Hemispheric contributions to pragmatics

Twenty-seven patients with right-hemisphere damage (RBD) and thirty-one patients with left-hemisphere damage (LBD) received a new pragmatics battery in Hebrew consisting of two parts: (1) comprehension and production of basic speech acts (BSAs), including tests of assertions, questions, requests, and commands, and (2) comprehension of implicatures, including implicatures of quantity, quality, relevance, and manner. Each test had a verbal and a nonverbal version. Patients also received Hebrew versions of the Western Aphasia Battery and of the Right Hemisphere Communication Battery. Both LBD and RBD patients were impaired relative to controls but did not differ from each other in their overall scores on BSAs and on Implicatures when scores were corrected by aphasia and neglect indices. There was a systematic localization of BSAs in the left hemisphere (LH) but not in the right hemisphere (RH). There was poor localization of Implicatures in either hemisphere. In LBD patients, BSAs were associated with language functions measured with the WAB, suggesting the radical possibility that the classic localization of language functions in aphasia is influenced by the localization of the BSAs required by aphasia language tests. Both BSAs and implicatures show greater functional independence from other pragmatic, language and cognitive functions in the RBD than in the LBD patients. Thus, the LH is more likely to contain an unmodular domain-nonspecific set of central cognitive mechanisms for applying means-ends rationality principles to intentional activity.     

Effects of Right- and Left-Hemisphere Damage on Understanding Conversational Implicatures

Processing of implicatures was examined in 27 right-brain-damaged (RBD) and 31 left-brain-damaged (LBD) stroke patients with focal lesions using a new implicatures battery (IB) as part of an exploration of the neural basis and modularity of natural language pragmatics. Following Grice, we sampled implicatures of Quantity, Quality, Relation, and Manner. Verbal implicatures consisted of two-sentence conversational vignettes which are literally problematic. Nonverbal implicatures consisted mostly of famous paintings that are literally problematic (e.g., Magritte's "Le Domain d'Arnheim"). The patient has to identify and solve the problem. To compare with performance on the IB, patients also received a Hebrew adaptation of Gardner and Brownell's Right Hemisphere Communication Battery, a new test of basic speech acts (verbal and nonverbal assertions, questions, requests, and commands), a Hebrew version of the Western Aphasia Battery, and standardized neuropsychological tests. Both LBD and RBD patients were significantly impaired in implicature processing relative to age-matched normal controls. In general, both patient groups showed weak correlations of implicatures with extents of lesions in left perisylvian language area or its right-hemisphere (RH) homolog. However, performance of LBD and RBD patients on the IB revealed different patterns of correlations with other pragmatic, language, and nonlanguage tests. In LBD patients, there was a greater association between performance on verbal and nonverbal implicatures and between performance on implicatures and basic speech acts than in RBD patients. Given the different modes in which right-and left-hemisphere (LH) damage affect the processing of conversational implicatures, it remains to be discovered how the two hemispheres interact to process natural language pragmatics in the normal brain in real time.     

The Use of Contextual Information by Right Brain-Damaged Individuals in the Resolution of Ambiguous Pronouns

Two experiments were conducted with the primary purpose of investigating the ability of right brain-damaged (RBD) individuals to use contextual information—at the level of the single sentence, in terms of the integration of information between clauses, and at the level of a minimal discourse (i.e., two sentences)—in the resolution of ambiguous pronouns. The investigation was extended to a group of left brain-damaged (LBD) and non-brain-damaged (NBD) individuals. Contrary to the prevailing view that RBD patients have difficulty in the use of contextual information to process language, both experiments were consistent in demonstrating that the RBD group was influenced by contextual information in a manner similar to that demonstrated by both the LBD and NBD groups.     

