Finger pulse wave amplitude response during sleep to environmental noise

Changes in finger pulse wave amplitude (FPWA) are a sensitive marker of autonomic and electro-encephalographic (EEG) activation responses evoked by relatively high level acoustic stimuli presented during sleep. FPWA responses could therefore be a particularly useful marker of physiological activation responses and sleep fragmentation caused by environmental noise during sleep. In this study we explored the FPWA response evoked by ecologically relevant environmental noise exposures at moderate sound pressure levels (SPLs) up to 48 dB(A) during sleep. Twenty-three healthy participants took part in two noise exposure nights in a sleep laboratory, separated by a recovery week. We found a significant increase in FPWA response occurrence probability after noise onset at levels down to 33 dB(A). The size of evoked FPWA responses was small and similar to the size of spontaneous responses irrespective of noise level. These data support that FPWA responses are a sensitive marker of physiological disturbances to environmental noise during sleep, although the physiological and potential clinical significance of frequent autonomic activation responses remains to be determined.