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Poster B35, Thursday, August 16, 3:05 – 4:50 pm, Room 2000AB

Effects of auricular vagus nerve stimulation on novel orthography acquisition: a pilot study

Tracy Centanni1, Vishal Thakkar1, Alexis Jefferson1, Carly Stacey1, Navid Khodaparast2;1Texas Christian University, Fort Worth, TX, USA, 2Nexeon MedSystems Inc., Dallas, TX, USA

For typically developing adults as well as for children with dyslexia, the acquisition of a novel orthography is a difficult task and fluency is often unattainable. While the brain is hardwired for language, the reading network must be allocated and optimized from scratch in every individual brain. In dyslexia, the visual word form area is often hypoactivated and recent studies suggest this lack of involvement may lead to poor fluency. Invasive cervical vagus nerve stimulation (cVNS) can drive plasticity in the adult brain and has shown recent promise in the treatments of tinnitus and post- stroke motor impairment. This invasive approach is not practical for reading-based interventions. However, the auricular nerve, a branch of the cervical vagus nerve, innervates the cymba conchae region of the outer ear and projects to similar brain regions as cVNS. This pilot study evaluated whether or not this non-invasive form of vagus nerve stimulation could be useful in driving plasticity for newly learned letter-to-sound correspondences. Adults between the ages of 18-24 years old were recruited for this study. All participants had no history of reading or language impairment, ADHD, or other neurological diagnoses, scored in the average range on nonverbal IQ and reading measures, and were not taking any medications at the time of the study. Participants completed ten 30-minute training sessions in which they learned letter-to-sound correspondences in Hebrew. Participants were randomly assigned to one of two control conditions (training with an in-person tutor vs. a customized computer program) or the active stimulation group. In the active group, participants completed the computer-based training program while receiving low levels of electrical stimulation to the left cymba conchae. Participants were tested at 3 time points to track progress on letter identification, rapid letter reading, and pseudoword reading: once at the halfway point, (on Day 6) once on the final day of lessons (on Day 10), and once more at least a week following their final lesson (retention). Participants receiving stimulation were monitored daily to ensure no adverse reactions to the intervention and to ensure the level of current was well within tolerable levels. There were no differences in performance between the two control groups, so these groups were combined for comparison with the active stimulation group. The active stimulation group exhibited faster reading times and higher accuracy on pseudoword reading compared to the control group as early as day 6. We present these findings as well as the longer-term performance of the stimulation group and possible behavioral predictors of individual success in the training program. This pilot study demonstrates for the first time that non-invasive auricular vagus nerve stimulation may be a valuable tool in improving reading acquisition and fluency not only in a typically reading adult, but perhaps also in individuals with dyslexia. Additional studies are ongoing in our lab to optimize the parameters of this approach for maximum improvement, evaluate the neural correlates of this training, and to evaluate its efficacy in populations with communication disorders.

Topic Area: Language Therapy