their impedance function works. Each machine has a slightly different method. So for instance, some machines use a specific electrode or combination of electrodes as part of the impedance operation. So, if this is the case, knowing which leads are used for impedance function will help your staff know the most important electrode to prep well and prep consistently. Example: a machine may use the ground electrode as part of the impedance function. If this is the case, ensure you prep Ground really well, as a high Ground could cause all your other leads to read high. Second, verify your machine is working properly by taking a set of cup electrodes and putting them in a glass of water and running the impedance test. The water can simulate a patient. It won’t give fine details about the integrity of your electrodes but should ensure the impedance function is working on your system. If the impedances are low and balanced (as they should be in that test situation at about 1-3K) the machine works fine and the cause of any disappointing impedances are probably application. This does not mean your application technique is bad but means you may have to realize that getting consistently to a 5K level may not occur very often.

      Why does such a recommendation exist? Because high impedances produce noise data, right? Well, maybe. If you can’t get to the 5K level, the next best thing is for your impedances to be balanced. The equipment amplifier is looking for balanced electrodes so the amplifier’s features can work properly and produce clean looking high quality data. So, if you can’t get to 5K, can you get to 10k or 12K or 15K consistently? If so, make your policy for all leads to be within 10-15K. This will ensure your amplifier collects “common” noise between electrodes and can better use the amplifier’s common mode rejection features to eliminate the unwanted noise. Noise and artifacts are one of the main reasons for the a low impedance recommendation--amongst a few other reasons. It is better to have 10 electrodes showing an impedance of 13K than two electrodes reading 2K and 8 reading 15K. This is because the artifact, for instance 60 cycle, will be seen differently between these two electrode groups and the noise will not be “common information” for the amplifier. So, the CMR feature (common mode rejection) of the amplifier can’t “reject” the 60 cycle because it doesn’t look common. But, if I have 10 leads that all have impedances of 10K, then the 60 cycle will look the same to the amplifier across all electrodes and the data on your screen will look clean even though the impedances are higher than preferred. So, I hope this helped with your situation--it’s a tough one especially with pediatrics. But, keep the impedances balanced and the data being recorded should look good and keep working towards the 5K -10K goal.

  4. What is the best way to clean gold cup electrodes so that they are cleaned appropriately and last as long as possible?

    • Hard to answer which is the “best” method because as long as the electrode gets cleaned and disinfected, mission accomplished. But as long as you are following proper procedures to clean and disinfect, any strategy can be “the best." Tips to keep your gold leads working like new as long as possible:

      --Use caution with the connection point where the electrode cup attaches to the lead wire. This connection is typically crimped or soldered and can be at risk for breakage. This is a big issue for labs who don’t recognize the nature of that connection. So, if you hang your electrodes before or after cleaning, be sure that connection point is not being bent or stressed.

      --Be attentive to how your head box is positioned and what the positioning of that head box does to the connection points of your electrodes.

      --Clean your gold cups with a standard cleaning detergent (any type that your facility recommends) to remove paste and debris. Be careful using a toothbrush to scrub the electrode to avoid scrubbing too aggressively and deteriorating the gold plating on the outside of the cup.

      --After cleaning with detergent (and you may choose to use a disinfecting wipe such as a CaviWipes on the lead wire), use any of the commercially available disinfecting products such as Cidex, Sanizide, Metricide, and others according to their directions.

      Beyond the suggestions above, it is difficult to say what will preserve the life of your electrode longer. If you are experiencing electrodes that are not lasting as long as you would expect, you can contact your vendor and ask about warranty of the electrodes and if needed contact other manufacturers of electrodes to compare products. It is not an issue to mix and match electrodes from various manufacturers. My suggestion though is to keep the metal and style the same. For instance, if you use gold casted electrodes from one vendor then be sure to ask for gold casted electrodes from the other vendor. But there should be no problem using them on the same patient as long as the paste is the same. But it will provide a direct comparison to see if one type works better for you than another.

      Sometimes life of the product is also simply differences between testing techniques. For instance, if you use collodion versus a paste to secure your leads; or the type of conductive paste you use; or how long you leave paste in an electrode before it’s cleaned, etc. Sorry that I was unable to provide a more concrete answer.

  5. We have used the Piezo leg leads for some time and have been asked to change to the surface electrodes (2 per leg) per AASM recommendations. We have tried the ECG snap-on type and gold cups. We have 60Hz interference and are having trouble getting our impedences done. Do you have any advice on this?

    • Well, the good news is that most likely the two problems you are experiencing (impedance and 60 Hz) are related so if you fix one you will most likely fix both.

      Impedance is the top priority to resolve because if you can get a handle on your impedances the 60Hz will resolve because low and balanced impedances allow your amplifier to eliminate the 60Hz artifact. To address your impedance problems, I suggest troubleshooting from a very basic perspective. First, verify the jack on the head box is working OK by prepping a spot on the scalp, apply an electrode, and verify a good impedance. Now, take that “known good” electrode and unplug it from the amplifier jack and plug it into your jack that you use for your leg leads. Check the impedance again and if the jack is setup properly and functioning the impedance should be the same as it was in the previous jack. If not, I suggest calling your equipment vendor to troubleshoot settings or hardware.

      If the impedance is the same, your jack is fine and you have to focus on your skin prep as the next troubleshooting step. For this step, I suggest using a volunteer, if possible, and simply experimenting with different preps, different types of electrodes, and different application techniques. Leg leads and their impedances can be very challenging, but using these steps should assist in knowing where the problem lies which then will help you concentrate on the resolution. Also, as mentioned, once the impedance is resolved your 60Hz should resolve as well. 60 Hz is seen when you have high or imbalanced impedances and the amplifier is unable to manage the “noise” and eliminate it for you. The key is balanced impedances between electrodes and as low a you can get them; and if this is accomplished your CMR feature (Common Mode Rejection) of your amplifier will “see” the 60Hz as a common artifact and will be able to eliminate it for you.

  6. Is it okay to mix silver and gold electrodes for the EEG?

    • The correct answer is “no”--it is not preferred to mix gold and silver electrodes for testing because you are risking the introduction of artifacts which can be caused by mixing metals. But in reality, lots of folks do it every day with very few problems in most cases. If you have differing metals avoid referencing these leads together. For example, if you use gold metal on the patient’s scalp for EEG and silver electrodes for the chin, simply avoid referencing the leads to each other. Keep chin leads referencing to each other and scalp leads referencing to each other in your montage.

      This doesn’t completely eliminate the risk as you may have mixed metals being referenced by your amplifier depending how the amplifier jacks are configured; but, in reality, if you are careful, it is doubtful that you will see many issues. If you struggle with artifacts, I would avoid the mix if possible.

  7. Is it necessary to use both ground and reference electrodes? If so, where are they commonly placed?

    • Yes, it is necessary. If you are referring to the port on your head box labeled reference--yes, you need it.

