More Light! Improving Well-Being for Persons Suffering from Dementia

Daylight regulates the wake-sleep cycle by acting on specific receptors of the retina that are sensitive to the blue component of the spectrum. Especially in the winter months, the amount of daylight exposure is insufficient for adequate control of the circadian rhythm in many people because they increasingly stay indoors. This is particularly true for elderly or mobility-impaired persons, as well as for residents of care homes, where prevailing levels of illuminance and colour temperature are frequently too low. This not only has negative consequences for the residents’ cognition, but also impairs their sleep-wake rhythms. Starting from the hypothesis that suitably designed, biologically effective artificial lighting can compensate for the lack of daylight and lead to regulation of the wake-sleep rhythm, a study comprising approximately 60 participants investigated whether an improvement in the mental and emotional condition of the residents can be achieved. Appropriate lighting was installed in four wards of two Caritas Socialis care homes in Vienna and from October 2012 until April 2013: basic illumination (static, 300 lux, 3000 K) and intervention illumination (dynamic, 800-1200 lux, 3000-6500 K) were alternated (roughly every four weeks). The results indicated that agitated behavior (as measured by the Cohen-Mansfield Agitation Inventory) increased with basic illumination and decreased in the intervention situation. Communicative behavior (observation inventory) was likewise positively influenced, particularly the non-verbal component.