Biomedical subjects

K Rammohan

Publications and source records attributed to K Rammohan.

4 recordsLinked to original sources

PubMed1996

Screening for cognitive dysfunction in multiple sclerosis.

BACKGROUND: With the use of comprehensive neuro-psychological assessments, a substantial proportion of patients with multiple sclerosis have been found to have substantial cognitive impairment. Although data generated from comprehensive examinations are useful in making recommendations for treatment interventions and compensatory strategies, the cost of such assessments prohibits their use with all patients. OBJECTIVE: To develop a screening battery to detect cognitive impairment in patients with multiple sclerosis that is sensitive, specific, brief, and cost-effective, and could identify patients who might benefit from a more comprehensive neuropsychological examination. DESIGN: On the basis of a comprehensive neuropsychological assessment battery, the presence of significant cognitive impairment was determined in patients with multiple sclerosis. The screening battery consisted of a subset of tests from the comprehensive battery. Performance on the screening battery was then used to predict presence of cognitive impairment on the comprehensive battery in validation and cross-validation samples. Severity of impairment on the screening battery was also regressed on ratings of functional impairment derived from the Expanded Disability Status Scale. RESULTS: In the validation sample, the screening battery had 100% sensitivity, 80% specificity, and 88.1% overall diagnostic accuracy. In the cross-validation sample, the screening battery had 100% sensitivity, 81.8% specificity, and an overall diagnostic accuracy rate of 90.7%. chi 2 tests showed that the accuracy of the screening battery was significantly better than chance in both samples. Performance on the screening battery also predicted the level of disability ratings on the Expanded Disability Status Scale and functional systems scales. CONCLUSIONS: The screening battery had a high degree of sensitivity, specificity, and diagnostic accuracy, while maintaining a brief administration time and high cost-effectiveness. The screening battery also predicted higher levels of disability and functional impairment as assessed by the Expanded Disability Status Scale, thereby enhancing its clinical utility. Despite its advantages, the findings do not suggest that the screening battery may be an effective substitute for a more detailed examination.

Adult↗

PubMed1987

Magnetic resonance imaging correlates of dementia in multiple sclerosis.

Thirty-two patients with clinically definite multiple sclerosis were evaluated with neuropsychological procedures and magnetic resonance imaging (MRI). Neuropsychological evaluation included assessment of language, memory, cognition, visuospatial skills, and depression. Significant impairment in any three areas, compatible with diagnosis of a dementia syndrome, was observed in 28% of these patients, and lesser or no cognitive impairment characterized the remaining patients. Magnetic resonance imaging was used to evaluate the number and distribution of lesions as well as the presence of cerebral atrophy and atrophy of specific anatomic structures such as the corpus callosum. Results suggest that neither the number of lesions, the distribution of lesions, nor the extent of generalized cerebral atrophy was significantly greater in demented compared with non-demented patients. The primary finding was that atrophy of the corpus callosum was significantly more extensive on MRI scans in demented patients. Although the callosum itself may not be implicated directly in the pathogenesis of dementia, the presence of callosal atrophy on MRI scans should alert the physician to the possible occurrence of dementia in patients with multiple sclerosis.

Adult↗

PubMed1986

Red-green mixture thresholds in congenital and acquired color defects.

A color television display was used to measure thresholds for mixtures of red and green on a white background; red and green components could be either incremental, decremental or zero. Ellipses are fitted to a plot of green contrast as a function of red contrast, and it is argued that the length of the ellipse is a measure of red-green color discrimination and the width of the ellipse is a measure of luminance discrimination. It is shown that the technique reliably distinguishes normals from congenital color defectives and also protan from deutan subjects. For some cases of acquired color defects (e.g. optic neuritis), there is a roughly equal loss of color and luminance discrimination whereas, in other cases (e.g., hereditary optic atrophies), the loss of color discrimination is much greater than the loss of luminance discrimination.

Adult↗

PubMed1986

Evaluation of the structural proteins of the hamster neurotropic strain of measles virus with monoclonal antibodies.

The virus-specified proteins produced by cells persistently infected with hamster neurotropic strain (HNT) of measles virus were assessed by a panel of monoclonal antibodies. In comparison to the Edmonston strain a number of differences were detected. The HA protein lacks epitopes identified by certain monoclonal antibodies. Some of the absent epitopes may relate to agglutination, because this biological phenomenon is not produced by HNT virus. Phosphoprotein (P) of the usual size (70 kDa) was not detected. Instead a protein with an approximate MW of 36 kDa which reacted with one monoclonal anti-P was identified. Although matrix protein (M) was not detected, mRNAs for P and M proteins were present. However, these in contrast to the mRNAs from Edmonston strain, did not translate in vitro. These abnormalities may relate to neurotropism and the capacity of HNT to produce persistent CNS infection.

Animals↗