      Reference electrodes are used by your amplifier to allow the process of reformatting to occur. Essentially the machine takes each electrode and ties it to the electrode plugged into “reference” on your jackbox. Then the machine will use basic math to cancel out the reference to remontage. Example:

      O1 – refO2 – ref

      If I want to see O1 to O2 in my montage, the machine will simply cancel out the reference information and then the result will be O1 –O2. But, having the reference is critical in the process.If you don’t have reference on the patient, your O1 and O2 will be connected to an OPEN jack which is pure artifact and noise. The result is very noisy and possibly unreadable data. This one is very critical to have on the patient and ensure impedances are low. Because of their importance, I would choose any spot that is easy to get good impedances and a relatively “quiet” data area such as around PZ, in between PZ and occipitals, or behind the ears, back or the neck, etc. There is no magic location but I’d try a few spots and see what seems to work best for your service. I would avoid any high artifact areas like forehead or temporal due to EMG. Now, ground is not really what you think it may be. Your machine most likely has an isolated ground. So, the port on your jackbox labeled ground is not a “ground” as you would think from a safety standpoint--as that is covered by your isolated grounding. I am sure an engineer can answer this much more accurately; however, my limited knowledge of "ground" says you need it to help things like keeping your baseline consistent and things of that sort but if you don’t have it connected to the patient, the system will work but the baselines may not be stable and other artifacts could be introduced. For better grounding information, you may want to call your manufacturer. But, long story short, I would always connect both unless you are very clear what you are affecting if you don’t.

      Ground placement, again: any location that is easy to get low impedances as sometimes the ground lead is part of the system’s impedance function--so the lower the better on that lead; and a place where it won’t come off very easily. Perhaps between Fz and Cz or someplace like that. Good questions.

  8. How can we overcome poor EEG signals when a patient uses an overabundance of hair gel or spray (despite our instructions)? We work hard to get great impedance values with these patients, yet still have unacceptable waveforms.

    • It’s a tough one. Gels and sprays make the impedance challenge much harder to accomplish. Keep educating the patients and in the meantime simply keep using a bit more “elbow grease” to adequately prep the area. And, since you know you have extra challenges due to gels and sprays in the hair, be sure all of your impedances are low and balanced. Being balanced is as important as having low impedances.

      Your “best friend” for good quality data is your collection system and its ability to assist in cleaning up artifact. The equipment’s amplifier is looking for balanced electrodes so the amplifier’s features can work properly and produce clean looking high quality data. So, if you can’t get to 5K because of difficult patient scalps, can you get to 10k or 12K or 15K consistently? If so, make your policy for all leads to be within 10-15K and this will ensure your amplifier collects “common” noise between electrodes and can better use the amplifier’s common mode rejection features to eliminate the unwanted noise. It is better to have 10 electrodes showing an impedance of 13K than seven electrodes reading 2K and three electrodes reading 15K. This is because if impedances are not balanced the machine “views” the noise differently and it cannot be processed as common artifact. Even if your impedances are higher but balanced, the amplifier can eliminate “common” noise using its CMR (common mode rejection) feature of the amplifier.

      Long story short, we can’t control the patients but we can control our impedances and the maximum assistance of our amplifiers. Balanced and as low as possible will ensure good clean data despite the patient’s lack of preparation.

  9. What is the best way to apply a gold cup lead to the head? Would you use a small piece of gauze with a lot of paste or a large piece of gauze with a lot of paste? Also, can you clean the leads with boiling water to remove the paste fast? What other methods do you suggest on cleaning the leads?

    • The best way to attach any electrode to the patient’s scalp is “in the eye of the technologist." There are several ways to attach electrodes which get the job done. One of the best methods is the use of collodion glue. Many sleep and EEG labs use colllodion because when they get attached, they stay put. It is the most secured option. The negative is the fact collodion requires special handling and ventilation and isn’t an option for everyone.

      If you use paste and gauze, thoroughly prep the area for the electrode with NuPrep or LemonPrep or any other abrasive prep to ensure low impedances. Before you apply the electrode, make sure the area is “dry” and not slippery from the prep. Next, fill the electrode cup with enough paste that a small amount of extra paste seeps out after the electrode is pressed onto the prepared area of the scalp. Now, take a gauze square (recommend 1-inch x 1-inch) and press firmly on top of the electrode allowing the excess paste to soak into the gauze square. This should allow the gauze to hold onto the hair and help the security of the electrode. If needed add a small piece of tape can be placed on top of the gauze if you don’t use too much paste (if you use too much paste the tape can’t stick). To answer your cleaning questions, any temperature of water will work to clean the leads and remove the paste. Warm water being run over the leads or soaking the leads loosens the paste; typically it can be washed away fairly easily. But, remember after you clean the leads you must disinfect the electrodes with any number of disinfecting products such as Cidex or others. And the other suggestion is to evaluate disposable electrodes which have dropped in price and increased in quality. Disposables eliminate the need for any cleaning or disinfecting which saves you labor costs and chemical costs.

  10. When and why do you change high and low frequency filters? When do you use notch filters--60 Hz, 50 Hz?

    • High and low frequency filters (as well as the 60/50hz) are used to help us see the data that we care about and get rid of the data we don’t care about. Think of your filters as the “bass” knob on your stereo, you may like more bass than someone else so you change the setting to hear more bass in your songs. This doesn’t change the music coming into your stereo just how you hear it. The filters on your machine are exactly the same. Low frequency filters allow fast frequencies to pass but limits the slow frequencies we see on our display. High frequency filters allow the slower frequencies to pass but limit the fast frequencies we see on our display.

      60hz completely blocks anything that is being recorded at a frequency of 60hz (and frequencies around 60). 60 Hz or data is common environmental artifact/noise from other machines, TVs, monitors, dimmer switches, etc. 60Hz is also seen due to imbalanced impedances between electrodes, so be sure your impedances are balanced and low and you should not need your 60Hz filter. (50hz is the same as 60hz but is mainly seen outside of the United States).

      We always want to understand our filters so we understand what we are NOT seeing. And remember you are not changing the data just what you are seeing. And to ensure this is how your system is setup contact your equipment manufacturer and they can clarify your system’s setup configuration. I recommend using a previously collected PSG or EEG and change the filters; you will quickly see the differences that filters make. For example, if I use a high filter of 15Hz, I will see very “clean” data because I am not displaying faster frequencies like EMG, and this can help but it can also risk missing data you WANT to see like snoring. The recommended guidelines help each application have a starting point for filter settings but I encourage you to understand your filter options beyond the default settings. It could make your scoring tasks a lot easier if you understand filters and can make good decisions to help enhance your patient’s data. If you want guidance for filter settings also contact your equipment manufacturer and they can help you understand how your data is saved in each channel and which channels

  11. We have used acetone for years to remove collodian with no complaints from patients regarding hair loss. Just last week an African American patient returned to the sleep center and showed us a bag of hair and claimed the acetone made it break off and fall out. Any reports of this in the past? Are there any white papers I could read regarding safe use of acetone on hair for removing collodian?

    • I have never heard of this type of problem being reported or have seen any articles/white papers. My suggestion would be to go to the source which is the manufacturer of the product and ask for their feedback on the patient claim. You can also go on line and research adverse effects to the use of acetone and see what you can uncover. Your risk management folks also are a great resource for this type of research as well. But, I am not personally aware of any reports that have been published.

  12. What types of disposable electrodes do you recommend? And what are the pluses and minuses of using disposable leads?

    • Really any type of disposable can be considered as the quality has gotten very good. Disposable single patient EEG cups are available through a variety of sources (research Disposable EEG Cup Electrodes online to get a wide variety of options) and they function very well.

