Computerised screening for dyslexia in adults

Abstract

Identifying dyslexia in adulthood presents particular challenges because of complicating factors such as acquisition of compensatory strategies, differing degrees of intervention and the problem of distinguishing dyslexic adults from those whose literacy difficulties have non‐cognitive causes. One of the implications is that conventional literacy measures, per se, do not provide a satisfactory basis for screening for dyslexia in adulthood as some dyslexic adults have above‐average literacy skills and some non‐dyslexic adults have very poor literacy skills. This study examined an alternative approach to dyslexia screening, using three tests that depend heavily on phonological processing, lexical access and working memory, but which are not conventional measures of literacy. Using these tests, which are computer delivered, 70 dyslexic adults from three different types of educational institution were compared with 69 non‐dyslexic adults from the same institutions. The results showed that the dyslexic and non‐dyslexic groups were significantly different on all three computer‐based tests, with an average effect size of 1.55. Adaptive versions of these tests were then created to reduce overall administration time for the suite to about 15 minutes. Analysis showed that the combined scaled scores from the adaptive versions of the three tests significantly discriminated the dyslexic from the non‐dyslexic group with an increased effect size of 2.07 and with a sensitivity rate of 90.6% and a specificity rate of 90.0%. It was concluded that this approach is a valid and useful method of identifying dyslexia in adulthood, which, given the ease of administration to large numbers of adults, has noted advantages for education and employment.