Precise characterization and quantification of infantile spasms

Abstract

With the use of a time-synchronized video and polygraphic recording system, 5,042 infantile spasms were monitored and analyzed in 24 infants aged 1 to 43 months. Of these, 33.9% were flexor, 22.5% extensor, and 42.0% mixed flexor-extensor. Sometimes the spasms were followed by a period of akinesia and diminished responsiveness lasting up to 90 seconds, and rarely (1.0%) this "arrest" effect constituted the entire seizures. More than one type of seizure occurred in 21 of the 24 infants. In the same number, 78.3% of the seizures occurred in clusters, and the intensity and frequency of the spasms in each cluster often increased to a peak, then progressively decreased until they stopped. Predominantly, the clusters occurred soon after arousal from sleep. The number of seizures occurring at night (55.2%) was similar to the diurnal number (44.8%). The electroencephalographic seizure pattern was variable, but a marked generalized attenuation of electrical activity was a feature of 71.7% of the attacks. Attenuation episodes of similar degree and duration occurred with no evidence of a seizure.

Neuronal Networks in West Syndrome as Revealed by Source Analysis and Renormalized Partial Directed Coherence

“…It begins in infancy, mostly between 4 months and 6 months of life, before the age of 12 months in over 90% of cases (Kellaway et al, 1979). However, the later occurrence, up to 3 years of age, has been emphasized, it is easily overlooked and, therefore, inappropriately treated for many months before the diagnosis is done (Bednarek et al, 1998).…”

“…Many different ictal EEG patterns corresponding to the spasms have been described (Kellaway et al, 1979). Fusco and Vigevano (1993) Fusco and Vigevano (1993) established that the slow wave was present in all cases and always corresponded to the clinical manifestation of the spasm.…”

The clinical profile and outcome of children with West syndrome in KwaZulu-Natal Province, South Africa: A 10-year retrospective review

“…Spasms are classified as either flexors (flexion of the arms, legs and neck with contraction of the abdominal muscles in a jack knife or salaam attack), extensors (extension of the neck and trunk with abduction or adduction of the arms and legs), or mixed flexor-extensor spasms (flexion of the neck, trunk and arms with extension of the legs). [3] Spasms usually appear in the first 2 years of life, with a peak incidence between 4 and 6 months, and sometimes continue until adolescence. [2] Hypsarrhythmia is described as highvoltage, random, slow and spike waves in the cortex that vary in duration and location, and occasionally may become generalised.…”

Ictal Onset and Spreading of Seizures of Parietal Lobe Origin

“…Attenuation patterns represent the most common EEG expression of infantile spasms occurring in West syndrome. 10,11) Diffuse flattening of scalp EEGs may represent generalized seizure, possibly of brainstem origin. 5) Thirty-nine patients had diffuse electrodecremental ictal patterns on scalp EEGs in addition to seizures of diffuse cortical and brainstem origin.…”