Visual and auditory evoked potential correlates of cerebral malformations

To date there are no systematic studies of the evoked potential correlates of cerebral malformations. A total of 109 sensory evoked potential studies (20 ERGs, 61 VEPs and 28 ABRs) were performed in 27 children with defined cerebral malformations. Diagnoses were confirmed by CT scan, supplemented by MRI, cranial ultrasound, or neuropathological examination. Sensory evoked potential studies were abnormal in over half of patients studied, but the VEP was unable to identify or distinguish specific supratentorial cerebral malformations. ABR abnormalities were documented in cases of holoprosencephaly, lissencephaly, pachygyria and generalized megalencephaly. ABR abnormalities were not observed in septo-optic dysplasia or focal dysplasia of the cerebral cortex. We conclude that evoked potentials are not a diagnostic criterion of severe dysplasias, but rather serve as a supplementary tool for detecting the variable associated abnormalities of brain development that may affect visual and central auditory pathways or their cerebral cortical or brainstem targets.