Developmental Changes in Sleep Spindle Characteristics and Sigma Power across Early Childhood

Table 1

Descriptive statistics (M, SD) for sleep stage variables at ages 2, 3, and 5 years for the entire nighttime sleep episode. Significant post hoc paired -tests (2-tailed) are denoted as (2 years versus 3 years) and (2 years versus 5 years).

	2 years		3 years		5 years
	M	SD	M	SD	M	SD
Time in bed (min)	649.5	12.4	647.4	35.7	635.6	20.2
Total sleep time (min)	602.8	24.4	588.3	28.9	571.9	21.4
Stage 1 (min)	15.8	7.7	26.6	5.9	23.1	12.0
Stage 1 (%)	2.8	1.4	5.0	1.5	4.3	2.1
Stage 2 (min)	272.8	35.8	266.0	36.7	272.9	25.3
Stage 2 (%)	45.3	5.7	45.1	5.0	47.7	3.0
SWS (min)	138.1	26.7	136.0	25.6	134.9	21.0
SWS (%)	22.9	4.3	23.2	4.7	23.7	4.1
REM (min)	174.9	18.6	156.0	21.0	139.7	19.6
REM (%)	29.0	2.6	26.6	3.3	24.4	3.1