Right Hemisphere Damage Research Articles

The access and processing of familiar idioms by brain-damaged and normally aging adults.

Idiom interpretation tasks are routinely used in the clinical evaluation of adults with brain damage, and idiom processing has received increasing attention in the psycholinguistic literature. Clinical evidence suggests that adults with unilateral right-hemisphere damage (RHD) are insensitive to nonliteral meanings conveyed by idiomatic expressions and other figurative forms. However, this portrayal is derived from their terminal responses to tasks that reflect multiple aspects of mental operations (off-line measures), obscuring the source of poor performance. This study used an on-line word-monitoring task to assess RHD, left-hemisphere-damaged, and normally aging adults' implicit knowledge of familiar idiomatic expressions. Brain-damaged subjects performed similarly to normal controls on this task, even though the clinical subjects fared poorly by comparison on an off-line idiom definition measure. These results suggest that adults with unilateral brain damage can activate and retrieve familiar idiomatic forms, and that their idiom-interpretation deficits most likely reflect impairment at some later stage of information processing. Further, error analysis of idiom-definition performance did not support the customary characterization of RHD adults as excessively literal responders. The paper discusses clinical implications of the nature and use of idiom interpretation tasks.

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.

Language development after unilateral brain injury

This longitudinal study describes the growth of syntactic abilities and vocabulary size in nine children with unilateral antepartum or perinatal brain injury. Five children with left hemisphere damage (LHD) and four with right hemisphere damage (RHD), ages 15 to 48 months, were evaluated on three or more occasions. Language samples generated from parent-child interaction were transcribed, coded, and analyzed using the Child Language Data Exchange System. Individual growth trajectories were constructed by graphing three dependent variables—MLU, scores on the Index of Productive Syntax (IPSYN), and number of different words—as a function of the child's age. One subject remained in a prelinguistic stage throughout the study. Simple linear functions best described the growth of MLU, IPSYN scores, and vocabulary in the other eight children. The slopes of the individual growth trajectories, the graphic representations of rates of progress, were comparable in the eight children. Seven children showed developmental delays in initial word use and five in the onset of multiword utterances. However, by age 24 months, four children with LHD and two children with RHD had syntactic capabilities comparable to those of children without brain injuries. The developmental patterns suggested that both cerebral hemispheres may play critical roles in the very earliest stages of language acquisition. Some unilateral lesions caused little discernible effect on language outcome in the toddler-preschool years after the initial developmental delays.

Fluidity theory and neuropsychological impairment in alcoholism

In order to determine whether the "classic" alcoholic WAIS pattern is the result of right hemisphere damage or the loss of fluid intelligence abilities, right-hemisphere damaged, left-hemisphere damaged, alcoholic, and control groups of 40 subjects each were matched on the variables of age and education. They were administered the WAIS-Revised (WAIS-R) and four sensory and motor measures that were sensitive to lateralized damage but not to fluidity. The alcoholic group showed the "classic" pattern of a lower performance than verbal WAIS IQ. Although the left hand scores on the sensory and motor tests were significantly more impaired than the right hand scores for the right-hemisphere damaged group they were not for the alcoholic group. These results did not support the right hemisphere theory. Rather, as indicated by further analysis, the pattern is most adequately explained by the fluidity theory.

Fluidity theory and neuropsychological impairment in alcoholism

In order to determine whether the “classic” alcoholic WAIS pattern is the result of right hemisphere damage or the loss of fluid intelligence abilities, right-hemisphere damaged, left-hemisphere damaged, alcoholic, and control groups of 40 subjects each were matched on the variables of age and education. They were administered the WAIS-Revised (WAIS-R) and four sensory and motor measures that were sensitive to lateralized damage but not to fluidity. The alcoholic group showed the “classic” pattern of a lower performance than verbal WAIS IQ. Although the left hand scores on the sensory and motor tests were significantly more impaired than the right hand scores for the right-hemisphere damaged group they were not for the alcoholic group. These results did not support the right hemisphere theory. Rather, as indicated by further analysis, the pattern is most adequately explained by the fluidity theory.

