Seizure burden and neurodevelopmental outcome in neonates with hypoxic-ischemic encephalopathy.
Liudmila Kharoshankaya, Nathan J Stevenson, Vicki Livingstone and 4 others
PMID 27595841WHAT IT FOUND
In neonates with moderate or severe hypoxic-ischemic encephalopathy, seizures alone did not predict abnormal development.
High seizure burden, over 40 minutes total or over 13 minutes in one hour, was associated with abnormal outcome at 24 to 48 months.
Key findings
01The presence of electrographic seizures alone was not significantly associated with abnormal outcome, 62% of neonates with seizures versus 39% without seizures, p = 0.126.
02A total seizure burden over 40 minutes and a maximum hourly seizure burden over 13 minutes per hour were significantly associated with abnormal outcome, independent of electrographic HIE grade or therapeutic hypothermia.
03Five out of seven neonates who died, 10 out of 12 neonates with cerebral palsy, and all five neonates with later epilepsy had either high total seizure burden or both high total and high maximum seizure burden.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
The study was retrospective and small, with only 47 neonates analysed, and confidence intervals for some estimates were wide. Only neonates with moderate or severe electrographic HIE were analysed, so it does not address neonates with mild HIE. Outcome was assessed at 24 to 48 months using two different scales, Griffiths and Bayley-III, which are not directly comparable. Motor disability is usually diagnosed by 2 years, but cognitive and behavioural skills are better assessed at 6 to 7 years, so language and cognition findings may be incomplete. Neuroimaging was not available for most of the non-hypothermia cohort, so structural brain injury could not be fully considered. Many neonates received antiepileptic drugs, and their effects on seizure burden and EEG background were not analysed. EEG monitoring was shorter in the non-hypothermia group, so some seizures might have been missed. The cohort size did not allow simultaneous control for therapeutic hypothermia and HIE grade.
Declared interests
The supplied text does not report funding or conflicts of interest.
The easy way to misread this
Do not conclude that treating seizures will improve development or that any seizure means poor outcome. Seizures alone were not significantly associated with abnormal outcome, and only high seizure burden was associated, in an observational study that cannot prove cause.