Early neurophysiology and MRI in predicting neurological outcome at 9–10 years after birth asphyxia

ObjectiveTo assess whether early somatosensory evoked potentials (SEP) predict long-term neurodevelopmental outcome in normothermic, full-term infants with mild to moderate neonatal encephalopathy (NE), and to compare their predictive value to already available amplitude integrated EEG (aEEG) and magnetic resonance imaging (MRI).MethodsFifty-six infants with post-asphyxia NE were prospectively recruited, and their SEP, aEEG and MRI data were acquired during the first five days. Follow-up continued to 9–10 years for assessment of neuromotor and neurocognitive development. We analysed SEP latency (N1 component), normality of aEEG background pattern, as well as patterns of injury on the neonatal MRI. Neurological outcome measures at 9–10 years included conventional MRI, Movement-ABC and the WISC-III NL.ResultsA SEP latency <50 ms during the first five days was associated with a normal neuromotor outcome (p < 0.03), and a prolonged day 3 latency was associated with lower childhood IQ (p = 0.02). The presence of multiple seizures in aEEG, as well as a moderate or severe injury on the neonatal MRI was associated with a poor neuromotor score (p = 0.03 and p < 0.01, respectively). Combination of multiple techniques improved prediction of long-term outcome compared to single modality.ConclusionEarly SEPs provide information that is comparable to the already available aEEG and MRI paradigms in the prediction of long-term outcome of full-term infants with mild to moderate neonatal encephalopathy.SignificanceThe present results call for further studies using early SEP to aid early assessment of infants treated with hypothermia.

► SEPs can be readily measured from the asphyxiated infants offering an inexpensive, bedside alternative to follow brain recovery during the first days after birth.
► The prognostic information of SEPs into childhood is complementary to what is gained from neuroimaging.
► Implementation of SEPs into brain monitors could open a pathway to follow early recovery of subcortical brain mechanisms after perinatal injury.