Brief morning light treatment for sleep/wake disturbances in older memory-impaired individuals and their caregivers

Abstract

Scheduled exposure to bright light (phototherapy) has been used, with varying degrees of success, to treat sleep disruption in older individuals. Most of these studies have been done in institutional settings and have used several hours of daily light exposure. Such a regimen in the home setting may be untenable, especially when the individual with the sleep disruption has memory impairment and is being cared for by a family member. As such, we examined the effectiveness of a "user-friendly" phototherapy protocol that would be readily usable in the home environment. We exposed a group of 54 older caregiver/care recipient dyads, in which the care recipient had memory impairment, to two weeks of morning bright light phototherapy. Dyads were exposed to either bright white (∼4200 lux) or dim red (∼90 lux) light for 30 min every day, starting within 30 min of rising. All subjects also received sleep hygiene therapy. Objective (actigraphy) and subjective measures of sleep and mood were obtained at baseline and at the end of the two weeks of phototherapy. In care recipients, actigraphy- and log-determined time in bed and total sleep time declined in the active condition (p<0.05, ANOVA); there was no corresponding change in subjective insomnia symptoms (p's>0.37, ANOVA). The decrease in the time in bed was associated with an earlier out of bed time in the morning (p<0.001, Pearson correlation). The decrease in the total sleep time was associated with a decrease in sleep efficiency (p<0.001, Pearson correlation) and an increase in wake after sleep onset (p<0.001, Pearson correlation). In caregivers, there were no differential changes in actigraphic measures of sleep (p's>0.05, ANOVA). Actigraphy-measured wake after sleep onset and sleep efficiency did, however, improve in both conditions, as did sleepiness, insomnia symptoms, and depressive symptomatology (p's<0.05, ANOVA). Exposure to this regimen of phototherapy diminished sleep in older individuals with memory impairments. Their caregivers, however, experienced an improvement in sleep and mood that appeared independent of the phototherapy and likely due to participation in this protocol or the sleep hygiene therapy.