Special Education

What is hyperlexia?

Recently I asked on Instagram what people would like me to write about, and this was one of the topics requested.

So what exactly IS hyperlexia?

The Oxford Reference online dictionary definition comes from the Oxford Dictionary of Psychology and states:

A reading disorder characterized by advanced word-recognition skills in a person with pronounced cognitive and language deficits. People with hyperlexia manifest word-recognition skills by their ability to pronounce single words presented to them out of context, but they lack the ability to understand printed words and texts and therefore have poor reading comprehension. The condition was first identified and named by Norman E(sau) Silberberg (born 1931) and Margaret C. Silberberg in 1967. See also attentional dyslexia, dyslexia. [From Greek hyper over + lexis a word + –ia indicating a condition or quality]

I first heard the term as a relatively new teacher, introduced into conversation by a more experienced colleague as a sort of polar opposite to dyslexia. I don’t know whether they had over-simplified for the sake of less knowledgeable peers, or whether I misunderstood the explanation, but the best part of a decade must have passed before I really began to get to grips with the concept.

As long ago as 1917, in fact, the idea of a “Pseudo-talent for words” was reported by a teacher, Sarah Warfield Parker, in the journal The Psychological Clinic. She describes Gordon, a boy of 10 whose love of the appearance and sounds of words, combined with exceptional memory skills seem to have enabled him to listen to or read and memorise whole books, and to learn songs and poems after hearing them just once or twice. However, he was not able to use any of the information that he could recall.

Despite this, what we would now think of as his short term or working memory skills were weak. He was barely able to remember sequences of five familiar shown objects, five spoken numbers, four spoken ‘disconnected monosyllables’ or three colours (named or seen). Even when presented with words in a sentence, the number of syllables recalled was just ten.

Gordon was able to learn the answers to given questions, but not able to use the information to answer variations on the question. He could say the time from looking at a clock, but he could not understand what time it was from hearing another person say it. Sometimes, his speech would mimic the fanciful language of the stories he liked to read, and yet, he did not seem able to process language in a way that others might find useful. And so we come to comprehension: Gordon was able to simply and accurately define many of the single words presented to him, but he seemed quite unable to derive meaning from longer passages of text or extended pieces of spoken language. This seems to be the essence of hyperlexia.

Simple view of reading
A simple view of reading, from Rose (2006)

Looking at the diagram above, typical readers would be found in the top right quadrant. Those with severe dyslexia would fall into the bottom left quadrant, and those with what is sometimes called ‘compensated dyslexia’ might be seen in the top left quadrant. These people may struggle to decode complex, polysyllabic words, but their skills for comprehension tasks are good enough to glean apparent meaning through context. Faced with a tough text at school, or in a test, such readers might use well-developed search and scan skills to find probable answers to questions. The bottom right quadrant is where we might find those individuals with hyperlexia. As always, it is not quite that simple…

In 1968, Niensted conducted a study where participant children were somewhat arbitrarily deemed to be hyperlexic if their word reading age exceeded their reading comprehension age by at least 12 months. Numbers of children assessed with such a discrepancy were reported to be higher in schools where reading was taught through phonics. In fact, 26 of the 45 children tested were pronounced hyperlexic in this way. (This may come as no surprise to fellow UK primary trained teachers – five decades on we regularly see children about to transition to KS2 whose comprehension and general language skills are below their boosted phonics skills) Niensted’s answer was to immerse the ‘diagnosed’ children in a language-rich environment and explicitly teach them comprehension skills, sharing the techniques with parents. Perhaps unsurprisingly (particularly to specialist SpLD teachers and those with primary experience), within a single academic year with just an hour a week of intervention, all but one of the children were ‘cured’ . I can imagine what the Daily Mail’s headline reaction might have been.

