A double-blind randomized controlled trial to assess the effect of bright light therapy on depression in patients with Parkinson’s disease

Abstract

BackgroundA disturbed circadian rhythm seems to be a causal factor in the occurrence of depressive disorders in patients with Parkinson’s disease (PD). The circadian rhythm can be restored with light. Therefore, Bright Light Therapy (BLT) might be a new treatment option for depression in PD patients.Methods/designIn this double-blind controlled trial, 84 subjects with idiopathic PD are randomized to either BLT or a control light condition. The BLT condition emits white light with an intensity of 10,000 Lux, while the control device emits dim white light of 200 Lux, which is presumed to be too low to influence the circadian rhythm. Subjects receive 30 min of home treatment twice daily for three months. Timing of treatment is based on the individual chronotype. After finishing treatment, subjects enter a follow-up period of six months. The primary outcome of the study is the severity of depressive symptoms, as measured with the Hamilton Depression Rating Scale. Secondary outcomes are alternative depression measures, objective and subjective sleep measures, and salivary melatonin and cortisol concentrations. For exploratory purposes, we also assess the effects on motor symptoms, global cognitive function, comorbid psychiatric disorders, quality of life and caregiver burden. Data will be analyzed using a linear mixed models analysis.DiscussionPerforming a placebo-controlled trial on the effects of BLT in PD patients is challenging, as the appearance of the light may provide clues on the treatment condition. Moreover, fixed treatment times lead to an improved sleep-wake rhythm, which also influences the circadian system. With our study design, we do not compare BLT to placebo treatment, i.e. an ineffective control treatment. Rather, we compare structuring of the sleep-wake cycle in both conditions with additional BLT in the experimental condition, and additional dim light in the control condition. Participants are not informed about the exact details of the two light devices and the expected therapeutic effect, and expectancies are rated prior to the start of treatment. Ideally, the design of a future study on BLT should include two extra treatment arms where BLT and control light are administered at random times.Trial registrationThis trial was registered on ClinicalTrials.gov on May 17th 2012 (ClinicalTrials.gov Identifier: NCT01604876).

Nursing Problems of Patients with Parkinson’s Disease — Case Report

“…According to several scientific reports sleep disorders are a common feature in PD negatively affecting the quality of life [15]. In the study by Rutten et al [16] it was demonstrated that circadian rhythm disorders are a major cause of depressive disorders occurring in patients with PD. The presented case of the patient is also associated with sleep disorders.…”

Light Therapy in Parkinson’s Disease: Towards Mechanism-Based Protocols

“…In view of this, growing interest is currently underway in the development of alternative treatment modalities for PD. Light therapy is one of these novel therapies [2–6]. The rationale of introducing light therapy to PD clinic resides in the well-documented therapeutic effect of bright light in other neurological and neuropsychiatric disorders [7], some of which co-exist in PD patients [1].…”

“…Currently, the mechanisms of light therapy in PD are unknown. The results of an ongoing double-blind clinical trial are expected to shed some light on the relative contribution of circadian-mediated vs non-circadian processes to the therapeutic effects of light in PD patients [6]. However, two of the four trials conducted so far have shown that PD patients receiving supplemental light are able to reduce the amount of L-DOPA to 50% while maintaining therapeutic efficacy, compared to a 17% increase in L-DOPA requirements in untreated patients [2,4].…”

The therapeutic effects and safety of bright light therapy combined with escitalopram oxalate on insomnia in patients with poststroke depression

“…Accumulating evidence has demonstrated that light therapy is effective for seasonal and non-seasonal depression in the general population 12,[14][15][16][17][18][19][20][21] as well as clinical depression from Parkinson's disease, dementia, or during pregnancy. [22][23][24] Compared to antidepressants such as selective serotonin reuptake inhibitors, BLT is a safe, well tolerated, low-cost, easy-to-implement, and non-drug treatment, with minimal side effects. 12,18,25,26 Light therapy can improve sleep disorders, whether they are primary insomnia or that arising from illnesses, such as Parkinson's disease.…”

“…18 For example, many studies observed a protocol of light intensity ≥5000 lx or 10 000 lx for 30 minutes every day (8-9 AM) for 6 weeks. 19,20,23 We conducted a controlled study to investigate the efficacy of antidepressants (we used escitalopram oxalate tablets, or ESC) in combination with BLT in PSD patients. We hypothesized that this polytherapy would be more effective than monotherapy in alleviating depression-induced insomnia.…”