Abstract:

A methodological study was undertaken to investigate the sensitivity of sleep motility to noise-induced disturbances. Indoor noise exposure and sleep motility of 22 test subjects were measured for 109 subject nights under a range of conditions of noise exposure and familiarity of sleeping quarters. Recording accelerometers stored the number of times that vertical motion of the wrist-worn devices exceeded 0.0002 g at frequencies below about 3 Hz during a 2-s interval. Noise monitors continuously recorded 2-s time histories of indoor noise levels throughout each night of data collection. Additional sequences of varying epoch durations were constructed analytically from the 2-s intervals of noise levels and sleep motility data. Analyses of accelerometric recordings in 2-, 4-, 6-, 8-, 10-, 20-, and 30-s epochs included an examination of the relationship between synchronous indoor noise level and motility, description of motility observations on a nightly basis, characterization of general serial dependence in motility measurements, and characterization of motility measurements in consecutive epochs with and without movement. Characterization of sleep motility in epochs of short duration provided limited practical benefits for measurement of noise-induced sleep disturbance.