Table 2.

Sleep quality: Results of polysomnography and subjective assessment

Measures	Silent	Noisy	P
Global sleep parameters
Total sleep duration [min]	382±16	372±22	0.241
Sleep efficiency [%]	92±4	89±6	0.203
Latencies [min]
to sleep state 1	7.6±7.1	7.5±6.6	0.878
to REM sleep	69±16	90±32	0.074
Sleeping stage distribution [%]
Stage 1	11.2±4.4	13.7±5.5	0.059
Stage 2	52.1±4.9	49.8±6.2	0.386
Stage 3	10.1±3.8	11.0±3.8	0.241
Stage 4	3.8±4.5	3.8±3.8	0.674
REM	22.8±3.7	21.7±5.2	0.333
Sleep interruptions
Arousal index [/h]	14.3±5.7	16.2±4.9	0.139
Waketime after sleep onset [min]	23.8±11.4	32.4±25.7	0.878
Changes of sleep stages	7.8±2.4	9.0±4.3	0.507
Subjective sleep quality
Total score (20: High to 80: Low sleep quality)	28.1±3.7	30.3±6.2	0.092