Poster A47, Thursday, August 16, 10:15 am – 12:00 pm, Room 2000AB
Augmented reading outcomes for people with alexia following treatment paired with transcranial direct current stimulation.
Grace S. Lee1, Esther S. Kim1;1University of Alberta
BACKGROUND: Damage to language areas of the brain often leads to a language disorder called aphasia, which impairs speech, writing, and understanding. 68% of people with aphasia (PWA) also present with alexia, a reading impairment. Many existing reading treatments target single word reading and demonstrate little generalization to larger bodies of text. In contrast, multimodal reading therapies target both the sublexical and lexical-semantic routes and have resulted in functional treatment gains. Recently, Transcranial Direct Current Stimulation (tDCS) has been explored as a potential adjunct to augment outcomes of traditional language treatment. tDCS modulates ongoing neural activity to prime the brain for long-term consolidation. Extensive research demonstrates the positive effects of tDCS on the spoken language treatments. However, there remains insufficient investigation on tDCS with reading treatments. This study explored the effects of tDCS paired with a multimodal intensive reading treatment with an individual with alexia. Eye-tracking was also used as a real-time measure of cognitive processing during reading, to provide further insight into treatment induced changes. There is an urgent need for efficacious therapies to remediate reading disorders as the ability to read independently is essential for participation in life. METHODS: P1 was a 63 year old male, with non-fluent aphasia and apraxia of speech, 5 years post-onset of stroke. In a double-blinded, crossover design, P1 received 40 hours of reading treatment (2 hrs/day x 5 days/week x 2 weeks = 20 hours for each phase with 4 week washout between phases = 40 hrs total), in conjunction with anodal-tDCS and sham-tDCS. Reading treatment involved training grapheme-phoneme conversion abilities to target the sublexical reading route, combined with Oral Reading for Language in Aphasia, which is a text-based reading approach to target the lexical-semantic reading route. In addition to behavioural outcomes, eye-movement measures were taken during silent reading. Passages had congruent or incongruent antecedents and anaphors. Measures on the whole passage and individual words were used to compare reading abilities before and after therapy and 1 month after discharge. RESULTS: There were greater improvements in behavioural outcomes measuring lexical-semantic skills after treatment with anodal-tDCS relative to treatment alone. More substantial gains were observed in reading speed, accuracy, overall reading comprehension and context comprehension. Interestingly, treatment with tDCS did not result in augmented gains in sublexical measures. Both conditions of treatment resulted in similar sublexical improvements. A one-way repeated measures ANOVA on eye-movement measures revealed significant differences in overall fixation duration, number of fixations and gaze duration between pre-treatment, post-treatment and one month follow-up assessments. CONCLUSION: The improvements in both lexical and sublexical domains show that a multimodal reading approach is effective, and that integrating tDCS can lead to augmented treatment results in lexical reading. The significant differences in eye-movements reveals a change to mechanism of reading following treatment. Eye-movement analyses are preliminary, and further analyses are being conducted to better elucidate the nature of changes to the reading process after treatment. This study corroborates growing evidence for the use of tDCS in conjunction with reading therapy.
Topic Area: Language Therapy