The Clinical Effect of Blue Light Therapy on Patients with Delayed Sleep-Wake Phase Disorder

Efficacy of digital brief behavioural treatment for insomnia using a smartphone application in conjunction with light therapy in university students with insomnia symptoms with late chronotypes: A pilot randomized-controlled trial

The efficacy of digital brief behavioural treatment for insomnia using a smartphone application in conjunction with light therapy was investigated in university students who had insomnia symptoms with late chronotypes. In this two-arm parallel randomized-controlled trial, participants with insomnia symptoms and late chronotypes were recruited between October and November 2023. The duration of the intervention program was 4 weeks. The smartphone application provides digital brief behavioural treatment for insomnia, including programs for advanced phases. The intervention group used blue-light-emitting diode glasses in the morning after waking up for 2-4 weeks. The primary outcome was a change in the Insomnia Severity Index during the study period. The Insomnia Severity Index was obtained weekly using a web questionnaire. Of the 28 students, 14 each were assigned to the intervention and control groups. The mean Insomnia Severity Index scores at baseline were 12.2 and 12.5; after 4 weeks, they declined to 7.2 and 10.6 in the intervention and control groups, respectively. Primary analysis using a linear mixed model showed a significant improvement in the temporal trends of the Insomnia Severity Index in the intervention group (p < 0.001). The scores on the Morningness-Eveningness Questionnaire (p = 0.008) and RU-SATED (p = 0.005) significantly improved in the intervention group relative to the control group following the intervention. This study demonstrated the effectiveness of the digital brief behavioural treatment for insomnia with light therapy in participants with both insomnia symptoms and late chronotypes.

Association of chronotype pattern on the quality of sleep and anxiety among medical undergraduates - a cross-sectional study

OBJECTIVES

This study aims to explore the relationship between chronotypes, sleep quality, and anxiety among medical undergraduates, providing valuable insights for academic institutions seeking to enhance student well-being.

METHODS

A cross-sectional design was used, involving 200 medical undergraduates who were selected based on specific inclusion and exclusion criteria. Data collection included comprehensive clinical histories and the administration of three validated questionnaires: the Morningness-Eveningness Questionnaire Self-Assessment (MEQ-SA), the Pittsburgh Sleep Quality Index (PSQI), and the State-Trait Anxiety Inventory (STAI). Participants were recruited during class breaks, and informed consent was obtained prior to participation.

RESULTS

The majority of participants (76.5 %; n=152) exhibited a neutral chronotype, with a mean MEQ score of 50.18 (±7.781). No significant correlations were found between MEQ scores and variables such as sex, BMI, or electronic media use. However, individuals classified as evening types reported higher anxiety levels, with mean STAI-S and STAI-T scores of 56.09 (±4.566) and 49.09 (±6.202), respectively (ANOVA, F=31.798, p=0.001; F=30.294, p=0.001). The mean global PSQI score was 6.00 (±2.553), with 56 % of participants reporting poor sleep quality. Evening chronotypes had significantly poorer sleep quality, as evidenced by higher PSQI scores (8.14±1.670) (ANOVA, F=43.663, p=0.001).

CONCLUSIONS

The findings underscore the need for academic institutions to reconsider the alignment of academic schedules with students' chronotypes, potentially enhancing academic performance and reducing health risks. Despite these contributions, the study has limitations, including geographical and demographic constraints and reliance on self-reported data, suggesting the need for further research to provide more comprehensive insights.

Integrating Assessment of Circadian Rhythmicity to Improve Treatment Outcomes for Circadian Rhythm Sleep-Wake Disorders: Updates on New Treatments

Purpose of Review

Despite advancements in basic circadian research, development of new diagnostic and treatment strategies for circadian rhythm sleep-wake disorders (CRSWDs) has been slow. Here, we review the most recent innovations in human circadian assessment and emerging new therapies for CRSWDs.

Recent Findings

Researchers have improved existing circadian assessment methods to overcome logistical barriers and developed novel circadian assessment methods. New treatments for CRSWDs involve pharmacological and behavioral treatments that modulate circadian phase, amplitude, and/or robustness of the central circadian clock.

