Temporal association between sleep apnea-hypopnea and sleep bruxism events

There is some evidence suggesting that obstructive sleep apnea-hypopnea syndrome (OSAHS) is concomitant with sleep bruxism (SB). The aim of this study was to investigate the temporal association between sleep apnea-hypopnea events and SB events (AHEs & SBEs). In an open observational study, data were gathered from 10 male subjects with confirmed OSAHS and concomitant SB. Polysomnography and audio-video recordings were performed for one night in a sleep laboratory. Breathing, brain, heart, and masticatory muscle activity signals were analyzed to quantify sleep and sleep stage duration and number and temporal distribution of AHEs and SBEs. AHEs were collected within a 5-minute time window before and after SBEs, with the SBE as the pivotal reference point. Two temporal patterns were analyzed: 1) the interval between AHE termination and SBE onset, called T1, and 2) the interval between SBE termination and AHE onset, called T2. Of the intervals between SBEs and the nearest AHE, 80.5% were scored within 5 minutes. Most intervals were distributed within a period of less than 30 seconds, with peak at 0 to 10 seconds. The T1 interval had a mean length of 33.4 seconds and was significantly shorter than the T2 interval (64.0 seconds;p<0.05). Significantly more SBEs were scored in association with the T1 than the T2 pattern (p<0.05). Thus, in patients with concomitant obstructive sleep apnea-hypopnea syndrome and sleep 2 bruxism, most sleep bruxism events occurred after sleep apnea-hypopnea events, suggesting that sleep bruxism event occurring close to sleep apnea-hypopnea event is a secondary form of sleep bruxism.