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| Autism is distinguished by a pattern of symptoms rather than one single symptom. The main characteristics are impairments in social interaction, impairments in communication, restricted interests and repetitive behavior. Other aspects, such as atypical eating, are also common but are not essential for diagnosis. Individual symptoms of autism occur in the general population and appear not to associate highly, without a sharp line separating pathological severity from common traits. | | Autism is distinguished by a pattern of symptoms rather than one single symptom. The main characteristics are impairments in social interaction, impairments in communication, restricted interests and repetitive behavior. Other aspects, such as atypical eating, are also common but are not essential for diagnosis. Individual symptoms of autism occur in the general population and appear not to associate highly, without a sharp line separating pathological severity from common traits. |
| ==History== | | ==History== |
| Autism is defined in the [[DSM-IV-TR]] as exhibiting at least six symptoms total, including at least two symptoms of qualitative impairment in social interaction, at least one symptom of qualitative impairment in communication, and at least one symptom of restricted and repetitive behavior.
| | '''Family history''' |
| ===Autism Spectrum Quotient===
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| The Autism Spectrum Quotient, or AQ, is a questionnaire published in 2001 by [[Simon Baron-Cohen]] and his colleagues at the Autism Research Centre in [[Cambridge]], UK. Consisting of fifty questions, it aims to investigate whether normal adults have symptoms of [[autism]] or one of the other [[autism spectrum disorder]]s. The test was popularised by [[Wired Magazine]] in December 2001 when published alongside their article, "The Geek Syndrome" and is commonly used for [[self diagnosis]] of [[Asperger Syndrome]].<ref name="smith">M. Woodbury-Smith, J. Robinson and S. Baron-Cohen, [http://www.autismresearchcentre.com/docs/papers/2005_Woodbury-Smith_etal_ScreeningAdultsForAS.pdf Screening adults for Asperger Syndrome using the AQ : diagnostic validity in clinical practice], ''Journal of Autism and Developmental Disorders'' '''35''' 331-335 (2005) </ref>
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| * ''Format''
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| The test consists of fifty statements, each of which is in a forced-choice format. Each question allows the subject to indicate "Definitely agree", "Slightly agree", "Slightly disagree" or "Definitely disagree". Approximately half the questions are worded to elicit an "agree" response from normal individuals, and half to elicit a "disagree" response. The subject scores one point for each question which is answered "autistically" either slightly or definitely. The questions cover five different domains associated with the autism spectrum: social skills; communication skills; imagination; attention to detail; and attention switching/tolerance of change.
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| * ''Use as a Diagnostic Tool''
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| In the initial trials of the test,<ref>S. Baron-Cohen, S. Wheelwright, R. Skinner, J. Martin and E. Clubley, [http://www.autismresearchcentre.com/docs/papers/2001_BCetal_AQ.pdf The Autism Spectrum Quotient (AQ) : Evidence from Asperger Syndrome/High Functioning Autism, Males and Females, Scientists and Mathematicians], ''Journal of Autism and Developmental Disorders'' '''31''', 5-17 (2001)</ref> the average score in the control group was 16.4, with men scoring slightly higher than women (about 17 versus about 15). 80% of adults diagnosed with autism spectrum disorders scored 32 or more, compared with only 2% of the control group. The authors cited a score of 32 or more as indicating "clinically significant levels of autistic traits". However, although the test is popularly used for self-diagnosis of [[Asperger Syndrome]], the authors caution that it is not intended to be diagnostic, and advise that anyone who obtains a high score and is suffering some distress should seek professional medical advice before jumping to any conclusions.
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| A further research paper<ref name="smith"/> indicated that the questionnaire could be used for screening in clinical practice, with scores of 26 or lower indicating that a diagnosis of Asperger Syndrome can effectively be ruled out.
