Putamen dopaminergic dysfunction is associated with sleep disturbance in drug-naïve patients with Parkinson's disease

Sleep disturbance (SD) is common in Parkinson's disease (PD) and adversely affect the quality of life (QOL). Although dopamine dysfunction has been implicated, the specific role of dopaminergic activity in SD among patients with PD remains unclear. Given that dopamine-related medications can affect sleep, it is essential to assess SD in drug-naïve patients. This study investigated the association between SD and uptake of striatal dopamine transporters using Dopamine Transporter Single-Photon Emission Computed Tomography with ¹²³I-Ioflupane (DAT-SPECT).

We retrospectively analyzed 112 drug-naïve patients through the PD Sleep Scale-version-2 (PDSS-2) and DAT-SPECT. Patients were divided into SD and non-SD groups using a PDSS-2 cut-off score of 15. The Mann-Whitney U test and binomial regression were used to compare the groups.

SD was identified in 47.3 % of participants, correlating significantly with increased age, more severe motor symptoms, cognitive decline, depressive symptoms, and reduced QOL scores. Binomial regression analyses-adjusted for sex, age, motor dysfunction, cognitive function, and nocturnal autonomic cardiovascular dysfunction-showed that reduced DAT-SPECT uptake in the left anterior and posterior putamen significantly contributed to higher PDSS-2 scores.

This study demonstrated a link between SD and putamen DAT-SPECT uptake in drug-naïve patients with PD, indicating the role of dopamine in sleep regulation. These findings underscore the importance of managing SD in patients with PD to improve QOL and suggest the need for further investigation of the impact of dopaminergic dysfunction on sleep.