Playing with neurons: Identifying non-invasive tools for neural rehabilitation in aphasia

Abstract

Stroke rehabilitation necessitates assessment and intervention that addresses neural changes and language recovery after aphasia. Recently, there has been increased interest in direct neurological assessment through non-invasive electroencephalography, and intervention through non-invasive brain stimulation for post-stroke speech and language recovery. However, clinical practice is still far from widespread implementation of neuroimaging and neurostimulation in stroke intervention protocols. Further, there is lack of research exploring the perspectives of key stakeholders in managing language recovery through technological practices in non-fluent aphasia. The overarching aim of this dissertation was to describe ways of including technology for identifying neural changes and supporting neuroplasticity in post-stroke aphasia.This dissertation has five chapters. Chapter one is the introduction that expresses the need of close examination of neural changes in stroke rehabilitation. Stroke is one of the leading causes of chronic disability worldwide resulting in serious economic and social consequences. Long-term effects of stroke include deficits in cognitive, linguistic, motor, and emotional domains. Rehabilitation of stroke has gradually progressed towards identifying disrupted neural patterns to eventually support neurorehabilitation that move a person close to pre-morbid levels of functioning. This chapter introduces the use of electroencephalography and non-invasive brain stimulation for a rehabilitation protocol that supports neuroplasticity through heavy involvement of technology in conventional speech and language treatment paradigms for linguistic recovery in post-stroke aphasia. Chapter two is an electroencephalography study to identify whether changes in neural activity preceding spoken words can be used as objective markers of speech intention. This study specifically explored an event-related potential (ERP) in three speech production protocols in healthy young adults with a future goal of identifying the nature of ERP in older adults and individuals with aphasia. Chapter three is a scoping review to synthesize intervention research that uses high- tech augmentative and alternative communication (AAC) devices and non-invasive brain stimulation (NIBS) for aphasia rehabilitation. This study was aimed at identifying the clinical parameters for the implementation of AAC and NIBS. Specifically, the first evaluation was the current methods of access for high-tech AAC and methods of stimulation for NIBS. Secondly, this study recognizes the trend of incorporating technological intervention from acute to chronic stages of stroke recovery. Thirdly, it assesses the use of direct neurological assessment as an outcome measure for rehabilitation paradigms. Chapter four is a survey study to investigate stakeholders’ perspectives in using high-tech communication supports for aphasia rehabilitation. Specifically, it explores speech-language pathologists’ preferences in using high-tech AAC devices for linguistic recovery in their clinical practice. In addition, the study also explores how AAC clinical practice differs in developed and developing countries to identify definite factors that can support clinicians in incorporating high-tech devices for post-stroke linguistic rehabilitation. Chapter five concludes the dissertation by putting together the story of how electroencephalography can elicit event-related potentials (ERP) that can indicate speech intention in post-stroke aphasia. The specific ERP can be modulated through non-invasive brain stimulation and high-tech speech generating devices to stimulate appropriate feedback loops for errorless relearning of speech production.