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Cumulative semantic interference in individuals with temporal lobe epilepsy
Poster Session B, Wednesday, September 30, 4:30 - 6:30 pm, Wangari Maathai
Andrea Galvez-McDonough1,2, Alena Stasenko3, Jerry Shih4, Taha Gholipour4, Eric Halgren4, Carrie McDonald3,5, Stephanie Ries1,2,6; 1San Diego State University / University of California San Diego Joint Doctoral Program in Language and Communicative Disorders, 2School of Speech, Language, and Hearing Sciences, San Diego State University, 3Department of Radiation Medicine & Applied Sciences, University of California San Diego, 4Department of Neurosciences, University of California San Diego, 5Department of Psychiatry, University of California San Diego, 6Center for Clinical and Cognitive Neuroscience, San Diego State University
Individuals with temporal lobe epilepsy have previously been reported to present with word-finding difficulties (e.g., Bell et al., 2001; Hamberger, 2015). However, most studies examining word retrieval in temporal lobe epilepsy have not used paradigms specifically designed to investigate semantic interference resolution, a core aspect of word retrieval. It has been debated whether semantic interference, as may be elicited through picture naming paradigms, reflects increased competition at the level of lexical selection (Damian et al., 2001) or whether it is a result of incremental learning (Oppenheim et al., 2010), or other mechanisms. The cumulative semantic interference effect refers to the observation that picture naming times increase with each to-be-named item in a given semantic category (Howard et al., 2006). It has been attributed to lexical retrieval becoming increasingly difficult as a result of the previous retrieval of semantically-related neighbors and the strengthening of corresponding lexicosemantic connections (Oppenheim et al., 2010). In the current study we examine this cumulative semantic interference effect in individuals with intractable temporal lobe epilepsy (n = 23) tested while undergoing intracranial EEG monitoring prior to resective surgery, and age-matched controls (n=47) tested through an online platform. We examined the effect of Position within category (ranging 1-6) and Group. We found a significant effect of Position within category (Wald χ2(1) = 83.19, p < .001), a marginal effect of Group (Wald χ2(1) = 3.37, p < .067), and a significant interaction between Position within category and Group (Wald χ2(1) = 6.18, p < .01) on reaction times. Thus, although both groups showed a significant cumulative semantic interference effect on reaction times, the slope of this effect was steeper in the patient than in the control group. Patients also showed significantly lower accuracy rates (Wald χ2(1) = 37.65, p < .001) than controls. There was a significant effect of Position within category (Wald χ2(1) = 4.11, p = .04), where accuracy decreased the more items in a semantic category were previously named, but no interaction between Position within category and Group (Wald χ2(1) = .38, p = .54) on accuracy. Overall, these findings are aligned with previous reports indicating naming deficits in individuals with temporal lobe epilepsy and suggest that these deficits may stem from lexical retrieval more specifically. In line with the incremental learning account, the steeper cumulative semantic interference effect observed in the individuals with temporal lobe epilepsy could result from an impaired incremental learning process. This is noteworthy as this incremental learning process has been shown to be immune from explicit memory deficits as caused by hippocampal damage (Oppenheim et al., 2016). Follow-up analyses will focus on examining which aspect of incremental learning may be impaired in this population and on how this finding varies based on neurological and neuropsychological measures.
Topic Areas: Language Production, Meaning: Lexical Semantics