Hyperlexia in children: what is it and what to look for?

Darold Treffert MD
Child reading a book

Hearing a child read a book aloud to his or her preschool classmates is a bit of a jarring experience, or seeing an 18-month-old child reading aloud the names of all the over-the-counter drugs as he or she passes by them seated nicely in the shopping cart as mom wheels down the aisle can capture one’s attention. Imagine having a two-year-old boy or girl repeat the movie dialogue perfectly from memory, credits and all. All of these are quite sensational.

These things happen with children who read early, also known as hyperlexia. Did you know there are three kinds of hyperlexia?

  • Hyperlexia I, while relatively rare, is diagnosed when ordinary children (neurotypical is the term for ordinary these days) simply read early. As they enter kindergarten, they may be reading at a seventh grade level.
  • Hyperlexia II is when children on the autistic spectrum are hyperlexic. They are obsessed with letters and numbers, arranging them endlessly, taking magnetic tablets to bed instead of other toys or stuffed animals. They are likewise obsessed with memorizing license plates numbers, birthdays, the solar system or GPS-like trip directions. They show other signs of autism, such as withdrawal and isolation, avoidance of eye contact, and are adverse to giving or receiving affection. They are often overly sensitive to sounds or other forms of sensory overload. They too read early; way ahead of expected schedule.
  • Hyperlexia III occurs when children read early as above and, for a period of time, have “autistic-like” symptoms which, unlike children on the spectrum, fade over time and disappear. They often have impressive memory for music or movies. While reading comprehension is quite remarkable, verbal language can be delayed for a period of time.  Unlike children on the spectrum, there is good eye contact, they seek and give affection, and are socially comfortable, especially with adults.

In the past, there has been a tendency to classify all children with hyperlexia as being on the autism spectrum. As seen above, that is not the case, and making the correct diagnosis has many different treatment, intervention and outcome implications. Currently, at the Treffert Center, we have more than 300 hyperlexia cases brought to our attention from the many, “I’ve got a son or daughter who…..” e-mails the center receives daily. Parents are confused by differing diagnoses and are anxious about a possible diagnosis of autism.

Presently, a hyperlexia handbook is being prepared to help separate out the typical symptoms and behaviors in the three kinds of hyperlexia. Subscribe to the Treffert Center e-newsletter so you can be the first to know when the handbook is available.

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