睡眠時ブラキシズムにおけるリズミカル咀嚼筋活動／非リズミカル咀嚼筋活動と身体運動との間には特異的な運動パターンが欠如している

A lack of specific motor patterns between rhythmic/non-rhythmic masticatory muscle activity and bodily movements in sleep bruxism.

抄録

本研究の目的は、睡眠時ブラキシズム（SB）における顎運動と体動の時間的関係を検討し、リズミカル咀嚼筋活動（RMMA）の発生における運動過程を明らかにすることである。RMMAと非特異的咬筋活動（NSMA）は、筋電図とビデオ記録を用いて、脚、腕、頭、体幹の身体運動に関連してスコア化された。運動エピソードと体動の関係は、睡眠段階の分布と時間的関係の観点から評価した。結果 RMMAとNSMAの約80％が1つ以上の身体部位の運動と関連していた。RMMAおよびNSMAは、頭部（17-22％）および体幹（5-25％）の運動よりも、下肢（70-75％）および腕（40-55％）の運動と関連する頻度が高かった。口腔運動エピソードと体動の関係は、睡眠段階間で有意差はなかった。SB群とCTL群では、口腔運動エピソードと体動は一貫した時間的パターンを示さなかった。運動エピソードと体動の時間的関係にかかわらず、平均心拍数は運動エピソード開始の5拍前に有意に増加した。結論RMMAと体動の間に特異的な時間的運動パターンは認められなかった。RMMAとNSMAは睡眠中の覚醒関連自律神経運動反応のレパートリーを表している。

Purpose The aims of the present study were to investigate the temporal relationships between jaw and bodily movements and clarify motor processes in the genesis of rhythmic masticatory muscle activity (RMMA) in sleep bruxism (SB).Methods Video-polysomnography recordings were obtained from ten subjects with SB (mean age: 23.4 ± 1.6 years) and ten matched normal controls (CTL) (mean age: 24.4 ± 3.2 years). RMMA and nonspecific masseter activity (NSMA) were scored in association with bodily movements in the leg, arm, head, and trunk using electromyography and video recordings. The relationship between oromotor episodes and bodily movements was assessed in terms of sleep stage distributions and temporal relationships. Cardiac changes preceding oromotor episodes in stage N2 were assessed.Results Approximately 80% of RMMA and NSMA were associated with movements in one or more body sites. RMMA and NSMA were more frequently associated with movements of the leg (70-75%) and arm (40-55%) than movements of the head (17-22%) and trunk (5-25%). The relationship between oromotor episodes and bodily movements did not significantly differ among sleep stages. Oromotor episodes and bodily movements did not show a consistent temporal pattern in the SB and CTL groups. Regardless of the temporal relationship between oromotor episodes and bodily movements, the mean heart rate significantly increased by 5 beats before the onset of oromotor episodes.Conclusions No specific temporal motor patterns were found between RMMA and bodily movements. RMMA and NSMA represent a repertoire of arousal-related autonomic motor responses during sleep.