GP8 Amp vs. IOM or emWave, ease of use, accuracy

[Ryan Deluz]

Hi All,

This is in response to an e-mail I received wondering why to use the GP8 ECG, over the IOM or emWave.

IOM
This is a quick and easy sensor to attach. Its nice that it can be put on without help or outside physical contact.

Accuracy is a bit low for people with low HRV, due to data samples being 30 samples per second. We have a special way of getting good accuracy, even with the low sample rate, but still, for individuals who are older or who have low HRV (total variability at rest of 2-5 bpm) smoothness will not be very accurate, and these individuals may have a hard time training.

The IOM sensor is no longer made by the manufacturer, and the replacement IOM PE sensors we have tested are not sufficiently accurate for HRV.

Still, if you have an IOM, have reasonably high resting variability (total variability), and want to train quickly and easily, this is a good sensor choice.

The IOM is also nice in that it measures skin conductance and BVP. BVP is blood volume pulse, the measurement that we derive heart rate from, and it can be used for training in Alive Pioneer.

emWave
The emWave sensor reads at a higher data rate than the IOM, which would theoretically allow for increased accuracy. Unfortunately ear placements to read heart rate are a bit touchy. Its easy to get a bad signal (resulting in inaccuracy, a lot of red, or constant notices about sensor disconnection), and for about 10% of the population you can never get a clean signal on the ear.

If you use the emWave I suggest purchasing a finger sensor for $25 from the HeartMath store. We are now shipping with finger sensors.

As long as you get a good signal, or measure from the finger, this is an accurate (not ECG accurate, but pretty good) sensor, that should be able to work for most people (as long as you have the finger sensor as an option).

This sensor only measures heart rate, and does not measure skin conductance, or bvp, so if you want to view graphs of, or train, anything aside from heart rate or smoothness, for example compare heart rate to bvp, skin sweat, emg, etc., this isn't a good sensor option.

GP8 Amp
The GP8 Amp is a professional grade amplifier, designed for long term use. As opposed to the IOM, whose sensors wear out, or the emWave, whose sensors can break easily, the GP8 Amp sensors should last indefinitely. The sensors are easy and inexpensive to replace, and use common parts (the lead wires, electrodes, etc.).

Training with smoothness using the GP8 Amp returns a much more accurate result than training with IOM or emWave. As long as you are not moving, and if the sensors are placed well, you get a very accurate heart rate. This results in a more accurate reading of smoothness. Using the IOM or emWave sometimes you see a lower smoothness due to a single incorrect heart rate reading, causing a spike in the smooth wave. Due to the increased accuracy, and lack of spikes due to inaccuracy, people often can use a harder smoothness difficulty in Alive when using the GP8 Amp ECG.

That said, it does take longer to set up for ECG. I personally prefer disposable electrodes, as this eliminates set up time. I can set up wrist-to-wrist or wrist-to-ankle ECG in the same amount of time, in a few seconds. Using permanent electrodes requires more preparation of the site, to ensure its clean and has good contact, and then checking the signal. Over time, I find it gets quicker and quicker to set up ECG.

Using the ECG from the GP8 Amp also lets me compare smoothness, or heart rate, to other measurements such as skin sweat and temperature. Also, if not using ECG, or if I want to switch feedback, I can use the GP8 Amp to train muscle tension (EMG). You could also train EMG with skin sweat and temperature.

Because the GP8 Amp is much more durable, it is a better choice of hardware over time, although it is annoying to set up the ECG. When you do set up the ECG, though, you then get a more accurate and effective training.

Finally, we are working on new smoothness feedback games, that require both hands to play. Since the ear is prone to poor signal and movement artifacts of the head turning playing action games using both hands requires` ECG ankle-to-ankle, or on the chest, will allow people, with accurate smoothness feedback, which is pretty much only possible using ECG.

We are currently working with the manufacturer of the GP8 Amp to add a BVP option. This may require purchasing a new GP8 Amp. Therefore we are also going to sell a separate, Bluetooth, BVP heart rate sensor, that can be used simultaneously with the GP8 Amp. That will also allow training heart rate and EMG at the same time. This separate sensor will be available in a couple of months and cost $300 or less. This sensor will also open up possibilities for mobile games.

Best,

Ryan