I think we can kickstart someone’s beta and gamma waves by electromagnetic induction, because those brainwaves probably stimulate the heart to increase the flow of blood into the brain to keep it stable. Neurons may not be a simple conductor, but they are charged, due to the concentration gradient, which is what matters.
We use electromagnetic induction to change the delta (0 to 4 hertz) and theta (4 to 8 hertz) brainwaves as example, into beta (12 to 40 hertz) and gamma (40 to 100 hertz) brainwaves to awake them.
A moving magnetic field causes (but doesn’t create by direction) a moving charge (electrical brain signals) and that causes a moving magnetic field again, which causes moving charge (brainwaves), although it needs a frequency.
We use:
while using the frequency of mainly beta brainwaves for the electromagnetic waves.
The voltage must be the regular voltage for the neurons.
Note though, that delta brainwaves are present when we are recovering, hinting this may inhibit the recovery, so it may be the best option to delay it for a while.