BACKGROUND:: Very few data are available on the use of bispectral index (BIS) monitoring in children who are intellectually disabled. Epileptiform electroencephalogram activity, underlying cerebral pathology, or anticonvulsant/spasmolytic therapy might influence BIS monitoring.Our aim in this exploratory study was to first compare BIS values at 4 different stages of anesthesia between intellectually disabled children and controls. Our second aim was to investigate the discriminative properties of BIS between consciousness and unconsciousness for intellectually disabled children and for controls. METHODS:: Eighteen intellectually disabled children and 35 control children, aged 2-13 yr, were included. BIS values, landmark events, and standard monitoring values of vital functions were recorded throughout the whole procedure. The performance of BIS in distinguishing between a conscious and unconscious state was assessed from receiver operating characteristic curves. RESULTS:: Median (interquartile range) BIS values for the intellectually disabled group were significantly lower than those for controls in the awake state (72 [48-77] vs 97 [84-98], P < 0.001), during stable intraoperative anesthesia (34 [21-45] vs 43 [33-52], P = 0.02), and during return of consciousness (59 [36-68] vs 73 [64-78], P = 0.009). The discriminative properties of the BIS monitor for the state of consciousness were comparable between the 2 groups according to the receiver operating characteristic curves. Nevertheless, the optimal cutoff BIS value for discrimination between conscious and unconscious state was 28 points lower for the intellectually disabled group. CONCLUSIONS:: We advise anesthesiologists to be alert to possible lower BIS values in intellectually disabled children. There is a risk that they will inadvertently misinterpret the state of consciousness in intellectually disabled children. New multicenter studies must find the optimal manner of evaluating (un)consciousness in intellectually disabled patients with documented and confirmed specific etiologies of their intellectual disability. Copyright,
Anesthesia and Analgesia
Erasmus MC: University Medical Center Rotterdam

Valkenburg, A.J, de Leeuw, T.G, Tibboel, D, & Weber, F. (2009). Lower bispectral index values in children who are intellectually disabled. Anesthesia and Analgesia, 109(5), 1428–1433. doi:10.1213/01ANE.0b013e3181ba43b2