Reading Skills in Deaf Subjects: Role of Psycholinguistic Factors and Global Influences in Affecting Reading Performance

The present study examined the role of psycholinguistic variables, as well as the presence of a global factor, in modulating reading speed and accuracy in individuals with a severe hearing impairment. Thirteen deaf and thirteen hearing young adults who completed high school and were proficient in both oral lipreading and Italian sign language were examined and compared to a group of control subjects matched for gender, age and education. A wide spectrum of psycholinguistic variables affecting reading were examined, marking visual (letter confusability), sub-lexical (length, grapheme contextuality), lexical (frequency, N-size, stress) and semantic (age of acquisition and imageability) processes. Vocal reaction times (RT) in reading aloud single words were slower in deaf participants with respect to hearing subjects but they were affected by psycholinguistic variables in a very similar way than in the case of controls. Moreover, deaf individuals did not show a multiplicative effect as a function of word difficulty in their reading slowness but only a constant delay. Overall, the deficit shown by deaf participants was relatively limited and not associated to specific cognitive processes. This finding is in keeping with the idea that at least some individuals with a severe hearing impairment may reach reasonably high levels of word decoding.