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Poster B25, Wednesday, November 8, 3:00 – 4:15 pm, Harborview and Loch Raven Ballrooms

Effects of morphosyntactic therapy and tDCS on the spontaneous speech of individuals with aphasia

Vânia de Aguiar1,3, Adrià Rofes2,3, Roelien Bastiaanse4, Rita Capasso5, Marialuisa Gandolfi6,7, Nicola Smania6,7, Giorgio Rossi8, Gabriele Miceli9;1Department of clinical Speech and Language Studies, Trinity College Dublin, Dublin, Ireland, 2Global Brain Health Institute, Trinity College Dublin, Ireland, 3International Doctorate in Experimental Approaches to Language And the Brain (IDEALAB) Universities of Groningen (The Netherlands), Newcastle (UK), Potsdam (Germany), Trento (Italy) and Macquarie University (Australia), 4Center for Language and Cognition, University of Groningen, The Netherlands, 5S.C.A. Associates, Rome, Italy, 6Neuromotor and Cognitive Rehabilitation Research Centre, USO Neurological Rehabilitation, Azienda Ospedaliera Universitaria Integrata (AOUI) of Verona, Verona, Italy, 7Department of Neurological and Movement Sciences, University of Verona, Verona, Italy, 8Department of Neurology, Santa Maria del Carmine Hospital, Rovereto, Italy, 9Center for Mind/Brain Sciences (CIMeC), University of Trento, Italy

BACKGROUND. Language rehabilitation for individuals with post-stroke aphasia has positive effects, which can be enhanced by the use of transcranial direct current stimulation. Such effects are frequently demonstrated in carefully designed experimental outcome measures, which are closely related to the treatment task. These measures have high sensitivity to detect change, but lack the ecological validity necessary to determine whether such treatments may yield improvements in spontaneous language production. METHOD. Nine patients received a sentence-level treatment requiring the production of verbs in sentence completion and sentence construction tasks, and verb forms in the three most frequent tenses in Italian. Patients presented with varying clinical profiles, but in all cases had difficulties in verb and sentence production. At the beginning of each 1-hour treatment session, 20 minutes of tDCS were administered at 1mA, through 35cm2 electrodes. A bicephalic montage was used, with the anode placed over individually-tailored left hemisphere areas. The study used a within-subjects, randomized, sham-controlled, double-blind, cross-over design, with two 10-session treatment phases separated by a 2-week washout period. Connected speech samples were collected before and after each treatment, and at a 6-month follow-up assessment, in a standardized fashion. Changes over time were analyzed at group and individual levels, through comparison with a normative sample of 19 individuals. RESULTS. In group analyses, the Mean Length of Utterance (MLU) showed no significant change between before (t1) and after the first treatment (t2), but a significant decrease was detected after the second treatment (t3) in relation to t2 (z=-2.073, p=0.038) and t1 (z=-2.49, p=0.015). Two patients performed within norm at t1 and t2, and moved to below norm at t3 and t4. Another patient performed below norm only at t3. The remaining patients performed below norm in all assessments. No group-level change was observed in the proportion of subordinate sentences over time. One patient moved from below to within norm between t1 and t2, and then performed below norm again at t3 and t4 (6-month follow-up). Another patient moved from within to below norm between t1 and t2 and then performed within norm at t3 and t4. A third patient performed below norm at t3, while showing within norm performance at t1 and t2. No significant changes were detected in words per minute. To examine whether the decrease in MLU was related to a tradeoff between length and accuracy in sentence production, an analysis of errors was conducted. No significant changes were detected in the proportion of lexical, phonological, or morphosyntactic errors. Change in performance over time was also not significantly different in the tDCS treatment condition, when compared to Sham. DISCUSSION AND CONCLUSION. While treatment yielded improvements in lexical retrieval for treated and untreated verbs (de Aguiar et al., 2015), these effects did not transfer to connected speech. Further analyses with a focus on individual clinical profiles and lexical diversity measures are needed to establish if reduced MLU may be explained by strategic changes at the sentence planning level, or by changes at processing levels different to those considered so far.

Topic Area: Language Therapy

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