Objective: To compare non-motor symptom outcomes after globus pallidus internus (GPi) versus subthalamic nucleus (STN) deep brain stimulation (DBS) in Parkinson’s disease (PD).

Background: Non-motor symptoms (NMS) contribute substantially to disability, caregiver burden, and reduced quality of life in PD, yet most DBS studies primarily focus on motor outcomes. STN and GPi are established DBS targets with comparable motor efficacy, but potential differences in non-motor outcomes may influence individualized target selection in clinical practice.

Method: In this prospective, non-randomized cohort study, consecutive PD patients undergoing STN or GPi DBS were included. Clinical assessments were performed pre-DBS in the medication-ON state and at 6 months post-DBS in the stimulation-ON/medication-ON state. Outcomes included the Non-Motor Symptoms Scale (NMSS), Parkinson’s Disease Sleep Scale (PDSS), Parkinson Fatigue Scale-16 (PFS-16), King’s Parkinson’s Disease Pain Scale (KPSS), Parkinson’s Disease Questionnaire-39 (PDQ-39), Montreal Cognitive Assessment (MoCA), Frontal Assessment Battery (FAB), Beck Depression Inventory (BDI), and Apathy Evaluation Scale. Between-target comparisons were performed using multivariate regression and ANCOVA adjusting for baseline scores, demographics, and medication variables.

Results: Fifty-four GPi and 57 STN patients participated. STN patients were younger (p=0.019) and had worse baseline scores in NMSS, PDSS, PFS-16, KPSS and PDQ39 (p<0.01 for all scores). Both targets gave significant improvements in sleep, fatigue, pain, and depression (p <0.01 for all), with unchanged cognition, FAB and apathy scores. After adjustment for baseline differences, between-target differences were not observed in non-motor outcomes (all p >0.05). Among patients receiving antidepressants pre-DBS, dose escalation was required more frequently (p<0.001) after STN DBS (46.9%) than GPi DBS (6.9%). Reduction in levodopa equivalent daily dose was greater in the STN group (p<0.001).

Conclusion: STN and GPi DBS provide comparable short-term improvement in non-motor symptoms. The higher rate of antidepressant dose escalation after STN DBS suggests potential mood worsening, possibly related to limbic STN stimulation or dopaminergic medication reduction.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/comparison-of-non-motor-outcomes-after-subthalamic-nucleus-versus-globus-pallidus-internus-deep-brain-stimulation-in-parkinsons-disease/