Hyperlexia: Systematic review, neurocognitive modelling, and outcome

- Hyperlexia is characterised by strong decoding skills and delayed comprehension.
- Hyperlexia is strongly associated with autism (84% of cases are on the spectrum).
- Autistic children learn to read through an inverted, non-communicative, pathway.
- Hyperlexia is mediated by the extended use of the perceptual expertise system.
- Favouring hyperlexia may be tested during intervention to foster communication.

Hyperlexia is defined as the co-occurrence of advanced reading skills relative to comprehension skills or general intelligence, the early acquisition of reading skills without explicit teaching, and a strong orientation toward written material, generally in the context of a neurodevelopmental disorder. In this systematic review of cases (N = 82) and group studies (including 912 participants of which 315 are hyperlexic), we address: whether the hyperlexic profile is associated with autism and why, whether models of non-autistic reading can teach us about hyperlexia, and what additional information we can get from models specific to autistic cognitive functioning. We find that hyperlexia, or a hyperlexic-like profile, characterises a substantial portion of the autistic spectrum, in which the subcomponents of the typical reading architecture are altered and dissociated. Autistic children follow a chronologically inverted path when learning to read, and make extended use of the perceptual expertise system, specifically the visual word form recognition systems. We conclude by discussing the possible use of hyperlexic skills in intervention.

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