Epileptic spasms in clusters with focal EEG paroxysms: A study of 12 patients

OBJECTIVE We analyzed the electroclinical features, etiology, treatment, and outcome of 12 patients with West syndrome (WS) associated with focal hypsarrhythmia (FH). METHODS Between February 2005 and July 2013, 12 patients met the electroclinical diagnostic criteria of WS associated with FH. Hypsarrhythmia was considered to be focal when two or three brain lobes were involved. Patients with hemihypsarrhythmia were excluded. RESULTS All patients had epileptic spasms (ES) in clusters of a structural etiology. Four had a porencephalic cyst, two had focal cortical dysplasia, two had open-lip schizencephaly, and one each had unilateral polymicrogyria, shunted hydrocephalus, glioma, and cerebral hemiatrophy. Age at ES onset was between 2 and 8 months, with a mean age of 5 and a median age of 6 months. Seven patients had asymmetric ES, three had symmetric ES, and two patients had unilateral ES. FH was seen over the posterior regions in nine and over the anterior regions in three. Ictal EEG recordings showed diffuse high-amplitude slow waves in six patients, diffuse slow waves followed by voltage attenuation in three, and diffuse fast rhythms in three others. In three patients the ictal paroxysms were unilateral. Six patients responded well to surgery. CONCLUSION ES associated with FH are secondary to structural lesions. Surgery should be considered earlier in the management of this group of patients.