An internet search for the term ‘hyperlexia’ will return results indicating connections with e.g. developmental language disorder (DLD, formerly known as specific language impairment: SLI), or suggesting that any child who begins to read independently aged 3 is hyperlexic. It would be difficult to assess the mismatch between word reading and comprehension at an age where typically developing readers would not be able to understand the text in question. (There are probably books on quantum physics that I may be able to read aloud convincingly, with no mispronunciations and with knowledge of some of the vocabulary used, but I would have no idea what I was reading…) There is more to hyperlexia than precocious reading.

More recent research, notably by Professors Maggie Snowling and Dorothy Bishop, HAS shown a strong correlation between DLD (SLI) and reading. However, whereas Professor Snowling’s 1986 work with  Professor Uta Frith focussed on hyperlexia, this more recent work questions whether DLD and dyslexia are indeed part of the same syndrome. Because their focus (vertical axis) relates to phonology, whereas Rose’s relates to comprehension, the top left and bottom right quadrants are reversed in this diagram. Their definition of dyslexia is also more limited, in that it relates to word decoding and spelling only.  Questions related to hyperlexia remain unanswered.

Reading development, Snowling and Bishop, 2004

Over the past 50 years, much has been written and researched with reference to reading development. The term hyperlexia was coined by Silberberg and Silberberg in 1967, yet cognitive scientists, psychiatrists and psychologists have still to agree on a precise definition. In 2003, Grigorenko et al. conducted an extensive search of the literature related to hyperlexia. Little has changed since they published their findings, it seems, as Ostrolenk et al. discovered, in their updated review of 2017.

Some use the term hyperlexia to describe individuals whose reading comprehension is weak compared with their ability to read single words.

  • This would include a great many children as they begin to develop their reading skills (such as Niensted’s participants), and so it is argued that hyperlexia is present only
    1. when word reading is stronger than would be expected based on the individual’s general intelligence (Grigorenko et al.’s 2003 research required a discrepancy of at least two standard deviations, or a word reading age at least two years above age-equivalent intelligence level)
    2. AND reading comprehension is weaker than would be expected based on the individual’s general intelligence.

Hyperlexia is most often thought of as a super-ability to decode words possessed by a small proportion of people with so-called pervasive developmental disorders. It is strongly associated with autism, and suggestions have been made that related visual strengths in pattern recognition may be responsible for hyperlexic whole word detection, as opposed to letter-sound decoding seen in typical reading development.

Ostrolenk et al. (2017) posit that early development of visual skills and restricted interests related to the printed word in some autistic children allow hyperlexic access to language in cases where verbal communication and comprehension development are delayed. They suggest that an accessible strengths-based approach to reading comprehension through the provision of suitable written material, harnessing this interest in written language and skills for word recognition might also enhance the development of other communication skills.


Bishop, D.V. and Snowling, M.J. (2004) Developmental dyslexia and specific language impairment: Same or different?. Psychological bulletin130(6), p.858.

Bishop, D.V., Snowling, M.J., Thompson, P.A., Greenhalgh, T., Catalise‐2 Consortium, Adams, C., Archibald, L., Baird, G., Bauer, A., Bellair, J. and Boyle, C. (2017) Phase 2 of CATALISE: A multinational and multidisciplinary Delphi consensus study of problems with language development: Terminology. Journal of Child Psychology and Psychiatry, 58 (10), pp.1068-1080.

Grigorenko, E.L., Klin, A. and Volkmar, F. (2003) Annotation: Hyperlexia: disability or superability? Journal of Child Psychology and Psychiatry44(8), pp.1079-1091.

Ostrolenk, A., d’Arc, B.F., Jelenic, P., Samson, F. and Mottron, L. (2017) Hyperlexia: Systematic review, neurocognitive modelling, and outcome. Neuroscience & Biobehavioral Reviews79, pp.134-149.

Parker, S.W. (1917) A Pseudo-Talent for Words: The Teacher’s Report to Dr. Witmer. The Psychological Clinic11(1), p.1.

Snowling & Frith (1986), Comprehension in “hyperlexic” readers, Journal of experimental child psychology,  42(3), pp. 392-415.


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