Summary

Commercialization of these emerging tools will require overcoming barriers, such as additional testing to confirm the underlying pathology and mechanism of action of potential treatments. Clinicians and scientists are also called to survey adjacent fields and adopt existing diagnostic tools that may offer diagnostic clarity in CRSWDs. Lastly, we must continue to advocate for medical insurance coverage of current and future tools and technologies to improve patient care.

Circadian realignment and depressed mood: A systematic review

Chronotherapeutic interventions aimed at realigning the circadian system can improve depression. This systematic review evaluated the current evidence for circadian realignment as an antidepressant mechanism. A comprehensive search was conducted in studies that implemented a chronotherapeutic intervention in samples with depression and/or delayed sleep/circadian timing using PubMed, EMBASE, Cochrane Central Register of Controlled Trials (Wiley), Europe PMC, and PsycINFO. The Downs and Black checklist was used to evaluate study quality. There were 58 studies included, of which 23 studies reported the association between realignment and depression. Circadian realignment was associated with improved depression in studies that included participants with baseline delays and elevated depression. Randomized clinical trials measuring circadian phase markers are needed to further elucidate circadian realignment as an antidepressant mechanism.

A parallel-group randomized controlled trial of blue light versus red light for improving sleep, fatigue, and cognition following stroke: Pilot results and recommendations for further study

BACKGROUND

Disordered sleep and fatigue are common in the acute phase of stroke and can impede recovery.

OBJECTIVE

A randomized parallel group placebo-controlled pilot study compared daily morning exposure to blue light or red light (placebo) for improving daytime sleepiness, fatigue, nocturnal sleep, and cognition in patients receiving inpatient rehabilitation for acute stroke.

METHODS

43 patients with disordered sleep secondary to first episode stroke (n = 34 ischemic, n = 9 hemorrhagic; aged 66.2 ± 14.1 years) were randomized to receive 25 min of blue or red light for 5 or more days depending on inpatient rehabilitation length of stay (blue-light n = 21, red-light n = 22). At baseline and study discharge, daytime sleepiness was measured with the Karolinska Sleepiness Scale and Wits Pictorial Sleepiness Scale, fatigue with a visual analogue scale, and cognitive function with the Rey Auditory Verbal Learning Test and Trail Making Test (TMT). Wrist actigraphs measured nocturnal sleep parameters. Effect sizes were used to estimate sample sizes for larger studies.

RESULTS

Blue light exposure led to significant improvements in daytime sleepiness, fatigue, auditory verbal learning, and time to sleep onset (all p < .05) relative to red light exposure (effect size range 0.75 to 1.83). Change in TMT, minutes of nocturnal sleep, and number of awakenings after sleep onset were not statistically significant (effect sizes range 0.38 to 0.57).

CONCLUSION

Morning blue light exposure for 5 or more days after acute stroke led to greater improvements than red light exposure. Effect sizes suggest a larger study is warranted to confirm generalizability of pilot findings.

TRIAL REGISTRATION

ClinicalTrials.govNCT03125967 (Registered 01/01/2017).

Photophobia is associated with lower sleep quality in individuals with migraine: results from the American Registry for Migraine Research (ARMR)

BACKGROUND

Patients with migraine often have poor sleep quality between and during migraine attacks. Furthermore, extensive research has identified photophobia as the most common and most bothersome symptom in individuals with migraine, second only to headache. Seeking the comfort of darkness is a common strategy for managing pain during an attack and preventing its recurrence between episodes. Given the well-established effects of daily light exposure on circadian activity rhythms and sleep quality, this study aimed to investigate the relationship between photophobia symptoms and sleep quality in a cohort of patients with migraine.

METHODS

A cross-sectional observational study was conducted using existing data extracted from the American Registry for Migraine Research (ARMR). Participants with a migraine diagnosis who had completed the baseline questionnaires (Photosensitivity Assessment Questionnaire (PAQ), Generalized Anxiety Disorder-7 (GAD-7), Patient Health Questionnaire-2 (PHQ-2)), and selected questions of the ARMR Sleep questionnaire were included. Models were created to describe the relationship of photophobia and photophilia with various sleep facets, including sleep quality (SQ), sleep disturbance (SDis), sleep onset latency (SOL), sleep-related impairments (SRI), and insomnia. Each model was controlled for age, sex, headache frequency, anxiety, and depression.

