Biomedical subjects

N Monson

Publications and source records attributed to N Monson.

21 records · Page 2Linked to original sources

PubMedDate not supplied

Access to semantic memory in Parkinson's disease and multiple sclerosis.

The capacity to access semantic memory and the efficiency of the memory search were studied in patients with Parkinson's disease (PD) or multiple sclerosis (MS) using a modified version of the "Supermarket Test." PD and MS patients who performed normally on the Boston Naming Test generated as many specific exemplars and category labels as did controls, and these patients also searched their semantic memories as efficiently as controls. In contrast, PD and MS patients with impaired confrontational naming generated fewer specific exemplars, but a normal number of generic category labels. These naming-impaired patients searched their semantic memories less efficiently than controls. For both MS and PD patients, the efficiency of semantic memory search was significantly correlated with measures that reflect access to semantic memory (eg, performance on letter or category fluency tasks), but was not significantly related to measures of problem-solving ability derived from the Wisconsin Card Sorting Test. Inefficient search of semantic memory in MS and PD appears to arise from an inability to retrieve knowledge from semantic memory quickly or from the loss of information from semantic memory stores, rather than from impairment in the ability to formulate and deploy appropriate strategies for task solution.

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PubMedDate not supplied

Problem solving in Parkinson's disease: comparison of performance on the Wisconsin and California Card Sorting Tests.

Previous demonstrations that problem solving deficits may occur early in the course of Parkinson's disease (PD) have been taken to support the view that disturbances in the functioning of the frontal lobes are responsible for the initial cognitive deficits in this disease. However, no specific pattern of responding associated with poor problem solving by PD patients has been observed consistently. In an effort to clarify the nature of the problem solving deficits in PD we administered the Wisconsin Card Sorting Test (WCST) and the California Card Sorting Test (CCST), a new test which provides separate measures of concept generation, concept identification, and concept execution as well as several different measures of perseveration. On both tests PD patients of lower than normal mental status performed poorly and their patterns of performance resembled those previously described for patients with focal frontal lobe lesions, but PD patients of normal mental status performed normally. Because poor problem solving in association with increased perseverative responding was only observed for patients with global cognitive deficits these findings do not necessarily support the idea that frontal dysfunction is the principal cause of impaired cognition in PD. Although the overall pattern of results was similar for the WCST and the CCST, the CCST was more sensitive for detecting deficits than was the WCST.

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PubMedDate not supplied

Picture and motor sequencing in Parkinson's disease.

A recent report found that the discrepancy between scaled scores on the Vocabulary and Picture Arrangement subtests of the Wechsler Adult Intelligence Scale-Revised (WAIS-R) was much larger for patients with Parkinson's disease than for healthy controls or patients with Alzheimer's disease. On this basis, it was argued that Parkinson's disease causes a specific deficit in cognitive sequencing that occurs even when the memory and speed requirements of the task are minimal. However, other work indicated that Parkinson's disease patients are almost as severely impaired on other Performance subtests from the WAIS-R that do not require sequencing. In the present study, an extremely simple, untimed test of picture sequencing and a version of the Luria three-step test of motor sequencing were employed. Parkinson's disease patients were impaired on both tasks. The extent of their impairments on picture and motor sequencing were positively correlated, and the severity of deficits on both sequencing tests was related to global mental status and to performance on the Wisconsin Card Sorting Test, but not to neurologic measures of disease severity. However, the patients' performance on the picture sequencing test but not on the motor sequencing test was related to performance on Benton's Facial Recognition Test. These results demonstrate the existence of a generalized sequencing deficit in Parkinson's disease that appears dissociable from impairment in performing simple motor acts.

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