There was a short news report on this on the Beeb yesterday which reminded me of previous findings. Impairments in eye movements are found after concussion and may provide a quicker and more reliable diagnosis. Specifically this test measures impairments in something called 'smooth pursuit' - the ability to accurately track a moving target : Taking the guesswork out of diagnosing a concussion http://www.cnbc.com/2015/11/15/taking-the-guesswork-out-of-diagnosing-a-concussion.html Normally these and other symptoms resolve within a few weeks of the concussion. But in the case of Post-Concussion Syndrome, symptoms (which include fatigue, cognitive problems plus exacerbation of symptoms with exercise and alcohol intolerance to name a few) persist for months or years leading some to suspect that psychological factors intervence. These objective eye movement impairments also persist though leading researchers to conclude that "Poorer subconscious oculomotor function in the PCS group supports the notion that PCS is not merely a psychological entity, but also has a biological substrate." : Impaired eye movements in post-concussion syndrome indicate suboptimal brain function beyond the influence of depression, malingering or intellectual ability (bolding added) http://brain.oxfordjournals.org/content/132/10/2850 Interesting that similar problems have been found in ME/CFS : Characterising eye movement dysfunction in myalgic encephalomyelitis/chronic fatigue syndrome. (bolding added) http://www.ncbi.nlm.nih.gov/pubmed/23918092 Do these ME/CFS findings also 'indicate suboptimal brain function beyond the influence of depression, malingering or intellectual ability' ?