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Treatment-related motor complications such as dyskinesias are a major problem in the long-term management of Parkinson's disease (PD). In sporadic PD, a relatively early onset of the disease is known to be associated with an early development of dyskinesias. Although linked with early onset, patients with Parkin-associated PD often show a stable long-term response to dopaminergic therapy without developing treatment-induced motor complications. Therefore, we reasoned that this difference in vulnerability to develop dyskinesias under long-term dopaminergic therapy may be associated with differences in movement-related activation patterns in Parkin-associated compared to sporadic PD. To test this hypothesis, medicated non-dyskinetic patients with either Parkin-associated or sporadic PD underwent functional magnetic resonance imaging (fMRI) while performing externally specified or internally selected movements. Patients with Parkin-associated and sporadic PD showed no difference in movement-related activation patterns. Moreover, the covariates 'age' and 'disease duration' similarly influenced brain activation in both patient groups. The present finding suggests that a stable long-term motor response in some patients with Parkin-associated PD may not be related to differences in cortical recruitment. In conclusion, our findings corroborate a substantial pathophysiologic overlap between Parkin-associated and sporadic PD and lend further support to the notion that Parkin-associated PD is a suitable genetic model for sporadic PD. [ABSTRACT FROM AUTHOR]

Objective: We report a patient with an ischemic lesion in right somatosensory cortex who developed dystonic posturing and pseudo-athetotic involuntary left-sided finger movements during voluntary muscle contractions.Methods: Motor excitability was assessed using transcranial magnetic stimulation techniques and electrical peripheral nerve stimulation. Results obtained from abductor digiti minimi muscles of both hands were compared.Results: On the affected side, silent period duration and intracortical inhibition were reduced, indicating a loss of inhibitory properties. Intracortical facilitation was enhanced. Stimulus-response curves showed a smaller increase of motor evoked potential amplitudes when recorded during muscle relaxation, but not during voluntary muscle activation.Conclusions: The results suggest that, under normal conditions, somatosensory cortex modifies inhibitory as well as excitatory properties in the motor system. [Copyright &y& Elsevier]