Acute effects of bilateral subthalamic nucleus stimulation on clinical andkinematic parameters in Parkinson's disease

After implantation with subthalamic stimulators, nine patients with advance d Parkinson's disease were studied on the task of tracing out, as accuratel y as possible, the four corners of a square with the dominant hand. The tas k was performed in four treatment conditions: on stimulation-off medication , off stimulation-off medication, off stimulation-on medication, and on sti mulation-on medication. Movement times and peak velocities improved signifi cantly only in the on stimulation-on medication condition compared to off s timulation-off medication. The improvement in clinical parameters with stim ulation only (relative to off stimulation off medication) was of borderline significance, while consistent and significant clinical improvement was on ly obtained with addition of medication (on medication-on stimulation). Thi s study provides quantitative evidence of the effect of subthalamic stimula tion on kinematic measures in Parkinson's disease (PD) and suggests that co mbined treatment (medication and stimulation) is superior to either treatme nt alone. (C) 2001 Movement Disorder Society.