There is a great deal of attention these days, appropriately, to autistic spectrum disorder (ASD).  It is a serious condition and deserves serious attention. But discussions continue whether an apparent increase in the disorder is due to expanding criteria and better identification, or whether there is in fact an actual increase in incidence and prevalence. This is an important question because if we are to make accurate diagnoses, develop effective treatment, and hopefully someday create preventative strategies, we need be careful to properly identify the condition. Because, as elsewhere in medicine, the beginning of wisdom is to call things by their right name from both clinical and research standpoints.

One example of an area where that becomes especially important is hyperlexia—children who read early. In these children it is critical to sort out “autistic-like” symptoms from “autism” because of very different treatment interventions and very different outcomes. Let me explain.

In my work with my specialty, savant syndrome, I get numerous, “I have a son or daughter who…” questions, almost daily, on my web site. These are messages from concerned parents wondering about certain unusual, but remarkable, savant-like skills including precocious music, art, or math skills for example. Sometimes the special, conspicuous ability is a startling, advanced ability to read words in a very young child, well beyond that expected at the child’s chronological age. This is usually coupled with an intense fascination with letters or numbers. This is hyperlexia.

In such precocious readers, in spite of intense preoccupation and ability with words, there are, correspondingly, significant problems in understanding and expressing verbal language. Comprehension of that which is masterfully read is often poor, and thinking is concrete and literal. There is difficulty with, and paucity of, abstract thinking. There may be some development delays and there may be some “autistic-like” behaviors and symptoms commonly associated with autism spectrum disorders as well. Those might include echolalia (repeating rather than initiating conversation), pronoun reversals, intense need to keep routines (obsession with sameness), auditory or other sensory hypersensitivity, specific intense fears, strong auditory & visual memory, and selective listening with the appearance of suspected deafness.

Usually parents of hyperlexic children, when they inquire of this web site, have had their children go through numerous evaluations, with various confusing and contradictory diagnoses such as autism, Pervasive Developmental Disorder not otherwise specified (NOS), behavior disorder, language disorder, gifted, Attention Deficit Disorder, or Asperger’s just to name a few. In other instances there is no diagnosis applied except “precociousness.” If the parent goes to the World Wide Web to learn about “hyperlexia,” as they often do, they are likely to find that “hyperlexia” is, mistakenly, always linked to autistic spectrum disorder.

But the reality is, in my experience, that there are several types of “hyperlexia” and distinguishing among the several types is critical if appropriate treatment and educational decisions are to be made. And equally important, the good news is that there are very different, positive outcomes in children with this advanced reading ability depending on the type of hyperlexia present. This fact can provide a great deal of relief to parents worried that their child’s hyperlexia is automatically a part of autistic spectrum disorder, especially of course if their child already has been given such a diagnosis.

The critical consideration is that when hyperlexia is present it should be carefully separated into three separate sub-types with special attention to separating “autistic-like” symptoms and behaviors from “autism.” To that end there are, in my experience, several types of hyperlexia to be considered.

Hyperlexia, Type I

These are very bright, neurotypical children who simply read early to the amazement of their parents, grandparents, teachers, peers, and parents of their peers. Often one or both parents have read frequently and patiently to their children. Very early the child begins to “read” the book which is actually rather prolific memorization of the book triggered by the words and pictures on the pages themselves. Soon however the child is actually reading the words in the book, rather than just memorizing them, and that reading ability can then be transferred to other books. The child is a precocious reader at that point and is reading at a first or second grade level in pre-school, kindergarten or even before. At some point, of course, most of the other children in the class catch up as they learn to read at the usual pace. This group of bright, neurotypical children who read early I classify as having hyperlexia, type I.

Hyperlexia, Type II

This is a group of children who do have hyperlexia presenting as a ‘splinter skill’ as a part of an autistic spectrum disorder. They read voraciously usually with astonishing memory for what they read, often accompanied by other memorization skills and abilities, sometimes linked with number or even calendar calculating capability. These ‘splinter skills’ are seen along with, and in the midst of, the characteristic language, social and behavioral symptoms seen in autistic spectrum disorders. They usually carry a diagnosis of autistic disorder, Asperger’s disorder or pervasive developmental disorder (PPD/NOS) for example. These cases include the several sub-types of autistic disorder such as early onset, classic early infantile autism, or later onset, regressive, autism to name several. In this group it is the hyperlexia as a splinter skill that raises the “savant syndrome” questions. Clinical presentation, course of the illness and prognosis are those seen in characteristic autistic spectrum disorders. These children are appropriately diagnosed as having “autism.”

