Circadian characteristics of spontaneous physical activity and body temperature in narcoleptic patients

Abstract

Objective To assess circadian characteristics of spontaneous physical activity and deep body temperature in narcoleptic patients.  Methods Fourteen narcoleptic patients and 14 healthy age- and sex-matched control subjects were enrolled. Nocturnal polysomnography (PSG) was recorded, followed by standard multiple sleep latency test (MSLT). Then all subjects were required to wear the actigraphy (actiwatch) at home with continuous monitoring of spontaneous physical activity for 1-2 weeks and complete the daily sleep record. All subjects' deep body temperatures were measured at 20 time points.  Results In comparison with control subjects, PSG data suggested narcoleptic patients had significantly longer time in bed at night (P = 0.008), decreased sleep efficiency (P = 0.001), increased awakenings (P = 0.000), extended wake time after sleep onset (P = 0.000) and sleep onset rapid eye movement period (SOREMP, P = 0.002). MSLT data suggested decreased average sleep latency (P = 0.000) and increased SOREMPs (P = 0.000). Actigraphy data suggested increased nocturnal activity and nocturnal activity per hour (P = 0.000, for all), decreased daytime activity and daytime activity per hour (P = 0.000, for all) and increased nocturnal activity per hour/daytime activity per hour (P = 0.000, for all). The deep body temperature in both groups showed significant circadian rhythms. The differences in mesor, amplitude and peak phase of deep body temperature between 2 groups had no statistical significance (P = 0.177, 0.730, 0.488).  Conclusions Narcoleptic patients are characterized by impaired circadian rhythm of sleep-wake and spontaneous physical activity. The limited effects on deep body temperature suggest the relative conservation of thermoregulation in narcolepsy.

DOI: 10.3969/j.issn.1672-6731.2016.07.010