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| ==DSM-IV Criteria Symptoms==
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| ===Social Development===
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| People with autism have social impairments and often lack the intuition about others that many people take for granted. Noted autistic [[Temple Grandin]] described her inability to understand the social communication of [[neurotypical]]s as leaving her feeling "like an anthropologist on Mars".<ref>{{cite book|title=[[An Anthropologist on Mars]]: Seven Paradoxical Tales|author=[[Oliver Sacks|Sacks O]]|publisher=Knopf|date=1995|isbn=0679437851}}</ref>
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| Social impairments become apparent early in childhood and continue through adulthood. Autistic people are prone to commit social ''[[faux pas]]'' because of an inability to predict others' reactions. Autistic infants show less attention to social stimuli, smile and look at others less often, may also neglect social niceties like knocking or returning a greeting and respond less to their own name. Similarly, they may be overly trusting or paranoid of strangers. It may be best summed up as an inability to understand/perceive the intent or emotional wants and needs of others around them. Autistic toddlers have more striking social deviance; for example, they have less [[eye contact]] and anticipatory postures and are more likely to communicate by manipulating another person's hand. This leads others to conclude that they are shy, uninterested or evasive. Three- to five-year-old autistic children are less likely to exhibit social understanding, approach others spontaneously, imitate and respond to emotions, communicate nonverbally, and take turns with others. They may appear somewhat removed or [[Dissociation (psychology)|dissociated]] or dreamy at times, especially when in [[sensory overload]] or from a perception of extreme social pressure. However, they do form [[Attachment (psychology)|attachments]] to their primary caregivers.<ref>{{cite journal|journal=Ment Retard Dev Disabil Res Rev|date=2004|volume=10|issue=4|pages=221–33|title=Early detection of core deficits in autism|author=Sigman M, Dijamco A, Gratier M, Rozga A|doi=10.1002/mrdd.20046|pmid=15666338}}</ref> They display moderately less [[Attachment in children#Secure attachment|attachment security]] than usual, although this feature disappears in children with higher mental development or less severe ASD.<ref>{{cite journal|journal=J Child Psychol Psychiatry|date=2004|volume=45|issue=6|pages=1123–34|title=Autism and attachment: a meta-analytic review|author=Rutgers AH, Bakermans-Kranenburg MJ, van IJzendoorn MH, van Berckelaer-Onnes IA|doi=10.1111/j.1469-7610.2004.t01-1-00305.x|pmid=15257669}}</ref> Older children and adults with ASD perform worse on tests of face and emotion recognition.<ref name=Sigman>{{cite journal |journal= Annu Rev Clin Psychol |year=2006 |volume=2 |pages=327–55 |title= Autism from developmental and neuropsychological perspectives |author= Sigman M, Spence SJ, Wang AT |doi=10.1146/annurev.clinpsy.2.022305.095210 |pmid=17716073}}</ref>
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| Unlike those with low-functioning autism, people with high-functioning autism are not [[Mental retardation|mentally retarded]]; persons with high-functioning autism have an IQ at the average to above-average range. High-functioning autism (HFA) is an informal term applied to individuals with [[autism]], an [[IQ]] of 80 or above, and the ability to speak, read, and write.<ref>[http://www.nichd.nih.gov/news/releases/autism_affects_brain.cfm Study Provides Evidence That Autism Affects Functioning of Entire Brain: Previous View Held Autism Limited to Communication, Social Behavior, and Reasoning] National Institute of Health News, Aug. 16, 2006</ref> HFA may simply refer to autistic people who have normal overall intelligence; that is, are not cognitively challenged.<ref>[http://www.maapservices.org/MAAP_Sub_Find_It_-_Publications_Volkmar_Article.htm Validity and Neuropsychological Characterization of Asperger Syndrome: Convergence with Nonverbal Learning Disabilities Syndrome] A. Klin et al (1995) The Journal of Child Psychology and Psychiatry and Allied Disciplines, Vol. 36, No. 7, pp. 1127-1140, 1995. Reprinted with permission from Cambridge University Press. See section titled "Validity of Asperger syndrome"</ref>
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| Although they may have an adequate vocabulary, they may have a delay in communicating events and use less emotional content in their speech. They may also appear not to notice non-verbal cues from others such as when others have become bored with the topic of conversation they appear oblivious and continue.
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| Contrary to common belief, autistic children do not prefer to be alone. Making and maintaining friendships often proves to be difficult for those with autism. For them, the quality of friendships, not the number of friends, predicts how lonely they are.
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| There are many anecdotal reports, but few systematic studies, of aggression and violence in individuals with ASD. The limited data suggest that in children with mental retardation, autism is associated with aggression, destruction of property, and tantrums. Dominick ''et al.'' interviewed the parents of 67 children with ASD and reported that about two-thirds of the children had periods of severe tantrums and about one-third had a history of aggression, with tantrums significantly more common than in children with a history of language impairment.
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| Generally, there are difficulties with social interaction. This might not adversely affect their ability to interact with others on a day-to-day basis at a basic working level, although they may be seen as being overly serious or earnest, and as being without any "small talk" in conversation. In many instances though, these individuals have such severe social delays and difficulties that interaction within a "normal" social setting can be severely hampered.
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| They may have difficulty initiating love and friendship relationships, often being rejected because potential partners perceive them as being either too "nerdy" or too intelligent. This can lead to low self esteem or loneliness, which further impairs their ability to find meaningful companionship.