RESULTS

A total of 852 patients meeting the inclusion criteria were included in the analysis (mean age (SD) = 49.8 (13.9), 86.6% (n = 738) female). Those with photophobia exhibited significantly poorer sleep quality compared to patients without photophobia (p < 0.001). Photophobia scores were associated with SQ (p < 0.001), SDis (p < 0.001), SOL (p = 0.011), SRI (p = 0.020), and insomnia (p = 0.005) after controlling for age, sex, headache frequency, depression, and anxiety, signifying that higher levels of photophobia were associated with worse sleep-related outcomes. Conversely, photophilia scores were associated with better sleep-related outcomes for SQ (p < 0.007), SOL (p = 0.010), and insomnia (p = 0.014).

CONCLUSION

Results suggest that photophobia is a significant predictor of poor sleep quality and sleep disturbances in migraine. These results underscore the necessity for comprehensive and systematic investigations into the intricate interplay between photophobia and sleep to enhance our understanding and develop tailored solutions for individuals with migraine.

Circadian light therapy and light dose for depressed young people: a systematic review and meta-analysis

Background

Empirical evidence has shown that light therapy (LT) can reduce depression symptoms by stimulating circadian rhythms. However, there is skepticism and inconclusive results, along with confusion regarding dosing. The purpose of this study is to quantify light as a stimulus for the circadian system and create a dose-response relationship that can help reduce maladies among adolescents and young adults (AYAs). This will provide a reference for light exposure and neural response, which are crucial in the neuropsychological mechanism of light intervention. The study also aims to provide guidance for clinical application.

Methods

The latest quantitative model of CLA (circadian light) and CSt,f (circadian stimulus) was adopted to quantify light dose for circadian phototransduction in youth depression-related light therapy. Articles published up to 2023 through Web of Science, Cochrane Library, Medline (OVID), CINAHL, APA PsycINFO, Embase, and Scholars were retrieved. A meta-analysis of 31 articles (1,031 subjects) was performed using Stata17.0, CMA3.0 (comprehensive meta-analysis version 3.0) software, and Python 3.9 platform for light therapy efficacy comparison and dose-response quantification.

Results

Under various circadian stimulus conditions (0.1 < CSt,f < 0.7) of light therapy (LT), malady reductions among AYAs were observed (pooled SMD = -1.59, 95%CI = -1.86 to -1.32; z = -11.654, p = 0.000; I2 = 92.8%), with temporal pattern (p = 0.044) and co-medication (p = 0.000) suggested as main heterogeneity sources. For the efficacy advantage of LT with a higher circadian stimulus that is assumed to be influenced by visualization, co-medication, disease severity, and time pattern, sets of meta-analysis among random-controlled trials (RCTs) found evidence for significant efficacy of circadian-active bright light therapy (BLT) over circadian-inactive dim red light (SMD = -0.65, 95% CI = -0.96 to -0.34; z = -4.101, p = 0.000; I2 = 84.9%) or circadian-active dimmer white light (SMD = -0.37, 95% CI = -0.68 to -0.06; z = -2.318, p = 0.02; I2 = 33.8%), whereas green-blue, circadian-active BLT showed no significant superiority over circadian-inactive red/amber light controls (SMD = -0.21, 95% CI = -0.45 to 0.04; z = -2.318, p = 0.099; I2 = 0%). Overall, circadian-active BLT showed a greater likelihood of clinical response than dim light controls, with increased superiority observed with co-medication. For pre-to-post-treatment amelioration and corresponding dose-response relationship, cumulative duration was found more influential than other categorical (co-medication, severity, study design) or continuous (CSt,f) variables. Dose-response fitting indicated that the therapeutic effect would reach saturation among co-medicated patients at 32-42 days (900-1,000 min) and 58-59 days (1,100-1,500 min) among non-medicated AYAs. When exerting high circadian stimulus of light therapy (0.6 < CSt,f < 0.7), there was a significantly greater effect size in 1,000-1,500 min of accumulative duration than <1,000 or >1,500 min of duration, indicating a threshold for practical guidance.

