Abstracts

The characteristic stereotypy of motor representation may be altered in patients with malformations of cortical development showing wider or anomalous representation, or involvement of supplementary or bilateral sites in the perirolandic regions. We report a child with motor representation of the ipsilateral face within a focal dysplastic lesion involving the middle temporal gyrus. EW, a 13 year old right handed female presented with medically resistant seizures characterized by lip smacking and confusion evolving to tonic and clonic movements. VideoEEG confirmed seizure onset from the left temporal lobe. MRI revealed left hippocampal sclerosis and focal cortical dysplasia involving the mid-inferior temporal gyrus extending 3.5 cm posteriorly from the temporal tip.
Extraoperative subdural functional mapping confirmed the presence of receptive language cortex within the superior temporal gyrus. Unexpectedly, stimulation of dysplastic cortex reliably produced ipsilateral facial contraction involving the left eye and angle of the mouth at threshold intensities of 5-6 mA that did not elicit an after discharge. There was no sensory provocation. MR tractography utilizing a DTI sequence revealed an atypical white matter tract arising from the region of the dysplsia that curved around the temporal stem into the internal capsule. White matter tracts in the right hemisphere were normal. The occurrence of ipsilateral motor face representation within dysplastic temporal lobe is a highly anomalous finding that is best explained by aberrant tangential neuronal migration and apoptosis. We speculate that abnormal connectivity may occur more commonly than recognized in children with substrates of cortical malformation, and has important implications for seizure semiology and surgical planning.