Correlation of antero-dorsal active contact location with weight gain after subthalamic nucleus deep brain stimulation: a case series

Abstract Background Weight gain is a frequently reported side effect of subthalamic deep brain stimulation; however, the underlying mechanisms remain unclear. The active contact locations influence the clinical outcomes of subthalamic deep brain stimulation, but it is unclear whether weight gain is directly associated with the active contact locations. We aimed to determine whether weight gain is associated with the subthalamic deep brain stimulation active contact locations.Methods We enrolled 14 patients with Parkinson’s disease who underwent bilateral subthalamic deep brain stimulation between 2013 and 2019. Bodyweight and body mass index were measured before and one year following surgery. The Lead-DBS Matlab toolbox was used to determine the active contact locations based on magnetic resonance imaging and computed tomography. Fluorodeoxyglucose-positron emission tomography data were also acquired before and one year following surgery, and statistical parametric mapping was used to evaluate changes in brain metabolism. The relationship between weight and active contact locations was evaluated with a Spearman rank test with a corrected p-value < 0.008. We examined which brain regions’ metabolism fluctuation significantly correlated with increased BMI scores and PET data.Results The body mass index increase was 2.03 kg/m2 1 year post-surgery. Weight gain was correlated with anterior and dorsal locations of the left-side active contacts, as well as with lateral locations of the right-side active contacts. Furthermore, weight gain was correlated with increased metabolism in the left-side limbic and associative regions, including the middle temporal gyrus, inferior frontal gyrus, and orbital gyrus.Conclusions Although the mechanisms underlying weight gain following subthalamic deep brain stimulation are possibly multifactorial, our findings suggest that anterior subthalamic deep brain stimulation alters the activities in the limbic and associative cortical regions, which may then lead to weight gain. Weight gain could be prevented by avoiding stimulation to the anterior part of the subthalamic nucleus.