The human tongue during sleep: Electromyographic activity of the genioglossus muscle

The effect of rapid eye movement (REM) sleep on upper airway mechanics in normal human subjects

“…Second, as discussed above, if the assumption is that the intraluminal pressure reflects the transmural pressure, a decreased compliance during REM sleep would have to be associated with increased neuromuscular activity or increased intrinsic stiffness of the airway wall. Since increased neuromuscular activity has not been observed (Sauerland & Harper, 1976;Sauerland et al 1981;Wiegand et al 1991), non-neuromuscular properties of the upper airway, not neuromuscular activity, may be the critical determinants of compliance during sleep. In other words, in the absence of significant neuromuscular activity, as is seen in REM sleep, changes in compliance are secondary to changes in the non-neuromuscular properties of the airway wall.…”

“…Alternatively, since we studied only the nasopharynx, we could have missed a segment of even greater narrowing in the oropharynx, where the genioglossus is the primary dilator muscle. Genioglossus activity has clearly been shown to be decreased during REM sleep (Sauerland & Harper, 1976;Sauerland et al 1981;Wiegand et al 1991) and it is conceivable that REM sleep is characterized by greater collapse in the oropharynx than the nasopharynx. However, this is speculative as all the previous studies on the site of upper airway narrowing in normal subjects and apnoeics have been performed during either NREM sleep or general anaesthesia (Isono et al , 1997Morrison et al 1993).…”

“…Previous work has shown that airway wall stiffness is related to both the upper airway neuromuscular activity and the non-neuromuscular properties of the airway wall (Isono & Remmers, 1994;Rowley et al 1996;Rowley, Williams, Smith & Schwartz, 1997). Previous work on the effect of REM sleep on upper airway neuromuscular activity has clearly shown that the neuromuscular activity to upper airway muscles was either decreased (Sauerland & Harper, 1976;Sauerland, Orr & Hairston, 1981;Wiegand, Zwillich, Wiegand & White, 1991) or unchanged (Wiegand, Latz, Zwillich & Wiegand, 1990b) during REM sleep. Thus, REM sleep should be associated with either increased or similar airway compliance compared with NREM sleep.…”

“…This would be unusual as the upper and lower airways are synchronized in normal, spontaneously breathing subjects. Second, changes in upper airway physiology may have been found if we had investigated the oropharynx, where the genioglossus has a larger influence on airway patency and which has been shown to have decreased EMG activity during phasic REM sleep (Sauerland & Harper, 1976;Wiegand et al 1991). Third, the definition we used to separate phasic from tonic breaths may not be sufficiently discriminating.…”

Differences in respiratory neural activities between vagal (superior laryngeal), hypoglossal, and phrenic nerves in the anesthetized rat.

“…Respiratory electrical activities in the cranial nerves and their innervating muscles are, however, assessed to be more sensitive to anesthesia or to general neural depression during sleep than the activities in the phrenic nerve (COHEN, 1979 ;MURAKAMI and KIRCHNER, 1974 ;SHERREY and MEGIRIAN, 1977). An interesting example of depression during sleep is the pharyngeal airway obstruction due to reduction in inspiratory activities in the genioglossus muscle (REMMERS et al, 1978 ;SAUERLAND and HARPER, 1976). It is, therefore, probable that changes in phasic neural outflows from the bulbo-pontine respiratory complex under various conditions are not always similar in different groups of respiratory efferent fibers.…”