Auditory brainstem responses in postconcussion syndrome.

Evidence that head injuries can shear nerve fibers and end bulbs in the tracts between the diencephalon and brainstem led us to hypothesize that auditory brainstem responses might be abnormal in patients with postconcussion syndrome. We recorded brainstem responses in 11 patients and 12 control subjects. Comparing the two populations, our chief finding was that the patients showed significant delays for wave 3. This finding indicates organic changes involving a region at least as central as the superior olivary complex, thus refuting many authors' claims that the syndrome is entirely psychogenic.