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Biomedical subjects

S Sevush

Publications and source records attributed to S Sevush.

28 records · Page 2Linked to original sources
PubMed1991

Improved verbal learning after outpatient oral physostigmine therapy in patients with dementia of the Alzheimer type.

BACKGROUND: Previous investigators have reported improvements in verbal learning in outpatients suffering from dementia of the Alzheimer type (DAT) when they were treated daily with oral physostigmine for periods of days to months. Questions remain, however, regarding both the specificity of the induced cognitive changes and the time course of the biological activity of the drug when physostigmine was used to treat DAT patients. We examined both of these parameters in an outpatient, double-blind, placebo-controlled study that examined the effect of physostigmine on memory and other cognitive functions. METHOD: Eight DAT patients were treated for 3 weeks with oral physostigmine administered four times daily in a double-blind, crossover, placebo-controlled study. An auditory verbal learning test (AVLT) was administered to assess verbal learning. Digit span, word fluency, and frequency of intrusions served as controls for nonspecific changes in attention and verbal responsiveness. RESULTS: AVLT scores improved after drug administration compared with scores for baseline and placebo performances (p = .04). Other measures were unchanged. Improvement was unrelated to the time interval between memory testing and last ingested dose. CONCLUSIONS: These results indicate a longer period of biological activity for physostigmine than previously considered and extend previous reports of improved verbal learning after oral physostigmine treatment to a more convenient dosing schedule. These results suggest further that the improvements induced by physostigmine result specifically from enhancement of long-term memory processes.

Administration, Oral↗
PubMed1989

Positional dyslexia.

Position-specific errors in word reading are usually associated with neglect or visual extinction on the same side as the reading problem. In this study, two patients with left-hemisphere lesions showed visual extinction on the right but reading difficulty on the left side of words and pseudowords. Further study of one patient revealed that he also had problems reading the beginning of words presented tachistoscopically or in vertical orientation. In addition, the positional difficulty was apparent when he named the letters in words. The pattern of results indicates that the positional dyslexia in these patients was not likely attributable to general deficits in visual perception or attention but may have reflected a disorder at a later stage of letter processing.

Attention↗
PubMed1987

Accurate reading by nonlexical means: a case study.

Accurate reading of irregular words is generally assumed to require intact lexical reading mechanisms. A nonlexical mechanism is usually deemed insufficient for this type of stimulus processing. The maximum level of accuracy attainable by nonlexical means, however, has not been adequately evaluated. We now describe a patient with acquired dyslexia due to impaired lexical reading mechanisms who retained the ability to read irregular words. The patient's poor performance on tasks requiring lexical decision and access to word meaning provided evidence that his lexical mechanisms were impaired. Nevertheless, errors on irregular words became apparent only with special tests that circumvented the patient's ability to use his intact speaking vocabulary to ensure that reading responses were words. The results demonstrate that relatively accurate reading of irregular words is possible despite damage to lexical mechanisms and that this can be achieved by filtering potential responses through the speaking vocabulary.

Dyslexia, Acquired↗
PubMed1984

A case of literal alexia: evidence for a disconnection syndrome.

We describe a patient with literal alexia, agraphia, and only minimal aphasia, resulting from a left occipito-parietal ischemic infarction. Neither impaired visual processing nor impaired oral output could explain the patient's letter reading deficit, since he retained the ability to match letters of mixed case, and remained able to spell aloud and to pronounce and comprehend orally spelled words. His residual word reading was characterized by better performance for nouns and highly imageable words than for functors , poorly imageable words, and nonwords. We propose that this patient's letter reading deficit was due to a partial disconnection of his visual from his linguistic systems, with residual word reading accomplished by a semantically mediated compensatory mechanism. We suggest, further, that the dissociations between word and letter reading observed in some alexic individuals may be attributed, in part, to a difference in the relative contributions of dorsal and ventral occipital structures to the reading process.

Agraphia↗
PubMed1983

Pure Gerstmann's syndrome from a focal lesion.

It is controversial whether a focal lesion can specifically induce Gerstmann's syndrome (dyscalculia, left-right disorientation, finger agnosia, and agraphia). Also, Gerstmann's tetrad has been attributed to other cerebral symptoms, particularly aphasia. We examined a patient who had all four symptoms of Gerstmann's syndrome, without other symptoms or signs, and who had a discrete left parietal lesion.

Aphasia↗
PubMed1983

Phonological agraphia: writing by the lexical-semantic route.

Two writing routes (phonological and lexical) have been postulated. We studied four patients who had disruption of the phonological route (ie, inability to write pronounceable nonwords) but with a preserved lexical route. Results showed that the phonological route has two components: segmentation and phoneme-grapheme conversion. Disruption of either function may induce phonological agraphia. The preserved lexical route uses a whole-word mechanism and is strongly affected by semantic factors, such as imageability, emotionality, and grammatic class. Results of CT suggest that a portion of the supramarginal gyrus is the most likely anatomic substrate of phonological agraphia.

Adult↗
PubMed1983

Preserved oral reading in Wernicke's aphasia.

In two patients with Wernicke's aphasia, both oral reading and reading comprehension were relatively preserved despite total destruction of Wernicke's area. The pattern of oral reading suggested an intact ability to derive phonology directly from print; the pattern of reading comprehension implied at least partial ability to interpret syntactic constructions. These features are not readily compatible with current notions of right hemisphere function and may suggest that undamaged left hemisphere structures mediated residual reading in these patients.

Aphasia↗