Predicting cognition after subthalamic Deep Brain Stimulation in Parkinson’s Disease

Background Cognitive deficits have a high impact on quality of life of patients with Parkinson’s disease (PD). Age > 70 years and dementia are considered risk factors for cognitive decline after deep brain stimulation (DBS) but evidence on the highly relevant individual cognitive prognosis is scarce. This study takes into account the multifaceted etiology of cognition in order to refine estimation of the cognitive outcome after DBS surgery in PD. Methods Clinical, neuropsychological, perioperative, neuroimaging- and laboratory-based risk factors for cognitive dysfunction were prospectively assessed prior to DBS surgery in 57 patients with PD (21 female; age 60.2 ± 8.2; disease duration 10.5 ± 5.9 years). In addition to univariable correlations, elastic net regularized regression and leave-one-out cross-validation were used to fit a multivariable model with the Montréal Cognitive Assessment (MoCA) one year after surgery as primary outcome. Results Of all assessed possible predictors, the backward span of the SSP had the most robust association with the cognitive outcome (rho = 0.499, p < 0.001**; c = 0.302). Other factors significantly associated with cognition after DBS surgery were CSF dementia markers, serum C-reactive protein, severity of motor fluctuations, the number of impaired cognitive domains, forward spatial span length, multitasking performance and the duration of postoperative delirium. Based on our multivariable model results, we propose a post-hoc prediction model for cognition based on the baseline MoCA and backward span (R² = 0.50). Conclusions Our findings highlight the multifaceted influencing factors on the cognitive outcome after DBS. After clinical validation, our short and easily applicable prediction model could improve informed therapeutic decision making.