Neurolinguistics and the Atypical Acquisition of Signed & Spoken Language

DR. BENCIE WOLL & HARRY SIERETAZKI
Department of Language & Communication Science
City University, Northampton Square, LONDON

ABSTRACT

Since the beginning of neurolinguistics, studies of atypical language have been crucial to the understanding of normal language processing. More recently, comparative studies of signed and spoken language have provided a new window into these mechanisms. In our study we combine these approaches to case studies of atypical language development, presenting data on contrasting abilities in English and British Sign Language (BSL) in two different medical conditions with recognised language impairments: Down syndrome (DS) and Landau Kleffner syndrome (LKS). LKS is an enigmatic form of childhood epilepsy which may cause complete and sometimes irreversible loss of both comprehension and production of spoken language. Non-verbal cognitive abilities are not generally affected. There is evidence to suggest that the impairment results from a severe functional disturbance of phonological processing in early to mid-childhood, after initially normal language acquisition. Down syndrome, a well known chromosomal disorder, is characterised by overall impaired cognitive abilities, but with relatively poorer verbal than non-verbal skills. It has been suggested that this pattern is related to impaired auditory, relative to visual, processing. It might therefore be hypothesised that in both DS and LKS, use of signing might improve language abilities compared to spoken language. Data will be presented on four cases – two with DS and two with LKS. Ruthie and Sallie are hearing identical twins with DS who have Deaf parents, and who have grown up using both English and BSL. Steven and Annie both have LKS. Steven is an adult who has been aphasic for spoken language since 5 years of age and who began to use BSL in his early teens. Annie is an 11 year old girl who began to learn BSL at age 6. Comprehensive longitudinal behavioural data will be presented on all four cases, together with fMRI data on Steven and Annie, which provide insight into neurolinguistic mechanisms as well as into the relative strengths and weaknesses in language processing which characterise these two conditions.

HOST: Dr. Isabelle Barriere