      Benefits to disposables are felt in a couple of areas but the most obvious is: lowered risk of cross contamination with patients. Despite all of our efforts to clean and disinfect thoroughly, we cannot dispute that a risk of cross contamination is always present when using reusable electrodes (with the exception of sterilization). The next benefit is: cost. That’s right--cost. I know many of you won’t believe it, but I encourage you to do a FULL cost analysis of use of reusable to use of disposables. There are sources available who offer this service at no charge and you will be shocked how equal or less expensive it is to use disposables versus reusables in your service. Contact your favorite source and get a quote for disposable EEG cups for your service and spend time running through an analysis exercise. But, analyze the costs completely including every minute of labor (including salary and benefits), cost for chemicals, cost of unused inventory in your storage room, etc. The direct purchase price of disposable electrode will be much higher per year than reusable, but that is only a portion of the actual cost of maintenance of our electrodes.

      Disadvantages to disposables is the absence of a gold disposable electrode. The truth is gold plating (that is what is on the outside of the electrode) is expensive and the cost of using a “gold” disposable would be difficult to justify in the budget. Notice I did not list “quality” anywhere in either the pro or con section. This is because you need to determine quality using your staff, your application techniques, your patient demographics, etc. I strongly encourage you to contact Disposable EEG Cup Electrodes sources and ask for a sample of disposable EEG cup electrodes and test them on one of your patients and see how they perform compared to your reusable. I predict you will find the quality is equal to a reusable but I recommend that you test this for yourself.

  13. Any suggestions for alternative application methods for LTM or Ambulatory EEGs? We currently use Collodion and would prefer to NOT use that method.

    • Your question is very timely as I recently received this same question from some other folks. It’s a tough question to answer as it depends greatly on your patient demographic. But, one trick that I like to share is the use of EC2 cream (and no my company does not make this product so in case anyone fears I am shamelessly promoting one of our products). This cream is conduction, but its unique characteristic is that it dries very hard (I like to say it dries like “concrete” even though it’s obviously not concrete.) and many folks use it very successfully as a collodion alternative. I personally found it takes some time to get accustomed to using as I struggled with either using too much or not enough. But, once you practice using the product it can be used as a collodion alternative for both LTMs and AEEGs.

      Prep your patient’s site, use EC2 or another conductive material in the cup (or on the surface if you are using a flat EEG electrode), then use some EC2 over top of the electrode and you can place a small gauze square, small bit of tape, or a little cotton on top to help secure. I then strongly recommend that you check impedances and immediately wrap the patients’ head with gauze (over/around the head and under the chin to secure like a hat). Hopefully you will find success with this as a secure option to collodion or other adhesives. One more thing, be sure to allow for strain relief of your electrodes so a small “tug” doesn’t affect the connection.

      To remove, use a towel or cloth soaked in warm water to loosen the paste. Basically place a warm towel on the electrode site for several seconds or so to loosen the EC2 and continue to use warm water until removed and cleaned. There may be more options such as different adhesives that could work for your needs but this is the one option that is completely adhesive-free that seems to work in my experience.

  14. Techs at our labs sometimes see unexplained cardiac artifact through the EEGs. Is this due to inadequate preparation of the reference signal site or ground site? Or is it just bad placement of an electrode over a muscle close to the head surface (especially, lead C3/4)?

    • The artifact could be caused by any of these reasons, but the core issue is typically imbalanced impedances between the reference lead and your active lead. A reference lead can mean either the “system” reference or the “montage” reference so this is why overall balanced impedances is so critical to an artifact free recording. If you don’t know which electrode is your “system” reference be sure to contact your equipment manufacturer so they can tell you which electrode is used for the digitization of the signals. This electrode is your system reference. But, of the two potential problems, the most common is an imbalance between the two electrodes being used in your montage (i.e. C3-A1).

      These impedances should be as low as possible and within 2-3 Kohms of each other. By having balanced impedances your amplifier can accurately use its CMRR (Common Mode Rejection) feature which allows the amplifier to “see” common information and filter it out for the display. If your impedance are low and balanced, and the problem persists, experiment using different electrodes or different jacks in your head box to eliminate any hardware or electrode issues.

  15. Is it OK to soak the entire electrode wire in hot water for paste removal before disinfecting? Seems like paste residue could find its way inside the box connection end and eventually degrade the wire's conductivity.

    • You are correct that paste residue can get inside the connector (the jack box end of the electrode) and degrade the connector and affect its ability to perform. But, soaking the entire lead can also degrade the connector as well. The reality of the situation is that the connection points (crimp junctions) can (and most likely will) degrade over time even if proper cleaning and disinfecting steps are taken.

      If you have a specific issue with paste all over the leads, be very careful with soaking the entire lead (meaning you are submerging the connector end) because if water gets inside the connector it can corrode the connection points. Clean and disinfect thoroughly but with as much caution as possible. And, if you have frequent breakages or frequent situations where paste or other materials are getting on the connection points you should consider a disposable single-patient electrode as an alternative.

  16. Can you tell, by looking at it, when a gold cup electrode needs to be replaced?

    • Well, not really. There are just a couple of things that you should watch for such as if the gold plating on the outside of the electrode starts to wear off you will have the silver metal underneath exposed. Now, this by itself doesn’t necessarily cause a replacement to be necessary but this may cause a greater risk of artifact issues being seen.

      And, if you see any damage or any part of the connection points are exposed, meaning if you see any of the “small wires” from inside the lead wire or anything similar, I would replace as your risk of a bad lead (at of course the worst possible time) is imminent.

  17. I'm looking for suggestions for the type of tape to use to attach electrodes to the face (F3 & 4, E1 & 2) and chin (EMG 1,2 3). Do you recommend the perforated cloth tape, foam tape, plastic, or something else? The chin leads in particular are problematic.

    • Tough one to answer as it really becomes technique and personal preference. I have always liked cloth tape/paper tape, but it’s the type of question that could be answered with a bunch of viable options. Perhaps talk to your vendor for accessories and see if you can get an array of samples to test out.

  18. Just want to follow up on another question. In my experience, boiling the water will weaken the connection (head) between the electrode and the wire. Warm water is great, but are you advocating them boiling or microwaving water to boiling to clean the electrodes?

    • No, I am not advocating boiling water. Warm water is sufficient to remove debris.

  19. What sort of electrodes/sensors would you recommend for use in EEG monitoring/epilepsy research for the type of animal models used in preclinical research?

    • It’s tough to fully answer unless I had a few more details, but subdermal needles and custom made implantable can be very beneficial.

  20. Is it appropriate to clean the EEG site with alcohol before using the NuPrep if the person has really oily skin? And, your previous answers said to make sure the site is "dry" when done prepping. Does this mean we shouldn't leave the NuPrep in place, it needs to be wiped off with gauze?

    • Many clinicians use alcohol to prep the site in addition to NuPrep in certain situations, but I have not personally felt the need to add that step unless I am in the operating room using needle electrodes. And you can keep the NuPrep in place, but if you have an excessive amount, I would recommend wiping off the excess.

