The analytic/holistic distinction applied to the speech of patients with hemispheric brain damage

The emotional basis of linguistic and nonlinguistic intonation: implications for hemispheric specialization

Clinical and experimental studies suggest that the right cerebral hemisphere is dominant for intonation or the "melody of language." In light of this brain-behavior correlation, an assessment of intonation is a useful adjunct of the linguistic, cognitive, and neurological evaluation of patients with brain damage. However, the neural basis of intonation is controversial. This article examines 1 of the unresolved issues--the hypothesis that emotional versus linguistic categories of intonation are lateralized to the opposite hemispheres. A review of linguistic and neurobehavioral evidence fails to support the claim that intonation is divided into dichotomous categories. Linguistic analysis suggests that even intonation patterns traditionally described as nonemotional have their underpinnings in the speaker's emotions. Similarly, studies of adults and children with brain damage indicate that intonation patterns described as either linguistic or emotional are mediated by right-hemisphere substrate specialized for emotional experience. The cross-disciplinary findings support a general right-hemisphere hypothesis that unifies linguistic and emotional uses of intonation in children and adults. Implications of the hypothesis are discussed in relation to the diagnosis of developmental disorders, with special attention to the problem of identifying language impairment in infants and toddlers.

The temporal organization of affective and non-affective speech in patients with right-hemisphere infarcts

To evaluate the right hemisphere's role in encoding speech prosody, an acoustic investigation of timing characteristics was undertaken in speakers with and without focal right-hemisphere damage (RHD) following cerebrovascular accident. Utterances varying along different prosodic dimensions (emphasis, emotion) were elicited from each speaker using a story completion paradigm, and measures of utterance rate and vowel duration were computed. Results demonstrated parallelism in how RHD and healthy individuals encoded the temporal correlates of emphasis in most experimental conditions. Differences in how RHD speakers employed temporal cues to specify some aspects of prosodic meaning (especially emotional content) were observed and corresponded to a reduction in the perceptibility of prosodic meanings when conveyed by the RHD speakers. Findings indicate that RHD individuals are most disturbed when expressing prosodic representations that vary in a graded (rather than categorical) manner in the speech signal (Blonder, Pickering, Heath et al., 1995; Pell, 1999a).

Fundamental frequency encoding of linguistic and emotional prosody by right hemisphere-damaged speakers

To illuminate the nature of the right hemisphere's involvement in expressive prosodic functions, a story completion task was administered to matched groups of right hemisphere-damaged (RHD) and nonneurological control subjects. Utterances which simultaneously specified three prosodic distinctions (emphatic stress, sentence modality, emotional tone) were elicited from each subject group and then subjected to acoustic analysis to examine various fundamental frequency (F(0)) attributes of the stimuli. Results indicated that RHD speakers tended to produce F(0) patterns that resembled normal productions in overall shape, but with significantly less F(0) variation. The RHD patients were also less reliable than normal speakers at transmitting emphasis or emotional contrasts when judged from the listener's perspective. Examination of the results across a wide variety of stimulus types pointed to a deficit in successfully implementing continuous aspects of F(0) patterns following right hemisphere insult.

Gestalt laws of perceptual organization in an embedded figures task: evidence for hemispheric specialization

An embedded figures task was used to investigate hemispheric specialization for visual parsing. Error data from 40 normal right-handed males revealed a right-hemisphere advantage for parsing governed by the Gestalt laws of organization. In contrast, for parsing that violated those laws, subjects who could perform such parsing at better-than-chance levels showed a left-hemisphere advantage. A simple left hemisphere/analytic, right hemisphere/holistic dichotomy is too ambiguous to account for the results, because it fails to specify the level of visual structure (e.g. whole figures, intermediate components, or elementary segments) that is to be taken as a reference point for defining particular tasks as analytic or holistic; what is analytic from one point of view is holistic from another. We focus instead on principles of perceptual organization that characterize the results of perceptual processing, regardless of whether those results are seen as the outcome of analytic or holistic processing.

Clausal intonation after unilateral brain damage

Thirteen right-handed adult speakers, including five patients with unilateral left-hemisphere damage, four patients with unilateral right-hemisphere damage, and four patients with non-neurological damage, read aloud sentences designed to test influences of clause and utterance length on two acoustical measures of intonation, fundamental voice frequency ( Fo) and timing. Patients with unilateral damage to the left-hemisphere exhibited more abnormality in Fo and speech timing than did patients with right-hemisphere damage.