High colour temperature light improves restless behaviour and circadian rhythm of institutionalised older adults with dementia.

Non-pharmacologic interventions, like light, can play an important role in managing behavioural disturbances like nocturnal restlessness and wandering by patients with dementia. Research showed that high intensity light has the capacity of restoring this disturbed cycle to the normal, 24-hour, rhythm again. Moreover, the action spectrum for non-image forming effects lies in the bluish part of the light spectrum. Therefore, the question is if full-spectrum, blue-enriched highintensity light in a regular setting has better results than red-enriched light. Method: Ceilingmounted luminaires emitting high-intensity light (1,800 lx, horizontal at table level) with a high correlated colour temperature (CCT~6,500 K) and low correlated colour temperature (CCT~2,700 K) were placed in the 2 living rooms of a psycho geriatric ward. A third living room accommodated the control group, where dim light conditions were maintained. The Dutch Behaviour Observation Scale for Intramural Psycho geriatrics (GIP) and tympanic temperature were used to asses the effects of the lighting conditions. Results: A significant improvement of restless behaviour as well as a significant increase in the range of tympanic temperature was found after the lighting condition with the high CCT. Further evidence is found that institutionalised adults with dementia benefit from high-intensity light with a high CCT, which improves both restless behaviour and circadian rhythmicity.