DURATION OF HYPSARRHYTHMIA OVER THREE WEEKS CORRELATES WITH LOWER MENTAL OUTCOME

Objectives: Objective: Infantile spasms (IS) or West syndrome represent one of the major causes of acquired mental retardation in childhood. The aim of the study was to assess the correlation between the duration of hypsarrhythmia and mental outcome.

Methods: Methods: Medical records of children diagnosed as IS, admitted to our hospital from Jan 1, 1985 to Dec 31, 1995 were studied retrospectively. All children had complete diagnostic work-up. Duration of hypsarrhythmia (in weeks) has been estimated from the spasms onset, first EEG and from consecutive EEG (recorded in sleep every 7 to 10 days during first month of therapy). The follow-up study was performed in 1998; measures of good outcome: normal/borderline mental development and seizure-free status for 3 years, a poor outcome in cases with mental retardation and/or seizures.

Results: Results: Forty eight infants fulfilled the diagnostic criteria: 18 children (38.2%) had cryptogenic IS. The interval from the onset of spasms to the start of treatment was one to four weeks in 35 (73%) children. At follow-up, normal mental development was found in 14 children (30%). Outcome was significantly better in cryptogenic group comparing to symptomatic (p=0.002, χ²). Duration of hypsarrhythmia more then three weeks correlated with poor outcome (log odds ratio).

Conclusion: Conclusion: The duration of spasms (and hypsarrhythmia) over 3 weeks after treatment onset should alert the clinician about a difficult to treat condition. Therefore, further thorough investigations in such a patient are needed to find and – if possible – to treat the underlying condition, in order to achieve better mental outcome.