Relationship between Apathy and Subjective Poor Night-time Sleep in de novo, Untreated Parkinson's Disease

Sleep disturbance is one of the most common non-motor symptoms of Parkinson's disease (PD). However, the confounding effects of dopaminergic medication on sleep are a major challenge in understanding the impact of sleep disturbance in PD. We investigated the sleep disturbance and associated clinical features in patients with de novo, untreated PD.

One-hundred-eight patients with de novo, untreated PD were included. Night sleep disturbance was evaluated using the night sleep subscale of the Scales for Outcomes in Parkinson's Disease (SCOPA-Sleep). Depression, anxiety, and apathy were assessed using the Geriatric Depression Scale (GDS), Beck Anxiety Inventory (BAI), and Apathy Evaluation Scale (AES), respectively. Early perfusion and dopamine transporter imaging of F-18 FP-CIT PET/CT were performed together with statistical parametric mapping analysis.

The night sleep SCOPA-Sleep sub-score was correlated with the AES (p = 0.014), BAI (p = 0.014), and GDS (p = 0.023) scores. Patients with poor night sleep were more apathetic (p = 0.013). Additionally, there was increased perfusion in the left posterior cingulate in patients with sleep disturbance and apathy compared to those with sleep disturbance only.

Night sleep disturbance was related to mood disorders, particularly apathy, in patients with de novo, untreated PD.