"What is the retail cost of a pack of electrodes?"

Using our standard definition for a pack of electrodes (i.e., a pack of four 2" x 2" square foam-top carbon electrodes), we can safely say that the Internet is a good indicator of retail prices.
We have used a simple formula to determine an approximate retail cost for the electrode contestants in the Theratrode Challenge:

There are many private-label electrodes on the market. Through our research, we have identified and presented in our Theratrode Challenge easily identifiable products with reliable retail pricing.

"What is the wholesale cost of a pack of electrodes?"

A pack of electrodes can be defined as one package of four 2"x2" foam-top carbon electrodes. There are many combinations of size and construction available; however, this comparison is limited to the definition above.

Wholesale pricing is typically high-volume on a supply contract basis. It is designed for distributors of electrodes to retail dealers. We don’t quote our competitors’ pricing here. These are comparisons of wholesale "first offer" pricing to us for 2,000 packs of electrodes per month.

The wholesale price rankings are subject to revision as electrode manufacturers adjust their prices up or down to reflect market and raw material forces.

We added this element to the Theratrode Challenge for decision-makers who prefer USA-made electrodes to imported electrodes.

The Theratrode Challenge decisively proves there is no product-related advantage or disadvantage associated with an electrode’s country of origin. However, there is a perception that domestic electrodes are superior to import electrodes.

The H.E.C.A.T. (Hydrogel Electrode Comparison & Analysis Tool) performs objective tests and analyzes the results without regard to country of origin.

Electrodes made in the USA receive a bonus value of 10 and imports receive a value of 0.

"How many times can an electrode be re-applied?"

While we haven’t answered that question in the course of testing, we do answer the question of which electrode can be re-applied the most times (learn more).

Our re-application tests use a novel approach to testing for re-apply performance. We don’t make any claims regarding re-application and re-use, but our test methods lead us to solid conclusions regarding which electrode is best in this regard.

Electrical conductivity is the best measurement of an electrode’s performance. After all, its primary job is to transport electricity from the stimulation device and deliver as much of it as possible to the patient’s skin.
The electrical conductivity test measures an electrode’s efficiency, or how much electricity from the stimulator is delivered to the patient. During this test, a 9-volt AC electrical signal is supplied to the electrode. The electrode is attached to the H.E.C.A.T. (Hydrogel Electrode Comparison & Analysis Tool) electrode interface board and voltage measurements are taken at 324 points on the board.
H.E.C.A.T.’s advanced data acquisition capabilities obtain literally thousands of measurements, which are then analyzed and used to determine the subject electrode’s efficiency in terms of percentage of voltage delivered.
This test measures the electrodes and compares them based on the absolute values.

Learn more about electrical conductivity testing.

This is a widely misunderstood concept. Electrical resistance of an electrical element (i.e., an electrode) measures its opposition to the passage of an electric current. Electrical resistance is measured in OHMS (Ω).

The electrode industry routinely uses the term impedance, which is an AC current-specific term. Below we clarify the two terms:



Since electrical stimulators (TENS, IF, NMES, HVG micro current, etc.) can have either an AC or DC current, the use of the term impedance is incorrect. However, the term electrical resistance can apply to both types of currents and all types of stimulators and is therefore a preferred term.

Electrical resistance can be an important measurement, but a better measurement of an electrode's performance is electrical conductivity. Electrical conductivity refers to how much electricity is being conveyed from the stimulation device to the patient's skin.

We have seen many flawed methods of measuring impedance, varying in accuracy of measurement equipment, methods of obtaining the measurement, incorrect equipment settings, and such. Additionally, some electrode manufacturers only test the electrical resistance of the naked dispersion pad (carbon, silver, etc.) and quote those results without consideration of the effect on electrical resistance from the lead wire connector (pin connector), the lead wire itself, or even the hydrogel. In short, impedance or electrical resistance measurements from most electrode manufacturers are not reliable factors for comparison.

Conversely, using the H.E.C.A.T. (Hydrogel Electrode Comparison & Analysis Tool), the entire electrode can be tested � dispersion pad, connector, lead wires, and hydrogel. There are 324 electrical resistance test points for a 2"X2" electrode and in seconds, the H.E.C.A.T. takes thousands of measurements. The H.E.C.A.T. can also test electrical resistance on AC and DC currents. Its measurements are wholly reliable and represent the electrical resistance of the entire electrode.

Every electrode features a critical component called the dispersion pad. The dispersion pad receives the electricity from the lead wire and spreads the current over the area of the electrode.

