Effects of right and left hemisphere cerebrovascular lesions on discrimination of prosodic and semantic aspects of affect in sentences.

Ten nonaphasic left cerebrovascular accident (CVA) patients, 12 right CVA patients, and 16 normals were matched for age, education, lesion sizes, and postonset intervals; all were right handed. One task consisted of 36 sentences connoting one of six primary emotions (joy, sadness, fear, surprise, disgust, anger) presented binaurally with a neutral emotional tone. Subjects were required to point to the appropriate emotion name on a vertically arranged list. A second task consisted of the same 36 sentences voiced emotionally by humming with a closed mouth, presented binaurally, and requiring the same response as for the preceding task. A third task consisted of 18 of the sentences spoken with concordant emotional tone and the remaining 18 sentences spoken with discordant emotional tone, presented binaurally and requiring pointing to the word "SAME" or "DIFFERENT" arrayed vertically. The right hemisphere (RH) patients were significantly impaired, relative to the left hemisphere (LH) patients and normals, on the pure prosody task (2) and on the emotional concordance task (3), the latter effect being significant only for mismatch categorization. The LH patients performed (nonsignificantly) less well than the RH patients and normals on the verbal contextual task (1). Performances on the three tasks were not significantly correlated in the patient groups. It was concluded that the RH probably dominates for phonetic discrimination of vowel trains (fundamental frequency and/or single vowel or multivowel contour) and that the RH probably dominates for certain forms of selective attention in the verbal domain perhaps involving simultaneous mismatch treatment of ongoing sentence-level, distracting, complementary, verbal processes. Comparison of similar right and left, cortical (frontoparietal), and subcortical (capsule and basal ganglia) lesions suggested, but did not prove, that the RH pure prosody impairment is cortical whereas the RH tonal-semantic mismatch categorization impairment involves subcortical as well as cortical contributions.