Predictors of Burden in Carers of Patients with Impulse Control Behaviors in Parkinson's Disease.

Abstract

Impulse control behaviors (ICBs) are problematic, reward-based behaviors, affecting 15% to 35% of patients with Parkinson's disease. Evidence exists of increased carer burden as a result of these behaviors; however, little is known about the variables mediating this effect and their management. To identify factors predictive of carer burden in a cohort of patients with Parkinson's disease with ICBs to enable the development of targeted therapeutic interventions for carers. Data were collected from 45 patients with clinically significant ICBs and their carers, including levodopa equivalent daily dosage, motor and neuropsychiatric symptoms, cognitive function, and ICB severity. Carer burden was quantified by Zarit Burden Interview (ZBI). Univariate analyses were performed using the Spearman rank correlation. Linear regression was used to create a multivariate model for predicting ZBI. Univariate analysis identified significant correlations between ZBI and patient total Neuropsychiatric Inventory (NPI) (r s = 0.50), 4 NPI subscores (agitation/aggression, r s = 0.41; depression/dysphoria, r s = 0.47; apathy/indifference, r s = 0.49; and irritability/lability, r s = 0.38; all P < 0.02), and the carer 28-item General Health Questionnaire (GHQ-28) (r s = 0.52, P < 0.0005). Multivariate linear regression retained total NPI and GHQ-28 scores and were collectively predictive of 36.6% of the variance in the ZBI. Our study suggests that depressive symptoms and aspects of executive dysfunction (apathy and disinhibition) in the patient are potential drivers of carer burden in patients with ICBs. Such findings suggest the presence of executive difficulties and/or mood disturbance should point the clinician to inquire about burden in the caring role and encourage the carer to seek help for any of their own general health problems, which may compound carer burden.