Right Hemisphere Damaged Patients Research Articles

Knowledge of Scripts Reflected in Discourse of Aphasics and Right-Brain-Damaged Patients

Script knowledge was examined in discourse produced by 15 mildly to moderately impaired aphasics, 15 right-hemisphere-damaged (RHD) subjects, 15 neurological patients without central nervous system damage, and 30 normal controls. Experimental tasks were designed to elicit knowledge of particular scripts, various scripts from a category, metascripts, and plans. The results showed that the brain-damaged patients were able to produce information belonging to a given semantic category of scripts. Disorders demonstrated by both aphasics and RHD patients involved different discourse processes. Aphasics' impairment was mainly connected with discourse macroprocessing. Disturbances in the RHD subjects were found in text structures, contents, and macrostructure. The problems of the probable mechanisms of the observed discourse disturbances were discussed.

Spontaneous gestures following right hemisphere infarct

Neurobehavioral studies of gesturing have been largely limited to left hemisphere damaged (LHD) patients. We compared spontaneous gesturing in seven right hemisphere damaged (RHD) patients, seven LHD patients, and seven normal controls (NHD) during videotaped interviews. Two judges coded symbolic, expressive, grooming, and fidgeting gestures in 120 10-sec intervals of videotape per patient. We found that RHD patients made significantly more total gestures and grooming gestures with the hand ipsilateral to their lesion than did LHD patients. Furthermore, RHD patients made more total and grooming gestures with their right hand than NHD subjects did with either hand. There were no differences in gesture production between the right and left hands of NHD patients. These results suggest that RHD produces enhanced gesturing, particularly involving grooming behavior.

False recovery from auditory hemineglect produced by source misattribution of auditory stimuli (the ventriloquist effect)

Right-hemisphere-damaged (RHD) patients with contralesional neglect in the visual modality (n = 8) were found to differ from normal controls (n = 8), and also from RHD patients without visual neglect (n = 7), in their ability to identify auditory stimuli delivered through a loudspeaker on the left side. When the same stimuli on the left were administered in the presence of a fictitious source of sound (a dummy loudspeaker) visible in the homolesional space, a significant increase in the identification score was obtained (the 'ventriloquist effect'). The result is in keeping with a notion of a strong coupling between auditory and visual systems. It is attributed to the activation by the fictitious stimulus of the audio-visual map in the left hemisphere. We draw attention to the possibility that the symptomatic relief associated with the above effect could be translated into certain clinical gains over time.

Dissociation of autonomic and subjective responses to emotional slides in right hemisphere damaged patients

Autonomic and subjective responses to emotional and neutral slides were studied in patients with right hemisphere damage (RHD), left hemisphere damage (LHD) and normal controls (CON). Orienting and habituation to a series of pure tones (1000 Hz) were also examined. All subjects showed appropriate slide recognition and there were no group differences in subjective ratings. The CON group showed higher skin conductance responses (SCRs) to the emotional slides relative to the neutral slides, while the RHD group showed lower SCRs to both sets of slides. The LHD group showed higher SCRs independent of slide type. The results support the hypothesis (H EILMAN and W ATSON, Handbook of Neurology, Elsevier Science, 1989) that emotional paucity in RHD patients may be related to reduced autonomic arousal. However, there were no significant differences between groups in the orienting response or habituation to loud tones, suggesting that decreased arousal following RHD is not ubiquitous.

MMPI correlates of poststroke neurobehavioral deficits

MMPI profiles of 130 male veterans with cerebrovascular accidents were examined in relation to type and degree of neuropsychological deficit, hemispheric location of lesion, and time poststroke. Three neurobehavioral factors (Verbal, Visuospatial, Sensorimotor) were extracted from the Halstead-Reitan Battery and Wechsler Memory Scale. Canonical analyses revealed verbal impairment to be associated with greater openness in reporting emotional difficulties (Scale F) and limited social facility (Scale Hy). Sensorimotor deficits were associated with anxiety and distress (Pt) in patients with left hemisphere (LHD) but not right hemisphere damage (RHD). Although RHD and LHD patients had similar composite MMPI profiles, neuropsychological deficits in RHD were unrelated to MMPI scores. Time poststroke was independent of MMPI findings in both LHD and RHD samples .

