The Upper Airway Resistance Syndrome: Pathophysiology of Daytime Symptoms

The Upper Airway Resistance Syndrome: Pathophysiology of Daytime SymptomsTherefore, given the existing data on the absence of snoring in some patients with UARS and OSAS, the paucity of data supporting a direct association or progression from snoring to UARS or OSAS, and the improvement in snoring but not in OSAS in many cases following palatal surgery, it is reasonable to conclude that snoring is not simply the mild end of a pathophysiologic continuum, but rather a separate entity that frequently coexists with other forms of sleep-disordered breathing.
Pathophysiology of Daytime Symptoms
The key feature used to identify episodes of IUAR in the seminal studies of UARS was the brief arousal that occurred in the absence of oxyhemoglobin desaturation. Therefore, brief arousals were a logical focus for studying the etiology of associated symptoms. In 1993, Strollo and Sanders questioned the relationship between nonapneic snoring and adverse health effects including EDS, but they concluded that there was insufficient evidence to arrive at an answer through epidemiologic means read more online antibiotics. Previous work had shown a correlation between daytime sleepiness and nocturnal sleep disruption, commonly from arousals or awakenings longer than those typically seen in UARS. Using the MSLT, Philip et al were able to demonstrate a significant decrease in mean sleep latency in eight healthy young adults following a night with repetitive brief arousals (averaging 11 s) provoked by auditory stimulation. The mean (± SD) MSLT scores decreased from a baseline of 15 ± 4 to 8.8 ± 5 s (p = 0.009). Additionally, the researchers found higher arousal thresholds during slow-wave sleep (SWS), during rapid eye movement (REM) sleep, and later in the night. Martin and colleagues reported similar results using auditory stimulation during sleep. They observed brief arousals following auditory stimuli that were defined as at least a 3-s shift to alpha or theta in the EEG frequency. The investigators were able to demonstrate changes in mood (energetic arousal and hedonic tone mood dimension scores) and cognitive function (Trailmaking B and paced auditory serial addition task 4-s tests) after just one night of brief arousals.


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