Communicative gestures in aphasia

Gestural communications of 10 mild and moderate aphasics and five controls were examined in two conditions: Face-to-face informal dyadic conversation and restricted visual access between speaker and listener. Gestural production was significantly reduced with restriction of visual access, supporting the posited communicative function of the hand and arm gestures investigated in this study. No differences were found between aphasic and control subjects in the rate of gestural communication in the natural condition of face-to-face interaction. Moderate aphasics, however, were found to produce proportionally fewer of the complex semantic modifying and relational communicative gestures and more nonspecific, nonconsensually shared, unclear gestures. Gestural complexity was significantly negatively correlated with measures of linguistic impairment for the aphasics. The relationship between the frequency and complexity of communicative gestures and concurrent verbalizations was also examined. The findings of this study provide confirmation for the view that there is an identifiable class of gestures utilized by aphasics for communication, aphasics are impaired in their gestural communicative competence in natural conditions of communication, and the quality of aphasics' gestural communications parallels changes in their verbal communication patterns.     

Communicative impairment in traumatic brain injury: a complete pragmatic assessment

The aim of the present study was to examine the communicative abilities of traumatic brain injury patients (TBI). We wish to provide a complete assessment of their communicative ability/disability using a new experimental protocol, the Assessment Battery of Communication, (ABaCo) comprising five scales—linguistic, extralinguistic, paralinguistic, context and conversational—which investigate all the main pragmatic elements involved in a communicative exchange. The ABaCo was administered to 21 TBI subjects and to a control group. The results showed that performance by TBI patients was worse than that of controls on all scales; moreover they showed a trend of increasing difficulty in understanding and producing different pragmatic phenomena, i.e., standard communication acts, deceits and ironies, whether such phenomena are expressed through the linguistic or extralinguistic modality.     

The role of intonation cues in aphasic patients' performance of the grammaticality judgment task

This study investigated the possibility that the reported success of agrammatic aphasic patients in performing auditory grammaticality judgments results from their use of intonational cues to sentence well-formedness. Two agrammatic aphasics, two anomic aphasics, and two nonagrammatic patients with comprehension deficits for semantically reversible sentences were asked to judge grammatical well-formedness in three conditions. Results in a "natural" listening condition replicated the finding of M.C. Linebarger, M.F. Schwartz, and E. M. Saffran (1983, Cognition, 13, 361-392) that agrammatic patients are sensitive to grammaticality despite poor ability to use syntatic cues in comprehension tasks. Two additional listening conditions employed signal-processed auditory stimuli in which the fundamental frequency was normal or was set at a constant level. Right-hemisphere-damaged and normal controls showed no performance deficit for judgments of monotone sentences. The aphasic patients' performance was slightly worse for both signal-processed conditions, but there was little apparent effect of removing sentence intonation on their ability to judge sentence grammaticality. These results indicate that the high levels of performance on grammaticality judgement tasks have not resulted from patients' detection of intonational cues in ungrammatical sentences.     

Aphasic adults' use of heuristic and structural linguistic cues for sentence analysis

Eight aphasic adults with relatively preserved auditory comprehension and 12 normal adults were tested for their ability to analyze sentences in which the functional relations between the verb and nouns was either directly reflected by word order expectancies, or marked by a functor or non-NVN word order. The subjects' task was to designate the agent of each sentence. Results indicated that aphasics utilize word order expectancies but are impaired in their ability to exploit functors and particularly, word order markers for sentence analysis. Results are discussed in terms of aphasics' use of heuristic versus structural linguistic cues for interpreting sentences.     

Reaction time and accuracy in individuals with aphasia during auditory vigilance tasks

Research indicates that attentional deficits exist in aphasic individuals. However, relatively little is known about auditory vigilance performance in individuals with aphasia. The current study explores reaction time (RT) and accuracy in 10 aphasic participants and 10 nonbrain-damaged controls during linguistic and nonlinguistic auditory vigilance tasks. Findings indicate that the aphasic group was less accurate during both tasks than the control group, but was not slower in their accurate responses. Further examination of the data revealed variability in the aphasic participants' RT contributing to the lower accuracy scores.     

Prosody, linguistic demands, and auditory comprehension in aphasia.

