Effects of biological lighting

Elderly in Albertslund are participating in a clinical & anthropological research project on the effects of Smart lighting in an assisted living facility.

What was the purpose of the project? 

Lightel investigates the connection between the effects of circadian adjusted LED light and health care for senior citizens. With the collection of health data and knowledge of the reception of the new technology, we can promote the uptake of energy efficient technologies in eldercare.

The aim of the present clinical trial is to investigate sleep quality, well-being and delirium in the two groups of senior citizens living in a retirement home: a group of frail elderly with mobility disabilities and a group of elderly with dementia. We hypothesize that circadian adjusted LED light will have a positive, but different effect on sleep quality, well-being and delirium in elderly with mobility disabilities compared to elderly with dementia. Thus, the project investigates – in a randomised clinical trial design – the possible effect in physical and mental functioning based on a comprehensive analytic design of measurements of aging, health, mobility, nutrition, sleep, fatigue and quality of life

Chosen solution 

Due to the complex nature of care for the elderly i.e. psychological well-being, personalised space, adaptations to functional decline and therapeutic focus, the evaluation of a circadian lighting system for geriatric use must incorporate data from widely dispersed fields. This trial relies on both qualitative and quantitative data from three fields: anthropological, sensor-based and medical, forming a “holistic approach”:

In this context, the framework for the data collection and analysis is combining sets of qualitative and quantitative data and consists of a cross-over non-blinded randomised trial involving three target groups:


Participants Week 0 Randomization

Week 1-8

Period 1

Week 9-16

Period 2

Group A, frail elderly receiving CALED Baseline Subgroup A1 Intervention Control
Subgroup A2 Control Intervention
Group B, residents with dementia receiving CALED Baseline Subgroup B1 Intervention Control
Subgroup B2 Control Intervention
Group C, frail elderly not receiving CALED Baseline Non Control Control

Quantitative data collection

The trial participants will be assessed at baseline and after 4, 8, 12 and 16 weeks, respectively. The test panel will consist of questionnaires, functional and cognitive tests, and a blood sample for detecting underlying causes of delirium and illnesses during the trial.


Variables Baseline 4-week 8-week 12-week 16-week
Primary outcome; quality of sleep
PSQI; total sleep time x x x x x
Secondary outcomes: sleep efficiency, mobility and immunological status
 1. Actigraphy, Actiwatch; sleep and wake activity x x x x x
2. ESS; daytime sleepiness x x x x x
3. Biomarkers; immunological status x x x x x
4. CAM; delirium and confusion x x x x x
5. MoCA, MMSE; cognition x x x x x
6. MDI; depression x x x
7. ActivePal; mobility x x x x x
8. EQ-5D; well-being x x x
9. ADL; self-efficacy; x x x
Additional variables
10. Registration; medication x x x
11. IVI-test; vision x x
12. MNA; nutritional status x x x

Qualitative data collection

The aim of the anthropological study is to reveal changes in experiences and practices of everyday life with an emphasis on how elderly experience and practice their home lives, as a consequence of the intervention, from a phenomenological perspective:

  • The interview guide will be built on Spradley’s ethnographic interview, for the method’s ability to gain in-depth information about perceived reality from the participant’s point of view. The semi-structured interview format allows comparisons between participants and allows hypothesis testing, and is at the same time flexible.
  • The interview will be supplemented by a social mapping method which is inspired by cartography
  • The observation will be semi-structured with a moderate degree of participation which will allow informal talks with the participants. The observation will look into the behaviour of the participants, and look at changes in their rhythms, routes and routines, with a special emphasis on daytime drowsiness, and how they interact with the light in the space.
  • Staff interviews will be used to account for non-representative observation sampling, and also as a proxy interview to elucidate the view of the dementia patients based on the idea that the staff are experts in interpreting their behavior


Week Baseline 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Group A, frail elderly receiving CALED
Interview x x x x x x x
Social mapping x x x x x
Group B, elderly with dementia receiving CALED
Observation x x x x x x x
Staff interview x x x x x x x
Group C, frail elderly not receiving CALED
Interview x x x x x x
Social mapping x x x x

By using this framework, a holistic evidence combining quantitative and qualitative data analysis can be defined and support the use of circadian adjusted LED lighting for housing facilities for the elderly.

Collaborating partners 

The project has been implemented by the municipality of Albertslund, Aalborg University, Hvidovre Hospital, Chromaviso and Gate 21. The municipality of Albertslund is lead partner.

Aalborg University is responsible for the collection and analysis of qualitative social antropological data as well as quantitative data from light sensors and the analysis of the energy consumption data, and Hvidovre Hospital is responsible for the clinical data.

Chromaviso is the supplier of the applied circadian lighting and the clinical validated light protocol, adjusted lighting design, technical health care products and implementation.

Technical specifications 

The applied circadian lighting has been designed by the Danish company Chromaviso to enhance circadian entrainment by use of electrical lighting so elderly and demented that stay indoor due to mobility and institutionalization will have proper circadian entrainment like people get with normal access to daylight.

Since the photo transduction is not completely understood, the lighting design is imperatively explorative. However, all elements of it are based on proven relations between light and human or mammals and between human circadian rhythm and the light-dark cycle of daylight.

The entrainment has two main components – Circadian phase and circadian strength. The first relates to the synchronization of the sleep/wake cycle of the elderly and the dark/light cycle of daylight. The latter relates to the amount of diurnal light exposed that leads to increase in sleep drive and immunity to circadian disruption by nocturnal light exposure.

Measurable effects 

The sensors collect data and senses movement, so we get evidence-based knowledge of how the light affects the elderly. In collaboration with doctors and researchers from Aalborg University, physical effects will be mapped as well as the social acceptance of the new technology and its user interface

Lessons learnt? 

Lightel focuses on proving the benefits of using circadian adjusted LED lighting for housing for the elderly and specifically elderly with dementia. The next step is to find the optimal version of circadian lighting in order to maximise the beneficial impacts, aiming at a more personalised and profile-based circadian lighting.

In such projects, the participation and the help of the staff is of great importance, and the right communication, presentation and goals of the project are really beneficial to this context.

Secure more time for technology testing in terms of stability and integration in the existing building.

Strong focus on implementation is very important, and preferably the elderly had time to get used to the new light before the test period.

Date of opening: (Not applicable for this project)

Visiting info (Visiting address to Demo Project, opportunities & restrictions)

The project has a clear advantage in the fact that all tests and measurements are performed in the elderly people’s own home and not, for example, in a laboratory. But for that reason, the installations are not accessible for public access. You can schedule a visit with Kristina Aggergaard, the official contact person for the project.

The future

The Lightel project is a specific and documented business case in the municipality of Albertslund, but has the potential to transfer key elements and findings to other Danish municipalities.

Every year, the municipality of Albertslund and DOLL Green Lab receive a great number of visitors from Danish municipalities and international delegations and companies, where the results are mediated, and it is possible to creates synergies.

Contact info 

Email: Kristina Aggergaard     Phone: +45 51 62 84 53

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