The Risk of Lower Mental Outcome in Infantile Spasms Increases after Three Weeks of Hypsarrhythmia Duration

Abstract

Summary:To assess the correlation between hypsarrhythmia duration and mental outcome in infantile spasms (IS) the medical records of 48 infants with IS were reviewed retrospectively and psychological assessments undertaken at follow-up at the age of 3 to 13 years. We found 18 (38%) cryptogenic IS cases with typical hypsarrhythmia and 30 symptomatic with modified hypsarrhythmia-further classified into 15 cases as multifocal, 10 as pseudoperiodic and 5 as unilateral hypsarrhythmia. A short treatment lag (one to two weeks) occurred in 25, three to four weeks in 10 cases. Spasms ceased within one month after treatment in 23 infants. At follow-up 15 children had normal mental outcome (borderline included). A correlation between hypsarrhythmia duration longer than three weeks and lower mental outcome was found using the logistic regression model. The duration of hypsarrhythmia represents a sensitive prognostic parameter in IS; the risk of mental retardation increases after three weeks of hypsarrhythmia. Key Words: Infantile spasmsDuration of hypsarrhythmia-Mental outcome-Children.Infantile spasms (IS), i.e., West syndrome, as an epileptic encephalopathy, represents one of the major causes of acquired mental retardation in early childhood (Roger and Dulac, 1994). Prognosis largely depends on etiology, being most unfavorable in prenatal cases with evolution to resistant epilepsy and severe mental retardation. However, infants with cryptogenic/idiopathic etiology can have favorable outcome with lifelong remission of seizures and normal or nearly normal mental development (Lombroso, 1983;Dulac et al., 1993;Riikonen, 1996).Among prognostic factors, the treatment lag and duration of spasms have been recognized as being significant (Lombroso, 1983;Eisermann et al., 2003;Goh et al., 2005). In most studies a treatment lag of up to one month correlates with a better prognosis. Prolonged duration of spasms despite treatment increases the risk of mental retardation (Eisermann et al., 2003;Goh et al., 2005). In some infants hypsarrhythmia continues despite the cessation of spasms. Therefore we explored the impact of hypsarrhythmia duration on mental outcome in 48 children with IS; the epidemiologic part of the study was published in 2002 (Rener Primec et al., 2002 MATERIALS AND METHODSThe medical records of 48 infants diagnosed with IS were studied retrospectively. IS were defined as a syndromic condition (Roger and Dulac, 1994;Lux and Osborne, 2004). The methodology applied has been described previously (Rener Primec et al., 2002), when epidemiologic features of 47 children (permanent residency in Slovenia) were presented. One additional child (immigrant) was included here. The essentials for this study were standard 12-channel EEG recordings taken in wakefulness and sleep at the time of diagnosis of IS and subsequent EEG recordings obtained every 7 to 10 days during the first 2 months or until remission (whichever came first), then monthly for the first 6 months after diagnosis of IS. If the spasms reoccurred an infant was admi...

Recent Advances in the Pharmacotherapy of Infantile Spasms

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Infantile spasms: review of the literature and personal experience

“…This events may be very difficult to treat [92]. The risk of a cognitive problems in children with a cryptogenic IS increased when treatment was started after more than three weeks of hypsarrhythmia duration [93]. …”

Long-term outcomes in patients with West syndrome: An outpatient clinical study

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