West syndrome is characterized by the onset of epileptic spasms, typically in the first year of life.
Global developmental impairment (with or without regression) is typically seen.
Clinical Context
Onset of epileptic spasms occurs between 3 and 12 months of age, although later onset may occur.
Infants may have had no antecedent history, or the antecedent history may reflect the underlying cause (e.g., acquired structural brain abnormality).
In some cases, infants with Ohtahara syndrome or other early-onset epilepsies (typically with focal seizures) may evolve to have clinical and EEG features of West syndrome after 3-4 months of age.
Both sexes are affected, with a higher incidence in males.
Head size and neurological examination may be normal or findings may reflect underlying structural brain abnormalities.
Global developmental impairment (with or without regression) is typically seen at the onset of epileptic spasms.
Occasionally, development may be normal, and the developmental trajectory continues as expected.
