Auditory-verbal analysis in aphasia

Background: Comprehension deficits are more pervasive in aphasic syndromes than initially believed. They affect differentially distinct levels of auditory-verbal comprehension. Current evidence from functional imaging studies in healthy subjects indicates that distinct levels of auditory-verbal analysis involve specific networks.

Aims: The aim of this study is (1) to assess the different levels of auditory-verbal analysis with real-time monitoring tasks in patients with aphasia, (2) to compare the performance profiles across aphasia types, (3) to analyse patterns of dissociations vs. co-occurrence at specific levels, and (4) to establish correlations between disturbances at specific levels of auditory-verbal analysis and sites of lesions.

Methods & Procedures: Forty-two right-handed patients with aphasia associated with a first unilateral left-hemispheric lesion underwent tests monitoring (1) phonetic-phonological, (2) lexical, (3) morphosyntactic, (4) semantic-pragmatic (at sentence level), and (5) linguistic prosody processing. Anatomo-clinical correlations were established by means of voxel-based lesion-symptom mapping.

Outcomes & Results: Widespread deficits at multiple levels occurred across aphasic syndromes. In a given patient, more levels tended to be impaired in Wernicke’s and global aphasia than in Broca’s or conduction aphasia. Syllable and word processing double-dissociated behaviourally and partially anatomically. Morphosyntactic deficits were always accompanied by semantic-pragmatic deficits. Anatomo-clinical correlations implicated the dorsal auditory stream in syllable discrimination, the ventral stream in semantic processing at lexical level and in linguistic prosody and both streams in lexical frequency effect. Basal ganglia were implicated in syntactic and semantic processing at sentence level.

Conclusions: At prelexical and lexical levels, syllable and word processing appear to be independent of each other. At sentence level, parsing of syntactic structure appears to be necessary for successful semantic-pragmatic analysis. Thus, the fine-grained evaluation of auditory-verbal processing capacities and of the integrity of specialised processing networks in brain-damaged patients provides a sensitive diagnostic tool.     

Egocentric conditional associative learning: effects of restricted lesions to the hippocampo-mammillo-thalamic pathway

Rats with lesions of the hippocampus, the mammillary region, the anterior thalamic nuclei, and normal control animals were trained on a conditional associative learning task in which they had to learn to make one of two motor responses (i.e., turn left or right), depending on which one of two visual cues was presented. Damage to the hippocampus severely impaired performance of this task. By contrast, rats with lesions of the mammillary region or the anterior thalamic nuclei were able to acquire the task at a rate comparable to that of the normal animals. These findings demonstrate that hippocampal lesions impair the ability to form arbitrary associations between visual cues and kinesthetic responses (body turns) and, furthermore, suggest that the hippocampus does not rely on input from its major subcortical targets for learning such visual-kinesthetic associations.     

Schizotypal thinking and associative processing: a response commonality analysis of verbal fluency.

OBJECTIVE: To determine whether people with high scores for schizotypal thinking generate more uncommon words in a letter fluency task than people with low scores. DESIGN: Prospective study. SETTING: University psychology department. PATIENTS: Forty healthy, right-handed students. INTERVENTIONS: Students were administered the Magical Ideation (MI) Scale and a 2-minute letter fluency task in which they named as many nouns as possible beginning with "A" or "F," in any order. OUTCOME MEASURES: Total number of words produced and percentage of unique, rare and common words (as determined by the responses of the whole group); scores on MI scale. RESULTS: Participants with high scores (above the median) on the MI scale generated as many words as those who had low scores. People in both groups also generated a comparable number of unique words (named by only 1 person) and common words (named by 6 or more people). As hypothesized, people with high scores on the MI scale generated more rare words (named by fewer than 6 people) than those with low scores. CONCLUSIONS: These findings support the view of a disinhibition of semantic network functioning as the neuropsychological basis of creative thought, magical ideation and thought disorder.     

Neurolinguistic analysis of recurrent utterance in aphasia

A linguistic analysis of 97 recurrent utterances (RUs) is reported which delineates 2 separate types of RU - Real Word Recurrent Utterances (RWRUs) and Non-Meaningful Recurrent Utterances (NMRUs). The range, frequency and distribution of phonemes occurring in RUs is similar to normal English in RWRUs, but not in NMRUs. NMRUs do not break the phonotactic constraints of the language and RWRUs rarely break the syntactic rules. It appears to be possible to classify RWRUs into certain groups among which a Pronoun + Verb and an Expletive group are the most interesting. Expletive RUs were all produced by male subjects and Pronoun + Verb RUs deserve further investigation. Implications for rehabilitation are discussed.     

