Analysis of the bispectral index during natural sleep in children.

The Bispectral Index (BIS) is a system used to measure sedation levels. Some investigators recently analyzed changes in the BIS during natural sleep in adults and found that the BIS diminished considerably as sleep became deeper. No such studies have been undertaken to investigate changes in the BIS in sleeping children. The aim of this work was to assess the trend of the BIS in the various stages of sleep in a group of children, performing a descriptive analysis on a limited number of cases. We evaluated 15 children with negative clinical findings and a normal electroencephalogram (EEG) as part of their follow-up for prior episodes of epilepsy, recording the BIS and EEG in a waking state, in the various stages of sleep and on reawaking. For each stage, the mean value, the standard deviation, and the range of BIS values were calculated. The results showed that the BIS decreased progressively as sleep became deeper. The correlation between the stage of sleep and the BIS was significant. On reawaking, a slow increase was apparent in the BIS.