Persistent nonfused segments of the basilar artery: longitudinal versus axial nonfusion.

Embryologic development of the basilar artery occurs along two axis systems: longitudinal fusion and axial fusion. Longitudinal fusion consists of midline fusion of paired ventral arteries and reflects the simplified pattern of arterial anatomy found in the spinal cord. Axial fusion consists of fusion of the distal basilar artery, which arises from the caudal division of the internal carotid artery, to the midbasilar agenesis to the posterior inferior cerebellar artery termination of the vertebral arteries. Persistent longitudinal nonfusion (or complete duplication) of the basilar artery is very rare, and persistent axial nonfusion is even rarer. We report one case of persistent longitudinal nonfusion of the basilar artery in a 3-year-old boy and a case of persistent axial nonfusion of the basilar artery in a 43-year-old man.

Agyria-pachygyria: clinical, neuroimaging, and neurophysiologic correlations.

Agyria-pachygyria complex is a disorder of neuronal migration and organization. Patients suffer either motor or intellectual retardation. We report our experiences of 10 patients with agyria-pachygyria complex and evaluate their clinical features, electroencephalography, and evoked potentials. Of nine electroencephalography examinations, five patients demonstrated characteristically high-amplitude fast activity. One of nine patients had an abnormal brainstem auditory-evoked potential. Three of seven patients had abnormal goggled visual-evoked potential. Six patients received somatosensory-evoked potential examinations, and five of these were abnormal, including four with prolonged central conduction times. Of the 10 patients, eight survived with variable intellectual and motor retardation; two died of sepsis. Patients with grades 1-4 agyria-pachygyria had high incidences of somatosensory-evoked potential abnormalities and also suffered worse neurologic outcomes. Normal brainstem auditory-evoked potential but abnormal cortical somatosensory-evoked potential components and prolonged central conduction time in these patients indicate that agyria-pachygyria is a supratentorial disease. We conclude that somatosensory-evoked potential examination is supplemental to neuroimaging in predicting the neurologic prognosis of patients with agyria-pachygyria.

A clinically recognizable neuronal migration disorder: congenital bilateral perisylvian syndrome. Case report with long-term clinical and EEG follow-up.

Congenital bilateral perisylvian syndrome (CBPS) is a recently described, neuronal migration disorder, characterized by pseudobulbar palsy, epilepsy and mental retardation and bilateral perisylvian dysplasia. A 15-year-old boy was diagnosed with CBPS according to the typical clinical, and magnetic resonance imaging (MRI) features. The patient was suffering from atypical absence seizures, repeating daily in spite of antiepileptic drug therapy, since age 7 years. He had also experienced rare generalized tonic-clonic seizures and complex partial seizures. Neurological examination showed severe restriction of tongue movements, severe dysarthria, dysphagia, facial diplegia, mild pyramidal signs and moderate mental retardation. A computed tomographic (CT) scan demonstrated bilateral perisylvian enlargement. The diagnosis was corrected with MRI after six years. Frequent irregular generalized spike and wave abnormalities and focal sharp and slow waves over the posterior regions of both hemispheres were shown by electroencephalograms (EEG). The patient was treated with Na-Valproate, carbamazepine and lamotrigine but did now show any significant change in seizure frequency in the eight-year follow-up period. Intractable seizures, mental retardation and particularly congenital pseudobulbar palsy suggest this congenital entity. Those patients who exhibit these typically clinical features, must have MRI.

Congenital muscular dystrophy: brain alterations in an unselected series of Western patients.

The typical form of congenital muscular dystrophy (CMD) described in Western countries is generally considered different from its Japanese variant because of the absence of CNS involvement. Evaluations from both a clinical and a neuroradiological point of view were made of the CNS functions of 12 unselected Western children affected by CMD. In five patients, clinical observation and intelligence tests showed a mild to severe mental retardation. One of these patients suffered also from a severe form of epilepsy. In the same five patients, various degrees of white matter hypodensity, ventricular enlargement and cerebral atrophy were also detected. Similar neuroradiological abnormalities were also found in five of the seven children who did not have clinical symptoms or signs of CNS involvement. In one of these cases, necropsy neuropathological examination showed the gyral anomalies characteristic of the Japanese type of CMD. This study clearly indicates the high frequency of subclinical CNS alterations in typical Western CMD, suggesting that it should be considered a type of myoencephalopathy like its Japanese counterpart.