Recognition of prosody following unilateral brain lesion: influence of functional and structural attributes of prosodic contours.

The perception of prosodic distinctions by adults with unilateral right- (RHD) and left-hemisphere (LHD) damage and subjects without brain injury was assessed through six tasks that varied both functional (i.e. linguistic/emotional) and structural (i.e. acoustic) attributes of a common set of base stimuli. Three tasks explored the subjects' ability to perceive local prosodic markers associated with emphatic stress (Focus Perception condition) and three tasks examined the comprehension of emotional-prosodic meanings by the same listeners (Emotion Perception condition). Within each condition, an initial task measured the subjects' ability to recognize each "type" of prosody when all potential acoustic features (but no semantic features) signalled the target response (Baseline). Two additional tasks investigated the extent to which each group's performance on the Baseline task was influenced by duration (D-Neutral) or fundamental frequency (F-Neutral) parameters of the stimuli within each condition. Results revealed that both RHD and LHD patients were impaired, relative to healthy control subjects, in interpreting the emotional meaning of prosodic contours, but that only LHD patients displayed subnormal capacity to perceive linguistic (emphatic) specifications via prosodic cues. The performance of the RHD and LHD patients was also selectively disturbed when certain acoustic properties of the stimuli were manipulated, suggesting that both functional and structural attributes of prosodic patterns may be determinants of prosody lateralization.