Test-retest scores for patients who display neuropsychological impairment following "mild head injuries" from mechanical impacts.

A total of 20 patients who had sustained of significant mechanical energies to the skull (> 40 km/hour) were assessed at Time 1, about one year (68% between 2 mo. and 12 mo.) postincident while Time 2 was about two years later. During Time 1 this group was impaired (proficiency z < -2.00) according to two standardized neuropsychological indices and exhibited abnormally elevated psychometric depression (z > 2.00). There were no statistically significant improvements for the scores between Times 1 and 2 on the Halstead-Reitan Impairment Index, the Memory Quotient, Depression, or an impairment index composed of standardized scores for 31 neuropsychological tests. These results indicated that the presumption of some neuropsychologists that patients with "mild head injury" have fully recovered within one year or will continue to improve after about one year following the incident may not be valid for all patients who sustain such brain trauma.