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Biomedical subjects

S Sevush

Publications and source records attributed to S Sevush.

5 recordsLinked to original sources
PubMed1991

Positron emission tomographic studies during serial word-reading by normal and dyslexic adults.

Positron-emission tomography (PET) was used to study regional cerebral metabolic activity during oral reading in right-handed adult males with, and without a childhood and family history of developmental dyslexia. Significant group differences in normalized regional metabolic values were revealed in prefrontal cortex and in the lingual (inferior) region of the occipital lobe. Lingual values were bilaterally higher for dyslexic than normal readers. In contrast to the asymmetry observed in prefrontal and lingual regions in nondyslexic subjects during reading, the dyslexic pattern was more symmetric. These results demonstrate that individuals who suffered from familial developmental dyslexia as children, activate different brain regions during reading as adults, as compared to individuals without such childhood history.

Adult↗
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↗