How do we understand and produce words? How does the brain support these processes? How do people with aphasia process language? What are the processes involved in spelling a word (or a non-word)? Are there differences in how we process words in English or Greek, or across other languages?
These are some of the central questions I am addressing in my research, aiming both at advancing our understanding of language processing across several domains, as well as at translating this knowledge into clinical and treatment advancements for people with language impairments.
Primary Progressive Aphasia and Spelling
Primary Progressive Aphasia (PPA) is a degenerative disorder with three different variants: semantic, logopenic and non-fluent. Previous findings suggest differences in the written spelling performance between the three variants, but no attempts have been made to comprehensively study the spelling behavior in PPA. The aim of the project is to see whether these differences reflect impairment in certain components of the cognitive architecture of spelling and how this can help to better understand the underlying deficits of the three PPA variants. Also, we are investigating the extent to which a simple spelling task can provide accurate classification of the PPA variants, which can serve as a valuable tool for therapists that can save both time and money.
White Matter Integrity and Language Processing
While the majority of imaging work in language research has focused on analysis of grey matter structural and functional data, the analysis of White Matter (WM) data has gained much interest in the past couple of decades. Diffusion Tensor Imaging (DTI) has become a widely-used tool to evaluate how water diffuses in the brain. Using DTI data from both people with PPA and healthy controls this project aims to further our understanding of (1) the way PPA alters WM integrity, and (2) the relationship between the integrity of certain WM tracts across both hemispheres and three language components: semantic processing, syntactic processing and the least-investigated, spelling.
Morphological Processing in Greek and English, using MEG
The project investigates both the decomposition and recomposition of visually presented, morphologically complex items in Greek and English using magneto-encephalography (MEG). We aim in providing evidence for the four main stages involved in this process, each localized to a different brain region and a different time interval relative to stimulus onset: (1) early, form-based decomposition in the left fusiform gyrus, (2) lexical lookup in middle to superior left temporal regions, (3) syntactic licensing anterior to the visual word form area in the ventral processing stream, and (4) semantic composition in orbito-frontal regions. Importantly, it is the first attempt to understand the neurocognitive mechanisms involved in morphological processing in Greek using MEG and an opportunity to investigate the differences between the processing of prefixed (in English) and suffixed (in Greek) words.