FOCAL EPILEPTIC SPASMS INVOLVING ONE LEG EMERGING DURING THE CLINICAL COURSE OF WEST SYNDROME (WS)

Objectives: Epileptic spasms (ES) in WS are classified into generalized seizure type. However, evidence of a focal neocortical origin has been obtained mainly from surgical WS series. We report herein two infants with WS, whose ES subsequently evolved into focal ES.

Methods: Medical records, electroencephalographic and neuroimaging findings were retrospectively analyzed.

Results: A 2 year-old Japanese girl developed WS at 3 months of age. Focal ES of the right leg emerged one month after successful ACTH therapy at 6 months of age. Brief jerking of the left leg occurring every few seconds appeared immediately after awakening. A video-polygraphic study revealed that fast wave-bursts recorded from the midline vertex region corresponded to the surface EMG activity of the left thigh. Neuroimaging findings suggested focal cortical dysplasia in the left fronto-temporal lobe. A 7 month-old girl with symptomatic WS developed postural tonic seizures at 2 months of age. They were gradually replaced by ES at 3 months of age. A videopolygraphic study demonstrated ES with localized accentuation in the right leg that progressed to focal ES of the right leg, corresponding to a biphasic slow wave complex. Neuroimaging revealed no abnormal findings although interictal EEG demonstrated left centro-parieto-temporal localized spike foci.

Conclusion: The focal ES involving one lower limb, following treatment of ES in these 2 infants with WS, suggests that the former arose from a neocortical focus involving the motor cortex of the lower limb and the latter from the more widespread bilateral cortical area.