Article

Sleep-wake disturbances are highly prevalent following traumatic
brain injury (TBI), impeding rehabilitaion and quality of life. However, the
mechanisms underlying these sleep disturnbances are unclear, and efficacious
treatments are lacking. To investigate possible mechanisms underlying sleep
disturbance in TBI, we examined characteristics of the circadian rhythm of
melatonin, a hormone involved in sleep-wake regulation. We compared TBI patients
reporting sleep disturbance with age- and gender-matched healthy volunteers.
METHODS: We conducted an overnight observational study with salivary melatonin
samples collected hourly in 9 patients with severe TBI and 9 controls. Salivary
dim light melatonin onset (DLMO) as well as melatonin synthesis onset (SynOn) and
offset (SynOff) were used to determine circadian timing. Total overnight salivary
melatonin production was calculated as the area under the curve from melatonin
synthesis onset to offset. RESULTS: Compared with healthy individuals, TBI
patients showed 42% less melatonin production overnight (d = 0.87; P = .034). The
timing of DLMO was delayed by approximately 1.5 hours in patients with TBI
compared with controls (d = 1.23; P = .003). CONCLUSIONS: In patients with TBI,
melatonin production was attenuated overnight, and the timing of melatonin
secretion was delayed. We suggest that disruption to the circadian regulation of
melatonin synthesis is a feature of severe TBI, possibly contributing to the
sleep difficulties that are commonly reported in this population.
CI - (c) The Author(s) 2016.

Langue : ANGLAIS