The role of the right hemisphere in the control of speech prosody in propositional and affective contexts

Sixteen right-handed adult males with localized insult to either the right or left hemisphere and five control subjects without brain damage read aloud target sentences embedded in paragraphs, while intoning their voices in either a declarative, interrogative, happy, or sad mode. Acoustical analysis of the speech wave was performed. Right-anterior (pre-Rolandic) and right-central (pre- and post-Rolandic) brain-damaged patients spoke with less pitch variation and restricted intonational range across emotional and nonemotional domains, while patients with right posterior (post-Rolandic) damage had exaggerated pitch variation and intonational range across both domains. No such deficits were found in patients with left posterior damage, whose prosody was similar to that of normal control subjects. It is suggested that damage to the right hemisphere alone may result in a primary disturbance of speech prosody that may be independent of the disturbances in affect often noted in right-brain-damaged populations.     

The effects of right and left hemiparkinsonism on prosody

Recent studies show right hemisphere dominance in the mediation of emotional prosody and left hemisphere contribution to linguistic prosody in patients with cortical injury. The present study investigated emotional and linguistic functions of prosody as well as facial and musical processing in 21 patients with lateralized subcortical disease. Fourteen right hemiparkinsonians (RPD) and 7 left hemiparkinsonians (LPD) were compared to 17 normal controls (NC). Patients were impaired on receptive and expressive tests of emotional and linguistic prosody. Patients were also selectively impaired on emotional processing of facial stimuli and in the musical processing of pitch and tonal memory, though not timber. These findings suggest that monotone speech reported in PD is of multimodal origins and may involve dysfunction in neural centers involved in emotional and linguistic processing. There were no differences between RPD and LPD groups in the pattern of deficits, suggesting bilateral involvement in emotional processing at the subcortical level.     

Neurodevelopmental differences in emotional prosody in normal children and children with left and right temporal lobe epilepsy

Emotional prosody, which has been defined as the emotional aspects of speech which communicate pleasure, fear, sorrow, anger, etc., has been demonstrated to be primarily a function of the nondominant hemisphere (typically, the right hemisphere) in adult populations. However, few researchers have addressed the developmental or lateralized nature of emotional prosody in children. In this study, an instrument was developed to measure the receptive aspects of emotional prosody in pediatric populations and administered to normal children ages 6 to 11 years old. An analysis of variance revealed significant age-related differences. Additionally, the instrument was administered to 12 children with right temporal lobe epilepsy and 11 children with left temporal lobe epilepsy. Analysis of variance indicated that there was no significant difference in scores between the left temporal and right temporal lobe groups. However, right temporal epileptic patients scored significantly lower than normal children on all sections of the instrument, suggesting that in children like adults, the right temporal lobe may be dominant with respect to the receptive aspects of emotional prosody.     

Training of School Psychologists in Neuropsychology and Brain Injury: Results of a National Survey of Training Programs

A previous study evaluating receptive language after unilateral brain damage in childhood hypothesized lateralized attention and memory deficits without direct measurement. Our study directly measured attention, memory, and language in order to evaluate empirically the severity and laterality of sequelae. The performances of 11 individuals with a unilateral ischemic-lesion (7 right and 4 left hemisphere) were compared to controls matched on age, sex, and socioeconomic status. Results suggest subtle but persistent deficits in verbal memory, functional memory, and speed of processing after a lesion to either hemisphere. Lesions sustained before two years of age were associated with the lowest IQ scores. Our findings provide support for a configural representation of language that can to some extent compensate for inefficient or damaged components (Bates, 1994), and the middle-ground lateralization position (Thal et al., 1991) that asserts initial hemispheric specialization with the potential for reorganization.     

Attention,Memory, and Language after Pediatric Ischemic Stroke

A previous study evaluating receptive language after unilateral brain damage in childhood hypothesized lateralized attention and memory deficits without direct measurement. Our study directly measured attention, memory, and language in order to evaluate empirically the severity and laterality of sequelae. The performances of 11 individuals with a unilateral ischemic-lesion (7 right and 4 left hemisphere) were compared to controls matched on age, sex, and socioeconomic status. Results suggest subtle but persistent deficits in verbal memory, functional memory, and speed of processing after a lesion to either hemisphere. Lesions sustained before two years of age were associated with the lowest IQ scores. Our findings provide support for a configural representation of language that can to some extent compensate for inefficient or damaged components (Bates, 1994), and the middle-ground lateralization position (Thal et al., 1991) that asserts initial hemispheric specialization with the potential for reorganization.     

