Autistic Children at the Age of Diagnosis Are More Interested in Letters Than Typical Children

Background:

Hyperlexia is defined by advanced reading skills relative to comprehension, acquired at an early age in the absence of explicit teaching, concurrent with a strong orientation toward written material, and accompanied by a neurodevelopmental disorder. Hyperlexia is the most common special ability reported in autism. Ostrolenk et al.’s (2017) literature review of 82 individual cases of hyperlexia and 22 group studies (including 315 hyperlexic subjects) showed that the reported prevalence of hyperlexia in autism varies between 6 and 21%. Furthermore, Ostrolenk et al., (2017) found that of the published hyperlexic case studies reviewed, a significant proportion (84%) were on the autism spectrum. However, within this literature, there are no group studies specifically investigating children’s interest in written material.

Objectives:

Our objective was to estimate the prevalence of atypical interest for written material in a representative population referred for an autism diagnosis assessment.

Methods:

Participating families were referred to our clinic after autism was suspected in their child. They were administered a six-minute questionnaire by the psychiatrist; questions about the child’s interest in written material, their related skills and behaviours, as well as questions about their comprehension and oral language level were included. The parents of 79 children answered the questionnaire at intake, of which 40 subsequently received an autism diagnosis at the end of the evaluation (50.63%). The children were 28 to 86 months old (mean = 46.29; SD = 12.26). The two groups (autism diagnosis and no diagnosis) did not differ in their age. The children’s interest in written material was rated using 4 categories, coded with numbers 1 to 4; 1 - None < 2 - Moderate < 3 - Intense < 4 - Exclusive.

Results:

Children later diagnosed with autism had a mean interest for written material that was superior to the non-diagnosed group (means: 2.20 vs. 1.69 out of 4). An ANCOVA analysis using age as a covariate, demonstrated a significant interaction between diagnosis and interest for letters (p=.013). Significantly more autistic children had an intense or exclusive interest in written material compared to non-autistics (42.50% vs. 20.51%). For those who had an interest in written material, the mean age of the interest onset was similar in both groups (29.51 months).

Conclusions: Our study demonstrates the existence of an association between autism and an early interest in written material, with a significantly larger portion of autistic toddlers demonstrating an intense interest compared to non-autistic toddlers. These findings confirm the need for more research on hyperlexia in autism, the factors involved in its emergence, and its possible uses during diagnosis assessment and intervention.