Focal lesions in infantile spasms

Among 174 cases of infantile spasms examined by CT-scan between January 80 and December 85, 17 (9.8%) had a focal lesion without microcephaly. It consisted of an angioma (1 case), a cortical dysplasia (1 case) and porencephalic lesions (15 cases). In 11 cases with porencephaly, an acute event had occurred between 28 weeks of gestation and 3 months of life. In 7 cases, the lesion extended to the major part of one hemisphere. In the 10 others, it was localized either to the rolandic or to the temporo-occipital regions. In all the cases, the lesion concerned at least one of these areas. It involved the cortex in 15 cases but in the 2 others it seemed to only concern the white matter. The lesion was on the left in 14 cases. After steroids, the epilepsy recurred in 6 cases of which 5 involved the frontal lobe (P less than 0.05). This study seems to show that it is mainly the rolandic and the temporo-occipital areas that favour the occurrence of infantile spasms, whereas extension to the frontal area is responsible of a later partial epilepsy.