Sleep problems are very prevalent among patients with PD
A large proportion of people with Parkinson disease (PD) experience sleep problems, which can emerge at a very early stage of the disease, even before the onset of symptoms start. Sleep problems commonly affecting patients with PD include rapid eye movement (REM) sleep behavior, sleep fragmentation, insomnia, restless leg syndrome (RLS), sleep-related breathing disorders, and excessive daytime sleepiness.1 The etiology of these sleep problems is possibly diverse including aspects such as the effect of the nocturnal motor symptoms of the disease, the use of medications, and the progressive neurodegeneration of sleep-regulatory brain structures.2 Sleep alterations have profound negative effects on the quality of life of patients with PD reducing their functional independence and predisposing them to an increased risk of accidents. Due to the essential role that sleep plays in our family and social life, these sleep problems may also end up increasing caregivers’ burden and disrupt the normal daily routines of entire families.
Both sleep quality and architecture are altered in patients with PD
Besides subjective complaints in sleep quality, which can be assessed clinically and confirmed with sleep questionnaires and actigraphy monitoring, patients with PD also show alterations in different aspects of sleep architecture. These alterations can be diagnosed with polysomnography and include reductions in the duration of REM sleep as well as the slow wave phase of non-rapid eye movement sleep (NREM 3). The latter has shown to be clinically relevant because patients presenting with lower slow wave activity reveal a faster progression of the motor symptoms of the disease.3 The activity of sleep spindles, short bursts of oscillatory brain activity that appear mainly during the NREM 2 phase of sleep, also tends to be reduced in people with PD. Interestingly, this reduction appears to be more pronounced in patients who develop cognitive problems reinforcing the importance of sleep spindles in cognitive processes.4