Prosody plays a clear role in the auditory comprehension of narratives by aphasic listeners. Previous research, however, has pointed to questions regarding variables which increase task complexity (e.g., memory, reading level) and the influence of the severity of aphasia. This study examined the role of the severity of aphasia and linguistic complexity in narrative comprehension by aphasic listeners. Findings indicate that while all subject groups improved their auditory comprehension when emphasis was present, people with severe aphasia improved significantly more, but only in a low linguistic complexity condition. However, subjects had additional opportunity for improved performance in both low and high linguistic complexity conditions. These results pose additional questions about perceived task difficulty (and performance) and resource allocation strategies.     

Neuropragmatics: extralinguistic communication after closed head injury

This work is concerned with the decay of communicative abilities after head trauma. A protocol composed of 16 videotaped scenes was devised in order to investigate the comprehension of several types of communicative actions realized with extralinguistic means, like pointing or clapping. The protocol was administered to 30 closed-head-injured individuals. The results showed that performance decreased from simple standard acts to complex standard acts, deceits, and ironies. The subjects' performance was worse with the scenes reproducing failing, rather than successful, communicative actions. The results are compared with those we previously obtained with a linguistic protocol. A theory of the cognitive processes underlying intentional communication is outlined and used to explain the results.     

Extending formant transitions may not improve aphasics'' perception of stop consonant place of articulation

Synthetic speech stimuli were used to investigate whether aphasics' ability to perceive stop consonant place of articulation was enhanced by the extension of initial formant transitions in CV syllables. Phoneme identification and discrimination tests were administered to 12 aphasic patients, 5 fluent and 7 nonfluent. There were no significant differences in performance due to the extended transitions, and no systematic pattern of performance due to aphasia type. In both groups, discrimination was generally high and significantly better than identification, demonstrating that auditory capacity was retained, while phonetic perception was impaired; this result is consistent with repeated demonstrations that auditory and phonetic processes may be dissociated in normal listeners. Moreover, significant rank order correlations between performances on the Token Test and on both perceptual tasks suggest that impairment on these tests may reflect a general cognitive rather than a language-specific deficit.     

The relation between gesture and language in aphasic communication

Effective communication in aphasia depends not only on use of preserved linguistic capacities but also (and perhaps primarily) on the capacity to exploit alternative modalities of communication, such as gesture. To ascertain the capacity of aphasic patients to use gesture in their spontaneous communication, informally structured interviews were conducted with two Wernicke's aphasics and two Broca's aphasics, as well as with four normal controls. The performances of the patient groups were compared on the physical parameters of gesture, the points in the communication where gestures occurred, and several facets of the semantics and pragmatics of gesture. Generally speaking, the gestures of the aphasics closely paralleled their speech output: on most indices, the performance of the Wernicke's aphasics more closely resembled that of the normal controls. Wernicke's aphasics differed from normals in the clarity of their language and gestures: While individual linguistic units were often clear, the relation among units was not. In contrast, the Broca's aphasics equaled or surpassed the normal controls in the clarity of their communications. The results offer little support for the view that aphasic patients spontaneously enhance their communicative efficacy through the use of gesture; these findings can, however, be interpreted as evidence in favor of a “central organizer” which controls critical features of communication, irrespective of the modality of expression.     

On-line syntactic processing in aphasia: studies with auditory moving window presentation

Twenty-eight aphasic patients with left hemisphere strokes and matched control subjects were tested on an auditory moving windows task in which successive phrases of a sentence were presented in response to subjects' self-paced button presses and subjects made timed judgments regarding the plausibility of each sentence. Pairs of sentences were presented that differed in syntactic complexity. Patients made more errors and/or took longer in making the plausibility judgments than controls, and were more affected than controls by the syntactic complexity of a sentence in these judgments. Normal subjects showed effects of syntactic structure in self-paced listening. On-line syntactic effects differed in patients as a function of their comprehension level. High-performing patients showed the same effects as normal control subjects; low performing patients did not show the same effects of syntactic structure. On-line syntactic effects also differed in patients as a function of their clinical diagnosis. Broca's aphasic patients' on-line performances suggested that they were not processing complex syntactic structures on-line, while fluent aphasics' performances suggested that their comprehension impairment occurred after on-line processing was accomplished. The results indicate that many aphasic patients retain their ability to process syntactic structure on-line, and that different groups of patients with syntactic comprehension disorders show different patterns of on-line syntactic processing.     

