TY  - JOUR
PY  - 2019//
TI  - Effects of a dawn-dusk simulation on circadian rest-activity cycles, sleep, mood and well-being in dementia patients
JO  - Experimental gerontology
A1  - Bromundt, Vivien
A1  - Wirz-Justice, Anna
A1  - Boutellier, Marc
A1  - Winter, Seraina
A1  - Haberstroh, Markus
A1  - Terman, Michael
A1  - Münch, Mirjam
SP  - 110641
EP  - 110641
VL  - 124
IS  - 
N2  - Light is the most powerful "zeitgeber" signal to synchronize circadian sleep-wake cycles. In dementia, these rhythms are often fragmented - probably due to loss of neuronal function of the suprachiasmatic nuclei (the biological "master clock" in the brain) and/or weakness of external zeitgebers. We investigated the effects of a prototype dawn-dusk simulator (DDS) on circadian rest-activity cycles, sleep, mood and well-being in a balanced crossover design during fall and winter in 20 institutionalized patients with dementia (86 ± 6 y, 17 f). All participants had one baseline week followed by exposure to individually timed DDS over their beds for 7-8 weeks. They spent 8 weeks without DDS as a control. Mood, self-reliant daily activity, social behavior, agitation, and quality of life were assessed by standardized questionnaires and visual analogue scales, regularly rated by trained caregivers. Circadian and sleep characteristics of their rest-activity cycles were analyzed by actimetry over 17 weeks. DDS exposure led to significantly better mood in the morning hours after waking. The effects were most pronounced in the second 4 weeks with DDS, indicating that positive effects emerged gradually. Differences in circadian rest-activity cycles and sleep were mainly age-dependent. We found statistically significant correlations between measures of higher quality of life and better mood, greater alertness and circadian rhythm stability. We conclude that continuous, long-term application of dawn-dusk simulation at the sleep-wake transitions appears to increase external zeitgeber strength in institutionalized patients with dementia. The DDS may provide an effective, non-invasive tool to improve mood and ameliorate patients' quality of life.<br><br>Copyright © 2019. Published by Elsevier Inc.<p />  <p>Language: en</p>
LA  - en
SN  - 0531-5565
UR  - http://dx.doi.org/10.1016/j.exger.2019.110641
ID  - ref1
ER  -