Abstract
Background: Sleep disorders occur frequently in patients with Parkinson’s disease (PD). Neurotransmitters and neurosteroids are known to be involved in various neurophysiological processes, including sleep development.
Objective:We aimed to assess the association between peripheral neurotransmitter and neurosteroid levels and various sleep disorders in early-stage PD.
Methods: 59 patients with early-stage PD and 30 healthy controls were enrolled. Demographic and clinical data were collected and sleep conditions were comprehensively assessed with clinical questionnaires and polysomnography. Blood samples were obtained at 1:00 AM and 9:00 AM in all participants. The concentrations of plasma neurotransmitters and neurohormones were detected using high-performance liquid chromatography tandem mass spectrometry.
Results: Sleep disorders were common non-motor symptoms (81.4%) and coexisted in approximately half of the patients. Dysautonomia was significantly associated with the presence of multiple sleep disorders. RBD was associated with dysautonomia and was negatively correlated with plasma melatonin concentration at 1:00 AM (r = −0.40, p = 0.002) in early-stage PD patients. The RLS group had higher PSQI score, and RLS was negatively associated with the levels of 5-hydroxytryptamine (r = −0.40, p = 0.002) at 1:00 AM and glutamine (r = −0.39, p = 0.002) at 9:00 AM. SDB was associated with cognitive impairment, higher body mass index, and lower plasma acetylcholine concentrations at 1:00 AM.
Conclusion: Combined sleep disturbances were frequent in early-stage PD. Dysautonomia was closely related to various sleep disorders, including RBD, EDS, and insomnia. Changes in peripheral neurotransmitter and neurohormone levels may be involved in the development of sleep disorders.