The effects of bright-light therapy on actigraphical measured sleep last for several weeks post-treatment. A study in a nursing home population
We investigated the time-course of nocturnal actigraphic measures, following the termination of bright-light therapy for sleep disturbances in demented nursing home patients. From an earlier study, 11 nursing home patients (86 ± 9 years, Mini-Mental Status Examination score 12 ± 4) with actigraphically measured sleep efficiency <85%, were recruited to morning bright-light treatment (6000–8000 lux) 2 h per day for 14 days. Actigraphic measures were registered at pretreatment, treatment and at four monthly post-treatment periods. Each actigraphic recording period consisted of seven consecutive days. Sleep improved substantially with treatment; sleep efficiency increased from 73% to 86% and total nocturnal wake time was reduced by nearly 2 h. During the 16 weeks post-treatment period, actigraphic measures gradually returned to pretreatment levels. Sleep efficiency remained significantly higher than the pretreatment level 4 weeks after treatment termination. Sleep onset latency remained significantly reduced up until 12 weeks post-treatment. This study supports previous findings of beneficial effects of bright-light therapy for sleep disturbances in demented nursing home patients. Furthermore, these results are the first to suggest that post-treatment effects of short-term bright-light therapy may last longer than previously assumed.