A closer look at unilateral versus bilateral deep brain stimulation: results of the National Institutes of Health COMPARE cohort.
OBJECTIVE
In this paper, the authors' aim was to examine reasons underpinning decisions to undergo, or alternatively forgo, a second-sided deep brain stimulation (DBS) implantation in patients with Parkinson disease (PD).


METHODS
Fifty-two patients with Parkinson disease (PD) were randomized to receive DBS to the subthalamic nucleus or globus pallidus internus (GPi) as part of the COMPARE trial. Forty-four patients had complete data sets. All patients were offered a choice at 6 months after unilateral implantation whether to receive a contralateral DBS implant. All patients had advanced PD. The mean patient age was 59.8 years (range 43-76 years), and the mean duration of disease was 12.2 years (range 5-21 years). The mean baseline Unified Parkinson's Disease Rating Scale (UPDRS)-III motor score was 42.7. The main outcome measures used in this study were the UPDRS-III Motor Scale and the UPDRS-IV Dyskinesia Scale.


RESULTS
Twenty-one (48%) of the 44 patients in the cohort did not undergo bilateral implantation and have been successfully treated for an average of 3.5 years; of these, 14 (67%) had a GPi target. The most common reason for adding a second side was inadequacy to address motor symptoms. Patient satisfaction with motor outcomes after unilateral DBS implantation was the most common reason for not undergoing bilateral implantation. Those who chose a second DBS procedure had significantly higher baseline UPDRS-III motor and ipsilateral UPDRS-III scores, and a significantly lower asymmetrical index. The logistic regression analysis revealed that the odds of proceeding to bilateral DBS was 5.2 times higher for STN than for GPi DBS. For every 1% increase in asymmetry, the odds of bilateral DBS decreased [corrected] by 0.96.


CONCLUSIONS
Unilateral DBS is an effective treatment for a subset of patients with PD. Baseline asymmetry is an important factor in the effectiveness and decision-making process between unilateral and bilateral DBS. Patients with GPi DBS in this cohort were more likely to choose to remain with unilateral implantation.
Taba
Houtan A
HA
Department of Neurology, University of Forlida Movement Disorders Center, College of Medicine, University of Florida, Gainesville, FL 32611, USA.
Wu
Samuel S
SS
Foote
Kelly D
KD
Hass
Chris J
CJ
Fernandez
Hubert H
HH
Malaty
Irene A
IA
Rodriguez
Ramon L
RL
Dai
Yunfeng
Y
Zeilman
Pamela R
PR
Jacobson
Charles E
CE
Okun
Michael S
MS
D000328:Adult; D000368:Aged; D015331:Cohort Studies; D046690:Deep Brain Stimulation; D006801:Humans; D008875:Middle Aged; D009316:National Institutes of Health (U.S.); D010300:Parkinson Disease / Q000628:therapy*; D014481:United States