Story processing in right-hemisphere brain-damaged patients

The understanding of stories requires sensitivity to structural aspects of narrative, the emotional content conveyed by the narrative, and the interaction between structural and emotional facets of the story. Right-hemisphere-damaged (RHD) and normal control subjects performed a number of different analytic tasks which probed their competence at story comprehension. Results revealed that RHD subjects perform at a level comparable to that of normal controls with stories that follow a canonical form and that they show few difficulties with structural aspects of narrative. Contrary to expectation, they are strongly influenced by the “interest” level of a story and by other factors that tap emotional sensitivity. Findings are discussed in terms of the processing and arousal mechanisms which may give rise to the observed pattern of difficulties in RHD patients.

Sensitivity to conversational deviance in right-hemisphere-damaged patients

To participate meaningfully in conversation, speakers must be sensitive to statements which advance and those which block the direction of a discourse. The effect of right-hemisphere damage (RHD) on sensitivity to conversational advancers and blockers was investigated by asking subjects to interpret normal conversations and conversations which were blocked by violations of Gricean maxims: specifically, tangential and redundant statements. Results indicate that RHD patients functional normally in canonical, directed conversation. However, they have difficulty interpreting and judging the effect of blocking statements, particularly with regard to tangentiality. The results are discussed in terms of a mental model of directed conversation which incorporates both structural and affective components.

Idiosyncratic word associations following right hemisphere damage

Single oral word associations produced by right-hemisphere-damaged (RHD) stroke patients and age-matched healthy controls were analyzed to assess the right-hemisphere contribution to lexical-semantic processes. RHD patients did not differ from normals in terms of response times, in syntactic class of the response word, or in numbers of errors in response to words drawn from different grammatical categories and words differing in imageability/concreteness. Groups also did not differ in the number of high frequency, popular, associations produced. Despite their apparently intact ability to access high-frequency lexical associates, RHD patients, particularly those with frontal-lobe lesions, also sporadically produced lexical responses that were idiosyncratically related or that were totally unrelated to the stimulus word. An attentional disorder is suggested to explain these pragmatically deviant lexical associations.

THE ROLE OF THE RIGHT HEMISPHERE IN EMOTIONAL COMMUNICATION

Previous research has established that patients with right hemisphere damage (RHD) are impaired in the comprehension of emotional prosody and facial expression. There are several explanations for this impairment. It may reflect defective acoustic and visuospatial analysis, disruption of nonverbal communicative representations, or a disturbance in the comprehension of emotional meaning. In order to examine these hypotheses, we asked RHD patients, left hemisphere damaged patients (LHD) and normal controls (NC) to judge the emotional content of sentences describing nonverbal expressions, and sentences describing emotional situations. We found that RHD subjects performed normally in their ability to infer the emotion conveyed by sentences describing situations. However, RHD patients were impaired in relation to both LHD and NC in the capacity to judge the emotional content of sentences depicting facial, prosodic, and gestural expressions, suggesting a disruption of nonverbal communicative representations.

Autobiographical memory: Influence of right hemisphere damage on emotionality and specificity

This study investigated the ability of right hemisphere damaged (RHD) patients to recall autobiographical material in response to emotional versus nonemotional cues. A modified Crovitz paradigm was used in which patients were asked to recall a specific episode from their own life that related to a cue word. These episodes were rated for emotionality and specificity by independent raters. Patients also rated the emotionality of their own episodes. Independent raters judged the reports of the RHD patients as less specific and less emotional than those of matched nonneurologic control subjects. This was true for episodes in response to emotional as well as nonemotional cue words. RHD patients' own ratings of these episodes, however, did not differ from those of controls. These findings are discussed in terms of RHD patients' overall difficulties in processing emotional material and in terms of the nature of autobiographical memory.

