Some test procedures of the computer assisted instrumentation system COMBITEST 2 were examined in order to evaluate the strength of diagnostical differentiation. For this purpose tests for evaluating the concentration capacity and the psychomotor performance, especially tapping, were used in a sample of 92 neurological patients (60 patients with and 32 without cerebral impairment). It became evident, that performance differentiations between patients with cerebral impairment and others are predominantly characterized by speed parameters (reaction time, duration of test), scarcely by parameters of accuracy (number of errors). Configuration - frequency - analyses emphasize deceleration of psychic/psychomotoric speed as diagnostic indicator in cerebral impaired patients: the best pattern was the "configuration" of reduced speed in concentration test and in tapping.