Abstracts

Rationale: Prosody describes the rhythm, stress, and intonation of speech and may be used to convey emphasis, emotions or commands. The loss of prosodial ability has been documented in stroke, but ictal epileptic changes of prosody have not been studied systematically. We aimed to evaluate the localizing significance of ictal changes of prosody in focal epilepsies. A prerequisite for this evaluation is preserved consciousness during epileptic seizures which is characteristic of seizures arising from the non-speech dominant hemisphere. Methods: We compared ictal prosody by analyzing the speech frequency formants (frequency peaks) F1, F2, F3 and their energy as proxy for our analyses. We studied two groups of patients with epilepsy from our presurgical epilepsy monitoring unit. The first group comprised patients whose seizures were characterized by automatisms with preserved responsiveness (APR; n=29). This group had a predominantly right temporal seizure origin (15/29), four patients had a frontal lobe epilepsy and for seven patients the seizure onset could only be lateralized but not further localized to one lobe. The control group (n=14) was defined by ictal speech only and excluded patients eligible for the first group. Here the seizure origin was frontal or paracentral in nine patients, only one patient had a seizure onset in the left temporal lobe (1/14) and in four patients the exact region of seizure onset had not yet been determined. One seizure per patient was evaluated. Results: Right-sided TLE was more common in the APR group (83%; 15/18) than extratemporal or hemispheric epilepsies (17%; 3/18; p<0.001). Quantitative speech analyses could be performed in 41% of the APR group (12/29) and in 71% (10/14) of the control group patients. It demonstrated a loss of prosodial ability in the APR group. The ictal frequency peaks were all of equal or lower frequency than interictally (F1: 169 131 Hz vs. 327 221 Hz, p<0.01; F2: 427 269 Hz vs. 428 301 Hz, not statistically significant; F3: 211 132 Hz vs. 297 157 Hz. p<0.01). In the control group no decrease or leveling of prosody in the frequency peaks was shown.