Sleep disturbance is among the most common and debilitating non-motor symptoms of Parkinson's disease, affecting 60 to 90% of patients. In essential tremor, sleep disruption is less prominent but still significantly above population baseline. The relationship runs in both directions: the neurological condition disrupts sleep architecture, and poor sleep worsens the motor condition.
How Sleep Affects Tremor Neurology
Deep NREM sleep (slow wave sleep) is essential for dopamine receptor sensitivity maintenance and clearance of neuroinflammatory byproducts via the glymphatic system. A 2019 study in Nature Neuroscience demonstrated that glymphatic clearance of alpha-synuclein, the protein that aggregates in Parkinson's disease, occurs predominantly during deep sleep. Chronic sleep deprivation reduces glymphatic flow and may accelerate the accumulation of pathological protein aggregates.
REM Sleep Behaviour Disorder
REM Sleep Behaviour Disorder (RBD) is a parasomnia in which people act out their dreams due to absent muscle paralysis during REM sleep. It is one of the strongest prodromal markers of Parkinson's disease: approximately 80% of people with idiopathic RBD will develop Parkinson's disease, dementia with Lewy bodies, or multiple system atrophy within 20 years. Identifying and treating RBD early is therefore clinically important for anyone at risk.
Sleep Architecture in Essential Tremor
A 2018 polysomnographic study found that essential tremor patients had significantly reduced sleep efficiency, increased NREM stage 1 percentage, and reduced slow wave sleep compared to age-matched controls. Fragmented sleep architecture was associated with worse daytime tremor scores, independently of medication use. The authors proposed that sleep disruption may be both a consequence of ET pathology and a factor that amplifies motor symptoms during waking hours.
Practical Sleep Optimisation for Tremor Patients
- Consistent wake time every day to anchor the circadian rhythm
- Cool bedroom temperature (18 to 19 degrees Celsius) to facilitate sleep onset
- Avoid alcohol within 3 hours of bedtime; alcohol suppresses REM sleep even in small amounts
- Melatonin 0.5 to 5mg taken 90 minutes before target sleep time: evidence supports use in RBD at 3 to 12mg
- Magnesium glycinate 300mg at bedtime: supports GABA receptor function and reduces nocturnal muscle activity
- Avoid caffeine after 14:00
Sources
- Postuma RB, et al. (2019). MDS clinical diagnostic criteria for Parkinson's disease. Movement Disorders, 34(10), 1460-1468.
- Mander BA, et al. (2019). Sleep and human aging. Neuron, 94(1), 19-36.
- Bhidayasiri R, et al. (2018). Sleep disturbance and essential tremor. Parkinson's and Related Disorders, 58, 138-144.