Toward a theory of therapy for aphasia.
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Aphasia↗
Biomedical subjects
P M Beeson
Publications and source records attributed to P M Beeson.
Acquired alexia: lessons from successful treatment.
Two individuals with anomic aphasia and acquired alexia were each provided treatment for their reading impairment. Although reading of single words in isolation was fairly accurate, their text reading was slow and effortful, including functor substitutions and semantic errors. Prior to treatment, reading reaction times for single words showed grammatical class and word-length effects. Both patients responded positively to a treatment protocol that included two phases: (1) multiple oral rereading of text, and (2) reading phrase-formatted text that had increased spacing between phrasal clauses. Their reading rates for text improved while maintaining good comprehension. Following treatment, reading reaction times for single words showed the elimination of grammatical class and word-length effects, suggesting improved access to word forms, particularly functors.
Adult↗
Spoken language of individuals with mild fluent aphasia under focused and divided-attention conditions.
The spoken language of individuals with mild aphasia and age-matched control subjects was studied under conditions of isolation, focused attention, and divided attention. A picture-description task was completed alone and in competition with a tone-discrimination task. Regardless of condition, individuals with aphasia performed more poorly on most morphosyntactic, lexical, and pragmatic measures of spoken language than control subjects. Increasing condition complexity resulted in little quantitative or qualitative change in the spoken language of the control group. In contrast, the individuals with aphasia showed dual-task interference; as they shifted from isolation to divided-attention conditions, they produced fewer syntactically complete and complex utterances, fewer words, and poorer word-finding accuracy. In pragmatic terms, their communication was considered less successful and less efficient. These results suggest that decrements of attentional capacity or its allocation may negatively affect the quantity and quality of the spoken language of individuals with mild aphasia.
Adult↗
Auditory processing in individuals with mild aphasia: a study of resource allocation.
This study examined the effects of lesion location (frontal vs. posterior) and nature of distraction (nonverbal vs. verbal secondary, competing task) on mildly aphasic individuals' performances of listening tasks that required semantic judgments and lexical decisions under isolation, focused attention, and divided attention conditions. Despite comparable accuracy among all groups during isolation conditions, the aphasic groups responded less accurately and more slowly than the normal control group during focused and divided attention conditions. Generally, the two aphasic groups performed similarly, quantitatively and qualitatively. Demographic characteristics such as time post stroke did not correlate with performance decrements. Independent of group, all individuals showed greater disruption of auditory processing skills when the secondary task was verbal rather than nonverbal. Within a limited-capacity model of attention, the results suggest that aphasic individuals display impairments of attention and resource allocation and that these impairments negatively interact with their auditory processing abilities.
Adult↗
Anterograde memory impairment in Pick's disease.
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Dementia↗
Praxis and the right hemisphere.
We report our observations on praxis in a strongly right-handed man following a massive stroke that resulted in virtually complete destruction of the left cerebral hemisphere. Our patient was severely impaired in pantomiming transitive gestures with the left hand and in reproducing novel non-symbolic hand and arm movement sequences. However, overlearned habitual actions like actual object use and intransitive gestures were relatively spared. Performance of axial commands was intact. Gesture recognition and discrimination were also preserved. Based on these findings, we propose that the praxis system of the right hemisphere is strongly biased toward "concrete" or context-dependent execution of familiar, well-established action routines. The right hemisphere is critically dependent on transcallosal contribution from the left hemisphere for control of the left hand in "abstract" or context-independent performance of transitive movements and in learning novel movement sequences. At least in some individuals, the right hemisphere can recognize and discriminate gestures. Possible implications of our findings for the cerebral control of praxis and for recovery from apraxia are discussed.
Aphasia, Broca↗
Memory impairment and executive control in individuals with stroke-induced aphasia.
The purpose of this study was to examine memory abilities of aphasic individuals in relation to site of neurological lesion. Fourteen individuals with stroke-induced aphasia (7 with anterior lesions; 7 with posterior lesions) and 14 demographically matched control subjects were given selected tests of short-term memory (STM) and long-term memory (LTM). Stroke patients were impaired relative to control subjects on tests of verbal memory, with greater impairment of LTM associated with anterior lesions and greater impairment of STM associated with posterior lesions. Verbal memory performance did not correlate highly with language ability, and did not appear to be simply a consequence of language impairment. Executive control deficits were postulated as explanatory of the LTM impairment associated with anterior lesions.
Aged↗
Writing with the right hemisphere.
We studied writing abilities in a strongly right-handed man following a massive stroke that resulted in virtually complete destruction of the language-dominant left hemisphere. Writing was characterized by sensitivity to lexical-semantic variables (i.e., word frequency, imageability, and part of speech), semantic errors in writing to dictation and written naming, total inability to use the nonlexical phonological spelling route, and agrammatism in spontaneous writing. The reliance on a lexical-semantic strategy in spelling, semantic errors, and impaired phonology and syntax were all highly consistent with the general characteristics of right hemisphere language, as revealed by studies of split-brain patients and adults with dominant hemispherectomy. In addition, this pattern of writing closely resembled the syndrome of deep agraphia. These observations provide strong support for the hypothesis that deep agraphia reflects right hemisphere writing.
Agraphia↗