Deep brain stimulation improves performance of complex instrumental paradigms

Patients with Parkinson's disease (PD) show deficits of motion behaviour and cognitive function, which were assessed with various instrumental paradigms. Objectives of the present trial were to investigate the effects of bilateral deep brain stimulation (DBS) of the subthalamic nucleus (STN) on the performance of complex and simple movement series, on the execution of simple reaction time (SRT) paradigms following an acoustic or a visual stimulus, on scored motor symptoms and the interrelation of the various study parameters in PD patients. Motor symptoms, operation of complex movements, and the execution of SRT tasks significantly improved when the stimulator was switched on. Execution of simple movement series did not differ between the on and off conditions of the stimulator. Instrumental test results significantly correlated with scored motor symptoms in particular during the off condition. During the on state, significant correlations were found between the performance of complex motion sequences and the SRT outcomes. PD patients treated with DBS of the STN show better results for more complex instrumental paradigms with a higher need for cognitive effort during the on situation due to improvements in motor performance, function of the basal ganglia-thalamocortical circuitry and cognitive function.