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Child Development

Hyperlexia: Precocious Reading or Reading Disorder?

Hyperlexia can be a sign of developmental delays.

Key points

  • Hyperlexia is a condition in which word-reading ability exceeds language comprehension.
  • Hyperlexia is often associated with autism, though not all children with hyperlexia are autistic.
  • Children with hyperlexia could benefit from language interventions.

Hyperlexia first appeared in the literature in a 1967 paper describing young children with reading skills exceeding their language comprehension skills (Silberberg & Silberberg, 1967). The initial views of hyperlexia proposed that word recognition skills were separate from a child’s verbal functioning.

While hyperlexia is not a diagnostic term, it can be used to describe children with unusual reading behaviors. The problem arises in defining the threshold between typical reading development and hyperlexia. Researchers disagree on definitions of hyperlexia, such as debating how much more advanced the reading skill needs to be compared to peers and whether the advanced reading needs to be paired with developmental disabilities (Zhang & Joshi, 2019). The lack of consensus on a definition makes researching hyperlexia difficult for psychological, educational, and developmental scientists.

Hyperlexia can be thought of as the inverse of another reading disorder called dyslexia. Reading comprehension is understood to be a complex activity requiring both adequate decoding skills and listening comprehension. A child’s decoding skills and listening comprehension work together to support their reading comprehension. This is known as the simple view of reading (Hoover & Gough, 1990). The simple view of reading is understood best by the equation: Decoding x Listening Comprehension = Reading Comprehension.

Children with hyperlexia have excellent decoding skills and poor listening comprehension resulting in low reading comprehension. Children with dyslexia have poor decoding skills with average to above average listening comprehension, and their profile also results in low reading comprehension. Research studies as a whole support the hyperlexic profile as a child with good decoding ability and poor listening and reading comprehension (Zhang & Joshi, 2019). Children with hyperlexia therefore have impaired reading comprehension, a type of specific learning disorder that benefits from intervention and accommodation.

Hyperlexic profiles can be divided into three main types (Treffert, 2011):

Hyperlexia I: Neurotypical children who are best described as precocious readers. Many of these children may have early access to reading materials. Some researchers argue that precocious reading should not be considered hyperlexia (Ostrolenk et al., 2017), and most agree that there is no intervention needed for neurotypical children with advanced reading skills.

Hyperlexia II: Hyperlexia II is associated with autism spectrum disorder. Many autistic people have unevenly developed cognitive profile, and some have what is called a splinter skill (Treffert, 2014): a skill or interest that is unusually high compared to a person’s other skills. It has been estimated that between 6%-20% of autistic children also have hyperlexia (Ostrolenk et al., 2017).

Hyperlexia III: These children have hyperlexia paired with some features of autism, though their social communication profile may not align with the diagnostic criteria for autism. They may be sensitive to sensory information, echo language, and struggle with changes in routine. However, they also exhibit typical or near-typical social communication skills. Often, these autistic-like traits fade with age.

A typical evaluation of hyperlexia will usually start with a broad intelligence or developmental measure. Language testing, either performed by a speech pathologist or a psychologist, is also crucial. Word reading and reading comprehension are also assessed. Finally, because of the strong overlap between hyperlexia and autism, autism-specific evaluation tools should be administered. These can include a comprehensive developmental history, direct testing, record review, parent surveys, and inventories of autistic traits. Typical intervention recommendations include speech/language therapy.


Hoover, A., & Gough, B. (1990). The simple view of reading. Reading and Writing: An Interdisciplinary Journal, 2, 127–160.

Ostrolenk, A., Forgeot d’Arc, B., Jelenic, P., Samson, F., & Mottron, L. (2017). Hyperlexia: Systematic review, neurocognitive modelling, and outcome. Neuroscience & Biobehavioral Reviews, 79, 134–149.

Silberberg, N. E., & Silberberg, M. C. (1967). Hyperlexia—Specific Word Recognition Skills in Young Children. Exceptional Children, 34(1), 41–42.

Treffert, D. A. (2011). Hyperlexia III: Separating ‘Autistic-like’ Behaviors from Autistic Disorder; Assessing Children who Read Early or Speak Late. 110(6).

Treffert, D. A. (2014). Savant Syndrome: Realities, Myths and Misconceptions. Journal of Autism and Developmental Disorders, 44(3), 564–571.

Zhang, S., & Joshi, R. M. (2019). Profile of hyperlexia: Reconciling conflicts through a systematic review and meta-analysis. Journal of Neurolinguistics, 49, 1–28.

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