Masked ERP repetition priming in deaf and hearing readers

Masked ERP repetition priming in deaf and hearing readers

First Author: Karen Emmorey -- San Diego State University
Additional authors/chairs: 
Katherine J. Midgley; Phillip J. Holcomb
Keywords: Deaf/Hard of Hearing, Adult Literacy, ERP, masked priming, Word reading
Abstract / Summary: 

Purpose: Deaf readers can provide unique insights into how the reading circuit may be modified by altered linguistic and sensory input. A recent ERP study showed that deaf adults exhibit a more bilateral N170 ERP response to written words compared to matched hearing readers. We examined whether the different pattern of early ERP effects extends to pre-lexical processes associated with the N250 (orthographic to phonological mapping) and later lexico-semantic processes associated with the N400.

Method: In a visual masked priming paradigm, 31 deaf and 31 hearing adults (matched on reading ability) performed a go/no-go semantic categorization task (press for an occasional animal word) while ERPs were recorded. Target words were preceded by masked primes (a repeated or unrelated word). Prime duration (50ms vs. 100ms) and word frequency (high vs. low) were manipulated.

Results: Hearing readers exhibited typical N250 and N400 repetition priming effects with 50ms primes (greater negativity for unrelated than repeated primes) and smaller effects with 100ms primes. Deaf readers showed a surprising reversed priming effect with 50ms primes (greater negativity for related primes), and more typical N250 and N400 effects with 100ms primes. Correlation results showed that deaf readers with poorer phonological skills exhibited a larger reversed N250 in the 50ms prime condition (high frequency words). For hearing readers, lower vocabulary scores were correlated with a larger N400 response.

Conclusions: Visual changes associated with deafness may impact how masked primes are processed. Poor phonological skills in deaf readers impact sub-lexical processing, resulting in repetition enhancement, rather than priming.