Somnopole

Team

Principal investigator: Prof. Dr. Nathalie Pattyn (VIPER, Royal Military Academy)

Unit for Experimental Psychiatry, Division of Sleep and Chronobiology (University of Pensylvania)

Abbreviations

PDX = polysomnography; KSS = karolinska sleepiness scale; PVT = psychomotor vigilance task; MEQ = morningness/eveningness questionnaire; PSQI = Pittsburgh sleep quality inventory; VAS = visual analogue scale; POMS = profile of mood scales. After two weeks of bright light exposure in winter; and three weeks of melatonin supplementation in summer, the measurement session will be repeated.

What

Studying sleep in different conditions on the Antarctic continent: at sea-level, at altitude, in camps, on stations, during summer and during winter. So far, sleep disturbances remain among the most common complaints with regard to health and well-being in extreme environments, especially so in polar regions. The available scientific evidence shows altered sleep patterns, but there is not enough data to deduce the potential mechanism behind those disturbances. This project has been implemented so far at Princess Elizabeth (Belgian summer station, during its construction campaigns) ; Concordia (French-Italian year-round station) ; Dumont d’Urville (French year-round station) and will start next winter at Halley VI (British year-round station) and Neumayer (German year-round station). Furthermore, and for the first time, apart from the fundamental research regarding sleep disturbances, this project also includes an operational part, where two countermeasures are investigated: bright light exposure during the winter, and melatonin supplementation during the summer.

How

Polysomnography is the physiological study of sleep including brain activity recordings, the recording of eye movement, electrocardiography, respiration movements and muscle activity. To gain insight into the causes of potential disturbances, the measured parameters also include those influencing sleep-wake regulation: light/dark cycles (through the meteorological data); sleep and wake hormones (melatonin and cortisol, measured on saliva samples); physical activity (recorded through actigraphy; shared data with the “Eyes on Ice” team); and mood (evaluated through questionnaires). Cognitive performance is also measured, to quantify the consequences of sleep disturbances in terms of performance, and this is done through data sharing with the “SIMSKILL” team. The bright light exposure modality is 1 hour after wake-up through the device (Luminette (R), Lucimed). The melatonin supplementation will be through a 3 weeks nightly treatment with CIRCADYN (2 mg slow release melatonin, standard pharmacological form commercially available).

When

Both for the fundamental and the applied research, a baseline measure in constant daylight and constant darkness is necessary. In order to eliminate any residual dynamic adaptation effect, this baseline should be measured after at least 3 weeks exposure to the constant illumination condition. One measurement session follows the following protocol (times are given as indication of the desired frequency of measurements, and can be tailored to the specific schedule of participants).