The study will recruit 60 participants aged 60 and above, who suffered from insomnia for at least 3 months. Sleep parameters and chronotypes assessed with questionnaires and actigraphy, daytime sleepiness, and biological rhythm (dim light melatonin onset) will be measured. The intervention involves light exposure using a prototype device developed by GCSOL Tech Co., Ltd., a company with expertise in light therapy research and development. Three conditions will be tested (1) bright light; (2) near-infrared light; (3) bright light+ near-infrared light. Data analysis will employ paired t-tests to compare sleep parameters and dim light melatonin onset before and after treatment. Kruskal-Wallis tests and multivariate linear regression will be used to examine differences between intervention groups, controlling for gender and age. Safety analysis will include monitoring adverse events.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
60
Bright light will use a 5000-10,000 Lux LED light source. Exposure is for 60 minutes daily, between 7pm and 9pm.
Near-infrared light will use a wavelength of 850nm and a dose range of 1 - 6.5 joules/cm2. It is fixed on the neck with a band, the light source contacts the back of the neck, and is used for 60 minutes before going to bed.
After using the bright light device, then use the near-infrared light device on the back of the neck before going to bed.
China Medical University Hospital
Taichung, Taiwan
Actigraphy-derived sleep indicators
Participants will continue to wear activity recording watches during the three weeks of the study. We will capture weekly average sleep duration, sleep onset latency, wake time after falling asleep, and sleep efficiency.
Time frame: Baseline and the third week.
Dim-light melatonin onset
Participants will be required to provide saliva samples for melatonin analysis within their home environment. These samples will be collected at 30-minute intervals starting from 18:00 and continuing until 1 hour after their habitual sleep time on both the initial and final study dates. The concentration of salivary melatonin will be assessed utilizing a direct melatonin enzyme-linked immunosorbent assay (ELISA) kit. The Dim Light Melatonin Onset (DLMO) will be determined using the two standard deviation threshold method, which involves calculating the average of the first three melatonin data points and then adding two standard deviations to this average.
Time frame: Baseline and the third week.
Sleep quality
Pittsburgh Sleep Quality Index (PSQI) ranges from 0 (better) to 21 (worse).
Time frame: Baseline and the third week.
Emotional state
Beck Depression Inventory-II ranges from 0 (better) to 63 (worse).
Time frame: Baseline and the third week.
Daytime sleepiness
Epworth Sleepiness Scale ranges from 0 (better) to 24 (worse).
Time frame: Baseline and the third week.
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