  21. Do you have any data and cost analysis for gold electrodes vs disposable electrode use? I am also interested in articles that discuss the benefits of using either type of electrode.

    • Each facility and service is unique and you will first want to gather the following data to perform a full cost analysis. Disposables can be even lower in price depending on your vendor and usage. 1.       Cost of my Gold Electrodes (Cost per pouch of 10)2.       What has it cost your service to buy Gold Electrodes in the past 12 months? (This will help figure out how long they last.)3.       How many patients did you test in the past 12 months?4.       How many electrodes do you use on a typical patient?5.       How much have you spent on chemicals to clean and disinfect in the past 12 months? 6.       How many unopened Gold Electrodes are in your inventory? 7.       Critical data: Hourly wage of a technologist? (Add an extra 30-40% to include benefits to that wage amount)

  22. What is your opinion on the XactTrace Reusable RIP Belts made by Embla?

    • From what I have heard these work very well but I have not personally used them. Perhaps someone else may be able to answer this question better.

  23. Is there a recommended maximum length of electrodes used for sleep recordings (excluding legs, of course)?

    • The recommendation is to use a lead that is as short as possible to get the job done. The electrodes act like antennas for noise and artifact and the longer the electrode the better the antenna. It’s just like an antenna on a TV, to get a better signal you raised the antenna so you can get more signal. Our leads really function in the same way so whether you are using short or longer electrode always be sure to “bundle” the electrodes together so each electrode (aka your antenna) receives the noise and unwanted signals in a similar manner. If you have 10 electrodes that you have connected to your patient and nine electrodes are bundled together and one lead is hanging by itself, the bundle will receive the noise in a similar way and this allows the Common Mode feature of your amplifier to eliminate the noise better because the noise is “common.” But, that dangling electrode will receive noise completely different than the rest thus making the Common Mode feature ineffective and will allow the noise into your recording. So, use whatever length you need but do your best to keep the length as short as possible to assist your data collection efforts and ensure clean data signals and bundle any extra length and leads together.

  24. What is exactly metals in EEG electrodes--gold with silver, gold with gold, or gold with other metals?

    • Yes to all. Reusable metal electrodes can be a single pure metal or a combination of a base metal covered by a coating of another metal type. For instance, you can purchase pure silver electrodes which is called a Silver EEG Electrode. Or you can buy a Gold EEG Electrode which is really a silver based electrode that is plated with a thin layer of gold and this is probably one of the most common electrodes commercially sold. Unless you have a specific metal requirement, the “base” of the electrode can be different than the outer layer without causing any problems. This can keep costs down and allow the electrodes to be more affordable. And even disposable electrodes are typically an ABS plastic base covered by a thin layer of silver/silver chloride coating. To know the details of your specific electrode contact your supplier for the details and they can tell you the base and any outer metal material. But, I think you will be hard pressed to see many differences in the data between the most common metal types and combinations.

  25. At one time the recommendation was made that reusable surface electrodes, once cleaned, should be allowed to soak in a normal saline solution for re-ionization? Is this still the case? I haven't seen anything about this anywhere in recent years.

    • Not necessary for most of today’s reusable electrodes. But each manufacturer is different so I would recommend asking your electrode supplier if this is their recommendation for their currently available product(s).

  26. Can you mix electrodes (length and thickness of leads; cup leads with flat leads)?

    • The answer to the above question is “yes, in most cases." Any variable between electrodes has the potential to introduce artifacts but with the capabilities of today’s data collection amplifiers the concerns of years past can be overcome with a good amplifier. But, that does not mean that as clinicians we are not responsible to understand what potential artifact are being introduced with each variable.

      First is the length difference. Your lead wires are basically antennas. So, the longer the lead wire the “better” the antenna to bring in artifact. If I have one short lead wire electrode and one long lead wire electrode, the artifacts between those two electrodes will be different because of the length difference. But, if my impedances are equal and low my amplifier should be able to handle the difference in noise.

      Second is thickness of the lead wire. Thick would probably indicate a different type of lead wire. Differing lead wire can manage artifacts and noise differently so again just as with the length issue a difference in “type” of lead wire should be avoided but if it cannot be avoided the amplifier should be able to handle the difference. Lastly, the difference in design of the electrode such as cup versus flat. This probably has the least amount of issue since the design does not introduce artifacts as long as the application technique can achieve solid impedances and the surface area of the overall electrode is similar.

  27. Are there any EEG electrodes available for people with allergies to metal?

    • Nickel is one of the most common metal allergies and if this is the specific metal allergy being mentioned I recommend simply making calls to your electrode manufacturer(s) and find out if their electrodes contain nickel. If you are not sure of the specific metal that causes the reaction this can be more challenging. There are disposable EEG electrodes on the market which have less metal and may work with some patients who have metal allergies.

      Disposable EEG electrodes (either cup design or flat design) typically have a non-metal plastic base (i.e ABS plastic) but have a thin layer of silver/silver chloride coating. For some patient’s with metal allergies, the thin coating may have less reaction than a metal based reusable electrode. Reusable electrodes usually have a metal (i.e. silver) base and then coated with an outer metal coating (i.e. gold or silver/silver chloride). Metal based electrodes may not cause a reaction depending on the allergy of the patient. But again, I recommend gathering as much data as possible about your patient’s specific allergy and talk to the electrode manufactures about the options to meet the ends of your specific patient. Consulting with your dermatology department may also be useful.

  28. Are there any electrodes that are safe for use in a CT or MRI machine? This would be more for a LTM patient.

    • At the moment there are no reusable or disposable EEG electrodes (EEG cups, EEG needles, or Flat Webbed electrodes) approved as MR Conditional or Safe for sale in the United States.

      And as a reference, according to the ASTM (American Society for Testing and Materials, 2005), MR Safe is an item that poses no known hazards in all MRI environments. MR Conditional is an item that has been demonstrated to pose no known hazards in a specified MRI environment with specified conditions of use.

      There have been products marketed with other descriptions in the past such as “MR Friendly” which roughly means some clinicians have used this product in an MR setting, but that product has not been approved via an FDA process to commercially marketed as MR Safe or Conditional. So, in summary, “no” there are no currently available MR Safe Electrodes on the market for surface (scalp) EEG recordings.

      But, most EEG electrodes (disposable and reusable metals) can be used in a CT setting; but, I highly encourage you to contact your individual manufacturer to verify and research any artifact from the electrodes on the CT data with your radiology team.

  29. I am a sleep tech and have a question regarding the type of electrode that should be used to monitor chin EMG. Currently we use the gold cup electrodes, but we are wondering if using the sticky patch (EKG ECG) type of electrode would work as well. What is your opinion?

    • The metal and type of electrode being used for today’s data collection is really a decision of subjective preference. And part of the reason this is subjective is because today’s diagnostic sleep equipment is so good at digitizing the data that previous “reasons” for using one metal versus another is no longer an issue. For instance, before this could be answered, I would ask your lab why they started using gold electrodes initially? Was it to accentuate the slower frequencies? Is it because the rest of the electrodes being used on the patient were gold and thus a concern about differing metal induced artifacts? Once this question is answered you can discuss any negatives to switching to surface pad type of electrode. And, this conversation really needs to involve your capitol equipment manufacturer. But, without knowing the answering, I would tell you that in most cases it should not matter if your amplifier is setup accordingly. For instance, ask your capital equipment rep what is the amplifier “reference” for your chin leads? If I am using gold cup leads on the head and a sticky pad EKG type leads with silver or silver/chloride on the chin would the manufacturer expect any increased artifact? The manufacturer should be able to explain how the inputs are referenced and thus allowing you to predict if you will have an increased risk of greater artifacts.