The laterality of dreaming

The cortical locus of dream generation could be lateralized to the right or left hemisphere, or be bilaterally represented with either equal or unequal contributions from each hemisphere. In this paper we review the neurological literature for cases of loss or alteration of dream report after brain damage. The distribution of lesion sites is used to test the various hypotheses concerning the laterality of dreaming. The hypothesis receiving best support is that dreaming is lateralized to the left hemisphere in individuals with typical neurologic organization.     

From the left to the right: How the brain compensates progressive loss of language function

In normal right-handed subjects language production usually is a function oft the left brain hemisphere. Patients with aphasia following brain damage to the left hemisphere have a considerable potential to compensate for the loss of this function. Sometimes, but not always, areas of the right hemisphere which are homologous to language areas of the left hemisphere in normal subjects are successfully employed for compensation but this integration process may need time to develop. We investigated right-handed patients with left hemisphere brain tumors as a model of continuously progressive brain damage to left hemisphere language areas using functional neuroimaging and transcranial magnetic stimulation (TMS) to identify factors which determine successful compensation of lost language function. Only patients with slowly progressing brain lesions recovered right-sided language function as detected by TMS. In patients with rapidly progressive lesions no right-sided language function was found and language performance was linearly correlated with the lateralization of language related brain activation to the left hemisphere. It can thus be concluded that time is the factor which determines successful integration of the right hemisphere into the language network for compensation of lost left hemisphere language function.     

听觉障碍人群的言语机制

对听觉障碍人群言语机制的研究,提供了独特的视角来探讨人脑内语言专门化系统的组织。该回顾了近年来在该领域内进行的损伤研究及功能性成像研究,着重综述了三个问题：(1)左右半球损伤造成的手语失语症的特点;(2)手语加工过程中左右半球的激活模式;(3)先天聋被试在阅读唇语过程中的脑内激活模式及后部扣带皮层在唇语阅读过程中的可能作用。     

Communicative deficits in agenesis of the corpus callosum: nonliteral language and affective prosody

While some individuals with agenesis of the corpus callosum can perform normally on standardized intelligence tests, clinical observations suggest that they nevertheless have deficits in the domains of fluid and social intelligence. Particularly important for social competence is adequate understanding and use of paralinguistic information. This study examined the impact of callosal absence on the processing of pragmatic and paralinguistic information. Young adult males with agenesis of the corpus callosum (ACC) were evaluated in the areas of nonliteral language comprehension, proverb recognition and interpretation, and perception of affective prosody. Ten ACC individuals with normal Wechsler IQ were compared to 14 sex, age, and IQ matched normal controls. The Formulaic and Novel Language Comprehension Test (FANL-C), Gorham Proverbs Test, and LA Prosody Test were administered. ACC subjects exhibited significant impairment on the nonliteral items of the FANL-C, but no significant difference from controls in comprehension of literal items. ACC subjects also exhibited significant deficits in both self-generated interpretation and recognition of proverb meaning, and in recognition of affective prosody. These results demonstrate that normally intelligent individuals with ACC are impaired in the understanding of nonliteral language and emotional-prosodic cues that are important in social communication. In all three tests, the performance of individuals with ACC was similar to patients with right hemisphere brain damage. Thus, persons with ACC appear to lack interhemispheric integration of critical aspects of language processed by the right hemisphere.     

Kinematic analysis of limb movements in neuropsychological research: subtle deficits and recovery of function

In this brief review, we argue that a detailed analysis of the spatial and temporal characteristics of visually guided limb movements can provide important insights into the nature of neuropsychological deficits and the functional organization of the brain. In particular, we will show how kinematic analysis of a simple aiming movement can reveal differences that might not be apparent clinically in the behaviour of patients with unilateral brain lesions. We will argue that the subtle but distinctive deficits that follow damage to the left or right hemisphere can be related to the clinical syndromes of manual apraxia and hemispatial neglect, respectively. The fact that these deficits are apparent only with kinematic analysis demonstrates the potential of these techniques for evaluating recovery of function.     