Comprehension of Idioms in Turkish Aphasic Participants

Brain damaged participants offer an opportunity to evaluate the cognitive and linguistic processes and make assumptions about how the brain works. Cognitive linguists have been investigating the underlying mechanisms of idiom comprehension to unravel the ongoing debate on hemispheric specialization in figurative language comprehension. The aim of this study is to evaluate and compare the comprehension of idiomatic expressions in left brain damaged (LBD) aphasic, right brain damaged (RBD) and healthy control participants. Idiom comprehension in eleven LBD aphasic participants, ten RBD participants and eleven healthy control participants were assessed with three tasks: String to Picture Matching Task, Literal Sentence Comprehension Task and Oral Idiom Definition Task. The results of the tasks showed that in overall idiom comprehension category, the left brain-damaged aphasic participants interpret idioms more literally compared to right brain-damaged participants. What is more, there is a significant difference in opaque idiom comprehension implying that left brain-damaged aphasic participants perform worse compared to right brain-damaged participants. On the other hand, there is no statistically significant difference in scores of transparent idiom comprehension between the left brain-damaged aphasic and right brain-damaged participants. This result also contribute to the idea that while figurative processing system is damaged in LBD aphasics, the literal comprehension mechanism is spared to some extent. The results of this study support the view that idiom comprehension sites are mainly left lateralized. Furthermore, the results of this study are in consistence with the Giora’s Graded Salience Hypothesis.     

Anterior-posterior interhemispheric differences in the loci of lesions producing visual hemineglect

Five neuropsychological tests designed to measure the presence and severity of visual hemineglect were given to 101 patients with clearly defined unilateral lesions. Of these, visual hemineglect was present in 28 out of a total of 56 left brain damaged (LBD) patients and in 20 out of 45 right brain damaged (RBD) patients. The incidence of hemineglect in these groups did not differ significantly, but the severity of hemineglect was greater in the RBD group than in the LBD group. However, the two groups were found to differ significantly with respect to the loci of the lesions most likely to result in hemineglect. In the RBD group most patients with hemineglect had posterior lesions, and in the LBD group most patients with hemineglect had anterior lesions. Possible reasons for this were discussed first from the point of view of an inattention hypothesis and second in terms of the effects the lateralization of language representation might have on the representation of spatial functions.     

Emotion recognition in stroke patients with left and right hemispheric lesion: results with a new instrument-the FEEL Test

The aim of this study was to investigate the effect of a stroke event on people's ability to recognize basic emotions. In particular, the hypothesis that right brain-damaged (RBD) patients would show less of emotion recognition ability compared with left brain-damaged (LBD) patients and healthy controls, was tested. To investigate this the FEEL Test (Facially Expressed Emotion Labeling) was used, a computer based psychometric test that assesses one's ability to recognize facially displayed basic emotions via a forced-choice paradigm. We examined 24 patients after a stroke event (13 RBD, 11 LBD) and compared them with a matched group of healthy controls (HC, n=29). Results showed that the stroke patients performed significantly worse in the FEEL Test than did HC (p<.001). This deficit was especially evident for negative emotions (fear, anger, sadness, and disgust). In contrast to other studies we did not find any significant differences between RBD and LBD patients in their ability to recognize emotions. These results indicate that a stroke event has a negative effect on the recognition of facially displayed emotions but suggest that this effect is apparently not dependent on the side of the brain damage.     

The perception of positive and negative facial expressions by unilateral stroke patients

There remains conflict in the literature about the lateralisation of affective face perception. Some studies have reported a right hemisphere advantage irrespective of valence, whereas others have found a left hemisphere advantage for positive, and a right hemisphere advantage for negative, emotion. Differences in injury aetiology and chronicity, proportion of male participants, participant age, and the number of emotions used within a perception task may contribute to these contradictory findings. The present study therefore controlled and/or directly examined the influence of these possible moderators. Right brain-damaged (RBD; n = 17), left brain-damaged (LBD; n = 17), and healthy control (HC; n = 34) participants completed two face perception tasks (identification and discrimination). No group differences in facial expression perception according to valence were found. Across emotions, the RBD group was less accurate than the HC group, however RBD and LBD group performance did not differ. The lack of difference between RBD and LBD groups indicates that both hemispheres are involved in positive and negative expression perception. The inclusion of older adults and the well-defined chronicity range of the brain-damaged participants may have moderated these findings. Participant sex and general face perception ability did not influence performance. Furthermore, while the RBD group was less accurate than the LBD group when the identification task tested two emotions, performance of the two groups was indistinguishable when the number of emotions increased (four or six). This suggests that task demand moderates a study’s ability to find hemispheric differences in the perception of facial emotion.     