Hyperlexia, Type III

This is a less frequently recognized, and probably less common form of hyperlexia overall. These children also read early, often show striking memorization abilities, and sometimes have precocious abilities in other areas as well. They may some have “autistic-like” behaviors. For example, they may show unusual sensory sensitivity (to sounds, touch or taste.) There may be fascination with and insistence on routine with resistance to change. Unlike many autistic children, however, they tend to both seek and give affection and are generally more social, more outgoing, more interactive and less withdrawn than children with Autistic Spectrum Disorder. They do tend to make eye contact and can be very interactive with persons close to them although typically they are more comfortable with adults than peers. These children are quite bright, inquisitive, and precocious overall. Interest in, and mastery of, reading coupled with the enhanced memorization ability is conspicuous and quite amazing. There may other transient “autistic-like” symptoms or behaviors, but over time the autistic-like traits, symptoms and behaviors fade and then disappear. Some characterize this as the child having “outgrown” their autism. But in my view, rather, this better outcome is because the child did not have Autistic Spectrum Disorder to begin with. The prognosis for these children, based on correspondence and follow up with many parents, is in a word, excellent.
The purpose of this article is not to discuss either autistic spectrum disorder or hyperlexia in depth. Space precludes that. Rather it is to point out that when precocious reading ability and extraordinary fascination with words presents itself in a very young child, especially when accompanied by other language or social problems that might suggest an autistic spectrum disorder, a comprehensive assessment by a knowledgeable professional team familiar with the differential diagnosis of both autistic spectrum disorder and the several forms of hyperlexia is indicated so that a diagnosis of “autism” is not inappropriately or prematurely applied.
Many parents who had inquired on my website about their child with accelerated, savant-like precocious reading ability, obtained considerable help, and relief, when, in those particular instances, the diagnostic and treatment approaches consistent with the above were followed. Especially grateful were parents when it turned out their hyperlexic child was in group III above with “autistic-like symptoms” rather than Autistic Disorder. But even parents of group II hyperlexic children were also helped, and relieved, when directed to knowledgeable resources in their community in those cases where hyperlexia was indeed a “splinter skill” in a child with autism. Hopefully, as the literature continues to evolve on hyperlexia, there will be more clarification regarding the classification of hyperlexia into its component sub-groups, and then even more resources will emerge for comprehensive evaluation and application of appropriate treatment principles to individuals in both group II and group III.
Children Who Speak Late—The Einstein Syndrome
Hyperlexia is not the only circumstance in which the distinction between “autism” and “autistic-like” symptoms is important. An almost identical circumstance is seen in some very bright children who happen to speak late. In his two books—Late-talking Children and The Einstein Syndrome, Thomas Sowell describes a number of very bright children who developed speech later than usual as having the “Einstein Syndrome” where outcome, like in hyperlexia III, was excellent but the children were given a diagnosis of “autism” along the way. Like reading early, speaking late in children can have several causes, including but not limited to autism, and a comprehensive differential diagnostic work-up is vital in making the final diagnosis and prescribing appropriate treatment and education strategies.
Often, as elsewhere in medicine, particularly in puzzling cases, it is necessary to let the “natural history of the disorder” emerge before prematurely applying a definitive diagnosis or “label” that can have important, lasting consequences. Treatment can still be applied to target symptoms, but parents or others can, in those cases, be spared the unnecessary worry and fear that their child is “autistic” when in fact the prognosis overall is quite good. In hyperlexia III sometimes the social awkwardness or aloofness are the last to fade, but often as the child moves to first or second grade, for example, much of the behavior that “looked autistic” has faded and disappeared to everyone’s relief.
In summary, several conditions can contribute to the circumstance in which children read early or speak late. Sometimes those symptoms can be associated with Autistic Spectrum Disorder—but not always. In both children who read early or speak late, a comprehensive workup by a clinician skilled in diagnosis of autistic spectrum disorder, and a workup by a skilled Speech and Language therapist are indicated with emphasis on differential diagnosis being careful not to apply any diagnosis prematurely. Sometimes, in difficult cases, observing the natural history of the disorder without applying a definitive label is the preferred course until the true nature of the condition reveals itself.
For further information my paper in the Wisconsin Medical Journal titled “Hyperlexia III: Separating ‘Autistic-like’ Behaviors from Autistic Disorder: Assessing Children who Read Early or Speak Late” provides more detailed discussion and examples of instances in which children read early or speak late. It can be accessed on the website on the right menu under ‘hyperlexia.”


Dr. Treffert has had a career long interest in autism and savant syndrome. He has had numerous publications and documentaries on these topics and was a consultant to the movie Rain Man. Islands of Genius: The Bountiful Mind of the Autistic, Acquired and Sudden Savant is his most recent book on his work, and he also maintains a very active website at through the Wisconsin Medical Society.