Sleep Med Psychophysiol.  2010 Jun;17(1):41-49.

Detrended Fluctuation Analysis of Sleep Electroencephalogram between Obstructive Sleep Apnea Syndrome and Normal Children

• Kim EJ
• Ahn YM
• Shin HB
• Kim JW

Abstract

Unlike the case of adult obstructive sleep apnea syndrome (OSAS), there was no consistent finding on the changes of sleep architecture in childhood OSAS. Further understanding of the sleep electroencephalogram (EEG) should be needed. Non-linear analysis of EEG is particularly useful in giving us a new perspective and in understanding the brain system. The objective of the current study is to compare the sleep architecture and the scaling exponent (alpha) from detrended fluctuation analysis (DFA) on sleep EEG between OSAS and normal children. Fifteen normal children (8 boys/7 girls, 6.0+/-2.2 years old) and twelve OSAS children (10 boys/2 girls, 6.4+/-3.4 years old) were studied with polysomnography (PSG). Sleep-related variables and OSAS severity indices were obtained. Scaling exponent of DFA were calculated from the EEG channels (C3/A2, C4/A1, O1/A2, and O2/A1), and compared between normal and OSAS children. No difference in sleep architecture was found between OSAS and normal controls except stage 1 sleep (%) and REM sleep latency (min). Stage 1 sleep (%) was significantly higher and REM latency was longer in OSAS group (9.3+/-4.3%, 181.5+/-59.9 min) than in controls (5.6+/-2.8%, 133.5+/-42.0 min). Scaling exponent (alpha) showed that sleep EEG of OSAS children also followed the 'longrange temporal correlation' characteristics. Value of alpha increased as sleep stages increased from stage 1 to stage 4. Value of alpha from C3/A2, C4/A1, O1/A2, O2/A1 were significantly lower in OSAS than in control (1.36+/-0.05 vs. 1.41+/-0.04, 1.37+/-0.04 vs. 1.41+/-0.04, 1.37+/-0.05 vs. 1.41+/-0.05, and 1.36+/-0.07 vs. 1.41+/-0.05, p<0.05). Higher stage 1 sleep (%) in OSAS children was consistent finding with OSAS adults. Lower 'alpha' in OSAS children suggests decrease of self-organized criticality or the decreased piling-up energy of brain system during sleep in OSAS children.

Keyword

Child; Obstructive sleep apnea syndrome; Electroencephalogram; Detrended fluctuation analysis; Polysomnography; Sleep architecture

MeSH Terms

Adult
Brain
Child
Electroencephalography
Humans
Polysomnography
Sleep Apnea, Obstructive
Sleep Stages
Sleep, REM