Functional irregularities of short-term and long-term memory storage in patients with Parkinson's disease and Huntington's disease.

Memory performance of Parkinson's disease patients (PD patients). Huntington's disease patients (HD patients) and healthy subjects were compared by a single-trial free recall task following the presentation of a stimulus list consisting of 30 nouns. The patient groups were categorized according to the severity of the disease into mild, moderate, and severe. Healthy subjects reproduced significantly more words than PD and HD patients, while the two patient groups did not differ in the total number of words reproduced. The differences between healthy and demented subjects are attributed to the impaired functional capacity of long-term memory; there were significant differences between healthy subjects and patients as well as between PD and HD patients. When taking the severity of the disease into consideration, varied influence on the capacity of long-term memory for PD and HD patients was found. Concerning short-term memory, neither a difference between healthy subjects and patients nor between both patient groups could be established. An effect of the severity of the disease could not be proven.