The Japanese journal of neuropsychology

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ArticleTitle	Memory and the frontal-lobe-basal ganglia system in Parkinson's disease from a neuropsychological view point
Language	J
AuthorList	Tetsuhiro Maruyama
Affiliation	Department of Internal Medicine, Iida Municipal Hospital
Publication	Japanese Journal of Neuropsychology: 17 (3), 175-184, 2001
Received
Accepted
Abstract	Parkinson's disease (PD) is considered a human model of disordered basal ganglia function. Since a concept of 'subcortical dementia' emerged in neuropsychology, the basal ganglia are thought to play role not only in motor function, but also in cognitive function. Therefore, examining cognitive functions in patients with PD may be crucial to resolve the psychological function of the basal ganglia. These neuropsychological impairments associated with PD have been well documented. In our study, we have performed a series of neuropsychological assessments on patients with PD. Among the various cognitive disturbances, we have attempted to clarify three domains of explicit learning, memory associated with the frontal lobe such as working memory and prospective memory, and perceptual-motor skill learning, all of which are specifically disturbed in PD. In addition, we ewamined the neuropsychological relationships between these impairments and the stages of disease progress. We found that, under supraspan conditions, PD patients were explicity unable to encode information due to reduced central processing resources. As a result, they failed to gain total correct recall and delayed recall. Working memory spans were significantly reduced in the advanced PD group. Dopaminergic agents were effective in increasing the working memory span in the early group, but not in the advanced group. Prospective was impaired only in the advanced PD patients. Impaired prospective memory was considered to result from the deficiency of attentional resources, but not from a disturbed allocation of resources. The advanced PD group did not acquire perceptual-motor skills. In contrast, the early PD group acquired and preserved procedural learning, but they performed poorly in the transfer from one motor set another. These resultus suggest that specific memory impairments observed in the neuropsychological test may be attributed to an underlying pathology of frontal lobe, to which the basal ganglia are strongly linked.
Keywords	Frontal lobe, basal ganglia, Parkinson's disease, explicit memory, prospective memory, working memory, perceptual-motor skill learning