Carbon is an effective, economical material for electricity dispersion. Silver is even better, though much more expensive. An electrode with poor dispersion is undesirable. Poor dispersion can lead to "hot spots" which, under certain circumstances, can lead to unpleasant therapy experiences for the patient.

The H.E.C.A.T.’s (Hydrogel Electrode Comparison & Analysis Tool) 324 test points per 2"x2" sq. electrode and high quantity of test samples paint an excellent picture of an electrode’s dispersion characteristic. The H.E.C.A.T. also provides data for the analysis of current dispersion, which leads to objective comparative results.
Learn more about electrical dispersion testing.

Why is an electrode’s moisture content considered a performance characteristic?

Water is an essential element of a hydrogel electrode. It is the base component in all hydrogel formulas, combined with special ingredients that provide the electrode’s unique properties.

Water molecules provide the path for electrical current, and a reduction in moisture content is directly tied to electrical performance measures such as conductivity, electrical resistance, and current dispersion.

High moisture content maintains the adhesive properties of the hydrogel. As an electrode dries out, its adhesion suffers.

The H.E.C.A.T. (Hydrogel Electrode Comparison & Analysis Tool) tests for moisture content at 100 points on a 2"x2" electrode. Thousands of readings are taken and processed through a proprietary algorithm to determine localized and general moisture content. This information can be used to gauge the electrode’s moisture content when it is fresh out of the bag, or at any other point in its use.

Hydrogel electrode adhesion is not an easy property to quantify. As with all other electrode properties and performance characteristics, there are no industry standards to comply with or performance levels to meet.
Similarly, the ideal amount of adhesion is a standard that cannot be readily defined - because every patient, therapy and treatment environment is different. Adhesion that is not "sticky" enough for one patient may actually cause a painful removal for another.
For these reasons, we have chosen to define the average adhesion of any group of electrodes as the ideal for that group. We go further and rank the individual electrodes in the group based on the amount of deviation from the average adhesion. The electrodes deemed "too sticky" or "not very sticky" (at the extremes) rank the lowest.
Many samples were tested using calibrated force equipment and standardized test methods.
The values in this test are for fresh, out-of-the-bag electrodes. Adhesion tests were also conducted following an accelerated dry-out process to determine the effect of dry-out on the hydrogel electrode adhesive.

This test resembles the electrical conductivity test conducted on fresh, out-of-the-bag electrodes. However, this version is conducted on electrodes that have been forcibly dried out over a 12-hour period. (Learn more about the accelerated dry-out process.)

Moisture content is a vital element of hydrogel electrodes. As electrodes dry out and lose their moisture, there is a resultant drop in the following performance metrics:



Furthermore, electrodes exhibiting dryness levels that impair adhesion can lead to unsafe or unpleasant conditions for the patient (i.e. edge-biting, arcing, burns).

During this test, a 9-volt AC electrical signal is supplied to the electrode. The electrode is attached to the H.E.C.A.T. (Hydrogel Electrode Comparison & Analysis Tool) electrode interface board and voltage measurements are taken at 324 points on the board.

This test measures the electrodes and compares them based on the absolute values.(Learn more about the accelerated dry-out process.)

This test is similar to the electrical resistance test conducted on fresh, out-of-the-bag electrodes. However, this version is performed on electrodes that have been forcibly dried out over a 12-hour period.(Learn more about the accelerated dry-out process.)

Moisture content is a vital element of hydrogel electrodes. As electrodes dry out and lose their moisture, there is a resultant drop in the following performance metrics:



Furthermore, electrodes exhibiting dryness levels that impair adhesion can lead to unsafe or unpleasant conditions for the patient (i.e. edge-biting, arcing, burns).

Using the H.E.C.A.T. (Hydrogel Electrode Comparison & Analysis Tool), the entire electrode can be tested dispersion pad, connector, lead wires, and hydrogel. There are 324 electrical resistance test points for a 2"X2" electrode and in seconds, H.E.C.A.T. takes thousands of measurements. H.E.C.A.T. can also test electrical resistance on AC and DC currents.

H.E.C.A.T.’s electrical resistance measurements are wholly reliable and represent the electrical resistance of the entire electrode.

This test is similar to the electrical dispersion test conducted on fresh, out-of-the-bag electrodes. However, this version is performed on electrodes that have been forcibly dried out over a 12-hour period.(Learn more about the accelerated dry-out process.)