Efficacy of the Satz-Mogel short form WAIS—R for tumor patients with lateralized lesions.

The ability of the Satz and Mogel (1962) short form WAIS-R to provide equivalent information about IQ scores and age-corrected scale scores was examined as a function of side of lesion for 34 left hemisphere damaged (LHD) and 29 right hemisphere damaged (RHD) patients having primary brain tumors

Clinical validity of the speech-sounds perception test and the seashore rhythm test

The interpretive significance of the Speech-Sounds Perception Test (SSPT) and the Seashore Rhythm Test (SRT) was evaluated through literature review and empirical investigations. Subjects were 43 pseudoneurologic controls and 81 brain-damaged persons, divided into subgroups of subjects with left-hemisphere damage (n = 20), diffuse brain damage (n = 31), and right-hemisphere damage (n = 30). Our data indicate that the SSPT and SRT failed to discriminate left- and right-hemisphere damage. Furthermore, discriminant analyses demonstrated that these tests make no unique diagnostic contribution within the context of a neuropsychological battery. We question whether these tests should be routinely used.

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.

Computer management of automatic psychophysiological data: EEG, BP and EDA

Speculations about the neural substrates of hypnosis have often focused on the right hemisphere (RH), implying that RH damage should impair hypnotic responsiveness more than left-hemisphere (LH) damage. The present study examined the performance of a patient who suffered a stroke destroying most of his LH, on slightly modified versions of two hypnotizability scales. This patient was at least modestly hypnotizable, as indicated in particular by the arm rigidity and age regression items, suggesting that hypnosis can be mediated by the RH alone – provided that the language capacities normally found in the LH remain available. A further study of 16 patients with unilateral strokes of the LH or RH found no substantial differences in hypnotizability between the two groups. Future neuropsychological studies of hypnosis might explore the dorsal/ventral or anterior/posterior dichotomies, with special emphasis on the role of prefrontal cortex.

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.

Early lexical development in children with focal brain injury

Early lexical development in 27 children with focal brain injury was studied cross-sectionally and longitudinally. Data were obtained from children between 12 and 35 months of age who acquired their lesion prenatally or within the first 6 months of life. Results for the group as a whole provide clear evidence for delays in lexical comprehension and production, and for a larger number of comprehension/production dissociations than would be expected by chance. In addition, a significant number of children were observed having unusual difficulty mastering predication and/or using an atypically high proportion of closed class words (suggesting reliance on holistic/formulaic speech). Analyses by lesion type revealed no effect of lesion size. Analyses according to side of lesion revealed that children with right-hemisphere damage produced a higher proportion of closed class words, suggesting heavy reliance on well-practiced but under-analyzed speech formulae. Children with left-hemisphere damage were slightly better in comprehension than children with right-hemisphere damage. In addition, left posterior lesions were associated with greater delays in expressive language, and delays were more protracted in children with left posterior damage. No differential effects of left posterior damage were found for lexical comprehension.

Reference, sense and antonymy in the assessment of lexical semantic abilities in aphasia

Abstract Lexical semantic abilities in aphasia and following right-hemisphere damage were investigated. The performance of subject groups was examined across reference and sense tasks. Reference tasks involve matching a word to some extra-linguistic entity. Sense tasks involve intra-linguistic relations. The sense relation of antonymy was studied in detail and the hierarchy of difficulty across six antonym subclasses was established. Sense tasks were found to be more effective in differentiating aphasic fron non-aphasic groups. No evidence was found of differential impairments of lexical semantic processing across fluent and non-fluent forms of aphasia. The right-hemisphere-damaged group showed no evidence of lexical deficits on the convergent semantic tasks used in this study.

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.

Neuropsychological Characteristics of Right Hemisphere Damage: Investigation by Attention Tests, Concept Formation and Change Test, and Self-evaluation Task.