A linguistic deficit resulting from right-hemisphere damage

The ability of right-brain-damaged (RBD) subjects to correctly insert a word into a well-formed stimulus sentence was tested. Subjects also performed three evaluative tasks designed to establish their degree of general cognitive impairment. The performance of RBD subjects on these tasks was compared to that of left-brain-damaged (LBD) and non-brain-damaged (NBD) subjects. Although RBD subjects outperformed LBD subjects on the language-related evaluative tasks, the RBD group was significantly more impaired on a subset of the insertion task. This subset included items which required reassignment of the syntactic status of elements in the stimulus sentence in order for the insertion to be carried out. The results of this study permit refinement of the common characterization of RBD individuals as rigid in their interpretation of meaning and indicate right-hemisphere involvement in aspects of the grammar previously thought to be inaccessible to it.     

Characteristics of recovery of drawing ability in left and right brain-damaged patients

Drawings of a "person" were obtained from 21 patients with left brain damage (LBD) and 13 patients with right brain damage (RBD) at hospital discharge and 1 month postdischarge, corresponding to 2-4 and 6-8 weeks postonset, respectively. Early LBD drawings were simplistic and often incoherent. Most were placed in the upper left quadrant of the page. RBD drawings were scattered, fragmented, and elaborately detailed. Many showed evidence of left-sided neglect. The resolution of drawing disability also differed between the two groups: LBD subjects recovered drawing abilities more rapidly and more completely than RBD subjects. These differences in drawing characteristics and in the resolution of drawing disability were discernable for experienced neuropsychologists.     

Impact of emotional content on discourse production in patients with unilateral brain damage.

A picture story task was developed to examine expression of emotion via the verbal/lexical channel. The task elicited discourse with either emotional, visual-spatial, or neutral content and was administered to right brain-damaged (RBD), left brain-damaged (LBD), and normal control (NC) right-handed adults. Subjects were matched for gender, age, education, and occupational status. The brain-damaged groups were matched for months post-CVA onset and were similar with respect to intrahemispheric site of lesion. While the number of words produced was equivalent for each of the subject groups, the RBDs and LBDs expressed quantitatively less content than did the NCs. When content differences were examined within each subject group, there were no differences for LBDs and NCs, but the RBDs showed a selective deficit when producing emotional content. This finding suggests a special role for the right hemisphere in the production of emotional content in verbal discourse.     

Lateralization of egocentric and allocentric spatial processing after parietal brain lesions

The purpose of this paper was to verify whether left and right parietal brain lesions may selectively impair egocentric and allocentric processing of spatial information in near/far spaces. Two Right-Brain-Damaged (RBD), 2 Left-Brain-Damaged (LBD) patients (not affected by neglect or language disturbances) and eight normal controls were submitted to the Ego-Allo Task requiring distance judgments computed according to egocentric or allocentric frames of reference in near/far spaces. Subjects also completed a general neuropsychological assessment and the following visuospatial tasks: reproduction of the Rey-Osterreith figure, line length judgement, point position identification, mental rotation, mental construction, line length memory, line length inference, Corsi block-tapping task. LBD patients presented difficulties in both egocentric and allocentric processing, whereas RBD patients dropped in egocentric but not in allocentric judgements, and in near but not far space. Further, RBD patients dropped in perceptually comparing linear distances, whereas LBD patients failed in memory for distances. The overall pattern of results suggests that the right hemisphere is specialized in processing metric information according to egocentric frames of reference. The data are interpreted according to a theoretical model that highlights the close link between egocentric processing and perceptual control of action.     

