Head growth in infants with infantile spasms may be temporarily reduced.

Epileptic activity, as a component of epileptic encephalopathies, can interfere with brain growth and development. Infantile spasms as a syndrome represent such epileptic activity during the period of spasms and hypsarrhythmia. The rate of head growth in infants with infantile spasms during the period of spasms has not been studied previously. A retrospective study of head growth in 38 infants with infantile spasms and no other cause of abnormal head growth is presented. Mental outcome was assessed at follow-up. The mean head circumference of infants with infantile spasms was not significantly smaller than in the normal population, but the proportion of head circumference below the tenth percentile in the infantile spasms group was higher (27%). Head circumference below the tenth percentile in the fourth and fifth month after the onset of infantile spasms was significantly associated with later mental retardation (P = 0.004). There was no correlation with specific treatment of infantile spasms. Transiently diminished head growth in infants with infantile spasms coincides temporally with the onset of infantile spasms and "catches up" during remission of infantile spasms in favorable cases. This pattern can reflect the negative influence of epileptic activity on brain growth during the sensitive period. Head circumference can provide a reliable predictive value of mental outcome in children with infantile spasms.