| Abstract | Adequate language and reading skills are essential to our daily life. However, these are difficult to acquire, especially in adulthood. There are classroom-focused and computer-based training programs that aim to improve vocabulary learning and reading comprehension, but previous research has suggested that computer programs may take many weeks of intervention with poor retention. Thus, there is a need for a novel intervention that can accelerate learning and improve retention. One method that has driven long-lasting neural plasticity is cervical vagus nerve stimulation (cVNS), which, when paired with an external stimulus (e.g., tone or movement) decreased tinnitus symptoms and increased motor function recovery in post-stroke patients. While cVNS has shown promising results, it requires an expensive, invasive procedure, making it impractical for language and reading interventions. Neural imaging data have suggested that transcutaneous auricular vagus nerve stimulation (taVNS) to the posterior tragus of the left ear activates similar deep brain structures as cVNS, making it a viable, non-invasive alternative. taVNS paired with an external stimulus has led to enhanced motor function recovery, associative memory, and learning of novel letter-sound correspondences. To extend taVNS research, the objective for the current dissertation was to evaluate taVNS in language and reading skills. In Aim 1, we evaluated the effect of taVNS on the learning and retention of novel vocabulary words and found that higher frequency taVNS led to superior retention of trained words. In Aim 2, we evaluated the effect of taVNS on overall reading comprehension performance and found that taVNS led to improved performance on memory questions. However, taVNS did not aid in oral reading mechanics or performance on comprehension questions. In Aim 3, we presented a brief literature review of two reading skills, automaticity and fluency, since these are often interchangeably used in the literature. This causes theoretical confusion, especially since these skills are often used in dyslexia diagnoses and interventions. Importantly, further clarity on metrics of these skills is needed in order to effectively design future studies using taVNS. Collectively, the current dissertation expands on taVNS and reading literatures with implications for clinical applications. |
