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.