Attentional dysfunction and the punding spectrum in Parkinson's disease.

BACKGROUND Punding is a complication of Parkinson's disease (PD) treatment and stimulant abuse that features excessive preoccupation with repetitive and/or aimless behaviors. We hypothesized that cognitive impairment and functional limitations influence how punding behaviors manifest in PD. METHODS We extracted data on punding, hobbyism, and cognition from the Parkinson's Progression Marker Initiative (PPMI). Punding and hobbyism were measured with the Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease (QUIP) scale. We determined how cognition predicted punding and hobbyism behaviors-adjusting for levodopa dose, Hoehn & Yahr stage, disease duration, and age-using generalized estimating equation (GEE) logistic regression. Activities of daily living (ADL) and motor impairment were measured with the MDS-UPDRS scale. RESULTS In GEE logistic regression models, punding was selectively associated with lower scores on the Letter Number Sequencing test (LNS), the primary attention test in PPMI (Odds ratio: 0.87 (95% CI: 0.79-0.96); p = 0.022). This was corroborated by a subscale-analysis of Montreal Cognitive Assessment (MoCA) scores, as only the attention subscale was significantly associated with punding (OR: 0.59 (0.45-0.77); p < 0.001). Baseline impairment in LNS (Hazard ratio: 2.52 (1.22-5.20); p = 0.012) and MoCA attention (HR: 2.68 (1.32-5.42); p = 0.006) predicted earlier punding in Cox regression. In turn, ADL dysfunction predicted punding (OR: 1.55 (1.20-2.00); p < 0.001), but not hobbyism. CONCLUSION Attentional dysfunction is a domain-specific cognitive biomarker of punding risk in PD. Further, attentional capacity and functional impairment may determine the complexity of perseverative behaviors on the continuum from rudimentary punding to semi-purposeful hobbyism.