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Biomedical subjects

J Shuren

Publications and source records attributed to J Shuren.

10 recordsLinked to original sources
PubMed1998

Perseverative writing errors in a patient with Alzheimer's disease.

This study reports the writing performance of a dysgraphic patient with Alzheimer's disease and moderate dementia who frequently perseverated on strokes and letters. Letter formation errors were also frequently produced. Oral spelling was superior to written spelling. The habitual style of writing (cursive writing) was significantly more prone to perseverations than writing in uppercase letters, a form of writing less frequently used by the patient. Central (linguistic) spelling processes were relatively preserved. The pattern of preserved and impaired functions is consistent with impairment of the peripheral mechanism that generates the graphic motor patterns code. We suggest that damage to the peripheral orthographic mechanism may cause deficits in some patients with Alzheimer's disease.

Aged↗
PubMed1998

The effects of rotation on spatial attention.

Unilateral spatial neglect can be reduced by cold water caloric stimulation of the contralesional ear. Three hypotheses may account for this response. Caloric stimulation may increase the arousal of the damaged hypoaroused hemisphere. Moving stimuli to ipsilesional space improves the performance of patients with neglect. Caloric stimulation may move viewer-centered spatial maps in an ipsilesional direction. Unilateral neglect may be related to a spatial attentional bias. Vestibular stimulation may temporarily influence this bias. To learn if vestibular stimulation may induce an attentional spatial bias, the authors studied eight normal subjects by having these subjects attempt to bisect lines before and during vestibular stimulation. If caloric stimulation alters neglect because it changes the attentional spatial bias, the authors should be able to induce neglect in normal subjects by pertubating the vestibular system. Vestibular stimulation was induced by spinning a chair and then abruptly stopping the spinning chair. The authors found that after normal subjects were rotated to the left, they misbisected lines to the left but did not misbisect lines after they were rotated to the right. Although these results support the postulate that vestibular stimulation can induce an attentional spatial bias, the authors' results also suggest that there are intrinsic attentional asymmetries.

Adult↗
PubMed1996

Pictorial superiority during verbal learning tasks in moderate to severe closed head injury: additional evidence.

Evidence for picture superiority in verbal learning following moderate to severe closed head injury (CHI) was found in a study involving 31 participants with CHI and 31 noninjured participants. A multitrial free-recall paradigm was implemented incorporating three modalities: Auditory, visual, and simultaneous auditory plus visual. Participants with moderate to severe CHI learned fewer words and at a slower rate than the noninjured participants. The visual presentation of objects (with or without the simultaneous auditory presentation of names) resulted in better learning than the auditory presentation alone.

Adolescent↗
PubMed1995

Impaired perception of facial identity and facial affect in Huntington's disease.

We tested five patients with Huntington's disease on tasks of facial discrimination and facial affect discrimination and matching. Four patients were impaired on a task or tasks of face discrimination, and all patients were impaired on at least one task of facial affect discrimination. We suggest that these findings reflect the role of the basal ganglia or its connections in visual processing.

Adolescent↗
PubMed1995

Emotional facial imagery, perception, and expression in Parkinson's disease.

Patients with Parkinson's disease (PD) may be impaired at expressing emotional faces and perceiving emotional facial affect. We tested the hypothesis that patients with PD may be impaired at imaging emotional faces. We first compared 12 patients with PD and 30 control subjects on perceptual and imagery tasks. Patients were significantly impaired on a task of emotional facial imagery but not on a control task of object imagery. Patients were also impaired on a task of perceiving emotional faces. Subsequently, we found that PD patients were impaired relative to controls on making emotional faces. Performance on both the perceptual and motor tasks of facial expression significantly correlated with performance on the emotional facial imagery task. We suggest that the basal ganglia, together with the right hemisphere, are part of a neural network subserving emotional facial tasks.

Aged↗
PubMed1994

The neglected page.

Normal subjects bisect vertical lines above the true midpoint. We posited that the portion of the page farthest from the line or the page's geometric center, though not the focus of attention, would still engage attention. Therefore, subjects should make bisection errors in the direction of the distant portion or geometric center. We expected the greatest superior bisection errors to be made when lines were placed at the bottom of the page and the smallest errors to be made when the lines were placed at the top of the page. Ten young, normal subjects bisected vertical lines placed in 1 of 3 positions on a page (top, center, bottom) with the page located in 1 of 3 spatial locations (superior, middle, inferior). The results of our study were consistent with our predictions. Thus, although the page on which a line is bisected is often ignored, it is not neglected.

Adult↗
PubMed1994

Proximal intentional neglect: a case study.

Although neglect has been demonstrated in the horizontal, vertical, and radial planes of space and has been attributed to sensory-attentional, motor-intentional, and representational deficits, motor intentional neglect in the radial plane has not been previously described. A patient who had a right parietal infarct was tested with a modified cancellation task that uses a fixed window, thereby controlling attentional demands and allowing one to dissociate between intentional and representational neglect. This patient showed proximal (radial) intentional neglect (a failure to move towards or in proximal space). Unlike controls whose search times decreased with increasing window size, our patient showed no change in search time as a function of window size. This pattern of behaviour suggests that the patient's search strategy does not incorporate factors such as the relation between a fixed target space and a variably sized aperture, but rather was based on the allocation of a certain amount of resources for a fixed period of time after which, regardless of performance, the patient would stop searching.

Aged↗
PubMed1993

Insula and aphasia.

A 59-year-old woman developed impaired speech initiation as the result of a left anterior insular infarct. Findings from this case suggest that dominant hemisphere anterior insular lesions impair the speech initiation loop.

Aphasia, Broca↗
PubMed1993

Nonoptic aphasia: aphasia with preserved confrontation naming in Alzheimer's disease.

Patients with Alzheimer's disease (AD) frequently exhibit anomia early in the course of the disease. Current theories of naming describe lexical retrieval in visual confrontation naming as requiring processing through the semantic system before lexical access. We report on three patients with AD who demonstrated severely impoverished spontaneous speech, impaired list generation, but preserved visual confrontation naming. Extensive investigation of one of these patients revealed an impairment of semantic knowledge. Our results support previous theories that there are two routes to visual naming, one via the semantic system and one directly from the internal visual representation to the lexicon. We labeled this aphasia resulting from an impaired semantic system but a preserved direct route to the lexical system as "nonoptic aphasia" and suggest that it is the earliest language deficit in some patients with AD.

Aged↗