Long-term effects of environmental dynamic lighting on sleep-wake rhythm, mood and behaviour in older adults with intellectual disabilities.

We did not find a change in sleep-wake rhythm, mood or behaviour in older persons with IDs living in care facilities 1 year after installing the light. We did find evidence for a long-term effect on sleep duration and sleep timing. The results have to be interpreted with care as the current study had a limited number of participants. The need for more research on the long-term effects of enhancing environmental light in ID settings is evident.