A comparison of frequency of abnormal results in neuropsychological vs. neurodiagnostic procedures

Compared the frequency of abnormal Impairment Index values and abnormal results on neurodiagnostic procedures in patients (N = 102) classified as Brain-damaged, Normal, or Equivocal on the basis of final medical diagnosis. The Impairment Index called a higher percentage of the Brain-damaged Ss abnormal than did any single neurodiagnostic procedure. Although it called a higher percentage of the other two groups abnormal than did the skull X-ray, the Impairment Index did not differ from computed tomography (CT) or the EEG with respect to abnormality rates in those groups. Thus, in this sample of patients, the Impairment Index was more sensitive to brain damage than any neurodiagnostic measure, yet no more likely to call patients in the other two groups abnormal than were CT or the EEG. Limitations of the study and difficulties in conducting this kind of research are discussed.