Characterisation of the relationships between rhythmic masticatory muscle activities and limb movements in patients with sleep bruxism

Abstract

Summary Background Most rhythmic masticatory muscle activities (RMMAs) have been shown to be accompanied with limb movements (LMs) in sleep bruxism (SB) patients during sleep. Objectives To compare the relationships between RMMAs and LMs in SB patients and normal subjects. Methods Polysomnographic recordings were performed on eight SB patients and nine normal subjects and the frequencies and durations of RMMAs as well as LMs were determined. Linear regression and correlation analysis were performed to study the relationship between durations of RMMAs and LMs when RMMAs occurred with LMs. Results Most LMs in SB patients, but not in normal subjects, were accompanied with RMMAs. RMMAs in SB patients were more likely to be isolated, phasic or mixed, while RMMAs in normal subjects were more likely to be tonic. The frequencies of LMs, isolated RMMAs and RMMAs accompanied with LMs in SB patients were significantly higher than those in normal subjects. Furthermore, linear regression and correlation analysis showed that duration of RMMAs was significantly associated with that of LMs when RMMAs occurred with LMs. The duration of RMMAs, when accompanied with LMs, in SB patients was significantly longer than that in normal subjects. Conclusions Close relationships between LMs and RMMAs exist in SB patients and normal subjects, and SB episodes may be part of cortical arousal responses and the increased cortical activities associated with SB episodes may not just be localised to the central nervous system (CNS) that controls jaw movements but may also include other parts of CNS that controls LMs.

Changes in heart rate related to rhythmic masticatory muscle activities and limb movements in patients with sleep bruxism

“…Indeed, previous study reported that a much lower percentage of RMMAs could be evoked by peripheral stimulation in normal subjects than in SB patients although a similar percentage of transient cortical arousals could be evoked in both normal subjects and SB patients which suggests stronger and longer peripheral stimulation is needed to evoke occurrence of RMMAs in the normal subjects (eg AW) so longer cortical arousals (eg AW) would be more likely to occur and the resulting cortical excitation would be more likely to spread to more areas of the CNS, which might include the part controls LMs. This is supported by our recent findings that there was a lower frequency of RMMAs and a higher percentage of RMMAs accompanied by LMs in the normal subjects than in the SB patients and that there was a higher proportion of RMMAs with a companion of LMs associated with AW in the normal subjects than in the SB patients. Second, the parameters of HR increases associated with mixed RMMAs, but not with phasic and tonic RMMAs, in the SB patients were significantly different from those in the controls, which may be due to a lower (Wilcoxon rank‐sum test, P = .013) proportion of mixed RMMAs associated with AW and a significantly higher ( P < .05 for both) proportion of mixed RMMAs associated with mAR and NA in the SB patients than those in the controls, and no significant difference ( P > .05) in the phasic and tonic RMMAs associated with AW between SB patients and controls.…”

“…The data from the polysomnographic recordings in the second night were used for further confirmation of SB and data analysis described below. Polysomnographic recordings of EEG (F3‐A2, F4‐A1, C3‐A2, C4‐A1, O1‐A2 and O2‐A1), electrocardiographic (ECG) and electrooculographic (EOG) activities as well as thoracic and abdominal respiration, nasal air flow, body posture and capillary oxygen saturation (SpO2) in index finger or thumb were performed . In addition, EMG activities from mylohyoid, bilateral masseter and limb muscles (bilateral gastrocnemius and tibialis anterior muscle, and bilateral flexor and extensor carpi radialis) were also recorded.…”

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

“…Thus, in the SB group, the jaw motor system generating rhythmic activity may be more responsive to arousals [39]. Furthermore, previous findings showed that RMMA with limb and bodily movements was more closely related to higher cardiac and cortical activities [21,36,42]. Therefore, the close temporal relationship between oromotor and bodily movements may be mediated by a higher hierarchy of arousals that increases the excitability of multiple motor systems, such as at the trigeminal and spinal levels [6,7,10].…”

Assessment of Telomerase Reverse Transcriptase Single Nucleotide Polymorphism in Sleep Bruxism

“…It is worth noting that phasic bruxism is the most common SB subtype [51,52]. Tonic bruxism episodes are the rarest; however, in healthy subjects, tonic bruxism is more common [53]. Increased severity of phasic bruxism was observed in hypertensives, while the tonic activity was similar in hypertensives and normotensives [54].…”