| 2461 Quantitative Analysis of Muscle Tone between Wakefulness and Sleep | ||
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K. OKURA1, T. KATO2, P.H. ROMPRÉ1, J.Y. MONTPLAISIR3, and G.J. LAVIGNE1, 1Université de Montréal, Canada, 2Matsumoto Dental University, Nagano, Japan, 3Hôpital du Sacré-Cœur de Montréal, Canada Objectives: The remarkable decline in jaw muscle tone during rapid eye movement (REM) sleep is a well-known phenomenon. So far, only a few studies performed quantitative background muscle activity measurements during sleep. The aim of this study is to compare the various muscle tones between wakefulness and sleep stages quantitatively. Methods: Nine healthy human subjects (5F; 4M, 25.3±1.8yr) were selected for polysomnographic recordings that included electromyograms of suprahyoid, masseter, temporalis and anterior tibialis (leg) muscles. Quantitative assessment of muscle tone was done with the root mean square (RMS) and the frequency spectral analysis methods. Results: A significant reduction (repeated ANOVA, p<0.01) in the activity of the 3 cranial muscles was observed between wakefulness and sleep (suprahyoid: -31.5% for RMS, -37.5% for frequency respectively; temporalis: -37.9%, -43.2%; masseter: -24.4%, -41.9%). Furthermore, a reduction (repeated ANOVA, p<0.01) was also observed from non-REM to REM sleep (suprahyoid: -15.0%, -27.5%; temporalis: -12.1%, -16.7%; masseter: -11.4% only for the frequency variable). Both analysis methods showed a significant correlation for the 3 cranial muscles in this study (R=0.62-0.91). However, for the anterior tibialis, only minor reductions across sleep stage were observed and only a low correlation was noted between both analysis methods. No complete reduction in muscle tone of the four muscles studied was observed during REM sleep (one-sample t-test). Conclusions: This study confirms that the most important decrease in muscle tone during sleep is observed in suprahyoid muscles. This major reduction in suprahyoid muscles during sleep probably relates to altered airway patency as seen in patients with respiratory disturbance (e.g., sleep apnea). From wakefulness to non-REM and REM sleep, all 3 cranial muscles showed a significant decrease in muscle tone. On the contrary, the anterior tibialis muscle tone was relatively stable from wakefulness through all sleep stages. Support: FRSQ and CIHR. | ||
| Seq #248 - Orofacial Sensory Motor Function 10:15 AM-11:30 AM, Friday, 12 March 2004 Hawaii Convention Center Exhibit Hall 1-2 | ||
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