Insufficient melanopic equivalent daylight illuminance in nursing home dementia units across seasons and gaze directions

Abstract

Adequate illumination plays an important part in providing a healthy environment for nursing home patients with dementia. With increasing awareness of non-visual responses to light, new approaches to quantifying illuminance have emerged. In the present study, we assessed the illuminance in nursing home dementia units in terms of melanopic equivalent daylight illuminance, a metric which aims to quantify the non-visual physiological effects of light by weighing irradiance according to non-visual photoreception. It is among the most comprehensive studies of light conditions conducted in dementia units in terms of melanopic equivalent daylight illuminance to date, and the first to elucidate seasonal differences in melanopic illumination. Light conditions were assessed in all 15 nursing homes with dedicated long-term dementia units in Bergen municipality (60.39°N), Norway, during summer and winter. Results indicated that seasonal differences and gaze direction had some impact on melanopic equivalent daylight illuminance, but most measurements still fell below even conservative recommendations across seasons. The findings indicate a need for additional light sources that can compensate for limited natural daylight in dementia units. The ubiquity of insufficient melanopic equivalent daylight illuminance in dementia units suggests a role for lighting interventions in future research seeking to improve entrainment, sleep and mental health of dementia unit residents.

A field test of a simplified method of estimating circadian stimulus

“…The present results comply with those reported by Konis 23 and Kolberg et al , 33 who both confirmed that the light conditions typically found in nursing homes and senior care facilities rarely meet the requirements for good and healthy circadian lighting. Instead, the rather low amount of circadian effectiveness observed in all these studies is likely to result in a progressive disruption of the residents’ circadian rhythms that may lead to severe negative effects on well-being and behaviour, especially when access to natural daylight for compensation is further restricted, like, for example, experienced during the COVID-19-provoked lockdown in Germany.…”

“…The present study is the first to apply their proposed method in field measurements to report on the amount of circadian-effective light (including daylight entry) that is received indoors by the residents of a senior care facility in the Frankfurt Rhine-Main area. Based on the assessment of CS as a biologically meaningful quantity, this work adds further evidence to the findings of two recently published studies of Konis 23 and Kolberg et al , 33 who both confirmed the general inadequacy of lighting conditions in nursing homes in terms of equivalent melanopic lux 34 and melanopic equivalent daylight illuminance, 35 respectively. Even without the pandemic, the insufficient-lighting-situation in nursing homes is a serious problem in long-term care that should urgently be addressed by national health policy.…”

“…As these values were collected in such a way (curtains open; all lights turned on) that they represent a cross-sectional estimate for the maximum in circadian effectiveness (relative to the time of the year) of the light conditions experienced by the nursing home residents, an even lower effectiveness can be assumed under deviating preconditions, such as, for example, on a cloudy day or when the indoor light sources are switched on only partly. Thus, from the measurements reported here and the findings of Konis 23 and Kolberg et al , 33 it seems clear that the light conditions typically found in nursing homes and senior care facilities rarely meet the requirements for good and healthy circadian lighting. Instead, the rather low amount of circadian effectiveness observed in all these studies is likely to result in a progressive disruption of the residents’ circadian rhythms – a situation which is further exacerbated by the strict COVID-19 lockdown conditions as they massively limit the nursing home residents’ access to natural daylight for compensation.…”

The Calculated Circadian Effects of Light Exposure from Commuting

“…Several studies have used the melanopic equivalent daylight (D65) illuminance (melanopic EDI) to quantify light's circadian impact [55][56][57]. In addition to the five αopic irradiances, the melanopic EDI is defined as one of the five α-opic equivalent daylight (D65) illuminances (α-opic EDIs) by the CIE in CIE S 026/E:2018 [16].…”

The Effect of Bright Light Treatment on Rest–Activity Rhythms in People with Dementia: A 24-Week Cluster Randomized Controlled Trial

“…In addition, lifestyle changes or situational and contextual changes may further reduce daylight availability. For example, people with dementia are often exposed to low levels of environmental illumination, especially those living in nursing homes [ 15 , 16 , 17 , 18 ]. Providing a robust environmental time cue through bright light therapy (BLT) is a well-established treatment for disruption of the circadian rhythms in otherwise healthy adults [ 19 , 20 ], but the efficacy of BLT for people with dementia is not yet established.…”