Postictal generalized EEG suppression occurs more often in adults than in children and might be related to why adults have a higher rate of sudden unexpected death in epilepsy than that of children, according to results from a prospective study.
Cardiopulmonary abnormalities involving ictal apnea and bradycardia happened more frequently in children, whereas ictal tachycardia occurred more often among adults. However, there was no difference in desaturation or ictal bradypnea or tachypnea in children versus adults, reported Dr. Milena Pavlova of the division of epilepsy, neurophysiology, and sleep at Brigham and Women’s Hospital, Boston, and her colleagues.
"The evolution of ictal cardiorespiratory abnormalities [had] not been systematically studied for age-related findings," the researchers noted. "There is some evidence in adults that postictal generalized EEG suppression (PGES) may potentially be a risk marker for SUDEP [sudden unexpected death in epilepsy] and that age related maturation of brain may be involved in the manifestation of PGES, but not many studies have looked into the possible effect of this age-related brain maturation on PGES," they wrote (Epilepsy Behav. 2013 Oct. 17 [doi:10.1016/j.yebeh.2013.09.026]).
"The evolution of ictal cardiorespiratory abnormalities [had] not been systematically studied for age-related findings..."
The study involved 26 children with a mean age of 10.6 years (range of 2-20 years) and 22 adults with a mean age of 37 years (range of 22-62 years) who had been admitted to the long-term monitoring units at two hospitals for the evaluation of seizures. They underwent standard continuous video-EEG monitoring as well as electrocardiography, respiratory inductance plethysmography (RIP), and finger pulse oximetry. The investigators recorded 101 seizures in children (mean of 3.9) and 55 in adults (mean of 2.55).
After one or more seizures, 13 of 22 (59%) adults had PGES, compared with only 1 of 26 (4%) children. This was a significant difference with an odds ratio of 0.20. Furthermore, PGES occurred in 6 (6%) of the seizures recorded in children, compared with 13 (24%) in adults.
"The fact that PGES was more frequent in adults than in children and the fact that age had no correlation with PGES in adults lead us to hypothesize that age may play a role in the occurrence of PGES only up to a point where the brain is mature enough to exhibit PGES. Once the brain is mature enough to be capable of manifesting PGES, further increase in age may not have any additional effect. These findings further support the idea of a less mature ‘controlling network’ in the developing brain being less capable of exhibiting PGES," the investigators wrote.
Children had more than three times greater odds of developing ictal central apnea (odds ratio = 3.36) than those of adults (39 of 78 [50%] seizures in children with good RIP data vs. 17 of 55 [31%] in adults). None of the apnea events recorded in either children or adults were obstructive in nature.
Ictal bradycardia was nearly five times more likely to occur in children than in adults (15 of 63 [24%] vs. 4 of 55 [7%], respectively). In comparison, ictal tachycardia was 60% less likely to occur among children than in adults (31 of 63 [49%] vs. 35 of 55 [64%], respectively; OR = 0.40).
The rates of other cardiopulmonary abnormalities (ictal bradypnea and tachypnea, ictal and postictal bradycardia and tachycardia) did not differ significantly between children and adults.
The adult and pediatric cohorts had similar characteristics for patient (gender, body mass index, antiepileptic drug usage, MRI lesions) and seizure variables (seizure type, duration, localization, lateralization, secondary-generalization, body-position, sleep-wake state). However, seizures in children more often involved the frontal lobe (47 of 101, 47%) compared with adults (11 of 55, 20%), whereas temporal lobe seizures were nearly five times more likely to occur in adults (37 of 55, 67%) than in children (29 of 101, 29%).
The study was funded by a grant from the Harvard Catalyst. One author reported serving as a consultant for Digitrace and Best Doctors. No other authors had conflicts of interest to report.