Objectives: Epileptic spasms (ES) in West syndrome (WS) are classified as being of the generalized seizure type. However, evidence of a focal neocortical origin has been proposed based mainly on surgical WS series. We report herein two infants with WS, whose ES subsequently evolved into focal ES of the right lower extremity.
Methods: Medical records, electroencephalographic and neuroimaging findings were retrospectively analyzed.
Results: A 2 year-old Japanese girl developed ES at 3 months of age. Focal ES of the right leg manifested one month after successful ACTH therapy performed at 6 months of age. Brief jerking of the right leg, every few seconds, occurred immediately after awakening. A 7 month-old girl with symptomatic WS had developed focal seizures with postural signs at 2 months of age. The seizures gradually diminished and had been replaced by ES by 3 months of age. ES gradually evolved into focal ES of the right leg. A video-polygraphic study demonstrated the ES with marked predominance in the right leg corresponding to a left sided predominant paroxysmal biphasic slow wave complex. Brain MRI revealed no abnormal findings although interictal EEG demonstrated left centro-parieto-temporal localized spike foci.
Conclusions: The focal ES of one lower limb, following treatment of ES in these two infants with WS, suggests the origin of the ES in the first case to be a neocortical focus involving the primary motor cortex representing the lower limb while that in the second case involves more widespread neocortical area with predominance in the same motor cortex as the first case.