Impaired verbal reasoning and constructional apraxia in subjects with right hemisphere damage

In addition to causing visuospatial deficits, damage to the right cerebral hemisphere also impairs other cognitive abilities, including those requiring higher-order aspects of language. The present study used a standardized test battery to examine the relationship between visuospatial abilities and comprehension of narrative material in subjects having unilateral right hemisphere damage (RHD). In a series of 41 consecutively admitted RHD subjects, impairments in abstracting information from narrative passages were as prevalent and as severe in magnitude as constructional apraxia. Moreover, the extent of the visuospatial and linguistic impairments were highly correlated. Although age, educational levels, and degree of premorbid brain atrophy were all found to influence performance, analysis of a select subgroup of the population established that the covariation of visuospatial and verbal impairments is related to right hemisphere damage per se. Clinically, these findings may be of significance for understanding the pervasive cognitive impairments that are often evidenced by RHD patients.

Thalamic Mechanisms in Language and Rhythm (Temporal Perception and Expression)-Comparison of Cortical and Thalamic Damaged Patients from the Neurobehavioral Aspect

We investigated the relationship between language disturbances and the impairment of rhythmic capabilities (temporal perception & expression) in the patients with thalamic hemorrhage and compared them to patients with cortical lesions to probe the relationship of the thalamus to the mechanism of aphasic symptoms. 101 right-handed individuals, including 12 with thalamic hemorrhage, were studied to analyze language (verbal) and rhythmic (non-verbal) functions. Comparison of left- and right-hemisphere damaged patients revealed significant hypofunction of language and rhythmic capabilities in the group with lesions of left hemisphere. Some correlation could be seen between the rhythm disturbance and the language impairments in terms of severity and types. In contrast, the patients with thalamic hemorrhage showed a dissociation between the severely abnormal rhythm (non-verbal) and milder language (verbal) impairments. The language function values were constantly higher in the cases with thalamic hemorrhage than with cortical damages, while rhythmic capabilities were reduced, a tendency unlike that of the group with cortical damages. These findings suggest that language is primarily a function of the cerebral cortex of the dominant hemisphere, and that the thalamic area, necessary for the timing mechanism (rhythmic function), plays a part in the overall mechanism of aphasic symptomatology.

Characterizing sentence intonation in a right hemisphere-damaged population

Current production studies present a mixed view of right hemisphere-damaged (RHD) patients' ability to produce normal sentence intonation. The present study characterized the sentence intonation of RHD patients, focusing on a greater number of acoustic parameters than past works, and relying on more naturally elicited speech samples through use of a story completion task. Eight RHD speakers and seven nonneurological control subjects produced declarative and imperative sentences as well as yes-no and wh-questions. Slope of F 0 change, linearity of pitch contour, and variance of F 0 points were calculated for each utterance as a whole, as well as for the preterminal and the terminal contour separately. RHD contours were less linear and flatter in F 0 decline than normal controls for the declarative sentences. The patients' yes-no questions also differed from normal productions, displaying smaller F 0 dispersion around a mean F 0. Preterminal range values were more restricted for patients' utterances of yes-no questions, while terminal properties between groups differed for three of the four sentence types examined. The present results suggest some disturbance in the patients' ability to manipulate fundamental frequency across sentential domains. These data are discussed in terms of current theories of a general dysprosody in RHD patients.

Block constructions of chronic alcoholic and unilateral brain-damaged patients: A test of the right hemisphere vulnerability hypothesis of alcoholism

A detailed analysis of the block construction performance of chronic alcoholics, unilateral brain-damaged patients, and normal control subjects was conducted to test two hypotheses: (a) that alcoholics perform similarly to right-hemisphere damaged (RHD) patients but not left-hemisphere damaged (LHD) patients; and (b) that unilateral brain-damaged patients display qualitatively different strategies and errors. Differences in performance without a time limit and broken configuration errors suggest that the alcoholics have not incurred the type of visuospatial impairment characteristic of RHD patients. The LHD and RHD patients showed qualitative differences in their strategies and errors. Implications of the findings for research and clinical assessment of visuospatial dysfunction are discussed.

