Quite a while ago I ran into the a hearth variability training device that goes by the name of "emWave 2." With this one can increase "coherence," a state of "order and harmony in our psychological and physiological processes." In a way there is a lot of hype to this device and I'm here to give my honest findings.
emWave vs Meditation
First, this device does the same thing as meditation or prayer. It will help guide you into a certain mental state. Some people can achieve a state of coherence without the need of measuring devices, but with the emWave you can track numbers to see whether you are improving or not. When I tested the emWave and I reached a state of coherence I would often start feeling a "face tingling" which would then begin to spread all the way down to my neck. I'm unsure about the specifics of this tingling, and whether it's a good or bad thing. When I have done meditation I have also reached some face tingling, but the tingling has never been as strong as in the case of the emWave.
When participating in different activities the coherence state will change; this might be due to the stress induced by those activities. One useful thing about the emWave2, regarding gaming, is that one can become more aware of the body-mental state. Being aware then allows us to control ourselves and can lead to improved performance. If what I noticed in gaming can occur in other activities then the emWave could be a very good performance enhancer.
The emWave2 requires you to spend time. If you overdo training then you could really be wasting a lot of precious time. If I was to give advice regarding usage... it would be that you should only do a few sessions per week, and each session to be less than 10 minutes. I would also recommend doing training prior to important events as it can help reduce anxiety.
One complaint that I have about the emWave2 is the absurd price, somewhere around $180 at the time of this writing. In my opinion this device should sell for less than $100.
It is extremely attractive to think that there are devices that can improve our mental performance--it's almost like the idea of having a special diet pill that will make you skinny in a very short period of time. Please, don't buy the emWave2 based on an emotional state of wanting a quick fix to life problems. Don't fall prey to people selling you the emWave, look for discounts and used ones.
It's hard to recommend this device because I feel that some people need it and others do not need it at all. What I learned from it is that I can be in control of my performance state by simply controlling my physical and mental state. The physical state is often tied to breathing, and the mental state to just simply being positive. I strongly believe that you are better off if you can achieve coherence without the need of a gadget. In a way it's like weight management with a scale. If you are in control of your weight then you don't need a scale at all, but if you are trying to see measurable improvements, as in the case of people who are starting in managing their weight, then you really need that scale in order to feel motivation due to progress. Overall the purchase of the emWave2 is case dependent.