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Epilepsy in pervasive developmental disorder without brain MRI abnormalities

Tomoko Miyajima1, Nobusuke Kimura, Tomohiro Kumada

  • 1Department of Pediatrics, Shiga Medical Center for Children, Shiga, Japan. miyajima@terra.dti.ne.jp

Brain & Development
|September 25, 2010
PubMed

Insights

In patients with pervasive developmental disorder (PDD) and epilepsy but no brain MRI abnormalities, lower IQs correlate with later epilepsy onset and generalized epilepsy. Seizure freedom rates were similar between groups.

Area of Science:

  • Neurology
  • Developmental Neuroscience
  • Epileptology

Background:

  • Epilepsy is frequently observed in individuals with pervasive developmental disorder (PDD), with reported incidence rates between 5% and 40%.
  • Previous studies often included patients with brain magnetic resonance imaging (MRI) abnormalities or early-onset seizures, potentially confounding results.
  • This study focuses on PDD patients with epilepsy but without brain MRI abnormalities and excludes early-onset seizures.

Purpose of the Study:

  • To investigate the relationship between intelligence quotient (IQ) levels and epilepsy characteristics in patients with PDD and no brain MRI abnormalities.
  • To compare epilepsy onset, seizure types, and seizure control between PDD patients with lower IQs (Group A) and higher IQs (Group B).

Main Methods:

  • A retrospective analysis of 67 patients diagnosed with PDD and epilepsy, excluding those with brain MRI abnormalities or seizures within the first year of life.
  • Patients were categorized into two groups based on IQ: Group A (IQ < 50) and Group B (IQ ≥ 50).
  • Data on epilepsy onset, seizure classification, and seizure-free status were collected and analyzed.

Main Results:

  • The median age of epilepsy onset was significantly higher in Group A (8.8 years) compared to Group B (5.2 years).
  • Generalized epilepsy was less common in Group A (3%) than in Group B (27%).
  • Seizure-free rates after one year were 47% in Group A and 76% in Group B, a difference that was not statistically significant.

Conclusions:

  • The association between PDD and epilepsy may differ based on IQ levels in patients without brain MRI abnormalities.
  • Lower IQs in PDD patients without brain anomalies are associated with later epilepsy onset and a lower prevalence of generalized epilepsy.
  • Further research is needed to elucidate the distinct neurological underpinnings of epilepsy in PDD subgroups with varying intellectual capacities.
Abstract

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