Objective: To examine the impact of pallidal deep brain stimulation (DBS) on symptoms of Dopamine Dysregulation Syndrome (DDS) in Parkinson’s disease (PD).

Background: DDS is a debilitating complication of PD dopamine replacement therapy (DRT) in which patients pathologically use dopamine in excess of what is required to treat motor symptoms. DBS is a well-established treatment for PD motor symptoms and often allows patients to reduce levodopa dosing. Yet, studies examining DDS outcomes following DBS remain limited, particularly in those receiving pallidal stimulation.

Method: We completed a detailed retrospective chart review of seven patients from the Emory University Movement Disorders clinic who underwent unilateral or bilateral DBS implantation of the globus pallidus internus (GPi) in the setting of clinically defined DDS. For comparison, we also included three DDS patients who underwent STN implantation. Post-surgical persistence of DDS and associated features were analyzed using descriptive statistics. In addition, we investigated whether common screening tools for DDS used during pre-surgical evaluations were effective in recognizing and assessing the severity of the condition.

Results: Despite significant motor improvements and initial reductions in DRT dosing, six of the seven patients who underwent pallidal stimulation continued to meet clinical criteria for DDS six months post-surgery, displaying persistent pathological medication use, mood disturbances, and social impairment. Anxiety surrounding levodopa use and drug seeking behaviors were the most persistent DDS features following surgery. In contrast, other mood and behavioral symptoms decreased post-surgery, including depression, hypomania, aggression, punding, and hobbyism. The STN patients exhibited more sustained levodopa reductions over time, with two of the three demonstrating resolution of DDS at six months post-procedure. DDS screening tools underreported the presence and severity of the disorder prior to surgery throughout the entire cohort. Among patients who maintained post-surgical improvements in DDS, common themes included a strong support system at home and a positive attitude towards DBS outcome.

Conclusion: These results suggest that DDS should not be a primary indication for pallidal DBS, and that a more multifaceted and interdisciplinary approach is required for the effective treatment of this complex disorder.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/dopamine-dysregulation-syndrome-outcomes-following-pallidal-deep-brain-stimulation-in-parkinsons-disease/