Abstract

Sleep disturbances, which have been described for many years, are common in Parkinson’s disease (PD) patients. The underlying intrinsic pathophysiology of PD is likely one of the main reasons for sleep disturbances. Insomnia in PD patients usually presents as difficulty in initiating sleep and is more prominent in PD patients with depression or anxiety. Insomnia may also result from several conditions including pain, nocturia, restless legs syndrome (RLS) as well as severe motor symptoms of PD and dyskinesias. In addition, the incidence of RLS is higher in PD patients. The relief of RLS symptoms following pallidotomy in PD patients reinforces the role of sensoriomotor circuits of the basal ganglia in the development of RLS. Similar to RLS, periodic leg movements in sleep disorder is also common in PD patients. However, the most common sleep disorder in PD is rapid eye movement (REM) sleep behavior disorder (RBD), which may develop before PD symptoms appear. REM sleep behavior disorder is characterized by violent abnormal motor movements which may hurt either the patients or their bed partners. Therefore, RBD should be also treated to prevent medico-legal issues. Sleep-related breathing disorder (SRBD) is unlikely associated with PD, since the prevalence is higher in the adult population at this age. However, although SRBD often shows a correlation with the severity of rigidity and tremor, it may not be resolved with levodopa treatment. In addition, obstructive sleep apnea syndrome should be treated by non-invasive positive airway pressure therapy, which has been shown as the only treatment proven to eliminate the life-threatening complications of the disease. Rigid vocal cord adductors and tensors leading to stridor in sporadic PD patients are more common particularly in late-stage PD patients with severe swallowing problems.