Investigators from the Boston Children's Hospital, New York University, Brown University, and Birmingham School of Medicine, AL, studied the clinical epilepsy and imaging features of 87 patients with polymicrogyria (PMG) and epilepsy, recruited through the Epilepsy Phenome/Genome Project. Median age of seizure onset was 3 years (range <1 month to 37 years). Seizures were focal in 87.4%, some in combination with generalized seizures (23%). Of generalized seizures, infantile spasms were the most prevalent, occurring in 45.2%. MRI showed a bilateral PMG pattern in 56.7% and perisylvian in 77%. Generalized PMG presented with an earlier age of seizure onset (median age of 8 months) and an increased prevalence of developmental delay prior to seizure onset (57.1%). Perisylvian PMG was unilateral in 43.3%. Seizures lateralized to the same hemisphere as the PMG or the hemisphere with greater involvement in those with unilateral or asymmetric PMG, with trend toward more right-sided involvement. [1]

COMMENT. Polymicrogyria (PMG), a developmental brain malformation, is associated with variable clinical findings dependent on the localization of the lesion. In addition to generalized epilepsy, bilateral PMG may also feature pseudobulbar signs, cognitive impairment, and developmental delay. Seizures are often medically refractory and not surgically responsive or appropriate. Prior to the introduction of the MRI, PMG may have been misdiagnosed as ulegyria or cerebral cortical sclerosis due to perinatal or postnatal hypoxic-ischemia. Ulegyria that is bilateral and perisylvian may also be manifested by epilepsy and pseudobulbar palsy.

Perisylvian Ulegyria Pseudobulbar syndrome. In a report of 12 patients with perisylvian ulegyria, medically refractive seizures responded to resective surgery in 4 patients, despite the bilateral distribution of cerebral sclerosis. The recognition of ulegyria and distinction from PMG as the cause of a perisylvian pseudobulbar palsy syndrome is important in treatment and prognosis of the complicating medically refractive seizures. [2]