WoRHD. Written language processing in Hearing and Deaf
An issue dominating the current debate in the field of written language processing concerns the existence of brain areas dedicated to the visual perception of words.
Cohen et al. (2002) suggested that such visual specialization occurs in occipito-temporal region of the left hemisphere, namely at the ‘Visual Word Form Area’ (VWFA). Using Magnetoencephalography (MEG) and presenting words and anagrams for a lexical decision task, Pammer et al. (2004) showed that the activation of the VWFA was temporally preceded by activity in the posterior superior IFG. Such findings question the functional role of the VWFA as exclusively in the visual domain and suggest early topdown influences of frontal areas on fusiform gyrus. A way to further investigate the issue, and particularly the impact of phonology on visual word recognition would be to study the temporal activation of the brain regions responsible for phonological and visual processing when phonology is impaired but visual recognition is intact, as in deaf readers.
WoRHD is an exploration of the impact of auditory deprivation on the cortical network involved in word recognition.
Such investigation will show the overall impact of deafness on written language processing, by looking at similarities and differences between neural networks recruited by adults with and without auditory deprivation in a lexical decision task. Specifically, participants with auditory deprivation are prevented forming phonological representations of words and letters, which might affect the functioning of brain areas typically associated with phonological processing and/or their interaction with other regions of the brain.
WoRHD integrates in a multimodal approach classical cognitive experimental paradigm with brain imaging techniques such functional MRI, Electroencephalography and Diffusion Tensor Imaging.