Results: All subjects could operate the FLA. There was no significant difference between subjective assessment of sleep state of the measured night by means of visual analog scale (VAS) and that of usual nights. Recorded EMG baselines were stable. Distinct bursts including phasic bursts, tonic bursts and bursts with a low amplitude but considerably long duration were observed. The mean (± SD) number of SB-B per hour was 14.3±11.2 /h and the mean (± SD) duration of a SB-B was 2.28±0.92 sec. Individual data of these items analyzed for each subject were able to be compared with known standard data from previous studies.