Comparison of ambulatory and polysomnographic recording of jaw muscle activity during sleep in normal subjects

Abstract

Clinicians and investigators need a simple and reliable recording device to diagnose or monitor sleep bruxism (SB). The aim of this study was to compare recordings made with an ambulatory electromyographic telemetry recorder (TEL-EMG) with those made with standard sleep laboratory polysomnography with synchronised audio-visual recording (PSG-AV). Eight volunteer subjects without current history of tooth grinding spent one night in a sleep laboratory. Simultaneous bilateral masseter EMG recordings were made with a TEL-EMG and standard PSG. All types of oromotor activity and rhythmic masseter muscle activity (RMMA), typical of SB, were independently scored by two individuals. Correlation and intra-class coefficient (ICC) were estimated for scores on each system. The TEL-EMG was highly sensitive to detect RMMA (0·988), but with low positive predictive value (0·231) because of a high rate of oromotor activity detection (e.g. swallowing and scratching). Almost 72% of false-positive oromotor activity scored with the TEL-EMG occurred during the transient wake period of sleep. A non-significant correlation between recording systems was found (r = 0·49). Because of the high frequency of wake periods during sleep, ICC was low (0·47), and the removal of the influence of wake periods improved the detection reliability of the TEL-EMG (ICC = 0·88). The TEL-EMG is sensitive to detect RMMA in normal subjects. However, it obtained a high rate of false-positive detections because of the presence of frequent oromotor activities and transient wake periods of sleep. New algorithms are needed to improve the validity of TEL-EMG recordings.

Weak association between sleep bruxism and obstructive sleep apnea. A sleep laboratory study

“…These findings suggest that when EMG bursts of masticatory muscle are observed during sleep, activity such as swallowing, yawning, or body movements may influence the probability of observing oromotor activity that is non-specific to RMMA/SB during sleep in OSAH patients [12][13]. In the present study, a low association was found between SB incidence and AH (i.e., concomitant in only half the subjects), along with a low association with sleep arousal.…”

“…The presence of other movements that were not specific to SB could provide an alternative explanation [9,[12][13]. SB may have co-occurred with periodic limb movements in a subgroup of individuals [27].…”

“…The amplitude threshold was set at twice the baseline activity [13]. Bursts with a greater amplitude than the value with duration exceeding 0.25 seconds were selected after onset of sleep until wake-up in the morning.…”

“…EMG bursts of sleep rhythmic masticatory muscle activity with SB (RMMA-SB) and other oromotor activities were assessed according to published criteria [13,[14][15][16][17][18][19]. The amplitude threshold was set at twice the baseline activity [13].…”

“…In fact, recording and scoring of jaw muscle activity during sleep revealed that various types of muscle activity are not specific to SB events. These include myoclonic contraction, swallowing, sighing, and idiopathic or natural jaw muscle activity [12][13]. To assess the specificity of the putative association between OSAH and SB, it is critical to perform a discriminant analysis to distinguish typical RMMA in SB from other types of orofacial motor activity using polysomnography and audio-video recording (PSG-AV).…”