Lateralization of visuospatial attention across face regions varies with emotional prosody

It is well-established that linguistic processing is primarily a left-hemisphere activity, while emotional prosody processing is lateralized to the right hemisphere. Does attention, directed at different regions of the talker’s face, reflect this pattern of lateralization? We investigated visuospatial attention across a talker’s face with a dual-task paradigm, using dot detection and language comprehension measures. A static image of a talker was shown while participants listened to speeches spoken in two prosodic formats, emotional or neutral. A single dot was superimposed on the speaker’s face in one of 4 facial regions on half of the trials. Dot detection effects depended on emotion condition—in the neutral condition, discriminability was greater for the right-, than for the left-, side of the face image, and at the mouth, compared to the eye region. The opposite effects occurred in the emotional prosody condition. The results support a model wherein visuospatial attention used during language comprehension is directed by the left hemisphere given neutral emotional prosody, and by the right hemisphere given primarily negative emotional prosodic cues.     

The Effects of Brain Lateralization on Motor Control and Adaptation

ABSTRACT

Lateralization of mechanisms mediating functions such as language and perception is widely accepted as a fundamental feature of neural organization. Recent research has revealed that a similar organization exists for the control of motor actions, in that each brain hemisphere contributes unique control mechanisms to the movements of each arm. The authors review present research that addresses the nature of the control mechanisms that are lateralized to each hemisphere and how they impact motor adaptation and learning. In general, the studies suggest an enhanced role for the left hemisphere during adaptation, and the learning of new sequences and skills. The authors suggest that this specialization emerges from a left hemisphere specialization for predictive control—the ability to effectively plan and coordinate motor actions, possibly by optimizing certain cost functions. In contrast, right hemisphere circuits appear to be important for updating ongoing actions and stopping at a goal position, through modulation of sensorimotor stabilization mechanisms such as reflexes. The authors also propose that each brain hemisphere contributes its mechanism to the control of both arms. They also discuss the potential advantages of such a lateralized control system.     

The role of the cerebral hemispheres in music.

This review examines the cerebral control of musical behaviors. In clinical populations, impairment of related musical and linguistic functions, such as reading, writing, articulation, time sense, and prosody, implies the likely role of the language hemisphere in music. Similarly, for both clinical and normal populations, an investigation of mental abilities common to music and language points to left hemisphere control for certain aspects of temporal order, duration, simultaneity, rhythm, effector motor control, and categorical perception. While clinical studies have revealed deficits in various kinds of music capabilities with both left and right cerebral lesions, normal subjects similarly demonstrate varying degrees of asymmetry for components of music emphasizing pitch, harmony, timbre, intensity, and rhythm. Since differential laterality effects are apparent as a function of subjects' training or adopted strategies, the way musical information is processed may be an important determinant of hemispheric mediation. One hemisphere should not be regarded as “dominant” for music, but rather each interacts with the other, operating according to its own specialization.     

Processing of basic speech acts following localized brain damage: a new light on the neuroanatomy of language

We examined the effect of localized brain lesions on processing of the basic speech acts (BSAs) of question, assertion, request, and command. Both left and right cerebral damage produced significant deficits relative to normal controls, and left brain damaged patients performed worse than patients with right-sided lesions. This finding argues against the common conjecture that the right hemisphere of most right-handers plays a dominant role in natural language pragmatics. In right-hemisphere damaged patients, there was no correlation between location and extent of lesion in perisylvian cortex and performance on BSAs. By contrast, processing of the different BSAs by left hemisphere-damaged patients was strongly affected by perisylvian lesion location, with each BSA showing a distinct pattern of localization. This finding raises the possibility that the classical left perisylvian localization of language functions, as measured by clinical aphasia batteries, partly reflects the localization of the BSAs required to perform these functions.     

Cerebral mechanisms for understanding emotional prosody in speech

Hemispheric contributions to the processing of emotional speech prosody were investigated by comparing adults with a focal lesion involving the right (n = 9) or left (n = 11) hemisphere and adults without brain damage (n = 12). Participants listened to semantically anomalous utterances in three conditions (discrimination, identification, and rating) which assessed their recognition of five prosodic emotions under the influence of different task- and response-selection demands. Findings revealed that right- and left-hemispheric lesions were associated with impaired comprehension of prosody, although possibly for distinct reasons: right-hemisphere compromise produced a more pervasive insensitivity to emotive features of prosodic stimuli, whereas left-hemisphere damage yielded greater difficulties interpreting prosodic representations as a code embedded with language content.     

