Patients with Parkinson's disease (PD) exhibit impairments in the execution of highly practiced and skilled motor actions such as handwriting. The analysis of kinematic aspects of handwriting movements has demonstrated that size, speed, acceleration and stroke duration are affected in PD. Although beneficial effects of dopaminergic therapy in regard to execution of movements have been reported, the effects of pharmacological therapy on these measures have not been examined in detail. The present study has compared kinematic aspects of handwriting movements of 27 healthy subjects and 27 patients with PD both on their usual dopaminergic treatment and following withdrawal of dopaminergic medication. Healthy subjects were matched with PD patients according to age, sex, handedness and education level. A digitising tablet was used for the assessment of handwriting movements. Subjects were asked to perform a simple writing task. Movement time, distance, velocity, acceleration and measures of fluency of handwriting movements were measured. Compared with healthy subjects, the kinematics of handwriting movements in PD patients were markedly disturbed following withdrawal of dopaminergic medication. Although dopaminergic treatment in PD patients resulted in marked improvements in the kinematics of handwriting movements, PD patients did not reach an undisturbed level of performance. The results suggest that dopamine medication results in partial restoration of automatic movement execution.
We report on a patient with long standing, full-blown mitochondrial encephalomyopathy, lactic acidosis and stroke-like episodes (MELAS). In contrast to earlier publications, detailed neuropsychological assessment revealed no dementia but a pattern of distinct cognitive deficits with marked impairment of visuo-constructive and executive functions. Focal lesions and progressing atrophy mainly of the basal ganglia and the temporo-parieto-occipital area with preservation of hippocampal and entorhinal structures were present. Furthermore, a 4-year follow-up assessment revealed an increasing deterioration of distinct cognitive functions, including phasic alertness, tactile functions and the discrimination of tone pitch and rhythm. This may be because of chronic regional metabolic disturbances, as there was no further stroke-like episode in that period of time.
The results suggest either that TCAs have adverse effects on motor functioning or that they are less effective in the treatment of motor retardation than SSRIs.
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