Confrontation naming impairment in dementia

In tone languages pitch variations (tones) serve to distinguish the lexical meanings of words. This study was conducted to examine the extent and nature of impairment in the perception of tones by aphasic patients who were monolingual speakers of Thai, a tone language which has five contrastive tones (mid, low, falling, high, rising). Six subjects participated in the study: two Broca aphasics, one transcortical motor aphasic, one conduction aphasic, one right brain-damaged nonaphasic, and one normal control. Three sets of stimuli (two real-speech, one synthetic-speech) were presented for identification, each set containing five Thai words minimally distinguished by tone. Results of the perception tests indicated that the performance of all four left brain-damaged aphasics differed significantly from that of the normal control, while the performance of the right brain-damaged nonaphasic did not. The normal performance of the right brain-damaged nonaphasic patient on this tone identification task suggests that deficits in the perception of tone exhibited by left brain-damaged patients can be attributed specifically to pathology in the language dominant hemisphere rather than to a general brain-damage effect. No difference in performance among the left brain-damaged patients could be attributed to a specific type of aphasic syndrome. The pattern of tonal confusions of the aphasics in comparison to that of normals suggests that their deficit is primarily quantitative rather than qualitative. Although two (mid, low) of the five tones accounted for a large percentage of the aphasics' errors, no uniform rank order of tones in terms of identifiability could be established across aphasic subjects, which suggests that their deficit is general to all five tones rather than selective to individual tones.     

Adults' social cues facilitate young children's use of signs and symbols

Three experiments investigated the effect of an adult's social cues on 2- and 3-year-old children's ability to use a sign or symbol to locate a hidden object. Results showed that an adult's positive, engaging facial expression facilitated children's ability to identify the correct referent, particularly for 3-year-olds. A neutral facial expression and the presence of the adult's hand also facilitated performance, but to a lesser degree than did an engaging facial expression. The effect of the adult's social cues was greater for relatively unfamiliar signs and symbols (replica or arrow) than it was for a more familiar sign (pointing finger). These findings indicate that non-directional social cues such as facial expression help to convey communicative intent and facilitate children's comprehension of signs and symbols.     

Is there an advantage for recognizing multi-modal emotional stimuli?

Emotions can be recognized whether conveyed by facial expressions, linguistic cues (semantics), or prosody (voice tone). However, few studies have empirically documented the extent to which multi-modal emotion perception differs from uni-modal emotion perception. Here, we tested whether emotion recognition is more accurate for multi-modal stimuli by presenting stimuli with different combinations of facial, semantic, and prosodic cues. Participants judged the emotion conveyed by short utterances in six channel conditions. Results indicated that emotion recognition is significantly better in response to multi-modal versus uni-modal stimuli. When stimuli contained only one emotional channel, recognition tended to be higher in the visual modality (i.e., facial expressions, semantic information conveyed by text) than in the auditory modality (prosody), although this pattern was not uniform across emotion categories. The advantage for multi-modal recognition may reflect the automatic integration of congruent emotional information across channels which enhances the accessibility of emotion-related knowledge in memory.     

Neuropragmatics: Extralinguistic pragmatic ability is better preserved in left-hemisphere-damaged patients than in right-hemisphere-damaged patients

The aim of the present study is to compare the pragmatic ability of right- and left-hemisphere-damaged patients excluding the possible interference of linguistic deficits. To this aim, we study extralinguistic communication, that is communication performed only through gestures. The Cognitive Pragmatics Theory provides the theoretical framework: it predicts a gradient of difficulty in the comprehension of different pragmatic phenomena, that should be valid independently of the use of language or gestures as communicative means. An experiment involving 10 healthy individuals, 10 right- and 9 left-hemisphere-damaged patients, shows that pragmatic performance is better preserved in left-hemisphere-damaged (LHD) patients than in right-hemisphere-damaged (RHD) patients.     