Temporal integration of speech prosody is shaped by language experience: an fMRI study

Differences in hemispheric functions underlying speech perception may be related to the size of temporal integration windows over which prosodic features (e.g., pitch) span in the speech signal. Chinese tone and intonation, both signaled by variations in pitch contours, span over shorter (local) and longer (global) temporal domains, respectively. This cross-linguistic (Chinese and English) study uses functional magnetic resonance imaging to show that pitch contours associated with tones are processed in the left hemisphere by Chinese listeners only, whereas pitch contours associated with intonation are processed predominantly in the right hemisphere. These findings argue against the view that all aspects of speech prosody are lateralized to the right hemisphere, and promote the idea that varying-sized temporal integration windows reflect a neurobiological adaptation to meet the 'prosodic needs' of a particular language.     

音高模式加工的大脑偏侧化研究

作为一种超音段成分,音高在言语的理解和产生过程中承担着重要作用,这些作用主要包括:区别不同声调的词汇意义,区别陈述、疑问等不同的语调,标志话语的情绪色彩等。音段、语义和句法信息的加工具有左脑优势,但音高模式加工的单侧优势及其机制还存在很多争论,本文从音高模式加工的两个主要理论———功能假设和声音信号假设出发,对相关研究加以评述。     

Hemispheric processing of affective and linguistic intonation contours in normal subjects

In a previous study of the comprehension of linguistic prosody in brain-damaged subjects, S. R. Grant and W. O. Dingwall (1984. The role of the right hemisphere in processing linguistic prosody, presentation at the Academy of Aphasia, 1984) demonstrated that the right hemisphere (RH) of nonaphasic patients plays a prominent role in the processing of stress and intonation. The present study examines laterality for affective and linguistic prosody using the dichotic listening paradigm. Both types of prosody elicited a significant left ear advantage. This advantage was more pronounced for affective than for linguistic prosody. These findings strongly support previously documented evidence of RH involvement in the processing of affective prosody (R. G. Ley & M. P. Bryden, 1982. A dissociation of right and left hemispheric effects for recognizing emotional tone and verbal content, Brain and Cognition, 1, 3-9). They also provide support for the previously mentioned demonstration of RH involvement in the processing of linguistic intonation (S. Blumstein & W. E. Cooper, 1974. Hemispheric processing of intonation contours, Cortex, 10, 146-158; Grant & Dingwall, 1984).     

The sad, the angry, and the asymmetrical brain: dichotic listening studies of negative affect and depression

Dichotic Listening (DL) is a valuable tool to study emotional brain lateralization. Regarding the perception of sadness and anger through affective prosody, the main finding has been a left ear advantage (LEA) for the sad but contradictory data for the anger prosody. Regarding an induced mood in the laboratory, its consequences upon DL were a diminished right ear advantage (REA) for the induction of sadness and an increased REA for the induction of anger. The global results fit with the approach-withdrawal motivational model of emotional processing, pointing to sadness as a right hemisphere emotion but anger processed bilaterally or even in the left hemisphere, depending on the subject's preferred mode of expression. On the other hand, the study of DL in clinically depressed patients found an abnormally larger REA in verbal DL tasks which was predictive of therapeutic pharmacological response. However, the mobilization of the available left hemisphere resources in these responders (reflected in a higher REA) would indicate a remission of the episode but would not assure the absence of new relapses.     

Lesion localization in acquired deficits of emotional expression and comprehension

This study investigated the relationship between intrahemispheric location of lesion and disturbances of emotional expression and comprehension. Twenty-eight right hemisphere strokes, 18 left hemisphere strokes, and 20 controls were examined on a standardized test of the expression, repetition, and comprehension of emotional prosody as well as the visual recognition of emotional situations and faces. The patients were classified into aprosodic syndromes according to the test scores. The lesions were independently traced, and overlapped for each aprosodic syndrome. The results, for lesions in either hemisphere, indicated involvement of the basal ganglia most frequently in aprosodic syndromes followed by anterior temporal lobe and insula lesions. Basal ganglia damage was also seen most frequently in patients with impaired comprehension of emotional facial expressions and situations. The anterior temporal lobe was also frequently involved in patients with such deficits. The basal ganglia emerged as a structure of particular importance in the mediation of emotional expression and comprehension.