Brain morphometry is not associated with non-motor outcomes after deep brain stimulation in Parkinson's disease

Deep brain stimulation of the subthalamic nucleus (STN-DBS) is an established therapy in advanced Parkinsons disease (PD). Motor and non-motor outcomes, however, show considerable inter-individual variability. Morphometry-based metrics have recently received increasing attention to predict treatment effects. As evidence for the prediction of non-motor outcomes is limited, we sought to investigate the association between metrics of voxel-based morphometry and short-term non-motor outcomes following STN-DBS in this prospective open-label study. 49 PD patients underwent structural MRI and a comprehensive clinical assessment at preoperative baseline and 6-month follow-up. Voxel-based morphometry was used to assess associations between cerebral volume and non-motor outcomes corrected for multiple comparisons using a permutation-based approach. We replicated existing results associating atrophy of the superior frontal cortex with subpar motor outcomes. Non-motor outcomes, however, were not associated with morphometric features, limiting its use as a marker to inform patient selection and holistic preoperative counselling.