Limitations

The results have been based on limited samples and influenced by a small sample effect. The placebo effect could not be ignored.

Conclusions

Although the superiority of LT with higher circadian stimulus over dimmer light controls remains unproven, greater response potentials of circadian-active BLT have been noticed among AYAs, taking co-medication, disease severity, time pattern, and visual characteristics into consideration. The dose-response relationship with quantified circadian stimulus and temporal pattern had been elaborated under various conditions to support clinical depression treatment and LT device application in the post-pandemic era.

The effect of light therapy on sleep disorders and psychobehavioral symptoms in patients with Alzheimer's disease: A meta-analysis

BACKGROUND

Although Alzheimer's disease (AD) mainly affects cognitive function, it is often accompanied by sleep disorders and psychobehavioral symptoms. These symptoms, including depression, agitation, and psychotic symptoms, are prominent hospitalization causes among patients with AD. Currently, relatively more research exists on light therapy for sleep disorders, while those on psychobehavioral symptoms are gradually increasing. However, no consensus exists on these results because of the vulnerability of light therapy to multiple factors, including light intensity and duration. Thus, further research investigating this aspect is warranted.

OBJECTIVE

To evaluate the efficacy of light therapy in improving sleep disorders and psychobehavioural symptoms in patients with AD.

METHODS

In this meta-analysis, relevant literature was searched in Embase, the Clinical Trials Registry, Web of Science, PubMed, and the Cochrane Library up to December 2022. Furthermore, a fixed-effects model was used for data analysis.

RESULTS

Fifteen randomized controlled trials involving 598 patients with AD were included. In the case of sleep disorders, our meta-analysis revealed that light therapy significantly improved sleep efficiency (MD = -2.42, 95% CI = -3.37 to -1.48, p < 0.00001), increased interdaily stability (MD = -0.04, 95% CI = -0.05 to -0.03, p < 0.00001), and reduced intradaily variability (MD = -0.07, 95% CI = -0.10 to -0.05, p < 0.00001). With respect to psychotic behavior, light therapy was found to alleviate depression (MD = -2.55, 95% CI = -2.98 to -2.12, p < 0.00001) as well as reduce agitation (MD = -3.97, 95% CI = -5.09 to -2.84, p < 0.00001) and caregiver burden (MD = -3.57, 95% CI = -5.28 to -1.87, p < 0.00001).

CONCLUSION

Light therapy leads to significant improvement in sleep and psychobehavioral symptoms and is associated with relatively fewer side effects in patients with AD, indicating its potential as a promising treatment option for AD.

Blue light exposure-dependent improvement in robustness of circadian rest-activity rhythm in aged rats

The aging effects on circadian rhythms have diverse implications including changes in the pattern of rhythmic expressions, such as a wide fragmentation of the rhythm of rest-activity and decrease in amplitude of activity regulated by the suprachiasmatic nucleus (SCN). The study of blue light on biological aspects has received great current interest due, among some aspects, to its positive effects on psychiatric disorders in humans. This study aims to evaluate the effect of blue light therapy on the SCN functional aspects, through the evaluation of the rest-activity rhythm, in aging rats. For this, 33 sixteen-months-old male Wistar rats underwent continuous records of locomotor activity and were exposed to periods of 6 hours of blue light during the first half of the light phase (Zeitgeber times 0-6) for 14 days. After this, the rats were maintained at 12h:12h light:dark cycle to check the long-term effect of blue light for 14 days. Blue light repeated exposure showed positive effects on the rhythmic variables of locomotor activity in aged rats, particularly the increase in amplitude, elevation of rhythmic robustness, phase advance in acrophase, and greater consolidation of the resting phase. This effect depends on the presence of daily blue light exposure. In conclusion, our results indicate that blue light is a reliable therapy to reduce circadian dysfunctions in aged rats, but other studies assessing how blue light modulates the neural components to modulate this response are still needed.

Insomnia and circadian rhythm: a bibliometrics study and visualization analysis via CiteSpace

Objective

The present study aimed to use CiteSpace to analyze the status of insomnia and circadian rhythm, identify the hot spots and trends, and provide a basis for future study.