      And even with all this good information, I recommend simply trying it out on a “demo patient." Someone in your lab willing to have leads attached or at the end of a study if a willing patient will give permission to have the gold cup removed and sticky surface leads attached and record a few minutes as a direct comparison for yourself.

  30. In one of our lab rooms, there is very high interference with the electrodes and EKGs. We have been trying to figure out why for a very long time. The rooms all have the exact same equipment down to the style and brand of lamps and electronics. The only thing we could think of was that the setup in that particular room is a bit closer than the other rooms. There isn't much room for a different arrangement. Is there anything else we can check or do that will help eliminate the interference problem?

    • This can be a very challenging problem. Given the description of the setup, and assuming you have swapped all electrodes and peripherals patient devices, I would swap the amplifier(s) from one room to another. Talk to your equipment manufacturer as some systems have “dummy” boxes that sit close to the patient and some machines actually have preamplifiers that sit next to the patient. I would swap all equipment that connects from the patient to the machine from a good room to the bad room. This will help you rule out the equipment. Find out from your manufacturer where the data is digitized, in a remote amplifier or inside the CPU? Your problem is happening prior to the point of digitization, so knowing that information will help the investigation of the cause. This problem can be very frustrating and in general you can assume the problem is either with the room or the equipment so you have to rule out one or the other. If I were in your situation, I would swap as much of the equipment as needed (with the assistance of the equipment manufacturer) to rule out your equipment.

      If equipment swapping doesn’t resolve the artifact, consult your Biomed staff and show the results of the equipment swap and your Biomed folks will have to start looking at the room, wiring in the walls, grounding ,etc.

      There is a cause and it can be found, but it may need a team of folks to help find it.

  31. What is the best electrode to be used with a PSG? Is it gold cup or silver chloride electrodes, and why?

    • Given the technology available today with high-end sleep systems, this question has become more subjective than ever. Historically, the gold cup electrode has been preferred because the gold did a better job of accentuating the slower frequencies than silver or silver chloride electrodes. This characteristic was a benefit for PSG as those frequencies were, in general, of greater interest than the faster frequencies. But, fast forward many years and the equipment manufacturers have made such advancements with the amplifier technology and the ability to re-montage and re-display digital data that our electrode metal choice has become less of a concern.

      To really answer this question for your lab or service, you must do a comparison test. Use a volunteer and connect a small set of gold electrodes and run a short study. Then, remove those electrodes and repeat on the same volunteer. This head-to-head comparison will show you and your staff if any differences are present between the electrodes types and your particular equipment. In most cases I would bet no noticeable differences are evident but depending on the age of your equipment and the manufacturer, filters, etc., some slight differences may exist and you may find you have a preference. And this test can be done any time you are testing out options and want to verify if data quality will be affected negatively (or positively).

      But, I want to warn you of one more difference that should be documented: the type of lead wire being used on the electrodes. Whether you prefer gold or silver chloride electrodes the type of lead wire can affect artifacts and data quality, so don’t ignore that piece of your electrode. To accurately test as mentioned above, ensure both electrode types have the same lead wire type attached.

  32. Hi Leah, I have a few questions for you.

    I can see how a 1 cm cup electrode must have space for electrolyte; but, if we were to use the spider electrodes from Rhythmlink, what is the smallest size the wire touching the skin can be? Does Rhythmlink offer pediatric or preemie sized spider electrodes? Would it matter if one used such on adults? Can you tell us the point at which the size of the contact end of an electrode becomes useful?

    2) I find that collodian, with its insulating properties, allowed the closer application of electrodes, since there was no risk of a salt bridge. However, now that we apply electrodes using the same electrolyte that is under the cup, this actually makes the active site the size of the gauge on uses, and increases the size of the electrode site (picking up more activity) and increases the possibility of coming in contact with neighboring sites. If we had a paste that was insulating, that was used on the backside of the gauze in lieu of the conductive electrolyte, this would preclude these two exigencies, and make for cleaner recordings. To your knowledge, is there an insulating electrode cream that can be used for this purpose?

    • If I am interpreting your first question correctly--which asked "how small can an electrode to record on an adult patient be?--you can use whatever size of electrode you’d prefer; however, be aware that historical normative data has been collected from the standard size of a 10 mm/1 cm electrode. So whether you are using a standard cup or a flat lead, like a Spider, the size doesn’t matter except that you would want to probably do some collection of your own normative data if you choose to use a smaller size. The Spider does come in a smaller size, a 6 mm, which is mainly used and designed for smaller heads such as neonates and infants. But again, you’d probably want to collect normative data if you use a different size. As to your second question, you make a perfect point; and no, I don’t know of any insulating cream, but I wish I did because your point is right on. My only suggestion it to try to use the smallest amount of cream possible to limit the enlargement of your recording site.

  33. What type of wires give the best impedance--gold, silver, etc?

    • The type of wire isn’t the main factor of impedance. It’s really more your technique to achieve a good impedance that matters. The material on the outside of the electrode, whether gold or silver, silver chloride or tin, or whatever, is simply a conductive covering. You should be able to get a balanced impedance with any metal type. The critical points for a balanced and low impedance is good skin prep and appropriate use of the conductive material such as NuPrep, 10/20, Elefix, etc. You can survey everyone you know and you will find gold, silver, and silver chloride being the most popular metal types more because of affordability and historical preference than anything else. So choose your preference and practice good prep technique and you should be fine. But, also be aware that from vendor to vendor other factors can affect your experience with an electrode such as the lead wire type (not the metal type but what the wire is made out of). So if you decide you want to use silver electrodes be open to trying a few different versions from various vendors as the lead wire can have as much to do with your preferred electrode as the metal type.

  34. Can you point us to the definitive publication that describes the allowable error for measuring electrode placement?

    • Honestly, there is no definitive publication, only guidelines. The reason for this is because each situation can be unique; so, there are guidelines, but no definitive rules. You can find guidelines in a variety of places such as the 2008 American Clinical Neurophysiology Society guidelines at, various references from ASET at, and others.

      Typically the recommendation is to have your impedances as low as possible, ideally below 5kohm and within 2-3Kohms of each other. And in my experience the latter is the most important--keep your impedances within 2-3Kohms and your recording quality will most likely look good.

  35. Should you use "jumpers" to fix "60Hz artifact" and/or high impedance artifact?

    • No, unless you have a unique situation that this is your only option. Electrode jumpers are used to take information from one amplifier input and share it with another input. Or to average data from two or more inputs together. This is not a solution to your 60Hz artifact/high impedance artifact. You need to investigate the source of the 60Hz and bring those impedances to a balanced and low level and eliminate the use of jumpers. Jumpers can mask real problems and those real problems can mask real data that we care about. So, use with extreme caution.

