I've read Michael Hutchison's book Megabrain several times. It is peculiar for him to claim that Holosync is 'dangerous' when his book has a whole chapter devoted to sound and lots of information on binaural beats. All written from the perspective of positive benefits. Has Hutchison come to the conclusion that all binaural beats are bad? Is he concerned specifically about Holosync because of the lower frequencies than typical binaural beats? What would be the difference between Holosync, Hemisync,or Dane Spott's VERY LOW frequency technologies?
I've used Holosync for four years and don't have any brain damage I am aware of. That said, transendental meditation, without holosync or any technlogical assistance, does have the potential for problems in some people.
As Bill Harris says himself, the real beauty of meditation is that it pushes your brain beyond it's current limits where it is forced to reorganize at higher levels. This for me has always turned out positive and I assume for 99.999% of people it would.
But let's say for example you have a pre-existing brain aneurysm. I'm no neuro expert... But I'm not so sure that I would put on an hour of Holosync Level 4 before going into surgery the next day; simply because the structures of the brain are compromised because of the aneurysm and may simply not be able to handle the stimulus and reorganize as a healthy brain would. So I believe the safety factor of Holosync is much like that of a long distance runner. Fine for 99.9% of people to do but if you have a heart valve defect or a clogged artery it could be dangerous. I'm just not sure there has been enough research to suggest that it would 100% safe in people that have pre-existing physical defects in brain structure.
Futhermore, I called Centerpointe several years ago because I was having lots of tingling sensations in my brain, feelings like sinus pressure, and my ears would feel like I was at high altitude. Most of the sensations were very pleasureable but some were quiet uncomfortable. The people at Centerpointe told me that it was completely normal to have these sensations and that as my brain chemistry changes and 'evolves' to a higher level there would be strange sensations. That was several years ago and they were very right.
That brings me to my other 'concern' about Holosync that Centerpointe would never talk about. I'm not so certain that I now have the ability to really tell if I were having some sort of physical brain problem that is serious and real, or that I'm just having the common sensations resulting from meditating with Holosync. Because I'm now conditioned to basically ignore all these sensations (good & bad), and I've never had a stroke or aneurysm; I think there could be the possibilty that I could ignore a serious problem in the future, that without doing Holosync, I would have known was serious and would have seeked medical attention.
With all that said... I seriously love doing Holosync, it really does work and I plan to keep doing it. Meditation is not for everyone and even in tradtional meditation there are plenty of critics that claim you can damage your brain. Basically suggesting that for whatever reason, some people's brains do not rise to the challenge and in some way are affected very negatively as a result. While Hutchison tried to get people to look for negative info on Holosync, he could have easily directed people to look up dangers associated with mediation in general. One site, http://www.yogadangers.com/, talks specifically about circumstances when meditation triggers a "Kundalini Awakening." Bill Harris mentions in one of his articles that his early experiences with holosync triggered this in their research. Of course these were much lower frequencies than the awakening prologue starts you out at.
I believe for a healthy, non-diseased brain the physical danger from Holosync or any sort of meditation is next to nothing. But just like thousands of athletea that go out and runs 10 miles everyday, every once in a while there is a person whose cardiovascualar system, cannot handle the stimulous and they have some sort of heart failure.
That is why someone can't suggest that Holosync or meditation can kill you without acknowledging that running, swimming, biking, or just about any intense physical workout can kill people too. But that doesn't mean people stop working out and it doesn't mean that someone shouldn't meditate.
Good luck all!