Method

The Web of Science database was searched for studies related to insomnia and circadian from its inception to 14 April 2023. CiteSpace was used to generate online maps of collaboration between countries and authors and revealed hot spots and frontiers in insomnia and circadian rhythm.

Results

We searched 4,696 publications related to insomnia and circadian rhythm. Bruno Etain was the most prolific author with most publications, i.e., with 24 articles. The USA and the University of California were the leading country and the top institution in this field of study, with 1,672 and 269 articles, respectively. There was active cooperation between institutions, countries, and authors. Hot topics focused on circadian rhythm sleep disorders, circadian clock, light therapy, melatonin, and bipolar disorder.

Conclusion

Based on the CiteSpace results, we recommend a more active collaboration between various countries, institutions, and authors to conduct clinical and basic research related to insomnia and circadian rhythm. Ongoing research focuses on the interaction of insomnia with circadian rhythms and the corresponding pathways of clock genes and by extension, the role of circadian rhythms in disorders such as bipolar disorder. Modulation of circadian rhythms may be a hot spot for future insomnia therapies (such as light therapy and melatonin).

Brain Waste Removal System and Sleep: Photobiomodulation as an Innovative Strategy for Night Therapy of Brain Diseases

Emerging evidence suggests that an important function of the sleeping brain is the removal of wastes and toxins from the central nervous system (CNS) due to the activation of the brain waste removal system (BWRS). The meningeal lymphatic vessels (MLVs) are an important part of the BWRS. A decrease in MLV function is associated with Alzheimer's and Parkinson's diseases, intracranial hemorrhages, brain tumors and trauma. Since the BWRS is activated during sleep, a new idea is now being actively discussed in the scientific community: night stimulation of the BWRS might be an innovative and promising strategy for neurorehabilitation medicine. This review highlights new trends in photobiomodulation of the BWRS/MLVs during deep sleep as a breakthrough technology for the effective removal of wastes and unnecessary compounds from the brain in order to increase the neuroprotection of the CNS as well as to prevent or delay various brain diseases.

Effects of Morning or Evening Narrow-band Blue Light on the Compensation to Lens-induced Hyperopic Defocus in Chicks

SIGNIFICANCE

Exposure to blue light before bedtime is purported to be deleterious to various aspects of human health. In chicks, blue evening light stimulated ocular growth, suggesting a role in myopia development. To further investigate this hypothesis, we asked if brief blue light altered the compensatory responses to hyperopic defocus.

PURPOSE

Previous work showed that several hours' evening exposure to blue light stimulated ocular growth in chicks, but morning exposure was only effective at a lower illuminance. By contrast, rearing in blue light has inhibited ocular growth in untreated eyes and eyes exposed to form deprivation or defocus. We studied the effects of brief exposures to blue light on the compensation to hyperopic defocus.

METHODS

Chicks wore monocular negative lenses (-10 D) starting at age 10 days. They were subsequently exposed to blue light (460 nm) for 4 hours in the morning or evening for 8 to 9 days ("dim," 200 lux[morning, n = 9; evening, n = 11]; "bright," 600 lux[morning, n = 8; evening, n = 20]); controls wore lenses in white light (n = 14). Ultrasonography was done on days 1, 5, 8, and 9 for "evening" groups and days 1, 6, and 8 for "morning." All data are reported as interocular differences (experimental minus fellow eyes). Refractions were measured on the last day.

RESULTS

For evening exposure, dim blue light enhanced the axial compensation at all times (change in axial length: day 6: 465 vs. 329 μm/9 days, analysis of variance P < .001, P = .03; day 9: 603 vs. 416 μm/9 days, analysis of variance P < .001; P < .05). Bright blue light had a transient inhibitory effect (day 5: 160 vs. 329 μm; P < .005). Refractive errors were consistent with axial growth, with dim causing more myopia than bright (-9.4 vs. -4.7 D; P < .05). Morning blue light had no significant effect.

CONCLUSIONS

We speculate that these findings reflect a complex interaction between illuminance, defocus, and time of day.