Objective: The study aims to determine whether STN-DBS brings about clinical benefits for Parkinson’s disease dementia (PDD) patients and its association with metabolic change in FDG-PET.

Background: PDD is a contraindication for STN-DBS based on the hypothesis that the surgery deteriorates cognitive deficits. However, recent studies reported that PD with preoperatively cognitive impairment also obtained clinical improvements after STN-DBS.

Method: We retrospectively identified iPD patients who underwent STN-DBS and preoperative FDG-PET scans, as well as completed postoperative follow-ups within 2 years at Huashan hospital. Patients were classified into PDD, PD-MCI and PD-NC groups according to their presurgical cognitive assessments. PDD patients who received best medical treatment were included as controls. Motor, nonmotor, and cognitive evaluations were recorded at each visit. SPM was used to analyze metabolic change and its correlation with clinical variation. Multiple linear regression was performed to evaluate the predictive values of baseline FDG metabolism on postsurgical outcomes.

Results: PDD patients had significantly reduced MDS-UPDRS III scores at both med-on stim-on (-25.09±23.6, P<0.001) and med-off stim-on (-37.43±16.79, P<0.001) state, without between-group difference with PD-MCI and PD-NC groups. PDD patients also showed significant improvement in MMSE (3.11±3.25, P=0.002) and MoCA (4.25±4.64, P=0.003), while PD-MCI and PD-NC patients exhibited stable cognitive status. In contrast, PDD patients without STN-DBS presented worse motor and cognitive conditions during concurrently follow-ups. Occipital metabolism was significantly increased in PDD patients, which was associated with increased scores in MMSE (r=0.78, P=0.02) and MoCA (r=0.75, P=0.03) postoperatively. Furthermore, preserved metabolic activity in the frontal, precentral and cingulate gyrus preoperatively indicated greater cognitive benefits post STN-DBS.

Conclusion: STN-DBS showed dual benefits in motor and cognition for well-selected PDD patients and increased occipital metabolism explained cognitive improvement after the surgery. Preoperative metabolic preservation in frontal, parietal-temporal and limbic regions indicated better postoperative outcomes of motor and cognition in PDD patients. The study proves the positive effects of STN-DBS on PDD patients and renders advice of surgical candidate selection for PDD patients.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/stn-dbs-improves-motor-and-cognitive-functions-associated-with-increased-occipital-metabolism-in-pdd-patients/