2 research outputs found
Age-specific periictal electroclinical features of generalized tonic-clonic seizures and potential risk of sudden unexpected death in epilepsy (SUDEP)
Generalized tonic–clonic seizure (GTCS) is the commonest seizure type associated with sudden unexpected
death in epilepsy (SUDEP). This study examined the semiological and electroencephalographic differences
(EEG) in the GTCSs of adults as compared with those of children. The rationale lies on epidemiological observations
that have noted a tenfold higher incidence of SUDEP in adults.Weanalyzed the video-EEG data of 105 GTCS
events in 61 consecutive patients (12 children, 23 seizure events and 49 adults, 82 seizure events) recruited from
the Epilepsy Monitoring Unit. Semiological, EEG, and 3-channel EKG features were studied. Periictal seizure
phase durations were analyzed including tonic, clonic, total seizure, postictal EEG suppression (PGES), and
recovery phases. Heart rate variability (HRV)measures includingRMSSD (root mean square successive difference
of RR intervals), SDNN (standard deviation of NN intervals), and SDSD (standard deviation of differences) were
analyzed (including low frequency/high frequency power ratios) during preictal baseline and ictal and postictal
phases. Generalized estimating equations (GEEs)were used to find associations between electroclinical features.
Separate subgroup analyses were carried out on adult and pediatric age groups as well as medication groups
(no antiepileptic medication cessation versus unchanged or reduced medication) during admission.Major differences
were seen in adult and pediatric seizures with total seizure duration, tonic phase, PGES, and recovery
phases being significantly shorter in children (p b 0.01). Generalized estimating equation analysis, using tonic
phase duration as the dependent variable, found age to correlate significantly (p b 0.001), and this remained
significant during subgroup analysis (adults and children) such that each 0.12-second increase in tonic phase
duration correlated with a 1-second increase in PGES duration. Postictal EEG suppression durations were on
average 28 s shorter in children. With cessation of medication, total seizure duration was significantly increased
by a mean value of 8 s in children and 11 s in adults (p b 0.05). Tonic phase duration also significantly increased
with medication cessation, and although PGES durations increased, this was not significant. Root mean square
successive difference was negatively correlated with PGES duration (longer PGES durations were associated
with decreased vagally mediated heart rate variability; p b 0.05) but not with tonic phase duration. This study
clearly points out identifiable electroclinical differences between adult and pediatric GTCSs that may be relevant
in explaining lower SUDEP risk in children. The findings suggest that some prolonged seizure phases and
prolonged PGES duration may be electroclinical markers of SUDEP risk and merit further study