Article Figures & Data
Figures
- Figure 1.
Cross-sectional trajectories of sleep spindles and sigma power in 572 subjects aged 6–21. Data points are multivariable-adjusted means and their 95% CI and lines are multivariable-adjusted regression curves for sleep spindle and sigma activity. A, Spindle density (# of spindles/minute) overall. B, Spindle density stratified by sex. C, Spindle frequency (Hz) overall. D, Spindle frequency stratified by sex. E, Fast spindle percent (% of spindles in the 12–16 Hz range) overall. F, Fast spindle percent stratified by sex. G, Spindle power (μV2) overall. H, Spindle power stratified by sex. I, Sigma power (μV2) overall. J, Sigma power stratified by sex.
- Figure 2.
Sex (left column) and Tanner-related (right column) differences in the longitudinal trajectories of sleep spindles and sigma power in 332 subjects aged 5–12 at baseline followed-up at ages 12–22. Data are multivariable-adjusted percent change (95% CI) from baseline to follow-up in sleep spindle and sigma activity. Age groups represent transitions between baseline age (mean) 6.6 years to follow-up ages 12–14, from 8.7 years to ages 15–17, and from 10.3 years to ages 18–22. A, Spindle density stratified by sex. B, Spindle frequency stratified by sex. C, Fast spindle percent stratified by sex. D, Spindle power stratified by sex. E, σ power stratified by sex. F, Spindle density stratified by Tanner stage. G, Spindle frequency stratified by Tanner stage. H, Fast spindle percent stratified by Tanner stage. I, Spindle power stratified by Tanner stage. J, σ power stratified by Tanner stage. *p < 0.05, **p < 0.01.
Tables
Cross-sectionala Longitudinal (N = 332)b (N = 572) Baseline Follow-up Sex Male 300 (52.4%) 178 (53.6%) 178 (53.6%) Female 272 (47.6%) 154 (46.4%) 154 (46.4%) Race/ethnicity Non-Hispanic White 424 (74.1%) 252 (75.9%) 252 (75.9%) Racial/ethnic minority 148 (25.9%) 80 (24.1%) 80 (24.1%) Age 5 2 (0.3%) 6 (1.8%) 6 32 (5.6%) 35 (10.5%) 7 38 (6.6%) 53 (16.0%) 8 48 (8.4%) 51 (15.4%) 9 32 (5.6%) 72 (21.7%) 10 36 (6.3%) 57 (17.2%) 11 28 (4.9%) 51 (15.4%) 12 13 (2.3%) 7 (2.1%) 8 (2.4%) 13 27 (4.7%) 27 (8.1%) 14 40 (7.0%) 40 (12.0%) 15 50 (8.7%) 51 (15.4%) 16 59 (10.3%) 58 (17.5%) 17 53 (9.3%) 51 (15.4%) 18 46 (8.0%) 45 (13.6%) 19 31 (5.4%) 27 (8.1%) 20 21 (3.7%) 15 (4.5%) 21 8 (1.4%) 7 (2.1%) 22
237 (1.2%)
1 (0.2%)3 (0.9%) BMI percentile Normal weight 373 (65.2%) 232 (69.9%) 225 (67.8%) Overweight 113 (19.8%) 36 (10.8%) 61 (18.4%) Obese 86 (15.0%) 64 (19.3%) 46 (13.9%) Behavioral disorders None 449 (78.5%) 274 (82.5%) 248 (74.7%) Yes 123 (21.5%) 58 (17.5%) 84 (25.3%) Neurobehavioral measures Attention problems, score 54.6 (6.6) 54.3 (6.4) 54.8 (6.6) Thought problems, score 55.1 (6.6) 55.4 (6.9) 54.5 (5.8) Internalizing problems, score 50.5 (10.7) 50.6 (10.7) 50.4 (10.0) Externalizing problems, score 48.1 (10.8) 48.3 (11.0) 48.2 (10.0) Verbal IQ, score 105.8 (13.2) 107.0 (13.2) 102.0 (10.4) Non-verbal IQ, score 106.4 (15.5) 108.1 (15.5) 106.1 (11.6) Coding, scaled score 10.3 (3.2) 10.6 (3.3) 9.8 (2.6) Digit span backward, raw score 4.5 (1.7) 4.6 (1.6) 6.9 (2.4) PSG SOL, min 27.4 (22.2) 26.8 (22.3) 25.0 (20.0) WASO, min 61.6 (41.0) 43.9 (32.9) 69.2 (41.1) TST, min 448.6 (51.3) 461.3 (44.3) 448.0 (49.8) SE, % 83.6 (9.3) 86.7 (7.6) 82.9 (9.1) N1, % 2.0 (2.7) 3.5 (2.6) 0.9 (1.1) N2, % 51.1 (10.9) 46.7 (10.8) 53.2 (9.4) N3, % 27.9 (10.1) 29.9 (10.5) 27.1 (9.0) R, % 19.0 (5.2) 20.1 (5.3) 18.8 (4.7) AHI, events/h 1.9 (4.7) 0.8 (1.1) 2.5 (5.7) ↵a Data for 572 subjects in cross-sectional analyses.
↵b Data for 332 subjects in longitudinal analyses, including baseline and follow-up.
Data are means (SD) and number of cases (percentage) for continuous and categorical/ordinal variables, respectively. AHI = apnea/hypopnea index; BMI = body mass index; N1 = epochs scored as NREM stage 1; N2 = epochs scored as NREM stage 2; N3 = epochs scored as NREM stages 3 or 4; R = epochs scored as REM sleep; SE = sleep efficiency; SOL = sleep onset latency; TST = total sleep time; WASO = wake after sleep onset.
- Table 2
Correlation coefficients for sleep spindle/σ activity in the cross-sectional sample (above diagonal) and the longitudinal sample (below diagonal)
Spindle density Spindle frequency Fast spindle percent Spindle power σ power Spindle density --- 0.205 0.263 0.553 0.311 Spindle frequency 0.286 --- 0.931 −0.120 −0.104 Fast spindle percent 0.349 0.564 --- −0.061 −0.106 Spindle power 0.471 0.191 0.248 --- 0.628 σ power 0.553 0.262 0.225 0.671 --- Data are Pearson correlation coefficients. For the cross-sectional sample, the correlation coefficients for spindle density (#/min), spindle frequency (Hz), fast spindle percent (%), and spindle and σ power (μV2) were determined. For the longitudinal sample, the correlation coefficients for the percent change in each spindle metric from baseline (ages 5–12) to follow-up (ages 12–22) were calculated.
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