Item analysis of Halstead's Speech-Sounds Perception Test: quantitative and qualitative analysis of errors.

The pattern and type of errors on the Speech-Sounds Perception Test was examined in a sample of 513 patients referred for neuropsychological evaluation. There was considerable variability in the rate of correct response. Groups of patients with independently documented lesions were compared in regard to number and type of errors. It was found that patients with left-hemisphere lesions made a higher percentage of ending errors and a lower percentage of beginning errors than patients with right-hemisphere or bilateral lesions. These differences were maintained when the total error score was included as a covariate. It was also found that a cutoff score based on the percentage of ending errors correctly classified the unilateral-lesion patients at a statistically significant level. The potential clinical utility of these results were discussed.