Dichotic Listening in Children With Focal Epilepsy: Effects of Structural Brain Abnormality and Seizure Characteristics

Abstract

The study examined performance on a dichotic listening test in children with focal epilepsy. The aim of the study was to explore how factors related to brain pathology would affect ear advantage. The effects of lateralization of epileptogenic area, size and localization of structural abnormality on MRI findings, and seizure characteristics were studied. Children treated for focal epileptic seizures took part in the study (N = 35). The dichotic test consisted of pairs of words, nonwords, syllables and vowels. Results demonstrated that large congenital structural abnormality in the left hemisphere altered ear advantage whereas smaller abnormality and right-hemisphere abnormality did not. Further, epileptic seizures of left-hemisphere origin that had started at an early age affected ear advantage whereas seizure frequency at the time of the assessment did not. Children with early onset of seizures of right-hemisphere origin had a strong right-ear advantage. The total score did not differ between the groups. There was a strong negative correlation between the scores for the right-ear and the left-ear. The findings were interpreted to indicate altered functional dominance for perception of auditory, lingustic stimuli following early left-hemisphere pathology rather than unilateral functional suppression.