  36. How long should one soak gold plated electrodes in bleach solution to adequately disinfect, while preserving gold plating integrity of the electrode? There has not been a clear delineation of how many parts bleach to water in the bleach solution thus far, and varies from technician to technician. In addition, the time frame for soaking leads ranges anywhere from 10 or 20 minutes.

    • This is a question, and protocol, that should be defined using the expertise of your risk management team. As you are correct, there are variations all over the board but it is critical that the method you are using is approved and appropriate for your testing type and requirements for medium to high level disinfecting. And, your top priority must be to adequately disinfect and your second priority is the integrity of the electrode. If you don’t have access to a team to assist, I’d recommend considering the use of commercially available disinfecting solutions designed for medium to high disinfecting and following their directions completely. These chemicals and products can be found within a variety of supply company catalogs. Also, consult other services who have involved risk management departments and consider adoption of their policies and procedures regarding cleaning and disinfecting. This is not a topic to be taken lightly as studies have shown that improper cleaning and disinfecting can cause serious health issues to your patient population. This is one reason why many labs are shifting to disposable electrodes to eliminate this issue as cross contamination and infection risk.

  37. This question is in reference to subdermal electrodes. Can these needles be taken out of sterile packaging, bundled into the appropriate EMG pop fossa or cephalic leads, put back into the electrode package for use on a patient for IOM monitoring? I understand that once the package is open one might ask if the lead is still sterile since it has the plastic needle guard on, but is this an okay practice for use?

    • This is a very common practice but precautions must be taken to preserve patient safety. Certainly if you remove subdermal needles from their sterile pack, bundle the lead wires in a sterile environment, and use proper methods, you most likely have not compromised the sterility. But, if you remove electrodes from their sterile pouch and bundle them together in the tech break room on the table where everyone has been eating lunch without sterile gloves, etc., you probably have a problem.

      To solve this issue, simply perform your bundling in a sterile environment using appropriate methods or you can ask your electrode provider to custom pack your specific bundles together in advance of shipment. Also, the plastic guard is really only intended to reduce needle sticks not to ensure sterility. Example of that could be if an electrode pack is opened and someone sneezes next to the needle, the cover doesn’t stop the particles from the sneeze affecting the needle.

      And lastly, your risk management team or similar team is your best source for specific questions within your environment.

  38. How often should gold cup electrodes be replaced with new ones?

    • This varies from service to service but these are factors to consider when planning to replace a reusable gold electrode. 1. Talk to your electrodes vendor as they should be able to give an “average life expectancy." They may give the information in days (i.e., 90 days) or in patient usage.

      2. Is the surface of the electrode (i.e., the gold plating) getting discolored or starting to come off due to cleaning and disinfecting? If so, plan a replacement.

      3. Does the connection point between the electrode and the lead wire look worn? If so, plan a replacement.

      4. Are impedances stable or are they starting to fluctuate?

      5. Are you picking up a greater percent of artifact/noise?

      In general, It’s up to each service when they replace and using the recommendations of your electrode provider. But my experience is many services average a replacement every 60 days, give or take a little, and depending on their patient load.

  39. I have a room I set up at the hospital in Missouri Valley, Iowa. I always have trouble with 60 Hz interference, so I always have to use a notch filter. I have unplugged the bed and all nursing diagnostic equipment which makes it better but not clear. Is there anything else I can do?

    • If possible, try the following:

      1. Physically move your gear and use a different outlet.

      2. Talk to Biomed/Bioengineering and ask them to check the outlets. In most cases their outlets are probably functioning correctly with the proper grounding but it's definitely worth pulling them in on the issue.

      3. Talk to your equipment manufacturer as your gear could be the problem. Cables and connectors are common problems as equipment ages.

      4. Is this system portable? Can you move it to see if the poor quality remains in different environments? If so, it points to your equipment or cables.

      5. Do you have a second system that you can you swap out cables, amplifiers, or other peripheral gear to try to pinpoint the problem?

      6. Make sure your impedances are very balanced and as low as possible. For example, if you can get all of the electrode impedances below 10K and within 2-3K of each other you should be able to rule out artifact effect of imbalanced impedances.

      7. Replace any reusable electrodes especially any electrode being used for an amplifier reference or ground.

      8. Are there dimmer switches in the rooms? These can commonly cause issues even if turned off.

      9. And if all of these are checked and you still have the problem, talk again to your equipment vendor as they are the experts on their gear and most likely will have suggestions to help. Good luck with resolving the problem.

  40. Is bleach soaking still the standard? And which works better: gold or silver eletrodes?

    • Bleach soaking of electrodes or use as a disinfectant is still in use but, from my experience, has decreased in the past several years. The more frequently used disinfectant strategy is the use of commercially available disinfectants marketed specifically for certain levels of disinfection. These can be found online and from various accessory suppliers. The main reason for the trend is higher accountability of individual departments to ensure the disinfectant being used is appropriate for the type of disinfectant required for the situation. Because we “prep” the patient’s skin by abrading (rubbing). a medium to high level of disinfection of the electrodes is required. The commercially available products on the market typically list, on their product label, the level of disinfectant the product is designed to achieve and thus helps each department ensure compliance. The use of bleach and other disinfectants can certainly be used but documentation of the solution is critical and I would work with your risk management team or other appropriate department within your service or facility. If unsure, check out the commercially available options.

      As for gold versus silver electrodes, either type will work but some folks just have a preference. Many are shifting to single patient disposables to eliminate the disinfecting requirement and in some cases reduce overall budget expense. A recent report from a market research group, iData Research Inc, reports that nearly one-quarter of electrodes being used are disposables.

      Gold is usually more expensive but some professionals feel the low frequency data displays better with the gold metal. I would compare, compare, compare. The quality of the data relates both to your electrode and your amplifier so in many cases today's high quality amplifiers reduce differences between electrode metal types regarding data quality during testing.

  41. Are damaged electrodes and sensors repairable?

    • It’s really up to you depending on the situation, but I would decide if the repair is worth the cost and the risk of additional problems during patient testing. Electrodes and sensors are not designed to last forever and with the highlight of proper disinfecting techniques, electrodes and sensors should not be expected to last for excessive periods of time. For example, your electrodes are applied to non-intact skin (that is, skin that has been abraded/prepped) so proper disinfecting techniques are required to reduce/eliminate cross contamination between patients. The chemicals used to properly disinfect can, and will, take their toll on reusable electrodes and sensors. Electrodes and sensors should be replaced on a regular basis so repairing these devices may not be an efficient use of time and budget dollars. Not to mention the risk of lower quality testing results due to future problems. And lastly, if a repair takes place be aware you may be voiding any warranty or future support of the product by the manufacturer so consider speaking to your device manufacturer for service options or recommendations via their organization.

  42. Does it hurt or degrade paste-filled gold-plated electrodes to soak them in hot soapy water for 30-plus minutes before disinfecting them?

    • No, soaking the electrodes in soapy water before disinfecting should not cause any additional harm or degradation. The big issue is to be very careful with any scrubbing with a brush or other utensil. Scrubbing and brushing can harm the gold plating or silver-silver chloride coating, causing the conductive layer to be damaged over time and affecting recording reliability. But simply soaking should not affect your overall lifelong performance unless your electrode manufacturer instructs otherwise.

