Biomedical subjects

D W Desmond

Publications and source records attributed to D W Desmond.

3 recordsLinked to original sources

PubMed1992

Confusion and memory loss from capsular genu infarction: a thalamocortical disconnection syndrome?

We examined six patients with an abrupt change in behavior after infarction involving the inferior genu of the internal capsule. The acute syndrome featured fluctuating alertness, inattention, memory loss, apathy, abulia, and psychomotor retardation, suggesting frontal lobe dysfunction. Contralateral hemiparesis and dysarthria were generally mild, except when the infarct extended into the posterior limb. Neuropsychological testing in five patients with left-sided infarcts revealed severe verbal memory loss. Additional cognitive deficits consistent with dementia occurred in four patients. A right-sided infarct caused transient impairment in visuospatial memory. Functional brain imaging in three patients showed a focal reduction in hemispheric perfusion most prominent in the ipsilateral inferior and medial frontal cortex. We infer that the capsular genu infarct interrupted the inferior and anterior thalamic peduncles, resulting in functional deactivation of the ipsilateral frontal cortex. These observations suggest that one mechanism for cognitive deterioration from a lacunar infarct is thalamocortical disconnection of white-matter tracts, in some instances leading to "strategic-infarct dementia."

Aged↗

PubMed1992

Left hemiparalexia.

Three patients with left splenial lesions made paralexic errors restricted to the left end of words. Errors appeared more frequently when a correct response was highly dependent on the initial letter of the stimulus. One patient had full visual fields with hemialexia affecting the left visual field. The other two patients had complete right hemianopia. We attribute left-sided reading errors in the hemianopic patients to a retinotopically restricted disconnection pattern that selectively disrupts transfer of information originating from the peripheral left visual field. Functional resistance of the more numerous transcallosal projections representing visual field adjacent to the vertical meridian may account for such a pattern. The emergence of positional reading errors from retinotopically restricted left hemifield disconnection suggests that callosal information transfer during normal reading may primarily involve elemental sensory rather than lexical/semantic information.

Adult↗

PubMed1992

Dementia after stroke: baseline frequency, risks, and clinical features in a hospitalized cohort.

We determined the frequency of dementia in a cohort of 251 patients aged greater than or equal to 60 years hospitalized with acute ischemic stroke, based on examinations performed 3 months after stroke onset. Using modified DSM-III-R criteria, we found dementia in 66 patients (26.3%). Diagnostic agreement among raters was excellent (kappa = 0.96). In a control sample of 249 stroke-free subjects recruited from the community and matched by age, we found dementia in eight subjects (3.2%). Using a logistic regression model to estimate the risk of dementia associated with stroke in the combined samples, the odds ratio (OR) for stroke patients compared with control subjects was 9.4 (p less than 0.001). Advancing age and fewer years of education were significant, independent correlates of dementia, with a trend evident for race (non-white versus white). Confining the analysis to subjects residing in the Washington Heights-Inwood community of northern Manhattan, the OR was 10.3 (p less than 0.001) with significant age and race effects. We conclude that ischemic stroke significantly increases the risk of dementia, with independent contributions by age, education, and race.

Aged↗