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Authors: Hanford, Nicholas | Figueiro, Mariana

Article Type: Review Article

Abstract: Sleep disturbances are common in persons with Alzheimer's disease or related dementia (ADRD), resulting in a negative impact on the daytime function of the affected person and on the wellbeing of caregivers. The sleep/wake pattern is directly driven by the timing signals generated by a circadian pacemaker, which may or may not be perfectly functioning in those with ADRD. A 24-hour light/dark pattern incident on the retina is the most efficacious stimulus for entraining the circadian system to the solar day. In fact, a carefully orchestrated light/dark pattern has been shown in several controlled studies of older populations, with and …without ADRD, to be a powerful non-pharmacological tool to improve sleep efficiency and consolidation. Discussed here are research results from studies looking at the effectiveness of light therapy in improving sleep, depression, and agitation in older adults with ADRD. A 24-hour lighting scheme to increase circadian entrainment, improve visibility, and reduce the risk of falls in those with ADRD is proposed, and future research needs are discussed. Show more

Keywords: Alzheimer's disease, circadian rhythm, lighting design, light therapy, sleep, wayfinding

DOI: 10.3233/JAD-2012-121645

Citation: Journal of Alzheimer's Disease, vol. 33, no. 4, pp. 913-922, 2013

Authors: Sahin, Levent | Figueiro, Mariana G.

Article Type: Research Article

Abstract: Background: Coherent 40 Hz (gamma) neural oscillation indicates healthy brain activity and is known to be disrupted in Alzheimer’s disease (AD) patients. 40 Hz entrainment by flickering light is known to significantly attenuate AD pathology in mice. Objective: To demonstrate the feasibility of using a lighting intervention to promote coherent 40 Hz neural oscillation, improved working memory performance, and reduced subjective sleepiness among a population of healthy young adults. If successful, the intervention could be extended to address cognitive impairment associated with mild cognitive impairment and AD. Methods: Nine healthy participants (median age 22 years, five females) were exposed to one of two …lighting conditions per session in a within-subjects counterbalanced manner. The study’s two sessions were separated by 1 week. Custom-built light masks provided either a 40 Hz flickering red light (FRL) intervention or a dark control condition (i.e., total darkness, light mask not energized) at participants’ eyes. Data were collected four times per session: pre-exposure, after 25-min exposure, after 50-min exposure, and post-exposure. Each data collection period included a Karolinska Sleepiness Scale report, an electroencephalogram, and working memory (n -back) auditory performance testing. Results: The FRL intervention induced a significant increase in 40 Hz power and a modest increase in low gamma power. The intervention had no significant impact on working memory performance and subjective sleepiness compared to the control. However, increases in 40 Hz power were significantly correlated with reduced subjective sleepiness. Conclusion: The results clearly demonstrate the feasibility of using a flickering light to increase 40 Hz power. Show more

Keywords: 40 Hz neural oscillation, Alzheimer’s disease, electroencephalography, flickering red light, subjective sleepiness, working memory performance testing

DOI: 10.3233/JAD-200179

Citation: Journal of Alzheimer's Disease, vol. 75, no. 3, pp. 911-921, 2020

Authors: Figueiro, Mariana G. | Hamner, Robert | Higgins, Patricia | Hornick, Thomas | Rea, Mark S.

Article Type: Short Communication

Abstract: The absence of daily robust light-dark exposure patterns may contribute to sleep disturbances in persons with Alzheimer's disease and related dementias (ADRD). Personal light-dark and activity-rest patterns were measured for healthy older adults and for persons with ADRD. Persons with ADRD experienced lower light levels, exhibited lower activity levels, and had greater levels of circadian disruption than healthy older adults during winter. Seasonal differences were observed for persons with ADRD; lower levels of light exposure and greater levels of circadian disruption were seen during the winter than during the summer, although activity levels did not differ for the two seasons.

Keywords: Alzheimer's disease, circadian, circadian dysregulation, circadian light, phasor magnitude

DOI: 10.3233/JAD-2012-120484

Citation: Journal of Alzheimer's Disease, vol. 31, no. 4, pp. 711-715, 2012

Authors: Figueiro, Mariana G. | Sahin, Levent | Kalsher, Michael | Plitnick, Barbara | Rea, Mark S.

Article Type: Research Article

Abstract: Background: Persons with Alzheimer’s disease and related dementias (ADRD) frequently experience sleep–wake (circadian) cycle disturbances that lead them to remain awake at night, causing stress and fatigue for families and caregivers. Light therapy shows promise as a nonpharmacological treatment for regulating sleep in this population. Objective: We investigated the long-term impact of a circadian-effective lighting intervention on sleep, mood, and behavior problems in persons with ADRD. Methods: This 25-week clinical trial administered an all-day lighting intervention to 47 patients with ADRD in 9 senior-care facilities, employing wrist-worn actigraphy measures and standardized measures of sleep quality, mood, and behavior. Results: The …intervention significantly improved Pittsburgh Sleep Quality Index scores, from an estimated mean±SEM of 11.89±0.53 at baseline to 5.36±0.63 at the end of the intervention. Additional improvements were noted for sleep efficiency data from actigraph measurements. The intervention significantly reduced Cornell Scale for Depression in Dementia scores (mean±SEM of 11.36±0.74 at baseline and 4.18±0.88 at the end of the intervention) and Cohen-Mansfield Agitation Inventory scores (mean±SEM of 47.10±1.98 at baseline and 35.33±2.23 at the end of the intervention). Conclusion: A regular circadian-effective daytime lighting intervention can improve sleep at night and reduce depression and agitation in patients with dementia living in controlled environments. More importantly, the positive effects of the tailored lighting intervention on these outcomes appear to be cumulative over time. Show more

Keywords: Alzheimer’s disease and related dementias, circadian system, lighting intervention, mood, rest–activity, sleep

DOI: 10.3233/ADR-200212

Citation: Journal of Alzheimer's Disease Reports, vol. 4, no. 1, pp. 297-312, 2020