Discrepancies between standardized measures of cognitive level and Halstead-Rettan impairment indices as inferences of brain damage following head injuries

z scores for measures of intelligence, memory, educational achievement, and neuropsychological impairment were obtained for 193 patients who had susta ined impacts of mechanical energy to their skulls. Two sets of normative da ta, adjusted for ape and sex and not adjusted for these variables, mere emp loyed to compute indices of neurocognitive proficiency (the inverse of impa irment). 80% or 76 of the 96 patients whose Halstead-Reitan Indices were gr eater than 0.4 displayed scores for neurocognitive proficiency that were tw o or more standard deviations below the averages of their scores for intell igence, memory, and educational achievement. None of the patents whose Impa irment Indices were 0.4 or less displayed this discrepancy. There were no s tatistically significant differences between these two groups of patients w ith respect to the presence of unconsciousness following the injury or the duration of posttraumatic memory disruptions. The results indicate that qua ntitative scores for neuropsychological impairments are still the most accu rate criteria to discern brain dysfunction within the mild to moderate rang e.