IADR Abstract Archives
Rhythmic Masticatory Muscle Activity in Sleep Bruxism Children
Objectives: Prevalence of sleep bruxism (SB) is highest during childhood and decreases with age. Sleep architecture is known to change from children to adulthood. This study aims to investigate physiological characteristics of rhythmic masticatory muscle activities (RMMA) in children in comparison to young adults.
Methods: Overnight video-polysomnography was performed for ten children (M/F : 6/4, 10.1 ± 2.5 years old) and nine young adults (M/F : 5/4, 23.1 ± 1.4 years old) without any physical/neurological problems. Sleep variables were scored according to the standard rules. RMMA episodes were scored by masseter electromyographic activities and video records. Subjects were confirmed to have moderate-severe SB (the frequency of RMMA episodes >4 times/hr of sleep). Sleep architecture, arousals and leg/body movements were compared between the two group.
Results: RMMA index did not differ between children (6.0 ± 1.4 times /hr) and adults (6.5 ± 2.4 times /hr). In comparison to adults, total sleep time was longer and sleep efficiency was higher in children. Micro-arousals and awakenings were less frequent in children than in adults. In both groups, approximately 70% of RMMA were scored in light non-rapid eye movement (NREM) sleep, especially during the ascending phase within a sleep cycle. RMMA occurred in association with arousals in children (94.4 ± 3.7%) and in adults (91.7 ± 4.4%). A majority of RMMA episodes were accompanied by leg and body movements in the two groups (children : 74.7 ± 13.4%, adults : 68.0 ± 16.1%). Interestingly, RMMA occurred more frequently with body movements in children (51.0 ± 14.5%) than in adults (23.6 ± 18.8%) (p<0.05).
Conclusions: RMMAs in children and adults have common characteristics in the occurrence related to sleep architectures. RMMA in children can be associated with the higher hierarchy of arousal response than that in adults.
Methods: Overnight video-polysomnography was performed for ten children (M/F : 6/4, 10.1 ± 2.5 years old) and nine young adults (M/F : 5/4, 23.1 ± 1.4 years old) without any physical/neurological problems. Sleep variables were scored according to the standard rules. RMMA episodes were scored by masseter electromyographic activities and video records. Subjects were confirmed to have moderate-severe SB (the frequency of RMMA episodes >4 times/hr of sleep). Sleep architecture, arousals and leg/body movements were compared between the two group.
Results: RMMA index did not differ between children (6.0 ± 1.4 times /hr) and adults (6.5 ± 2.4 times /hr). In comparison to adults, total sleep time was longer and sleep efficiency was higher in children. Micro-arousals and awakenings were less frequent in children than in adults. In both groups, approximately 70% of RMMA were scored in light non-rapid eye movement (NREM) sleep, especially during the ascending phase within a sleep cycle. RMMA occurred in association with arousals in children (94.4 ± 3.7%) and in adults (91.7 ± 4.4%). A majority of RMMA episodes were accompanied by leg and body movements in the two groups (children : 74.7 ± 13.4%, adults : 68.0 ± 16.1%). Interestingly, RMMA occurred more frequently with body movements in children (51.0 ± 14.5%) than in adults (23.6 ± 18.8%) (p<0.05).
Conclusions: RMMAs in children and adults have common characteristics in the occurrence related to sleep architectures. RMMA in children can be associated with the higher hierarchy of arousal response than that in adults.