ADD / ADHD, ADD / ADHD Treatment, Autism, Autism Treatment, Dyslexia, Dyslexia Treatment, Science, Visual

Does Light Therapy Work? Some Real Evidence At Last

Light therapy for ADHD, dyslexia and autism is a contentious area. How could spending twenty minutes sitting in front of a flashing light help children learn to read or control themselves? I was highly skeptical until I tried it myself (see Light Therapy Follow Up). Even having tried it I could only speculate on why it had the effect it did. Now some researchers have shown that light can effect your memory.

By exposing participants to a flashing light for one second, researchers in Oxford found that participants were better able to recall a list of trigrams (semi-random groups of three letters). Most importantly the improvements only happened when the lights were flashed at frequencies on or around 10.2 Hz. A frequency related to the brain’s alpha waves and believed to be relevant to memory functions.
Alpha waves normally span the 8 to 12 Hz range but this study was looking at older people with a mean age of 78. As the brain gets older its brain waves shift slightly and 10.2 Hz is the peak frequency for those aged 80 or above. The researchers tested flicker frequencies of 9.0 Hz, 9.5 Hz, 10.0 Hz, 10.2 Hz, 10.5 Hz, 11.0 Hz, 11.5 Hz and 500 Hz. Only those frequencies in the 9.5 – 10.5 Hz range improved participants recall.
This well designed study shows a clear link between flickering visual stimulus (sometimes called photic driving) and memory performance with strong evidence that the mechanism relates to brain wave activity. However this was a test of short exposure to flicker very quickly followed by the memory test. It provides no evidence as to what happens if the exposure to the flicker is longer or to how long the effects last. Both of these points are vital to understand what, if any, effect light therapy can have on people with learning disorders


Here we move into the field of speculation. It is clear that brain wave patterns do relate to cognitive abilities and behaviour. It also changes as we age, notably during childhood. Is it possible that children with learning problems that are related to poor short-term memory are stuck with the alpha wave patterns of a young child? If this is the case, could repeated exposure to photic driving train the brain to have strong, more consistent alpha waves? It is possible but much more research is needed.

10 Hz flicker improves recognition memory in older people [ PDF ]. Originally spotted on the excellent Developing Intelligence who have their own informative write-up.


  1. No wonder I have problems. Too much time with 60hz. The light therapy does seem to be something I want to experiment with. Especially as I avoid light as much as possible. Thanks, as always for the intel.

  2. Jason R

    So if light does effect your memory then what about different kinds of light or light that is projected off of something. im writting a paper on the effects of light and memory for my psych class and i came up with a theory since i cant find anything online about it. i call it the moonlight memory theory, basically if certain lights can help you regain your memory easyier than couldnt more in tense light or light under certain circumstances effect your memory in other ways, such as the saying goes “the moon plays tricks on your eyes” but i believe that under the right circumstances like for instance with me, going through this personally. when i was about 9-10 years old i woke up in the middle of the night after passing out on the floor and the window was open and i could see the moon, then i looked at the other side of the room and i seen my mother in her pajamas, just standing there with her eyes closed, like any child i was scared to death but i called out her name. next think i knew she flicked on the light and it was gone and she came out from the back room. now i believe that was a memory of my mother projected, considering it was perfectly clear and the only time it has ever happened. ive also herd storys of people seeing there aunt moving to a cubored and replaying, and it just seems to me like anybody who has thease is beacause they look at this light and a certain point of awakness and a memory is projected in front of them of what ever cue is in front of them or of what they are thinking of. any comments email me

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