The neuropsychological spectrum was investigated in a traumatically brain-damaged population. In this spectrum neuropsychological measures were regarded as the most biologically oriented, achievement measures as the most acquired skill-oriented, and intellectual measures as having an intermediate position. It was found that the achievement measures correlated the most highly with each other, the intellectual measures intercorrelated to a lesser extent, and the intercorrelations of neuropsychological measures yielded a zero-order median correlation. It was further found that the correlations of measures with those in other categories had the same ranking. It was inferred that brain damage alters the pattern of the neuropsychological spectrum because of disproportionate impairment in the biological direction of the spectrum.