Cases reported "Aphasia"

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1/37. Cross-modal priming and explicit memory in patients with verbal production deficits.

    Implicit memory is often thought to reflect an influence of past experience on perceptual processes, yet priming effects are found when the perceptual format of stimuli changes between study and test episodes. Such cross-modal priming effects have been hypothesized to depend upon stimulus recoding processes whereby a stimulus presented in one modality is converted to other perceptual formats. The present research examined recoding accounts of cross-modal priming by testing patients with verbal production deficits that presumably impair the conversion of visual words into auditory/phonological forms. The patients showed normal priming in a visual stem completion task following visual study (Experiment 1), but showed impairments following auditory study in both implicit (Experiment 2) and explicit (Experiment 3) stem completion. The results are consistent with the hypothesis that verbal production processes contribute to the recoding of visual stimuli and support cross-modal priming. The results also indicate that shared processes contribute to both explicit memory and cross-modal implicit memory.
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2/37. Application of the correct information unit analysis to the naturally occurring conversation of a person with aphasia.

    The Correct Information Unit (CIU) analysis for measuring the communicative informativeness and efficiency of connected speech (Nicholas & Brookshire, 1993) was applied to the naturally occurring conversation of a person with moderate aphasia. Results indicated that, in this instance, reliable CIU measures could not be obtained. Intrarater reliability for CIU and %CIU was low, reaching only 72%, and interrater reliability was never greater than 63%. However, reliability of word counts was good. Post hoc analysis of rater disagreements in application of the CIU analysis revealed that the majority (72%) resulted from insufficiencies in the scoring rules that were originally designed to measure single speaker connected discourse. Two descriptive categories of disagreements were identified: interpretations of informativeness and absence of rules. The remaining 28% of disagreements were attributable to human error in the application of scoring rules. Comparison of findings with previous research and implications for future research are discussed.
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3/37. Similarity and categorisation: neuropsychological evidence for a dissociation in explicit categorisation tasks.

    A series of experiments are reported on a patient (LEW) with difficulties in naming. Initial findings indicated severe impairments in his ability to freesort colours and facial expressions. However, LEW's performance on other tasks revealed that he was able to show implicit understanding of some of the classic hallmarks of categorical perception; for example, in experiments requiring the choice of an odd-one-out, the patient chose alternatives dictated by category rather than by perceptual distance. Thus, underlying categories appeared normal and boundaries appeared intact. Furthermore, in a two-alternative forced-choice recognition memory task, performance was worse for within-category decisions than for cross-category decisions. In a replication of the study of Kay and Kempton [Kay, P., Kempton, W., 1984. What is the Sapir-Whorf hypothesis? American Anthropologist 86, 65-78], LEW showed that his similarity judgements for colours could be based on perceptual or categorical similarity according to task demands. The consequences for issues concerned with perceptual categories and the relationship between perceptual similarity and explicit categorisation are considered; we argue for a dissociation between these kinds of judgements in the freesort tasks. LEW's inability to make explicit use of his intact (implicit) knowledge is seen as related to his language impairment.
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keywords = perception
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4/37. functional neuroimaging of speech perception in six normal and two aphasic subjects.

    This positron emission tomography study used a correlational design to investigate neural activity during speech perception in six normal subjects and two aphasic patients. The normal subjects listened either to speech or to signal-correlated noise equivalents; the latter were nonspeech stimuli, similar to speech in complexity but not perceived as speechlike. Regions common to the auditory processing of both types of stimuli were dissociated from those specific to spoken words. Increasing rates of presentation of both speech and nonspeech correlated with cerebral activity in bilateral transverse gyri and adjacent superior temporal cortex. Correlations specific to speech stimuli were located more anteriorly in both superior temporal sulci. The only asymmetry in normal subjects was a left lateralized response to speech in the posterior superior temporal sulcus, corresponding closely to structural asymmetry on the subjects' magnetic resonance images. Two patients, who had left temporal infarction but performed well on single word comprehension tasks, were also scanned while listening to speech. These cases showed right superior temporal activity correlating with increasing rates of hearing speech, but no significant left temporal activation. These findings together suggest that the dorsolateral temporal cortex of both hemispheres can be involved in prelexical processing of speech.
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5/37. Late acquired words in childhood are lost earlier in primary progressive aphasia.

    The psycholinguistic nature of the dissolution of the mental lexicon in a primary progressive aphasic patient was investigated in light of the general regression hypothesis that language dissolution is the inverse of language acquisition. Four years after onset of the symptoms, the patient scored 60% correct on a picture naming test, exhibiting some effects of lexical and sublexical age-of-acquisition, but 7 years after onset, he scored only 15% correct. While even a weak form of the regression hypothesis is not fully supported, age-of-acquisition effects seem to be preserved throughout the course of the lexical dissolution. Some implications are briefly discussed for future research.
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6/37. The application of cognitive event-related brain potentials (ERPs) in language-impaired individuals: review and case studies.

