J Neurol (2002) 249 : 529 – 534 © Steinkopff Verlag 2002 ORIGINAL COMMUNICATION S. Thobois P. Mertens M. Guenot M. Hermier H. Mollion M. Bouvard G. Chazot E. Broussolle M. Sindou Subthalamic nucleus stimulation in Parkinson’s disease Clinical evaluation of 18 patients Introduction Long-term treatment of Parkinson’s disease (PD) with levodopa is complicated by motor fluctuations and dyskinesias. This explains the renewed interest in surgi- cal approaches during the last decade [15, 16, 23, 24]. Studies in a non-human primates model of PD reveal that lesions or high frequency stimulation of the sub- thalamic nucleus (STN) reduce overactivity of this brain JON 663 ■ Abstract The aim of the present study was to assess the efficacy and safety of chronic subthalamic nu- cleus deep-brain stimulation (STN- DBS) in patients with Parkinson’s disease (PD). 18 consecutive se- verely affected PD patients were included (mean age, SD: 56.9±6 years; mean disease duration: 13.5±4.4 years). All the patients Received: 30 May 2001 Received in revised form: 21 September 2001 Accepted: 26 September 2001 Dr. S. Thobois () · H. Mollion · M. Bouvard · G. Chazot · E. Broussolle Service de Neurologie D Hopital Neurologique Pierre Wertheimer 59 Bd Pinel 69003 Lyon, France Tel.: +33-4/72 35-72 18 Fax: +33-4/7235-7351 E-Mail: stephane.thobois@chu-lyon.fr P. Mertens · M. Guenot · M. Sindou Department of Neurosurgery A Neurological Hospital Pierre Wertheimer Lyon, France M. Hermier Department of Neuroradiology Neurological Hospital Pierre Wertheimer Lyon, France were evaluated clinically before and 6 months after the surgical procedure using the Unified Parkinson’s Disease Rating Scale (UPDRS). Additionally, a 12 months follow-up was available in 14 patients. The target coordinates were determined by ventriculogra- phy under stereotactic conditions, followed by electrophysiology and intraoperative stimulation. After surgery, continuous monopolar stimulation was applied bilaterally in 17 patients at 2.9 ± 0.4 V through 1 (n = 31) or 2 contacts (n = 3). One patient had bilateral bipolar stimulation. The mean frequency of stimulation was 140 ± 16 Hz and pulse width 68 ± 13 μs. Off medica- tion, the UPDRS part III score (max = 108) was reduced by 55 % during on stimulation (score before surgery: 44.9 ± 13.4 vs at 6 months: 20.2 ± 10; p < 0.001). In the on med- ication state, no difference was noted between the preoperative and the postoperative off stimula- tion conditions (scores were re- spectively: 17.9 ± 9.2 and 23 ± 12.6). The severity of motor fluctuations and dyskinesias assessed by UP- DRS IV was reduced by 76% at 6 months (scores were respectively: 10.3 ± 3 and 2.5 ± 3; p < 0.001). Off medication, the UPDRS II or ADL score was reduced by 52.8% during on stimulation (26.9±6.5 preop ver- sus 12.7 ± 7 at 6 months). The daily dose of antiparkinsonian treatment was diminished by 65.5 % (levo- dopa equivalent dose – mg/D – was 1045 ± 435 before surgery and 360 ± 377 at 6 months; p < 0.01). These results remained stable at 12 months for the 14 patients studied. Side effects comprised lower limb phlebitis (n = 2), pulmonary em- bolism (n = 1), depression (n = 6), dysarthria and freezing (n = 1), sialorrhea and drooling (n = 1), postural imbalance (n = 1), tran- sient paresthesias and dyskinesias. This study confirms the great value of subthalamic nucleus stimulation in the treatment of intractable PD. Some adverse events such as de- pression may be taken into account in the inclusion criteria and also in the post-operative outcome. ■ Key words Parkinson’s disease · neurosurgery · subthalamic nucleus · deep brain stimulation · UPDRS · depression