All problems involving cognition and affect begin and live in the brain. Cognition is simply thinking tasks like memory, calculation and related functions such as attention. Examples of cognitive disorders include dementia, Alzheimer’s, attention deficit and one called “brain fog”. Affect disorders are extremely common including anxiety, depression, PTSD and other mood function related problems. Some problems involve both cognitive function and affect such as often occurs following traumatic brain injury and stroke.

One of the effective tools that has emerged for “re-setting” brain function in disorders of both cognition and affect is photobiomodulation (PBM). The PBM is using light (photo) on living tissue (bio) to change its activity (modulation). Visible light will not penetrate into the brain. The longest wavelength visible light is red which is 650 nM. Brain PBM is done with infrared diodes that have a longer wavelength of 1064 nM. Infrared light will penetrate up to 40 mm into the brain. The infrared light produces 2 important clinical effects. The first is that it activates cell ATP or energy production. Diminished brain cell energy production is common in both disorders of cognition and affect.  


























The second effect is that infrared light can be used to change the frequencies of brain waves. Brain waves pulse at different frequencies to elicit different functions. For example, activating higher cognitive activity requires brain waves to activate in the beta range which is pulsing at 13-20 hertz. Pulsing the infrared light in this range raises that brain wave activity, a phenomenon termed “entrainment”.  

A good example of entrainment is listening to a band. Everyone listening is doing something to the beat of the music such as tapping their feet, hands or some other movement in the same frequency of the beat. The brain will follow light frequency the same as sounds producing brain EEG waves in a similar frequency. For example, a 10 hertz pulsing light will increase brain alpha waves which are 10 hertz. This moves the brain to the same relaxed frequency and state as does meditation which is helpful for anxiety and PTSD. Sleep involves transitioning to lower frequencies called theta and delta which are 2-7 hertz so they are suited to helping sleep dysfunction.

One of the first cognitive disorders where PBM was found to be effective was Alzheimer’s disease. The first brain waves to diminish in the early phases of the disease is high beta which pulse at a frequency of 40 hertz. Researchers observed in an animal model of the disease exposing them to recurrent periods of 40 hertz white light caused lowering of beta amyloid, the misfolded protein that has been associated with causing the brain degeneration.(1)
The problem in this study was that because white light cannot penetrate into the brain and could only be transmitted through the eye to the back of the brain where vision is processed, it did not help the front and side of the brain that is involved in the disease accounting for memory loss. The solution to this dilemma was to use infrared light over the areas directly affected by the disease. The use of PBM has now shown results in human Alzheimer’s Disease.(2)
PBM is a unique non-invasive, drug free therapy to restored brain function. It can be used across all age groups. 
 
(1) Iaccarrino AF. Gamma frequency entrainment attenuates amyloid load and modifies microglia. Nature, 2016;540:230–235.
(2) Saltmarche et al. Significant Improvement in Cognition in Mild to Moderately Severe Dementia Cases Treated with Transcranial Plus Intranasal Photobiomodulation: Case Series Report. Photomedicine and Laser Surgery, 2017;35, Number 8:432–441.