Course of Impulse Control Disorder Symptoms in Parkinson's Disease: Deep Brain Stimulation Versus Medications

Abstract

Background: The effect of surgery on impulse control disorders (ICDs) remains unclear in Parkinson's disease (PD) patients undergoing deep brain stimulation (DBS).

Objective: To examine changes in ICD symptoms in PD patients undergoing DBS compared to a medication-only control group.

Methods: The study was a 2-center, 12-month, prospective, observational investigation of PD patients undergoing DBS and a control group matched on age, sex, dopamine agonist use, and baseline presence of ICDs. Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease-Rating Scale (QUIP-RS) and total levodopa equivalent daily dose (LEDD) were collected at baseline, 3, 6, and 12 months. Linear mixed-effects models assessed changes in mean QUIP-RS score (sum of buying, eating, gambling, and hypersexuality items).

Results: The cohort included 54 participants (DBS = 26, controls = 28), mean (SD) age 64.3 (8.1) and PD duration 8.0 (5.2) years. Mean baseline QUIP-RS was higher in the DBS group at baseline (8.6 (10.7) vs. 5.3 (6.9), P = 0.18). However, scores at 12 months follow-up were nearly identical (6.6 (7.3) vs. 6.0 (6.9) P = 0.79). Predictors of change in QUIP-RS score were baseline QUIP-RS score (β = 0.483, P < 0.001) and time-varying LEDD (β = 0.003, P = 0.02). Eight patients (four in each group) developed de novo ICD symptoms during follow-up, although none met diagnostic criteria for an impulse control disorder.

Conclusions: ICD symptoms (including de novo symptoms) at 12 months follow-up were similar between PD patients undergoing DBS and patients treated with pharmacological therapy only. Monitoring for emergence of ICD symptoms is important in both surgically- and medication-only-treated PD patients.

Keywords: LEDD; Parkinson's disease; de novo ICDs; deep brain stimulation; dopaminergic medication.

Figure 1

Flow diagram of the study sample: from assessment for the study to the final analytic sample. *Eligible DBS+ patients were PD patients who had surgery scheduled in one of the participating institutions and who could be contacted by the study team prior surgery. Eligible participants for the control group were selected among PD patients who were not expected to require DBS within two years of enrollment in the study. ^§diagnosis was revised by the clinician’s patient. †no post‐baseline assessment available.

Figure 2

Trends in (A) QUIP‐RS scores and (B) LEDD during follow‐up.

Figure 3

Within‐subject presence/absence of ICD based on QUIP‐RS score.