Many people have very different responses to the same stimulation parameters. This can be for a lot of reasons. Just as an example:
Person #1 has trouble sleeping and has chronic back pain. They use the Alpha Wave setting on medium intensity on their lower spine, and it makes them sleepy.
Person #2 has trouble concentrating, and they use the Alpha Wave setting on medium intensity on their lower spine, and it makes them alert.
Totally different individual responses for exactly the same setting used on exactly the same anatomic location, but the individual responses are completely different. What is going on?
people are different.
They have differences in the details of their physiology, level of health, age, genetic predispositions, sensitivities, health history, age, expectations, emotional state, socio-economic circumstances, …
By the way, this example is just one of many real examples of real people who have had these very different reactions and who have talked to me about them.
How would I explain this difference? Well, I would speculate the following:
Person #1 had chronic pain that was keeping him awake. By using ICES-PEMF, his chronic lower-back pain was reduced, which made it much easier for him to sleep because he was in much less physical discomfort. So his reaction: sleepiness.
Person #2 had entirely different life circumstances, maybe some sort of CNS neuro-inflammation that was interfering with her concentration. By using ICES-PEMF on her lower spine, she had two effects: reduced neuro-inflammation and entrainment of the CNS to the alpha-wave state, which enhances a state of calm alertness.
I could be wrong about the explanations, but the individual differences were very real.