Verbal dichotic listening performance and its relationship with EEG features in benign childhood epilepsy with centrotemporal spikes

Summary 

Purpose

Benign epilepsy of childhood with centrotemporal spikes (BECTS) is the most common form of idiopathic partial epilepsy in children from 3 to 12 years old. Little and far from conclusive information is available on its chronic impact on the organization of higher cognitive functions during development.

The aim of this study was to assess the effect of interictal EEG discharges in the peri-sylvian regions on language lateralization in BECTS.

Methods

Twenty-four 7–12-year-old children with BECTS were compared with a control group of 16 healthy children matched for age, gender and schooling. Hemispheric speech lateralization was determined with the vowel–consonant dichotic listening (DL) test.

Results

DL data showed that BECTS children lacked the typical right ear/left hemisphere functional advantage. The side of the interictal spikes had no specific influence on DL performance, while a multifocal location of the discharges had a particularly significant effect on the laterality index, as shown by the complete loss of the right-ear advantage in favor of a symmetrical performance with the overall level of accuracy remaining constant. No correlation was found between spike frequency and DL data.

Conclusions

BECTS coincides with an atypical performance in DL test with the loss of the usual right ear/left hemisphere advantage, suggesting that interictal activity may induce a reorganization of speech perception lateralization, with a bilateral representation of the phonological processing of auditory and verbal stimuli. This was particularly evident in the group with multifocal spikes, which may mean that a widespread hyperexcitability can affect the network underlying DL performance more severely.

Keywords: BECTS, Dichotic listening, Language lateralization