Objective: Neuronal migration disorders (NMD) are a group of malformations of the brain which ultimately disrupt migrating neuroblasts from the germinal plate to the cerebral cortex, it consists of agyria-pachygyria, polymicrogyria, schizencephaly, hemimegalencephaly and heterotopia. This study aimed to investigate the clinical characteristics and diagnostic methods of NMD.
Methods: The clinical data, cranial imaging and experimental examinations of 37 patients with NMD were analyzed. The patients consisted of 21 males and 16 females whose age of first hospital visit ranged from 2 months to 14 years and 6 months. Among the 37 cases, 18 were followed up.
Results: Of the 37 patients, 21 were agyria-pachygyria, the main clinical manifestations were mental retardation (20 cases), epilepsy (14 cases), hemiparesis (6 cases), and 17 patients had microcephaly which was an important physical sign. Eight patients had agyria-pachygyria with other malformations, they presented mental retardation (6 cases), epilepsy (4 cases), and hemiparesis (2 cases). Of the 5 patients with heterotopia, 4 manifested epilepsy. 3 patients had schizencephaly and 2 presented with hemiparesis. EEG was performed in 16 cases. Generalized irregular sharp and slow wave complexes were present in 10 cases, focal spike and slow complex in one case, hypsarrhythmia in one case, and the normal EEG in 4 cases. Eighteen cases were followed-up from seven months to eight years and three months, 14 patients had epilepsy, and still had epileptic attacks with the treatment with anticonvulsives, motor development was improved but speech development delayed in 4 cases.
Conclusion: The results of this study suggest that NMD is characterized by mental retardation, epilepsy and hemiparesis. Cranial MRI is the best diagnostic method.