An overview of changes in fundamental frequency associated with cortical insult

Abstract Recent acoustic analyses of fundamental frequency contours of both lef hemisphere damaged aphasic patients and right-hemisphere damaged non-aphasic patients have provided new data to further our understanding of brain and language mechanisms. The literature, however, is complex and even, in certain aspects, somewhat contradictory. This article attempts to assess the present ‘state-of-the-art’ of such studies, in order to provide a framework for directing future research.

Comprehension of familiar phrases by left- but not by right-hemisphere damaged patients

Single words, familiar phrases (idioms and speech formulas), and novel sentences (matched to the familiar phrases in length, frequency, and structure) were selected for a picture-matching auditory comprehension task and administered to left- and right-brain damaged (LBD, RBD) subjects. The groups did not differ in single word comprehension. A 2 × 2 ANOVA revealed opposite patterns on the two other tasks, with LBD subjects performing worse on novel than familiar phrases, and RBD subject impaired on familiar phrase but not on novel sentence comprehension. The role of grammatical/referential vs. holistic/inferential meaning in left and right hemisphere function is discussed.

Intonational variability in the speech of right-hemisphere damaged patients

Intonational variability in the speech of right-hemisphere damaged patients

The neurological substrates for prosodic aspects of speech

The ability to comprehend and produce the stress contrast between noun compounds and noun phrases (e.g., gréenhouse vs. green hóuse) was examined for 8 nonfluent aphasics, 7 fluent aphasics, 7 right hemisphere damaged (RHD) patients, and 22 normal controls. The aphasics performed worse than normal controls on the comprehension task, and the RHD group performed as well as normals. The ability to produce stress contrasts was tested with a sentence-reading task; acoustic measurements revealed that no nonfluent aphasic used pitch to distinguish noun compounds from phrases, but two used duration. All but one of the RHD patients and all but one of the normals produced pitch and/or duration cues. These results suggest that linguistic prosody is processed by the left hemisphere and that with brain damage the ability to produce pitch and duration cues may be dissociated at the lexical level.

Comprehension of humorous and nonhumorous materials by left and right brain-damaged patients

Right hemisphere-damaged (RHD) and left hemisphere-damaged (LHD) aphasic patients were tested on a nonverbal cartoon completion task that included a humorous (Joke) and a nonhumorous (Story) condition. In both conditions, RHD patients performed worse than LHD patients. More importantly, the qualitative difference between the errors produced by the two groups suggests that right and left hemisphere brain damage impairs different components of narrative ability. RHD patients showed a preserved sensitivity to the surprise element of humor, and a diminished ability to establish coherence. Conversely, LHD patients, when they erred, showed an impaired sensitivity to the surprise element of humor, and a preserved ability to establish coherence by integrating content across parts of a narrative. These results suggest that the observed humor comprehension deficits of RHD patients result specifically from right hemisphere disease and not from brain damage irrespective of locus. The performances of the RHD and LHD patient groups together support a separation of narrative ability from the traditional aspects of language ability typically disrupted in aphasia.

Inference deficits in right brain-damaged patients

The inferential reasoning ability of right hemisphere-damaged (RHD) patients was tested by presenting pairs of sentences which were to be treated as single, integrated units. The two sentences treated together made one interpretation likely (a correct inference); one of the sentences in isolation encouraged a different interpretation (an incorrect inference). The position of the misleading sentence was systematically varied. Results showed that, in contrast to normal controls, RHD patients have more trouble answering inference questions, especially those concerning incorrect inferences, than answering questions about the factual content of the passages. Also, RHD patients made significantly more errors when the misleading information was contained in the first rather than in the second sentence; this finding indicates that these patients have difficulty revising previously acquired knowledge in light of new information. These results suggest the impairment of several components of normal discourse processing subsequent to right hemisphere brain damage.