Sleep Spindles Characteristics in Insomnia Sufferers and Their Relationship with Sleep Misperception

Table 6

Summary of multiple regression analysis for underestimation (Misperception Index > 0).

Variable	B	SE	Beta
Intercept	2.241	16.820
Stage 2 sleep spindles
Number		0.001
Density		0.374
Duration		0.691
Frequency		0.253
Amplitude	0.062	0.018
SWS sleep spindles
Number		0.001
Density		0.087
Duration		0.929
Frequency		0.182
Amplitude		0.016
Objective sleep measures
SOL (min)		0.017
WASO (min)		0.015
TST (min)		0.014
SE (%)		0.085
Stage 1 (min)		0.063
Stage 1 (%)	0.505	0.337
Stage 2 (min)	0.005	0.019	1.096
Stage 2 (%)	0.096	0.093	3.987
Stage SWS (min)	—	—	—
Stage SWS (%)	0.212	0.248	4.730
REM (min)	0.043	0.024	4.733
REM (%)

Note. = ; = .  B: unstandardized regression coefficient; SE: standard error of the coefficient; beta: standardized coefficient. SOL: sleep onset latency. WASO: wake after sleep onset. TST: total sleep time. SE: sleep efficiency. SWS: slow wave sleep. REM: rapid eye movement.