Frontal lobe epileptic seizures are accompanied by elevated pitch during verbal communication

Abstract

The objective of our study was to assess alterations in speech as a possible localizing sign in frontal lobe epilepsy. Ictal speech was analyzed in 18 patients with frontal lobe epilepsy (FLE) during seizures and in the interictal period. Matched identical words were analyzed regarding alterations in fundamental frequency (ƒo) as an approximation of pitch. In patients with FLE, ƒo of ictal utterances was significantly higher than ƒo in interictal recordings (p = 0.016). Ictal ƒo increases occurred in both FLE of right and left seizure origin. In contrast, a matched temporal lobe epilepsy (TLE) group showed less pronounced increases in ƒo, and only in patients with right-sided seizure foci. This study for the first time shows significant voice alterations in ictal speech in a cohort of patients with FLE. This may contribute to the localization of the epileptic focus. Increases in ƒo were interestingly found in frontal lobe seizures with origin in either hemisphere, suggesting a bilateral involvement to the planning of speech production, in contrast to a more right-sided lateralization of pitch perception in prosodic processing.