There are plenty of so called Audio-Visual-Stimulation (AVS) tools you can buy on the market (used to be called Psychowalkman). They usually claim that it can stimulate brain with sound/visualization to increase mental abilities such as ability to learn, help with sleep problems, headaches and much more.
So I am wondering, does this really work? And by this I mean, is there really ANY such device which can be demonstrated to work? Focus of this question is on the devices themselves, however it might be questionable whether the AVS mechanism works by itself...
I could not find a study that would prove/disprove this. The manufactures usually refer some articles that itself talk about some very specific property of the brain to adapt to audio/visual waves, but I find that weak, since this does not show that what they sell actually utilizes this feature (could be device that randomly creates noise/sound as far as i can tell). They also refer to some celebrities that are using the tool, other thing that seems suspicious. Even if lots of people are claiming it helped them in a way, how do I know it isn't a placebo effect?
So I guess one question is if this can work based on current knowledge? And if yes, does it actually work with devices one can buy?
Edit: Adding examples. First is site http://www.smarterway.com/AVS-MindsEye.html. It states there:
Modern scientific research has verified this phenomenon: brain activity becomes more active or more quiet in response to external rhythms of light and sound.
Another one http://www.mindmachines.com/
Mind Machines specializes in providing theraputic tools for relaxation, enhanced learning, mind power, biofeedback, neurofeedback, high tech meditation and personal achievement.
By presenting beats and pulses to the brain, the brain begins to mimic or follow the same frequencies. This process is referred to as entrainment. In essence, these instruments speak to the mind in it’s own language – the language of frequency.