Dissociation of recognition memory and associative learning by a restricted lesion of the chick forebrain

Bilateral lesions of a restricted part of the chick forebrain (IMHV) have been shown to impair the acquisition and retention of imprinting preferences. The present study sought to determine the effects of such lesions on an operant conditioning task in which the reward was the presentation of one of two conspicuous objects, a stuffed jungle fowl or an illuminated red box. Twelve hours after hatching 28 domestic chicks received bilateral lesions of IMHV. Thirty-two chicks served as sham-operated controls. On the following day all birds underwent two sessions of operant training. After the second session the chicks were given a preference test. In this test the reinforcing object (box or fowl) and a novel object (fowl or box, whichever had not been seen before) were simultaneously presented. One test was given 2 hr and a second 24 hr after the termination of the operant task. The lesioned birds were not impaired on the operant task or on measures of general activity. In contrast, these birds failed to show a preference for the reinforcing object whereas the sham-operated controls strongly preferred this object. These results suggest that object recognition and associative learning can be dissociated in young chicks. This dissociation is reminiscent of certain human amnesias. The lesion did not impair an expected increase in preference for the stuffed fowl which developed in all birds between the 2-hr and 24-hr preference tests.     

Lesion analysis of language production deficits in aphasia

Background: Three aspects of language production are impaired to different degrees in individuals with post-stroke aphasia: ability to repeat words and nonwords, name pictures, and produce sentences. These impairments often persist into the chronic stages, and the neuroanatomical distribution of lesions associated with chronicity of each of these impairments is incompletely understood.

Aims: The primary objective of this study was to investigate the lesion correlates of picture naming, sentence production, and nonword repetition deficits in the same participant group because most prior lesion studies have mapped single language impairments. The broader goal of this study was to investigate the extent and degree of overlap and uniqueness among lesions resulting in these deficits in order to advance the current understanding of functional subdivision of neuroanatomical regions involved in language production.

Methods & Procedures: In this study, lesion-symptom mapping was used to determine if specific cortical regions are associated with nonword repetition, picture naming, and sentence production scores. Structural brain images and behavioural performance of 31 individuals with post-stroke left hemisphere lesions and a diagnosis of aphasia were used in the lesion analysis.

Outcomes & Results: Each impairment was associated with mostly unique, but a few shared lesions. Overall, sentence and repetition deficits were associated with left anterior perisylvian lesions, including the pars opercularis and triangularis of the inferior frontal lobe, anterior superior temporal gyrus, anterior portions of the supramarginal gyrus, the putamen, and anterior portions of the insula. In contrast, impaired picture naming was associated with posterior perisylvian lesions including major portions of the inferior parietal lobe and middle temporal gyrus. The distribution of lesions in the insula was consistent with this antero-posterior perisylvian gradient. Significant voxels in the posterior planum temporale were associated with a combination of all three deficits.

Conclusions: These findings emphasise the participation of each perisylvian region in multiple linguistic functions, suggesting a many(functions)-to-many(networks) framework while also identifying functional subdivisions within each region.     

Qualitative methods in aphasia research: conversation analysis

The conversational behaviours of individuals with aphasia are becoming a more important consideration in clinical aphasiology. This is due to the increased focus on conversational dyads and conversational partners via supported conversation for adults with aphasia. This article provides an overview of a well-established analytic framework to investigate conversation in authentic settings. This framework, conversation analysis, is described according to its development and primary principles. Several examples of its application to clinical aphasiology are provided.     

Argumentation with restricted linguistic ability: performing a role play with aphasia or in a second language

The main objective of this study is to illustrate how adaptation to linguistic limitations takes place in a specific activity and is affected by factors pertaining to the social activity or the individuals. A man with aphasia is compared to an adult immigrant L2 learner. An argumentative role play was video-recorded, transcribed and analysed. Both subjects have a very limited vocabulary and produce short utterances. The L2 learner often uses words that are semantically related to the target word, while the subject with aphasia uses more general and vague words, like pronouns, in combination with adverbs and set phrases. Both subjects use gesturing as strategy, and it is suggested that the semantic specificity of words as well as gestures is important in determining the role of gesture. Apart from gesture, he L2 learner uses mainly simplification and appeal strategies, while the subject with aphasia uses mainly fluency and sociolinguistic strategies.     

Use of semantic feature analysis in group aphasia treatment

Background: Semantic feature analysis (SFA) is a treatment for lexical retrieval impairment in which participants are cued to provide semantic information about concepts they have difficulty naming in an effort to facilitate accurate lexical retrieval (Boyle, 2004b Boyle, M. 2004b. Semantic feature analysis treatment for anomia in two fluent aphasia syndromes.. American Journal of Speech‐Language Pathology, 13(3): 236–249.  [Google Scholar]). The majority of studies of SFA have concentrated on single‐word training, with inconsistent generalisation of improved lexical retrieval to connected speech. Expansion of SFA training in discourse has yielded modest success in the context of individual treatment, but has not been examined in the context of group treatment.