Aphasics' sensitivity to contextual appropriateness conditions for pragmatic indicators

Twenty normal and twenty aphasic subjects were tested for their understanding of implicit meanings of the French adverbs même (even), aussi (also), and surtout (mainly). Their sensitivity to the contextual appropriateness conditions of such items was analyzed in a multiple-choice paradigm requiring them to select from three figures the one which was best described by a sentence like "Show me the figure that is même (aussi, surtout) red." A global quantitative comparison indicates that aphasics' performance was inferior to that of the normal controls. Yet, the analysis of individual responses allowed the identification of three different subgroups of aphasics: the first produced responses identical to the normals' responses; the second seemed to ignore the adverb and systematically selected the figure with the highest amount of the asserted color; and the third produced responses identical to the normals' responses for surtout but had difficulties with même or aussi. As concerns the relationship between aphasics' performance and their scores on literal language comprehension tests, the data favor the dissociation between literal and pragmatic factors in comprehension. Finally, no clear relationship was observed between aphasia type and aphasics' performance, although three points are noted in the discussion: (1) all the conduction aphasics performed like normals, (2) among the Broca's aphasics, the one with the clearest agrammatic verbal output produced responses similar to those of the normals, and (3) there was no anomic patient in the second subgroup.     

Language and speech recovery in a case of viral encephalitis

The speech and language recovery course of a 47-year-old man with viral encephalitis is described. Over a 3-month period, the patient was evaluated six times using the same selected battery of tests. Results show that viral encephalitis can deleteriously affect communicative performance and that improvement in medical status is accompanied by rapid and dramatic gains on most standard speech and language measures. For this case changes appeared related to improved auditory attention and retention, increased efficiency in word retrieval, and improved mental status.     

The semantic organization and classification of fourteen words by aphasic patients

The purpose of this study was to assess both conceptual knowledge and classification skills in nonfluent and fluent aphasia by focusing on the aphasics' appreciation of class and function relations. The results illustrated that fluent and nonfluent aphasics appreciated both class and function relations. However, further study revealed that even though the fluent aphasic may know the function of an item, he is impaired in his ability to use this information. The nonfluent aphasics also illustrated this tendency not to use their knowledge about function, but to a lesser extent and without the consistency found in the performance of fluent aphasics.     

The relationship between limb apraxia and the spontaneous use of communicative gesture in aphasia

This study investigated the relationship between limb apraxia, as assessed by a formal clinical test, and the production of spontaneous communicative gesture, as measured by a newly designed rating scale--the Nonvocal Communication Scale (NCS). Subjects were aphasic adult males with cerebrovascular lesions of the left hemisphere. The performance of aphasic patients on the praxis test and the NCS was independent of demographic, neuroanatomic, linguistic, or cognitive variables, except for global aphasics who were low-scoring across the board. There was a significant positive correlation, however, between praxis ability and spontaneous gestural communication. Clinical implications of these findings are discussed.     

Hierarchical planning disability in the drawings and constructions of a special group of severely aphasic children

A small group of severely receptive aphasic children who appear to be suffering from a rare aphasic syndrome that has been referred to in the literature as "acquired aphasia with convulsive disorder in children" was tested on drawing and construction tasks which tap hierarchical planning abilities. Although they could draw and construct a complex figure when using a serial method, they could not do so when required to use hierarchical planning in building up the model in terms of its subunits. Their scores reflecting hierarchical ability were significantly lower than those of age-matched profoundly deaf and normal children. The nature of this disability is discussed and its effects noted on tasks in other modalities. It is argued that neither an auditory deficit theory nor a short-term memory deficit theory is adequate to account for the observed disabilities. Individual differences in the group were noted. It was also found that a smaller percentage of developmentally expressive aphasic children evidenced the hierarchical planning disability. It is concluded that a primary hierarchical planning disability in some aphasic children can account for some aspects of their linguistic disabilities and for disabilities on other nonlanguage and nonauditory tasks.     

Processing passive sentences in aphasia: deficits and strategies

Broca's and Wernicke's aphasics' ability to process passive sentences in the absence of semantic cues was investigated in an experiment which varies syntactic complexity and word order. The results indicate that Broca and Wernicke patients use different strategies for sentence comprehension. Wernicke patients use rather general strategies for interpretation, which assign syntactic function according to sequential arrangements of words. Broca's aphasics, by contrast, base their interpretation on specific structural elements of the sentence's surface form, without, however, being able to exploit the full syntactic information of these elements. The different strategies are interpreted to reflect differential underlying deficits.