Moisture content is a vital element of hydrogel electrodes. As electrodes dry out and lose their moisture, there is a resultant drop in the following performance metrics:



Furthermore, electrodes exhibiting dryness levels that impair adhesion can lead to unsafe or unpleasant conditions for the patient (i.e. edge-biting, arcing, burns).

This test measures the electrode’s dispersion and provides visual and numerical comparison data.

This test is similar to the moisture content test conducted on fresh, out-of-the-bag electrodes. However, this version is performed on electrodes that have been forcibly dried out over a 12-hour period. (Learn more about the accelerated dry-out process.)

Moisture content is a vital element of hydrogel electrodes. As electrodes dry out and lose their moisture, there is a resultant drop in the following performance metrics:



Furthermore, electrodes exhibiting dryness levels that impair adhesion can lead to unsafe or unpleasant conditions for the patient (i.e. edge-biting, arcing, burns).

This test measures the electrodes and compares them based on the absolute values.

Hydrogel electrode adhesion is a difficult property to quantify. Like all other electrode properties and performance characteristics, there are no industry standards to comply with or performance levels to meet.
Likewise, the question, "What is the ideal amount of adhesion?" is a hard one to answer - because every patient, therapy and treatment environment is unique. Adhesion that is not strong enough for one patient may actually cause pain on removal for another.
For these reasons, we have chosen to define the average adhesion of any group of electrodes as the ideal for that group. We go further and rank the individual electrodes in the group based on the amount of deviation from the average adhesion. The electrodes deemed "too sticky" or "not very sticky" (at the extremes) rank the lowest.
Many samples were tested using calibrated force equipment and standardized test methods.
The values in this test are for electrode samples that have been subjected to an accelerated dry-out process.

The two greatest enemies of hydrogel electrodes are fouling (contamination with skin dander, dirt, oils, etc.) and dry-out. Dry-out refers to the reduction of moisture content in the electrode from exposure to air.
Once an electrode is removed from its original sealed bag and exposed to air, the drying-out process has begun. When in use, the electrodes are further exposed to air and the process continues.
As the hydrogel dries out, its properties, characteristics and performance are detrimentally affected. Electrical resistance increases, electrical conductivity decreases, and dispersion becomes more fragmented, leading to unwanted "hot spots." Adhesion decreases, and, in some instances (depending on the manufacturer’s hydrogel formula), may even increase.
Generally speaking, an electrode has reached the end of its lifespan when it fails to safely adhere to the patient’s skin. However, an electrode’s performance can prematurely diminish due to excessive dry-out.
Dry-out resistance is therefore a desirable characteristic in a hydrogel electrode. Since all hydrogel electrodes are subject to dry-out, the optimal choice is the one that loses minimal moisture during use.
The best way to rate dry-out resistance is to measure an electrode’s moisture content right out of the bag, and then again after a measured and intense dry-out period.(Learn more about the accelerated dry-out process.)

"WARNING: Do not lift by the lead wire."

The message above is universal - nearly all electrode manufacturers include it in their products’ care and use instructions. However, we do not. In fact, we encourage users to remove Theratrode electrodes from the patient’s skin by using the lead wire to lift them.

The truth is that for providers and patients, it is simply less hassle to remove electrodes by pulling on the lead wire - and as humans, we naturally do what’s easiest. Yet an electrode with poor materials and construction will fail when removed in this fashion, resulting in the destruction or damage of the lead wire.

Theratrode employs higher-quality materials and advanced construction techniques to allow removal of our electrode via the lead wire. Ours is the only foam-top carbon electrode on the market today that will not fail in this regard.

In this test, we place the electrode pad into a hinged fixture, which tears (shears) the pad. The object is to measure the amount of force required to tear the pad.

While it’s likely that no electrode will ever be subjected to the stresses used in the "pad tear test," this test clearly demonstrates the superior materials and construction methods used in producing Theratrode.

This test is similar to the lead wire-to-electrode pad test. In this test, we forcibly pull apart the connector from the lead wire.

The electrodes in the challenge are ranked by the amount of force required to cause a failure. The higher the force, the higher the ranking score.

Watch a video of this test.

In this test, we measure how well the lead wire (known as the "pigtail") is attached to the electrode pad.

Using specially designed fixtures, we pull the lead wire from the electrode pad and record the amount of force (in kilograms) required to pull the lead wire from the pad.

The electrodes in the challenge are ranked by the amount of force required to cause a failure. The higher the force, the higher the ranking score.