Aims: The aim of the current study was to investigate training of SFA in connected speech during group aphasia treatment, which provides a natural context for analysing the effectiveness of discourse production, as well as representing an increasingly popular model of service delivery for aphasia treatment. It was hypothesised that lexical retrieval during discourse would improve, as would overall communication informativeness.

Methods & Procedures: Three individuals with aphasia participated in biweekly group treatment during which SFA was trained during discourse production tasks. Two of the three individuals participated in the entire course of treatment. Discourse of these two participants was analysed such that effect sizes could be calculated for measures of overall communication informativeness and efficiency (Nicholas & Brookshire, 1993 Nicholas, L. E. and Brookshire, R. H. 1993. A system for quantifying the informativeness and efficiency of the connected speech of adults with aphasia.. Journal of Speech & Hearing Research, 36(2): 338–350.  [Google Scholar]), and for item‐specific lexical retrieval (Mayer & Murray, 2003 Mayer, J. F. and Murray, L. L. 2003. Functional measures of naming in aphasia: Word retrieval in confrontation naming versus connected speech.. Aphasiology, 17(5): 481–497. [Taylor & Francis Online], [Web of Science ®] , [Google Scholar]).

Outcomes & Results: The two individuals who participated in the full treatment protocol both demonstrated improved lexical retrieval in discourse, with additional improvements observed in either general communication informativeness or efficiency.

Conclusions: Results provide preliminary support for the hypotheses that SFA administered during group aphasia treatment can be used successfully to facilitate word retrieval during discourse. Furthermore, results suggest that individuals with differing mechanisms of anomia may derive benefits from participation in this treatment protocol.     

Argumentation with restricted linguistic ability: Performing a role play with aphasia or in a second language

The main objective of this study is to illustrate how adaptation to linguistic limitations takes place in a specific activity and is affected by factors pertaining to the social activity or the individuals. A man with aphasia is compared to an adult immigrant L2 learner. An argumentative role play was video‐recorded, transcribed and analysed. Both subjects have a very limited vocabulary and produce short utterances. The L2 learner often uses words that are semantically related to the target word, while the subject with aphasia uses more general and vague words, like pronouns, in combination with adverbs and set phrases. Both subjects use gesturing as strategy, and it is suggested that the semantic specificity of words as well as gestures is important in determining the role of gesture. Apart from gesture, he L2 learner uses mainly simplification and appeal strategies, while the subject with aphasia uses mainly fluency and sociolinguistic strategies.     

Progressive associative phonagnosia: A neuropsychological analysis

There are few detailed studies of impaired voice recognition, or phonagnosia. Here we describe two patients with progressive phonagnosia in the context of frontotemporal lobar degeneration. Patient QR presented with behavioural decline and increasing difficulty recognising familiar voices, while patient KL presented with progressive prosopagnosia. In a series of neuropsychological experiments we assessed the ability of QR and KL to recognise and judge the familiarity of voices, faces and proper names, to recognise vocal emotions, to perceive and discriminate voices, and to recognise environmental sounds and musical instruments. The patients were assessed in relation to a group of healthy age-matched control subjects. QR exhibited severe impairments of voice identification and familiarity judgments with relatively preserved recognition of difficulty-matched faces and environmental sounds; recognition of musical instruments was impaired, though better than recognition of voices. In contrast, patient KL exhibited severe impairments of both voice and face recognition, with relatively preserved recognition of musical instruments and environmental sounds. Both patients demonstrated preserved ability to analyse perceptual properties of voices and to recognise vocal emotions. The voice processing deficit in both patients could be characterised as associative phonagnosia: in the case of QR, this was relatively selective for voices, while in the case of KL, there was evidence for a multimodal impairment of person knowledge. The findings have implications for current cognitive models of voice recognition.     

Visual associative agnosia and optic aphasia. A single case study and a review of the syndromes.

The case is presented of a patient who showed visual naming disturbances caused by a left occipital infarction. His performance on tests of visual naming, of recognition not requiring a verbal response, and of verbal-visual matching demonstrated a wide range of qualitatively different errors, including complete inability to recognize the object, access to partial semantic knowledge, and mere name finding difficulty. On the basis of the present case and of a review of the recent literature, the clinical distinction between visual associative agnosia and optic aphasia and the relation of these disorders with the anatomical site of lesion are discussed.