Non-language neuropsychological measures increase sensitivity of identifying language reorganization in patients with...

To examine neuropsychological characteristic differences between typical and atypical language dominance in adult persons with epilepsy (PWE) and mesial temporal sclerosis (MTS), including exploring the impact of selected clinical variables on detection of atypical language and neuropsychological performance.

Adults with intractable epilepsy and MTS (n = 39) underwent comprehensive, pre-surgical evaluation including fMRI and neuropsychological assessment. Participants with concordant lateralization of MTS and seizure onset were included. Participants were grouped by dichotomized typical or atypical language lateralization based on fMRI results. Neuropsychological performance and other relevant clinical variables of the aforementioned groups were then compared.

Those with atypical language demonstrated poorer performance across neuropsychological tasks as compared to those with typical language lateralization. Although, typical neuropsychological measures used to evaluate language lateralization were not among those significantly different between the groups. Differences in neuropsychological performance were particularly pronounced on TMT A, TMT B, Stroop (Color), GPB (Dominant), and GPB (Non-Dominant). ROC Curve was provided to evaluate reproducibility at different thresholds.

This pilot study revealed those with atypical language lateralization demonstrated greater cognitive dysfunction across neuropsychological tasks than those with typical language lateralization. Neuropsychological measures outside of the domain of language tests detected subtle changes of functional neuroanatomical reorganization while language domain tasks revealed no significant differences between aforementioned groups in pre-surgical evaluation of PWE. While these preliminary results require further replication, these are important implications for diagnostic and prognostic evaluation.