Sleep-wake rhythm disturbances in patients with Alzheimer’s disease (AD) make a strong demand on caregivers and are among the most important reasons for institutionalization. Several previous studies reported that the disturbances improve with increased environmental light, which, through the retinohypothalamic tract, activates the suprachiasmatic nucleus (SCN), the biological clock of the brain. The data of recently published positive and negative reports on the effect of bright light on actigraphically assessed rest-activity rhythms in demented elderly were reanalyzed using several statistical procedures. It was demonstrated that the light-induced improvement in coupling of the rest-activity rhythm to the environmental zeitgeber of bright light is better detected using nonparametric procedures. Cosinor, complex demodulation, and Lomb-Scargle periodogram-derived variables are much less sensitive to this effect because of the highly nonsinusoidal waveform of the rest-activity rhythm. Guidelines for analyses of actigraphic data are given to improve the sensitivity to treatment effects in future studies.

NPCRA Reference Paper.

Key Words: Actigraphy, Alzheimer’s disease, Bright light, Circadian rhythm, Complex demodulation, Cosinor, Dementia, Lomb-Scargle periodogram, Periodogram, Sleep, Statistical Methodology

Direct Link: https://doi.org/10.3109/07420529908998724

Journal: Chronobiology international. 1999 Jan 1;16(4):505-18

Keywords: NPCRA,

Applications: Reference,

CamNtech Reference: NP99001

Back to Search Results

UK & International customers

CamNtech Ltd.
Manor Farm
Fenstanton
Cambridgeshire
PE28 9JD, UK

US customers

CamNtech Inc.
630 Boerne Stage Airfield,
Boerne,
Texas 78006,
USA

Copyright

© 2020 CamNtech Ltd and CamNtech Inc

Company information

Registered in England No. 2221302
VAT No: GB486 3019 34


Privacy Policy