Elizabeth Saenger, PhD

When I interviewed Mirjam Münch, PhD, I was floored by the problems she and her colleagues overcame to do their elegant experiment. These barriers reminded me of a line from Shakespeare: “the course of true love (or innovative studies) never did run smooth.”

Fortunately, Dr. Münch’s tenacity paid off with findings suggesting immediate, meaningful applications to improve the quality of life for a large, and growing, segment of the population: people in nursing homes. In addition, there is a take-home message for us all in her generous attributions of credit to the people who struggled with her to bring a study to fruition.

I understand you and your colleagues just published a paper exploring the way changing the lighting in nursing homes affects patients. What did your experiment consist of?

Our team tested in 20 dementia patients whether a dawn-dusk simulation (DDS) had an impact on their sleep, circadian rest-activity cycles, mood and other behavioral variables. After a baseline week, patients were randomized to receive DDS either for the first eight weeks, or the second eight weeks of the study in a balanced, crossover design.

The patients continuously wore activity monitors on their wrist, and caregivers completed several questionnaires on a daily to bi-weekly basis. The study showed that mood and cheerfulness upon awakening was significantly higher with the dawn and dusk simulation. We also found positive associations with circadian stability, mood and quality of life. Because it is known that in this patient group the external ‘zeitgeber´ strength – the cues that help the inner clock stay on track – is often weaker than in healthy adults, any approach which may improve mood and indirectly also quality of life in these patients should be applied.

What prompted you to do this study?

The idea of a dawn-dusk simulation came up when Professor Anna Wirz-Justice approached me in 2013, after another light intervention study we did with dementia patients in Switzerland (Münch et al. 2017). Anna told me that there will be a prototype of a DDS available, with an algorithm developed by Professor Michael Terman to set dawn and dusk at any day of the year and latitude. The DDS lamps were aimed to be tentatively tested with institutionalized dementia patients in Basel (Switzerland). At that time, I was still working at the Federal Institute of Technology (Lausanne) in Switzerland, but was about to leave for Berlin.

We started planning the study in 2013. There was only a “minor” problem, which we clearly underestimated: the lamps had not been fully developed yet: there was no luminaire design or a software-user interface to program the DDS to the desired dawn and dusk simulation. In a nutshell, it took us another 1.5 years to develop this and make everything work. We had to postpone the study. including funding.

A huge effort from Professor Anna Wirz-Justice (who had at that time been already retired for several years), several colleagues from the lighting companies, the Fraunhofer Institute in Stuttgart (Germany), and the lamp designer (Markus Haberstroh, dip. Arch. FJ/SIA) made it finally possible to deliver and test ten DDS devices. The study was then performed in fall/winter of 2014/2015. The study completion was only possible because of the help of many caregivers and the head of wards at the nursing home (Marcel Boutellier), its director (Daniel Bollinger), and, of course, the study team: Vivien Bromundt, PhD, and Seraina Winter.

Do you think your results might encourage nursing homes to use dawn-dusk simulation, or other advances in lighting?

Absolutely! There are many approaches in lighting, which could be summarized in a dynamic time course of lighting. It is also important that during the night, there is no light, or if the nurses need to switch on lights, the light should not contain shorter wavelengths (blue) light, it should be orange and as dim as possible.

It would be important during the day to have high illuminance levels – ideally with daylight (with direct sun protection for skin and eyes as required). This would also have the effect of being outside, to perceive the weather and the season. My pledge anyway goes towards a multidimensional approach for nonpharmalogic interventions in this patient group: social and physical activity, meal timing, cognitive training, sleep timing and lighting.

What are you planning to do next?

I started a new position in New Zealand some months ago. I will be continuing to work on improved lighting for different groups. Now we are investigating sleep and circadian aspects in hospitalized patients. Dr. Bromundt recently told me that some of the lamps are currently on a neurorehabilitation ward and that they may be used in stroke patients, which could also be a very interesting application of the DDS. I hope similar luminaires will be produced in the future, to be used for different patient groups, and healthy children and adults.

For More Information:

Bromundt, A. Wirz-Justice, M. Boutellier, et al., Effects of a dawn-dusk simulation on circadian rest-activity cycles, sleep, mood and well-being in dementia patients, Experimental Gerontology, https://www.ncbi.nlm.nih.gov/pubmed/31252161