Perceiver and poser asymmetries in processing facial emotion

This study examined both perceiver and poser asymmetries in processing facial emotion. Posers were left brain-damaged (LBD), right brain-damaged (RBD), and normal control (NC) right-handed males videotaped while expressing happiness and anger. Perceivers rated the facial expressions for asymmetry in original and reversed orientations. Overall, expressions viewed in the reversed orientation were rated as more left-sided than in the original orientation. In the reversed orientation, the more extensive left hemiface of the NCs and LBDs fell in the perceiver's left hemispace. This finding is consistent with previous research demonstrating a left hemispace bias for free-field viewing of emotional faces. Expressions were produced significantly more intensely on the left than the right hemiface by NCs and LBDs; expressions of RBDs were not significantly lateralized.     

The Use of Contextual Information Related to General World Knowledge by Right Brain-Damaged Individuals in Pronoun Resolution

This study investigated the ability of right brain-damaged individuals (RBD) to use contextual information to resolve ambiguous pronouns. Subjects were presented with sentence pairs and required to resolve the ambiguous pronoun in the second sentence. Contrary to the prevailing view that RBD patients have difficulty using contextual information to integrate language, the RBD group demonstrated a normal pattern of response, demonstrating a sensitivity to the pragmatic information contained in the leading sentence. They responded more quickly to sentences with a pragmatically constrained preferred referent than to those sentences for which there was no preferred referent. As well, they chose the preferred referent significantly more often than the non-preferred referent. These results suggest that RBD patients can use contextual information at the level of a minimal discourse (i.e., two sentences).     

Psychometric Aspects of Verbal Pragmatic Ratings

This study examined the psychometric aspects of a verbal pragmatic rating scale. The scale contained six pragmatic features (i.e., Conciseness, Lexical Selection, Quantity, Relevancy, Specificity, and Topic Maintenance) based on Grice's cooperative principles. Fifteen right brain-damaged (RBD), 15 left brain-damaged (LBD), and 16 healthy normal control (NC) right-handed adult participants produced narratives while recollecting emotional and nonemotional experiences. Naive raters evaluated each pragmatic feature for appropriateness on a 5-point Likert scale. When reliability was examined, the overall internal consistency of the pragmatic scale was extremely high (alpha =.96). Factor analysis was conducted to examine the theoretical relations among the six pragmatic features. Three meaningful factors involving discourse content, conceptual unity, and parsimony were identified. Findings are discussed in light of Grice's model and the construct validity of the scale.     

A case study of strategic infarct dementia investigated with the cognitive assessment system

Two subjects with brain lesions who were matched on demographic variables were tested on the Cognitive Assessment System (CAS). AK had been dependent on caregivers after a frontal aneurysm 6 years previously despite intact receptive and expressive language skills and motor functions. GM sustained multiple infarcts although he continued to function well on his own. Nonparametric analysis showed that AK's T scores on CAS subtests were lower than that of GM's based on a comparison with a heterogeneous group of brain-damaged patients (p < .003). The CAS's broad range of complexity of items within subtests, apparent sensitivity in differentiating rates of cognitive decline in dementia, and convergence with dementia rating scales suggests that it could be useful for assessment of strategic infarct dementia.     

Metalinguistic Awareness and Reading Performance: A Cross Language Comparison

The study examined two questions: (1) do the greater phonological awareness skills of billinguals affect reading performance; (2) to what extent do the orthographic characteristics of a language influence reading performance and how does this interact with the effects of phonological awareness. We estimated phonological metalinguistic abilities and reading measures in three groups of first graders: monolingual Hebrew speakers, bilingual Russian–Hebrew speakers, and Arabic-speaking children. We found that language experience affects phonological awareness, as both Russian–Hebrew bilinguals and the Arabic speakers achieved higher scores on metalinguistic tests than Hebrew speakers. Orthography affected reading measures and their correlation with phonological abilitites. Children reading Hebrew showed better text reading ability and significant correlations between phonological awareness and reading scores. Children reading Arabic showed a slight advantage in single word and nonword reading over the two Hebrew reading groups, and very weak relationships between phonological abilities and reading performance. We conclude that native Arabic speakers have more difficulty in processing Arabic orthography than Hebrew monolinguals and bilinguals have in processing Hebrew orthography, and suggest that this is due to the additional visual complexity of Arabic orthography.     

