Morning bright light treatment for sleep-wake disturbances in primary biliary cholangitis: A pilot study

Patients with Primary Biliary Cholangitis (PBC) exhibit delayed sleep-wake habits,
disturbed night sleep and daytime sleepiness/fatigue. Such combination of symptoms is
reminiscent of delayed sleep-wake phase disorder (DSPD), which benefits from morning
light treatment. The aim of the present pilot study was to test the effect of morning light
treatment in a group of 13 well-characterized patients with PBC [all females; (mean ± SD)
53 ± 10 years]. Six healthy individuals (4 females, 57 ± 14 years) and 7 patients
with cirrhosis (1 female, 57 ± 12 years) served as controls and diseased controls,
respectively. At baseline, all participants underwent an assessment of quality of life,
diurnal preference, sleep quality/timing (subjective plus actigraphy), daytime sleepiness,
and urinary 6-sulphatoxymelatonin (aMT6s) rhythmicity. Then they underwent a 15-day
course of morning bright light treatment, immediately after getting up (light box, 10,000
lux, 45min) whilst monitoring sleep-wake patterns and aMT6s rhythmicity. At baseline,
both patients with PBC and patients with cirrhosis had significantly worse subjective
sleep quality compared to controls. In patients with PBC, light treatment resulted in
an improvement in subjective sleep quality and a reduction in daytime sleepiness. In
addition, both their sleep onset and get-up time were significantly advanced. Finally,
the robustness of aMT6s rhythmicity (i.e., strength of the cosinor fit) increased after
light administration but post-hoc comparisons were not significant in any of the groups.
In conclusion, a brief course of morning bright light treatment had positive effects on
subjective sleep quality, daytime sleepiness, and sleep timing in patients with PBC. This
unobtrusive, side-effect free, non-pharmacological treatment is worthy of further study.