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Poster E48, Saturday, August 18, 3:00 – 4:45 pm, Room 2000AB

Bimodal language in post-ictal aphasia: a descriptive study

Alexia Fasola1,2, Marion Tellier3, François-Xavier Alario2, Carlo Alberto Tassinari4, Agnès Trebuchon1;1Aix Marseille Univ, INSERM, INS, Inst Neurosci Syst, Marseille, France, 2Aix Marseille Univ, CNRS, LPC, Marseille, France, 3Aix Marseille Univ, CNRS, LPL, Aix-en-Provence, France, 4Department of Neurological Sciences, University of Bologna, Bologna, Italy

Introduction A pathological model of language deficits is drug-resistant epilepsy, which is known to induce impairments in verbal memory, naming or spontaneous speech. These deficits are typically described in inter-ictal states (i.e. between epileptic seizures). Drug-resistant epilepsy patients also show substantial language deficits (e.g. anomia) during the seizures and in the periods following them, called post-ictal states. Such post-ictal aphasia episodes have received very little attention and were the focus of the current research. We investigated jointly the production of speech and co-speech gestures, owing to the multi-modal nature of conversation and verbal interactions. Our exploration was mostly descriptive, addressing the following open questions: Is the production of co-verbal gestures modified during post-ictal states? Is there a difference between frontal versus temporal lobe seizures? Methods Patients We tested 12 drug-resistant epileptic patients (6 females), native speakers of French, right-handed with left hemisphere language dominance (mean age of 36; IQ above 80). They were tested during pre-surgical diagnostic investigations, therefore under drug restriction, with surface and intra-cerebral activity constantly monitored, and videotaped round-the-clock. We gathered data from a total of 21 seizures inducing post-ictal language deficits. Seven of them originated from left fronto-insular lobe and 14 started from the left anterior-basal temporal lobe. Experimental Design During testing, patients had to memorize, in 30s, a highly detailed picture to later describe what they had seen. The goal was to elicit a monologue that would be rich in speech and in co-speech gestures. We compared post-ictal to inter-ictal conditions in the same individual. We quantified the verbal flow in words per second. Following previous classifications, co-speech gestures were coded according to two categories: “Rhythmic” gestures are produced in support of speech building, presumably for the benefit of the speaker; “illustrative” gestures are produced to illustrate the speaker’s speech, presumably for the benefit of the interlocutor’s comprehension. EZ localizations were determined by experienced epileptologists. To simplify anatomical variables, each the left fronto-temporal area is divided in 5 sub-regions: anterior temporal (LTA), posterior temporal (LTP), temporo-basal (LTB), insular (LI) and inferior frontal (LF). Results During post-ictal compared to inter-ictal episodes, left temporal lobe epileptic patients show a slight decrease of verbal flow combined with a trend for an increase of rythmic gesture production, and a decrease of illustrative gesture production. For left fronto-insular lobe epilepsy patients, the modulation of communicative patterns was not straightforward. Discussion Communication patterns suggest a distinction in the use of rhythmic and illustrative co-speech gestures linked to reduced verbal flow in temporal lobe epilepsy patients. This contrast between co-speech gestures categories is congruent with previous literature in which rhythmic gestures has been linked to lexical retrieval processes. Further establishing the existence of a facilitative role of co-speech gestures during language difficulties could be useful in the context of multimodal language therapies for temporal lobe epilepsy patients.

Topic Area: Language Disorders