Bright light, sleep and thinking in older adults with insomnia

AI summary

From the trial's eligibility criteria. Machine-read from the registry text on this page, so it can be wrong. The registry text below and the trial team decide who can take part.

The trial is looking for older adults with long-term insomnia, and people with normal sleep of the same age and sex as a comparison group.

Age

55 years and older

Sex

All. Women must be past menopause.

Disease stage

Insomnia group: chronic insomnia disorder with poor sleep, at least 60 minutes awake at night on 3 or more nights a week, and PSQI score greater than 5. Control group: no insomnia and PSQI score ≤ 5.

Earlier treatment

No psychoactive, sleep, stimulant or pain medicines now or in the past month, except occasionally. No hormone replacement therapy. No beta-blockers, SNRIs, NDRIs or weight-loss medicines.

Biomarker or test result

MMSE score ≥ 26. HbA1C below 5.7.

Main reasons for not taking part

• Other sleep disorders, such as sleep apnea with AHI ≥ 15
• Neurological or psychiatric disorders, or BDI-II depression score greater than 19
• Heart conditions, diabetes or prediabetes, or unstable serious illness
• Eye problems that affect pupil response to light, such as significant cataracts or glaucoma
• Shift work, BMI > 35 kg/m2, smoking 6 or more cigarettes a week, or caffeine > 400 mg/day

The registry criteria, word for word

What the trial wants to find out

This study investigates the relationship between the noradrenergic (NA) system, sleep quality, and cognitive function in older adults with insomnia - a population at elevated risk for Alzheimer's disease-related dementias (ADRD) - compared to age and sex matched controls with normal sleep. The study characterizes NA function through multiple approaches: measuring 24-hour plasma levels of norepinephrine (NE) and its brain metabolite 3-methoxy-4-hydroxyphenylglycol (MHPG); evaluating central NA system response using the clonidine suppression test (a presynaptic α2 adrenoreceptor agonist that reduces locus coeruleus NA activity; and employing pupillometry as a non-invasive marker of autonomic function. To explore NA function's mechanistic role in insomnia, the study uses an intervention with bright light exposure to enhance daytime NA activity, with the goal of improving both sleep quality and cognitive performance.

The 2 groups in the trial

• Intervention on Subjects with InsomniaTreatment being tested

  The intervention in this study will involve 28 (+10) days of daily exposure to bright light (BL) for two 60-minute sessions (morning and afternoon). For the intervention, we will use Re-Timer® light glasses emitting light with an intensity of 230μW/cm2 (\~500lux) with a green blue 500nm dominant wavelength (between 480-520nm). Light with these characteristics has been shown effective in suppressing melatonin levels supporting their potential to exert effects on other biological non-visual functions associated with exposure to light relevant for this study. Throughout the intervention, participants will keep a diary to monitor daily use of the glasses. Participants will have weekly phone calls with the research team to encourage compliance and monitor potential side effects.

  Treatment: Light Exposure

• Dim Red LightExisting treatment, for comparison

  Participants randomized to the control group will wear for two 60-minute sessions (morning and afternoon) customized dim-red light (RL) control Re-Timer® light glasses (wavelength peak at 632nm, light intensity \< 3 lux). Participants will be instructed to wear the light glasses in habitual indoor environments, without engaging in strenuous activities. Throughout the intervention, participants will keep a diary to monitor daily use of the glasses. Participants will have weekly phone calls with the research team to encourage compliance and monitor potential side effects.

  Treatment: Placebo