Send to

Choose Destination
See comment in PubMed Commons below
Front Neuroinform. 2013 Dec 5;7:33. doi: 10.3389/fninf.2013.00033. eCollection 2013.

Electroencephalogram approximate entropy influenced by both age and sleep.

Author information

Institute of Neuroinformatics, University of Zurich and ETH Zurich Zurich, Switzerland ; Child Development Center, University Children's Hospital Zurich Zurich, Switzerland.
Child Development Center, University Children's Hospital Zurich Zurich, Switzerland.
Coma Science Group, Neurology Department, Cyclotron Research Centre, University Hospital of Liège, University of Liège Liège, Belgium.


The use of information-based measures to assess changes in conscious state is an increasingly popular topic. Though recent results have seemed to justify the merits of such methods, little has been done to investigate the applicability of such measures to children. For our work, we used the approximate entropy (ApEn), a measure previously shown to correlate with changes in conscious state when applied to the electroencephalogram (EEG), and sought to confirm whether previously reported trends in adult ApEn values across wake and sleep were present in children. Besides validating the prior findings that ApEn decreases from wake to sleep (including wake, rapid eye movement (REM) sleep, and non-REM sleep) in adults, we found that previously reported ApEn decreases across vigilance states in adults were also present in children (ApEn trends for both age groups: wake > REM sleep > non-REM sleep). When comparing ApEn values between age groups, adults had significantly larger ApEn values than children during wakefulness. After the application of an 8 Hz high-pass filter to the EEG signal, ApEn values were recalculated. The number of electrodes with significant vigilance state effects dropped from all 109 electrodes with the original 1 Hz filter to 1 electrode with the 8 Hz filter. The number of electrodes with significant age effects dropped from 10 to 4. Our results support the notion that ApEn can reliably distinguish between vigilance states, with low-frequency sleep-related oscillations implicated as the driver of changes between vigilance states. We suggest that the observed differences between adult and child ApEn values during wake may reflect differences in connectivity between age groups, a factor which may be important in the use of EEG to measure consciousness.


approximate entropy; consciousness; development; electroencephalogram; sleep

PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Frontiers Media SA Icon for PubMed Central
    Loading ...
    Support Center