Neuropsychological Characteristics of Right Hemisphere Damage: Investigation by Attention Tests, Concept Formation and Change Test, and Self-evaluation Task.

Re-Evaluating the Effect of Unilateral Brain Damage on Simple Reaction Time to Auditory Stimulation

Results of a previous experiments designed to test if there is a right hemisphere superiority over the left hemisphere in the capacity to react quickly to a stimulus have not lead to an unambiguous conclusion, although the majority of studies indicate that right-brain-damaged pa tients are generally slower than left-brain-damaged patients. The present experiment re-examines the speed of reaction time to auditory stimulation in a population of brain-damaged patients. Each case was presented with 120 auditory events and variable inter-trial intervals (from 1 s to 15 s). To ensure homogeneity of the population tested, only patients with a cerebro-vascular accident were chosen. The results show that the right-brain-damaged patients were not generally slower than left-brain-damaged patients. However, a marked deterioration in performance over time was observed in the right-hemisphere group while a small amount of improvement was found in the normal and left-brain-damaged patients. The outcome is discussed in terms of a sustained attention deficit associated with right-hemisphere damage.

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.

Beyond scripts: A note on the capacity of right hemisphere-damaged patients to process social and emotional content

Individuals with right hemisphere damage (RHD) can comprehend simple scripts but have difficulties understanding more complex forms of discourse such as stories and jokes. This study sought to discover the point beyond simple scripts at which such patients begin to experience difficulties. Three-sentence, script-like vignettes which described everyday situations were created along two major dimensions: a social dimension (reflecting presence or absence of interactions between characters); and an emotional dimension (reflecting a positive, negative, or neutral emotion felt by a protagonist in the situation). Right hemisphere-damaged patients were asked to provide emotional characterizations of, and continuations to, these situational vignettes. Results indicated that individuals with right hemisphere damage were more likely than control subjects to attribute a positive emotional state to a character in a neutral situation. In other respects, there were no significant differences between RHD subjects and controls, although the RHD subjects made significantly more factual errors in their continuations than did control subjects.

Components of neglect from right-hemisphere damage: An analysis of line bisection

Two versions of a line bisection task were given to patients with posterior right-hemisphere damage and normal control subjects. One, which we refer to as the directed-manual task, was the traditional bisection task in which lines were transected with a pen held in the right hand. In the other task, referred to as the directed-visual task, subjects observed the experimenter move a pen along a line from right-to-left (the left-scan task) or from left-to-right (the right-scan task) and they verbally indicated the subjective midpoint. Patients showed significant left neglect in the manual and the left-scan tasks only. Controls showed no consistent biases and no influence of scanning direction. Right and left cues biased bisection for both groups. The results indicate that when the directed manual response is eliminated, scan direction determined the presence or absence of neglect on bisection. The findings are discussed in terms of the efficiency of visual orienting.

Sensitivity to eye gaze in prosopagnosic patients and monkeys with superior temporal sulcus ablation

Accuracy at perceiving frontal eye gaze was studied in monkeys and human subjects using a forced-choice detection task on paired photographs of a single human face. Monkeys learned the task readily, but after bilateral removal of the banks and floor of the superior temporal sulcus (STS) they failed to perform the task efficiently. This result is consistent with the conclusion, based on recordings from single cells in awake, behaving monkeys [P erret et al., Physiological Aspects of Clinical Neuro-ophthalmology, Chapman & Hall, London, 1988] that this region of the temporal lobe is important for coding information about eye-gaze of a confronting animal. Human subjects were given identical stimuli in a task where they were asked to detect “the face that is looking straight at you”. Human performance is sensitive to the degree of angular deviation from the frontal gaze position, being poorest at small angular deviations from 0°. This was also true of monkeys viewing these stimuli, pre- and post-operatively. Compared with normal controls, two human prosopagnosics were impaired at this task. However the extent of impairment was different in the two patients. These findings are related to earlier reports (including those for patients with right-hemisphere damage without prosopagnosia), to normal performance with upright and inverted face photographs, and to notions of independent subsystems in face processing.