Beyond existing prosodic dichotomies: perception of aesthetic prosodic properties of speech and music in a right-hemisphere stroke patient

Speech and music processing impairments have been studied in parallel through the investigation of atomistic features such as pitch and duration and gestalt aspects of emotion. The present study explores another holistic dimension of speech and music prosody here termed ‘expressiveness.’ Novel tasks were designed to investigate whether such hitherto unexplored prosodic aspects of speech and music display processing differences. Five perceptual judgement tasks were employed, two of which involved music and speech stimuli manipulations of ‘expressiveness’. Effort was made to maintain more of their natural acoustic complexity, avoiding manipulations which derive music-like stimuli from speech tokens to artificially match items. We examined the performance of IB, an individual who had a right temporo-parietal lesion with frontal extension and compared his performance with 24 neurotypical controls on these prosodic judgements. IB’s performance was found to be comparable to that of neurotypical controls on a perceptual discrimination task of ‘expressive music prosody’, outperforming one-third of them, whereas he displayed severely impaired performance on ‘expressive speech prosody’. These results suggest that some prosodic elements may be perceived differently across the domains of language and music. Based on other inter-task comparisons, it is also proposed that the interplay among prosodic features such as loudness and duration might lead to different holistic processing between emotional prosody and ‘expressive’ prosodic qualities in the speech domain. Inevitably, the current work only provides preliminary evidence and future research with more patients sharing a lesion profile similar to that of IB is warranted