[Value of the brief neuropsychological tests for detection of acquired cognitive deficits. Exemplified by the Lehrl and Fischer c.I. (cerebral insufficiency) test].

The aim of the study was to find whether the c.I. test is useful for the exclusion and the demonstration of acquired cognitive deficits. In all, 195 patients with brain damage and 68 neurotic patients were examined with the c.I. test and with a comprehensive number of neuropsychological tests. The hit rate of the c.I.-test for the whole group was 67% and lay lower than the base rate of 74% brain damaged patients respectively only unessentially higher than the base rate of 64% patients with unambiguous acquired cognitive deficits. There were very low hit rates especially in patients with absent (46%) or low-grade cognitive deficit (54%) and with low (55%) or with high premorbid mental abilities (55%). Both the low correlations between the c.I. test and the validity criterion as well as the considerable overlapping of the c.I. test raw score distributions, grouped by grades of cognitive deficits, indicate serious deficiencies in the test. The extremely brief c.I. test possesses an inadequate grade of difficulty and cannot detect low- and medium-grade acquired cognitive deficits, and its orientation to ability-related global syndromes means that partial, multifactorial and general cognitive deficits are neglected. The c.I. test is therefore not useful as a screening method for the diagnosis of acquired cognitive deficits.