The value of sleep nasendoscopy in the evaluation of patients with suspected sleep-related breathing disorders.

Fifty patients with sleep-related breathing disorders were tested with nocturnal polysomnography and with nasendoscopic diurnal polysomnography after diazepam administration, and various indices of breathing disorders were examined, and the results obtained in the two sleep studies compared. There were no significant differences between the two sleep studies in either the type of apnoea or the indices of breathing disorder except for the longest duration of apnoea. There was a significant difference in the duration of REM sleep between the two sleep studies, but no significant difference in the duration of each stage of non-REM sleep. We speculate that nasendoscopic diurnal polysomnography with diazepam can be used as a substitute for nocturnal polysomnography in the clinical study of non-REM sleep stage but it is not sufficient in evaluating REM sleep stage, in patients with sleep-related breathing disorders without pathological obesity or abnormal respiratory function.