    There is a substantial body of basic research that has utilized ERPs to investigate the neurological basis of cognition. This research has, in turn, led to the development of practical applications of cognitive ERPs in patient populations. In particular, recent work has focused on the development of ERP-based assessment measures for the neuropsychological assessment of dyslexia and language impairments secondary to stroke. This review describes the innovative assessment methods program (IAMP), an initiative to utilize ERPs for a neuropsychological assessment of patients who cannot be evaluated by traditional methods. The success of this program has demonstrated that ERPs can be used to reliably evaluate an individual's reading and speech comprehension abilities, independent of behavioral and speech production impediments. In contrast to traditional neuropsychological assessment, these ERP methods can discern the cognitive strategies used by an individual to perform a task.
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7/37. Phonologically related lexical repetition disorder: a case study.

    Errors of repetition in aphasia are most often nonword substitutions. Phonologically related lexical errors, or formal errors, are real-word substitutions that overlap with target words in sound. In the present research we present the case of an aphasic patient, MMB, who produced an unusually high rate of formal paraphasias in repetition. Six experiments were conducted to investigate the combination of impairments contributing to MMB's pattern of repetition and to test the predictions made by two theories of formal errors. MMB's formal errors in repetition were influenced by target frequency, but not by target length or imageability. Formal errors tended to be more frequent than their targets and showed greatest phonological overlap with targets at initial consonant. These findings provided partial support for Martin and Saffran's fully interactive spreading activation account of formal errors and did not support Blanken's phonological interactive encoding account. In Experiment 6, the effect on repetition of increasing auditory verbal short-term memory (AVSTM) demands was examined using a paired word repetition experiment. Under these conditions, MMB produced semantic paraphasias for the first time, providing strong support for the Martin-Saffran hypothesis that phonologically related, and semantic, lexical repetition disorders lie on a continuum of severity moderated by the degree of AVSTM impairment.
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8/37. Experiences of ending aphasia therapy.

    Despite a considerable literature on assessment and treatment issues in aphasiology, little has been written about how therapy ends. We lack detail about how clinicians decide to terminate treatment and about how patients and carers view leaving therapy. This paper explores experiences and perceptions of aphasia treatment termination. It uses in-depth interview data gathered in south australia as part of a doctoral study with a speech pathologist, three ex-patients with aphasia and one spouse. This case study allows comparison of client and professional narratives to each other and also to the official discharge documentation in the medical file. The discharge process arising from this analysis is discussed.
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ranking = 9.7786076237753
keywords = perception
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9/37. Psychosocial aspects of aphasia: whose perspectives?

    This paper reviews some different meanings of the term 'psychosocial' and identifies the different ways in which the social and psychological sequelae of aphasia can be explored. These include qualitative methods, which seem well suited to addressing such complex issues. Having outlined some features of qualitative research, the paper describes a study in which fifty people talked about the consequences and significance of their long-term aphasia. Their 'insider perspective' on aphasia suggests its impacts are extensive, complex, direct and indirect, interconnected, systemic, dynamic and diversely experienced. The paper discusses the various implications of the study for clinicians and researchers concerned with the psychosocial aspects of aphasia and outlines how some of the issues raised in the interviews might be addressed.
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10/37. Impaired speech perception in aphasic patients: event-related potential and neuropsychological assessment.

    The mismatch negativity component (MMN) of auditory event-related potentials (ERP) was recorded in four aphasic patients and in age, gender and education matched controls. The MMN changes elicited by tone, vowel, voicing stop consonant and place-of articulation contrasts were recorded over both hemispheres. The results of MMN amplitude, latency and distribution differences between aphasics and controls were analyzed in detail. An extensive neuropsychological investigation was performed in order to highlight the assumed dissociation and possible interactions between the impaired acoustic/phonetic perception and deficient comprehension in aphasic patients. Our principal finding was that MMN elicited by pitch deviations is not enough sensitive to distinguish between patients and age-matched controls. The MMN elicited by consonant contrasts was found to be the most vulnerable in aphasic patients investigated. The MMN elicited by voicing ([ba:] vs. [pa:]) and place-of-articulation ([ba:] vs. [ga:]) could be characterized by total lack, distorted or very limited distribution and correlated with the patients' performance shown in the behavioral phoneme discrimination task. The magnitude of the deficient phoneme (vowel and consonant contrasts) processing shown by MMN anomalies was proportionally related to the non-word discrimination and did not interact with the word discrimination performance. The impact of deficient speech sound processing on higher level processes may depend on the type of aphasia, while the presence of perceptual deficits in processing acoustic/phonetic contrasts seems to be independent of the type of aphasia.
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ranking = 48.893038118877
keywords = perception
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