HEG is a non-invasive technique that uses reflected light to measure perfusion. Because the skull is actually translucent a light attached to the inside of a headband placed on the forehead penetrates the skull and is reflected back and detected by a photo sensor which can detect how much oxygen it carries.

The frontal area of the brain (pre-frontal cortex) is associated with planning and impulse control. Not surprisingly, this is one of the brain regions directly implicated in problems seen in Attention Deficit Disorder. Advanced neuroimaging techniques have confirmed this association. There have also been studies demonstrating that the activity level of this area is implicated in depression.

HEG has been used to help people with ADD and depression. Because of what we know from imaging studies it is not surprising that a technique that puts a greater part of the pre-frontal cortex to work would be of use with these problems.

Interestingly, HEG is also used to help with migraine. The nature of migraine is complex and its exact cause remains elusive. Muscle tension, vascular dilation and inflammation have all been implicated in its etiology. The exact mechanism by which HEG might abort or prevent migraine attacks is not known. But case reports have been promising.

HEG should not be considered a cure or treatment but rather as a form of training that strengthens certain brain functions that are thought to relate to the symptoms of these disorders.

NIR spectrometry (HEG), while well accepted in the medical community for other purposes, is a very new biofeedback modality, and there is not enough published research to prove its effectiveness, so it has to be considered investigational. However, case reports have been encouraging.