[Screening of sleep apnea syndrome using daytime polysomnography--its usefulness and the characteristics of daytime sleep in the patients with sleep apnea syndrome].

Some attempts have been made to screen sleep apnea syndrome (SAS). In this study, we performed daytime polysomnography (DPSG) as a means of screening SAS. 33 patients (28 males and 5 females, a mean age of 50.7 years) who were seen with the complaints of sleep-wake disorders, snoring and breathing disturbance in their nocturnal sleep were subjects for the screening. EEG, EMG, and EOG according to standard polysomnographic technique were recorded from 3:30 (p.m.) for 60 minutes, as additional indicators, oro-nasal airflow and abdominal movement were monitored simultaneously to confirm cessation of breathing. After the screening, we performed conventional polysomnography (PSG) to make a diagnosis of SAS, and compared the diagnosis with the appearance of apnea in the screening. We studied on the characteristics of daytime sleep in SAS and NonSAS by the comparison of EEG variables obtained from DPSG. Sleep apnea was detected in 20 cases with DPSG, 18 cases of these 20 were diagnosed as SAS. However, there were 6 patients who were diagnosed as SAS without the appearance of apnea in the screening. Dominant type of apnea in the screening were corresponded to ones confirmed with PSG, 16 cases showed obstructive type and 4 cases indicated central type. Some statistical differences of EEG variables between SAS and NonSAS were recognized. Number of stage shifts and percentage of stage W to total sleep time were significantly increased in SAS, on the contrary, percentage of stage 2 to total sleep time tended to be lower in SAS.(ABSTRACT TRUNCATED AT 250 WORDS)