Riassunto analitico
Aims: Polymicrogyria (PMG) is a malformation of cortical development, frequently associated to epilepsy, caused by an abnormal cortical organization, with an excessive number of disorderly arranged small gyri split up by superficial and expanded sulci, with cobbled aspect.
The clinical and radiological phenotype of these malformations may vary between patients, as the severity of the related epilepsy. The purpose of this study is to investigate the electro-clinical and radiological features of adult patients with PMG, and to evaluate the long-term outcome of the related epilepsy.
Matherial and Methods: This retrospective study included patients with epilepsy related to PMG, enrolled from the Epilepsy Centre of “Azienda Ospedaliero-Universitaria” in Modena.
Medical histories, neurological examination and clinical features were accessed. Brain MRI data were reviewed with the identification of two groups: simple forms (MCD represented only by PMG) and complex forms (PMG associated to other MCD, such as focal cortical dysplasia, periventricular or subcortical heterotopias, or schizencephaly). Scalp EEG traces were reviewed by two investigators. Outcomes in term of seizure-freedom (> 2 years at last follow-up) were then compared to the radiological and electro-clinical data.
Results: Twenty-two (mean age of 34,5 ±14 years) patients (11 females) with epilepsy related to PMG were included. Mean age of epilepsy onset was 173,3 ±111months. Mean number of AED per patient was 2. In 10 patients simple polymicrogyria was identified, while the remaining 12 patients had a complex cortical malformation. Seizure-freedom at last follow-up was similar in the PMG groups according to the neuroradiology phenotype. Eight patients had good outcome (more than 12 months without seizures) while the remaining 14 patients were classified as drug-resistant. Good outcome was associated to the male gender (p < 0.05). EEG features were similar for patients with good or bad outcome, while differences in the EEG abnormalities were identified between the patients with simple versus complex PMG (in the latter group slow activity, high amplitude spike-and-wave, and low-voltage fast activity were significantly higher).
Discussion and Conclusion: The radiologic “complexity” of PMG was not a determinant in the long-term outcome of epilepsy, while the male gender seemed to be significantly associated to good outcome. Further studies with larger cohorts should evaluate this preliminary finding. Moreover, a typical EEG pattern related to complex PMG has been identified.
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