%0 Journal Article
%T Bright Light Therapy in Parkinson's Disease: An Overview of the Background and Evidence
%A Sonja Rutten
%A Chris Vriend
%A Odile A. van den Heuvel
%A Jan H. Smit
%A Henk W. Berendse
%A Ysbrand D. van der Werf
%J Parkinson's Disease
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/767105
%X Sleep disorders are common in Parkinson's disease (PD) and seem to be strongly associated with depression. It has been suggested that sleep disorders as well as depression are caused by a disturbed circadian rhythm. Indeed, PD patients are prone to misalignment of their circadian rhythm due to various factors, and many patients with PD display a phase advance of their circadian rhythm. Current treatment options for sleep disorders and depression in patients with PD are limited and can have serious side effects; alternative treatments are therefore badly needed. Bright light therapy (BLT) restores circadian rhythmicity effectively in mood- and sleep-disturbed patients without PD. The few studies that focused on the efficacy of BLT in patients with PD demonstrated a positive effect of BLT not only on sleep and mood but also on motor function. More research on the neurobiology and efficacy of BLT in PD is warranted. 1. Introduction In addition to the characteristic motor symptoms, patients with Parkinson¡¯s disease (PD) experience many nonmotor symptoms, comprising a variety of cognitive, autonomic, sensory, neuropsychiatric, and sleep disturbances [1, 2]. Sleep disturbances and disorders (as defined in Table 1) including reduced total sleep time, reduced sleep efficiency, increased sleep fragmentation, rapid eye movement (REM) sleep behaviour disorder, and excessive daytime sleepiness, occur in about 60¨C95% of PD patients [3¨C6]. Sleep influences motor symptoms. The so-called ¡°sleep benefit¡±, an improvement of motor functions upon awakening that occurs in more than 40% of PD patients, is attributed to improved dopaminergic function as a result of increased storage of dopamine in nigrostriatal terminals during sleep [7]. Moreover, melatonin, a hormone secreted by the pineal gland at night, has been suggested to worsen motor symptoms in PD patients [8]. Table 1: Definitions of sleep terminology. Sleep disorders in PD often coincide with depression [6]. Depression occurs in 35¨C50% of patients throughout the course of the disease [9, 10]. It has a major impact on overall functioning of PD patients: depressed PD patients score lower on scales assessing activities of daily living and exhibit more cognitive problems [9, 11, 12]. Sleep disorders and depression are two of the most important factors influencing quality of life of PD patients and their caregivers [4, 9, 13, 14]. Unfortunately, treatment options are limited, and adding pharmacological agents raises nonadherence in PD patients [15]. Moreover, medication can induce serious side effects in PD patients.
%U http://www.hindawi.com/journals/pd/2012/767105/