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Outcome of children with hyperventilation-induced high-amplitude rhythmic slow activity with altered awareness

Alexander Barker1, Joanne Ng, Christopher D C Rittey

  • 1Department of Clinical Neurophysiology, Royal Hallamshire Hospital, Sheffield, UK.

Developmental Medicine and Child Neurology
|June 21, 2012
PubMed

Insights

Hyperventilation-induced high-amplitude rhythmic slow activity with altered awareness (HIHARS) in children often resolves spontaneously. However, those with generalized tonic-clonic seizures or focal motor seizures may indicate epilepsy.

Area of Science:

  • Pediatric Neurology
  • Clinical Neurophysiology

Background:

  • Hyperventilation-induced high-amplitude rhythmic slow activity with altered awareness (HIHARS) is an emerging electrographic phenomenon in children.
  • HIHARS is considered an age-related, non-epileptic event.

Observation:

  • This study retrospectively analyzed 15 children diagnosed with HIHARS.
  • Presenting symptoms included blank spells, generalized tonic-clonic seizures (GTCS), and deteriorating school performance.

Findings:

  • Children with HIHARS presenting solely with blank spells showed spontaneous symptom resolution in most cases.
  • HIHARS symptoms did not evolve into clearly epileptic events in isolated blank spell cases.
  • Children with HIHARS and features of GTCS, focal motor seizures, or epileptiform discharges were diagnosed with epilepsy.

Implications:

  • HIHARS with isolated blank spells appears to be a benign, self-limiting condition in children.
  • The presence of GTCS, focal motor seizures, or epileptiform discharges alongside HIHARS warrants further investigation for epilepsy.
  • Differentiating HIHARS from epileptic seizures is crucial for accurate diagnosis and management in pediatric neurology.

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