  43. We recently became part of the NeuroScience Institute. Maine is big in terms of rural areas that are not serviced by specialists. When patients come down to southern Maine for access to care, we try to coordinate services. Are you aware of CPT codes that are reimbursed if we perform a PSG AND full EEG? The EEG is read by the neurologist and the PSG is read by the sleep specialist.

    • I am not aware of a CPT code that allows you to get reimbursement for both tests without doing separate testing. So, if you are trying to perform an EEG simultaneously with the PSG data, it’s unlikely you will find much success. But of course you can record a PSG at night and then record a separate EEG at a different time and most likely be able to charge and receive reimbursement. I would check with the payors in your region to ensure your reports reflect the separate testing procedures and any other requirements.

  44. Do you have any experience with silver-silver chloride electrodes? If so, have you ever tried to record the DC frontal-occipital potential that supposedly is negative on the frontal pole of the brain and positive on the occipital pole while awake? I have read that this polarity reverses as one makes the transition from wakefulness to sleep. Have you ever read or heard anything about this?

    • Yes, I have fairly extensive experience with silver-silver chloride electrodes, but I have not personally recorded or analyzed the DC potentials you mention. Is your question whether silver–silver chloride is the proper electrode for that activity? If so, most likely that metal type can provide the DC information you are looking for. But depending on the specifications of your equipment amplifier, you may also want to look at using a gold electrode for an older or lower-end amplifier. It’s not simply the electrode that makes the difference but the amplifier’s ability to record and reproduce the signals you are after. A “head to head” gold to silver-silver chloride comparison may be a good idea.

  45. Hello Leah,
    I would like to get your expert opinion on EEG electrode care test after test. We are a sleep lab and prefer using silver cup electrodes. I read about using normal saline for soaking and keeping electrodes away from light and kept in an air-tight container. I suggested a snack-size zipper bag after covering with gauze. Any suggestions would be appreciated. This is to improve signal levels.
    Thank you,

    • I assume you are referring to a reusable electrode. To prolong the health of your electrode, I'd recommend using any mild material for soaking. I'm not sure what the purpose of an air-tight container would be, except to keep dust and dirt etc. away from the electrode and its connection points. But in this case be sure the product is completely dry. If indeed it is stored in an air-tight container, I would consult with your manufacturer of the product to verify this recommendation.

      Caring for your electrode after use has a few areas of main attention to prolong life of the product. One of the biggest points of concern and attention should be with the disinfecting process and how long it's left in the chemicals you're using to soak and disinfect your electrodes. It is common to soak your electrodes in something mild as step one to loosen debris and dirt, so something as simple as warm water with mild soap works well. After a few minutes of soaking, proceed with your disinfecting protocol per the directions of the disinfecting product being utilized. After your product is disinfected, let it dry and store in a place away for dirt, dust, etc. You can maintain the high quality of your electrode as long as it's appropriate.

      Paying attention to the connection points of an electrode when soaking and disinfecting is very important to help prolong the quality and health of your product. Remember you have an electrode that has a "little stem on the end" that you can't visibly see but this "stem" gets connected to the actual lead wire and then covered with a material that protects the connection point (usually a black material covering the connection point) . Avoid bending, twisting or getting dust, dirt or liquids in that connection point as that will ultimately cause your electrode life to be shortened. But also remember a reusable electrode has a defined lifespan and it is not designed to be used forever so I highly recommend asking the manufacturer that you're buying from for the expected life of the product. With the information the manufacturer provides you, be ready to replace electrodes appropriately as needed. And to learn more about your electrode, take an old one that is no longer needed and dissect it so you can see the manufacturing of the connection point to help you understand the importance of the care. Good luck and remember disposables are also an option and can be quite cost effective depending on your service. No soaking or storing is required.

  46. Has there been any progress made in the area of wireless electrodes? It seems like wireless electrodes would be much more comfortable for patients.

    • I have a clarifying question for you: What is your definition of wireless? Do you mean an electrode with no lead wire attached or do you mean an electrode that has an analog-to-digital converter on the electrode itself? This is an important distinction as it depends whether you are sending raw analog data or digital data from point A to point B.

      If you are referring to an electrode without a lead wire attached but no extra data conversion occurring at that electrode, it would basically be sending analog data through the air to land somewhere remotely to be digitized. One big negative to this would most likely be a limit of how far away the transmitter could be from the electrode. If it's too far away, you can "drop data points" (or, in other words, lose some data). And, what if something gets in the way of the transmission to stop the data from reaching the transmitter (again losing data)? Or because the data is yet to be digitized, it picks up extra noise and artifacts along the way to the transmitter? But the positive would be it would eliminate the cable issues and would/could be relatively inexpensive.

      If when you say "wireless," you are referring to an electrode that actually has an analog-to-digital converter attached to the electrode, then you will be moving your data digitally from point A to point B. Positives would be the digitized data can go any length away from the electrode, as well as it would not pick up any extra noises or artifacts along the way. The downside is/may be having the right technology to be comfortable for the patient and small enough to be attached to the electrode while having high enough quality to digitize all the pieces of the data we need for our market (meaning, it would be easier if we only cared about big signals and none of the little/finer morphology). Lastly, this would/could make your electrode presumably very expensive and would need to address the issues of reusable versus the push to move to disposables to reduce hospital infection risk.

      So, the answer to your question is "yes" there is a lot of research being done in both of these directions (and other directions too) and at some point in our future we will see these technologies hitting our marketplace. But right now there are still a lot of details to be worked out to make it a realistic and affordable option. But it's very exciting technology and research that's being investigated!

  47. What are the options and electrode types, single leads or head caps, best suited for continuous EEG monitoring up to 24 hours? Our department is starting this service with a Nicolet ICU monitoring system.

    • That is a big question because you have a variety of options depending on your patient’s imaging needs and your staffing structure.

      First, I’d strongly recommend whatever you use is single-patient disposable, if possible, as body fluid concerns are significantly higher in the ICU and emergent care areas than anywhere else. If you can’t use single-patient disposables, make sure you can have an option to sterilize your reusable electrodes when needed.

      Next, talk with your team about what kind of imaging the patients may need, CT and/or MRI? (CT imaging is probably the most popular in most patient situations.) This will help determine the right leads. Denser electrodes (like metal-based reusables) will cause starburst style artifacts on the image and in many cases can’t remain on the patient. If this is the case, you’d need staff to be available to reconnect electrodes EVERY time the patient has a CT, which can be very costly and tough to manage from a staff perspective. Plastic-based disposables are the electrode of choice for frequent CT imaging. They do not distort the image and can be left on the patient. Shop around and ask for samples from the various manufacturers.

      Next question, will the patient population need MRIs frequently? If so, this can help your electrode path as well because only FDA-cleared EEG Electrodes can enter an MRI unit, unless other modes of internal approval are completed. So if you use leads that aren’t MRI-cleared, you need to make a technologist available to reconnect the electrodes after each MRI image.

      There are two companies with FDA-cleared MR Conditional Electrodes on the market. Also, make sure the electrode you choose has been cleared for your MRI strength (of either 1.5T or 3T). Shop around and you can talk to these manufacturers. You can use non-FDA-cleared products, but you’d need internal approval to ensure patient safety. Only in the past 4 months have any FDA-cleared EEG electrodes been available to the market, so you are entering at a good time.