Poor hand-pointing to sounds in right brain-damaged patients: Not just a problem of spatial-hearing

We asked 22 right brain-damaged (RBD) patients and 11 elderly healthy controls to perform hand-pointing movements to free-field unseen sounds, while modulating two non-auditory variables: the initial position of the responding hand (left, centre or right) and the presence or absence of task-irrelevant ambient vision. RBD patients suffering from visual neglect, unlike RBD patients without neglect and healthy controls, showed a systematic rightward error in sound localisation, which was modulated by the non-auditory variables. Localisation errors were exacerbated by initial hand-position to the right of the body-midline, and reduced by the leftwards initial hand-position. Moreover, for the visual neglect patients, mere presence of ambient vision worsened localisation errors. These results demonstrate that although hand-pointing to sounds has often been considered a straightforward approach to investigate sound-localisation abilities in brain-damaged patients, in some patients it may actually reveal localisation deficits that reflect a combination of impaired spatial-hearing and spatial biases from other sensory modalities (i.e., vision and proprioception).     

Poor hand-pointing to sounds in right brain-damaged patients: not just a problem of spatial-hearing

We asked 22 right brain-damaged (RBD) patients and 11 elderly healthy controls to perform hand-pointing movements to free-field unseen sounds, while modulating two non-auditory variables: the initial position of the responding hand (left, centre or right) and the presence or absence of task-irrelevant ambient vision. RBD patients suffering from visual neglect, unlike RBD patients without neglect and healthy controls, showed a systematic rightward error in sound localisation, which was modulated by the non-auditory variables. Localisation errors were exacerbated by initial hand-position to the right of the body-midline, and reduced by the leftwards initial hand-position. Moreover, for the visual neglect patients, mere presence of ambient vision worsened localisation errors. These results demonstrate that although hand-pointing to sounds has often been considered a straightforward approach to investigate sound-localisation abilities in brain-damaged patients, in some patients it may actually reveal localisation deficits that reflect a combination of impaired spatial-hearing and spatial biases from other sensory modalities (i.e., vision and proprioception).     

Shift of visual field preference for English words in native Hebrew speakers.

Lateralization for visual verbal material was tested with Hebrew and English stimuli presented to Israeli adolescents in their second, fourth, and sixth years of study of English as a second language. Seventy-two children, 12 male and 12 female subjects in each class, were tested by means of a target-word recognition task. Laterality scores derived from reaction-time measures resulted in: (1) a left visual field preference for the English stimuli in the youngest group which decreased with increasing age, becoming a right visual field preference in the oldest group, and (2) a significant and equal right visual field preference for Hebrew stimuli for all groups. The data suggest right hemisphere involvement in acquiring the reading skills of a new language.     

Appreciation of pragmatic interpretations of indirect commands: comparison of right and left hemisphere brain-damaged patients

Indirect commands can elicit "literal" interpretations, directly reflecting the content and form of the utterance, or "pragmatic" interpretations, incorporating knowledge of paralinguistic, social, or historical cues. The aim of this study was to demonstrate how right brain-damaged (RBD) subjects would perform on judgments of these forms of communication. It was predicted that relative to normal controls or aphasic subjects, the RBD subjects would have significant difficulty appreciating the pragmatic interpretation relative to the literal one. Subjects judged the appropriateness of two-part exchanges consisting of indirect commands, direct commands, Wh-questions coupled with pragmatic responses, literal responses, responses verifying the physical surround, or syntactically similar responses. The results confirm that the RBD subjects had a selective difficulty appreciating the indirect commands. Their preference of literal over pragmatic interpretations was significantly different to that of aphasics or normal controls. Hypotheses are offered to explain these data.