What Are the Three Types of Hyperlexia?

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What is Hyperlexia?

Hyperlexia is a neurological condition used to describe precocious reading ability. Essentially this means that someone diagnosed with hyperlexia has a reading ability superior to that of their peers, age-wise. It is occasionally accompanied by precocious writing skills. Hyper originating from the Greek word for over and ‘lexis’ meaning words or diction in Greek. It is generally a term applied to children although there have been reports of hyperlexia existing in adults, albeit in small numbers. As far as neurological conditions go, it is relatively new, being formally termed by Norman E.Silberg and Margaret C. Silberg in 1967. Although it is worth noting that precocious reading has been documented by others earlier than 1967.

Hyperlexia is not included in the diagnostic medical classifications by itself. One such diagnostic classification, namely the DSM-5, lists hyperlexia as a part of autism. Unfortunately, the condition is not clearly defined from a medical perspective. As a result, there is no single, specific test one can take in order to get a diagnosis. Rather a whole constellation of symptoms and changes over time are observed in order to read a diagnosis. There are three distinct types of hyperlexia, imaginatively named hyperlexia I, hyperlexia II and hyperlexia III.

What is hyperlexia I and what are the signs?


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Hyperlexia I simply refers to hyperlexia, as described above, without any developmental deficits. These would be bright, neurotypical children with precocious reading ability. Advanced reading, more specifically, may take the form of being able to read fluently before the age of 4. Eventually, their peers catch up with them or at least shorten the disparity in reading capabilities. Unfortunately, this has been the cause of low self-esteem for type 1 ‘hyperlexics’. They initially have superior reading abilities; they then receive admiration for this ability and then everyone catches up to them making them feel as if they’re not special anymore. That’s why it is important to not overemphasise this ability within your children; praise them for their ability, just not excessively. Some of the characteristic signs of hyperlexia 1 are being able to learn quickly in the absence of much teaching or entirely through independent study, a strong interest in books and spelling words out in the air with their hands. The previous list is by no means exhaustive.

What is hyperlexia II and what are the signs?


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Hyperlexia II describes the co-occurrence of hyperlexia and autistic spectrum disorder (ASD). Interestingly, the DSM-5, which is the diagnostic medical classification for mental disorders used in the United States, only lists hyperlexia as a part of autism. In a case study conducted by Alexia Ostrolenk, et al. it was concluded that 84% of those diagnosed with hyperlexia also have autism or several autistic features. Berd and Kerbeshian (1985) estimated hyperlexia to be present in approximately 6% of children with autism. Other studies state this number to be higher however when the definition of hyperlexia is not as stringent as that in the aforementioned study the prevalence of co-occurrence increases. Individuals with this type of hyperlexia may experience deficits in expressive and receptive language skills, non-typical interaction skills and echolalia (repetition of speech); which are all symptoms of ASD. In addition to this, these people have an exceptional ability to remember; they may easily recall things such as licence number plates, geographical information and birthdates. Arranging and rearranging magnetic words on the fridge for hours is also another symptom.

What is hyperlexia III and what are the signs?

Last but not least, hyperlexia III describes a condition whereby the symptoms of hyperlexia exist alongside ‘autistic-like’ symptoms that subside over time. This sub-type of dyslexia is widely contested by professionals since these individuals may simply have learned how to mask: which is an autistic individual intentionally appearing to be neurotypical. Being less withdrawn and more engaged is one of the characteristics that distinguishes type 3 hyperlexia from type 2. Furthermore, they tend not to have the associated difficulties with eye-contact and emotional expression that we see in those diagnosed with autism.

How can you find out which type of hyperlexia you have?

As always, if you feel as though you or someone you know may have hyperlexia consult a professional medical practitioner and they shall have the suspected hyperlexic undergo all the necessary assessments. We, at Exceptional Individuals, do not have the capability to offer a diagnosis of any sort. That being said, our team has created this quiz which may serve as an indicator of hyperlexia. Please find our quiz here: Free Hyperlexia Test.

Webinar: Hyperlexia Uncovered

Nat Hawley, our Head of Community, has hosted a webinar about the signs of hyperlexia. Like this blog post, the webinar is not intended to diagnose hyperlexia.

Useful Links

How common is hyperlexia
Common myths about autism
Types of autism

Blog Author

Nathan Brown


Neurotypical