      So, if these answers are “yes” to frequent CTs or MRIs, your options are only a few (due to the FDA clearance issue), but you still have a lot to choose from in the market. You can use these MR conditional leads with templates, such as the Jordan NeuroScience template for ICU, to help with placement and security; you can use a new patented electrode designed for cEEG called the PressOn EEG Electrode made for quick, fast application by a technologist or nurse (which can save some dollars for application); you can use electrodes designed to reduce skin breakdown such as the Disposable Webbed Electrode; you can use standard non-MR EEG Electrodes (as long as you have staff for reconnection); you can use non-FDA-cleared electrodes with internal authorization; there are other products designed for cEEG such as the StatNet product, etc.

      I highly recommend doing some research and asking for many samples to evaluate and to give to your radiology team for evaluation and approval for use. If possible, you want to avoid having to remove electrodes each time the patient goes in and out of imaging to decrease labor costs and data recording wait time for the patient, and to protect the patient’s skin as multiple reapplications can take their toll on the patient’s skin integrity.

      So that's a long answer to your question, but, in short, you have lots of choices if you do your research to see what’s the best fit for your patient population and budget restraints.

  48. I have been a RPSGT for almost 10 years. I am really interested in IONM and took an introductory course in it. Other than in-hospital, how does one get into the field?

    • IONM (intraoperative neuromonitoring) has both hospital-based and private service employment opportunities.

      If you have reached out to traditional hospital opportunities, I would also recommend reaching out to the bigger segment of private IONM providers. In early 2012 a LinkedIn Group published a nice list of the top 100 IONM companies. Contact me directly if you have any trouble finding that listing at

      I’d recommend joining the groups on LinkedIn and get the word out regarding your interest and I think you’ll get leads on positions fairly quickly. Good luck!

  49. Recently our lab put together a new policy and procedure document in which it calls for the patient to be measured, marked, and electrodes applied in 40 minutes or less. The document states that this is according to "ACNS guidelines." I can not find any information in the guidelines that states a time limit. Am I just missing it? What are your thoughts on time?

    • I am also not aware of any actual time listed in any guideline. I know individual labs frequently set up their own guidelines, as this allows assessment of performance of staff members. But within a published general guideline, I am not aware of any such time listed either.

  50. How do I safely remove a PressOn electrode from a patient?

    • To remove the PressOn cEEG/EEG Electrode, hold skin taut with one hand and pull straight “up” with the lead wire. A tip is to grab close to the electrode by the black heat shrink and pull straight up. Little or no blood is expected in most cases. Care for the application area appropriately. For an example

  51. In your opinion, should someone with a RST credential be treated equal to a RPSGT since both are registered? I am finding that the RPSGT seems to be more favored. I did get my CPSGT and then took the RST, which I passed. I am just wanting your opinion because I get so many confusing opinions. I have been in the sleep field since 2008. Thank you.

    • Obviously, there are lots of strong opinions in this area, and most opinions, regardless of the side of the debate, have valid points. Because I have been in the field for 29 years, my initial feeling has always given the upper hand to the RPSGT, but if I really look at the information, I am not sure I have been completely fair to the RST.

      The reality is that two credentialing bodies can coexist and both, if standards are met, should be viewed equally (in my humble opinion). The debate continues to be whether or not standards are equal. The real answer to your question needs to left up to those in our field looking at the standards and making the hiring decisions. Because let’s face it, the hiring process, pay scale, and avenues for advancements are what really defines whether one credential is being elevated over another.

      What I can say is there are many models in healthcare where more than one credentialing body is recognized, such as nurse practitioners and others. I have always had the strong belief that more avenues for education and proof of competency do nothing but strengthen our field as long as the intention is high quality patient care.

  52. Do you have any electrodes that can be used during a head CT scan without causing undue artifact?

    • The answer is yes. Historically, many disposable EEG electrodes have been able to make the claim of CT compatibility (which was completely accurate) but, to your point, the issue has typically been lead wire artifact that can be deemed unacceptable. Reusable metal-based electrodes commonly cause starburst artifact on CT images to do with the reflection of the x-rays. The denser the electrode is, the more likely it is that the x-ray can be deflected or blocked, causing significant artifact on the reconstructed images. But, there are new options in the market and I encourage you to do an Internet search to compare the options available. For more information, contact me at

  53. Someone recently insisted that it is not true that using a large glob of conductive paste increases the effective area of a cup electrode. Any signal picked up that is not directly under the cup is minimal and not significant. Comment?

    • The reality is that any area in contact with conductive paste is being brought in as part of the data stream. If I place a 25 mm “glob” of conductive paste on a prepped location on the patient and then place my 10 mm cup electrode on top of that glob, I am picking up everything from that conductive paste area. Now, with that said, the area outside of the cup surface has a much bigger challenge to reach your amplifier because of not having direct contact with the electrode surface. So, in a way, the argument of significance can be understood. But I am not sure I would want to fully rely on the assumption that all activity outside the cup isn’t significant to the overall data being viewed. Don’t risk it: Use enough to get the job done and don’t overuse the conductive material.

  54. I've had problems with Nuprep irritating skin. Any suggestions for an alternate product?

    • You can certainly try other products and other manufacturers. My suggestion would be to contact MVAP, Consolidated Neuro Supplies, or other such groups to inquire about different products.

      But my first question would be to define what exactly the “irritation” actually is. Any “prep” by definition is an abrasive agent (thus why it works so well). Any abrasive can cause some irritation, as can the technique used for the prep. Try alternate techniques, such as a different prep style (ie, if you use a Q-tip to prep the area, then perhaps try a different type of swab) or try prepping with less pressure and see what that change does for the overall “irritation” of the skin. Just remember to view your impedances and data as well to find the right balance between prep and data expectations.

      Also, don’t discount the conductive material you are using within the electrode as a possible reason or contributor to irritation. The combination of the two could be a problem. Also, look at your physical electrodes. The “rim” of the electrode can be putting pressure on your abraded location, which can cause reports of irritation.

      In summary, analyze all materials as the combination of the prep, electrode type, and the conductive material can have reports of “irritations."

  55. What Cap systems are preferred for use for continuous EEG monitoring in the ICU? The RNs will be hooking up the patients on off hours. We are a community hospital, and EEG coverage is Monday to Friday, day shift. We want to make it as simple as possible for the nursing staff while getting the best possible recording for the neurologist.

    • There are many options available, and it’s really up to each individual service to decide what is best for their needs. My recommendation is to first make a checklist to identify your service’s needs. The checklist should include questions such as:

      1. How many electrodes do you intend to use?
      2. How long will the electrodes stay on the patient?
      3. Will the patient need CT or MRI imaging during the monitoring period?
      4. Is the preference for reusable products, which require disinfecting and/or sterilization, or fully disposable products?
      5. Will Neurology be involved once the patient is initially setup or during monitoring?

      With these questions answered, you can look into the options. Feel free to search the internet for direction (ie, cEEG electrodes) and that should give you a lot of options. And I’d suggest talk to the manufacturers and obtain samples to use and evaluate on your patient demographics.