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| People may label HFA people as "oddballs" or worse, and HFA people can easily become the target of bullying. This can be especially true from primary school through the late teens. Young, intelligent HFA people usually do best by seeking out the company of their intellectual peers or by joining hobby groups, while avoiding their age-group peers. Exposure to an age equivalent peer group within the autism spectrum on a regular basis can be especially beneficial.
| | '''Past medical history''' |
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| Given the proven crucial role of body language in job interviews, lack of eye contact in such a situation may be perceived by potential employers as indicating that the candidate is "not telling the truth" or "uninterested in the job", and thus lead to a cumulative difficulty in finding [[employment]]. Attending social and business events to network is also proven to play a crucial role in job hunting, but events such as these are the type that HFA people usually avoid due to their unease with the complex social interactions required. Difficulties with such pre-employment factors may contribute to comparative [[poverty]], although intelligent HFA adults can usually find a good job if they can specialise in their area of interest. Once in a good job, however, their talents may lead to promotion and they may find themselves in a new job description that does not fit their personality.
| | '''Social history''' |
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| Some may have minor to moderate difficulty with motor skills and co-ordination. This may manifest itself as mere clumsiness or awkwardness but in some instances can be found at a level where the child is a danger to themselves (this is especially true when younger), but may manifest itself in adulthood by "bumping into walls" and doors or other people without intention. "Sensory motor dysfunction" is a comorbid diagnosis that is increasingly being associated with individuals with HFA. Many of these motor skills and functional issues can be helped through the use of regular physical therapy.
| | '''Socioeconomic status''' |
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| Alongside deficiencies they may simultaneously benefit from some of the more positive aspects of autism. For example, they may have the ability to focus intensely and for long periods on a difficult problem. There is often an enhanced learning ability, although this often is not applied to subjects they are uninterested in. They often present no problems in a supportive, well-resourced educational institution and often do well academically if they can be stimulated by good teachers. People with HFA often have intense and deep knowledge of an obscure or difficult subject and a passion for pursuing it in an organized and scholarly manner.
| | == Symptoms == |
| | * The characteristic behaviors of autism spectrum disorder may be apparent in infancy (18 to 24 months), but they usually become clearer during early childhood (24 months to 6 years) |
| | * Symptoms of autism consist of three core symptom interaction: |
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| They are usually intelligent, [[gifted]], honest, hard workers when interested in a task and excellent problem solvers. People with HFA are thought to become excellent scientists and engineers or enter other professions where painstaking, methodical analysis is required. Some believe this particular assertion is a stereotype, as some HFA adults tend to struggle with the traditional work setting and the surrounding societally accepted ways of behaving.
| | === '''Social interaction difficulties''' === |
| | * Absent, preferential or inconsistent social smile. |
| | * Reduced ability to do non-verbal communication (problems with eye-contact, body language and facial expressions). |
| | * Inappropriate response to social overtures: aloofness, excessive shyness or fussiness if interaction is forced. Reduced attention span. |
| | * Inability to initiate a social encounter properly, resulting in social awkwardness and behaviors mistaken to be ranging from extreme friendliness to aggressive beaviors for example, inappropriate touching, stroking, pushing or hitting others |
| | * Reduced ability to develop friendships. |
| | * Indifference or excessive clinginess |
| | * Excessive familiarity, absence of social inhibitions and stranger anxiety. |
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| Speech and diction can be unusually precise in some individuals with HFA but this may be delayed or awkward in many other individuals.
| | === Communicative challenges === |
| | Meaningful speech does not develop in 30–50% cases. If it does, language is delayed or deviant. |
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| ===Communication===
| | '''Verbal communication''' |
| About a third to a half of individuals with autism do not develop enough natural speech to meet their daily communication needs.<ref>{{cite journal |journal= J Intellect Disabil Res |date=2006 |volume=50 |issue=9 |pages=621–32 |title= The ComFor: an instrument for the indication of augmentative communication in people with autism and intellectual disability |author= Noens I, van Berckelaer-Onnes I, Verpoorten R, van Duijn G |doi=10.1111/j.1365-2788.2006.00807.x |pmid=16901289}}</ref> Differences in communication may be present from the first year of life, and may include delayed onset of [[babbling]], unusual gestures, diminished responsiveness, and the desynchronization of vocal patterns with the caregiver. In the second and third years, autistic children have less frequent and less diverse babbling, consonants, words, and word combinations; their gestures are less often integrated with words. Autistic children are less likely to make requests or share experiences, and are more likely to simply repeat others' words ([[echolalia]]) or [[Pronoun reversal|reverse pronouns]]. Joint attention seems to be necessary for functional speech, and deficits in joint attention seem to distinguish infants with ASD: for example, they may look at a pointing hand instead of the pointed-at object, and they consistently fail to point to "comment" about or "share" an experience at age-appropriate times. Autistic children may have difficulty with imaginative play and with developing symbols into language.<ref name=Landa>{{cite journal |journal= Ment Retard Dev Disabil Res Rev |date=2007 |volume=13 |issue=1 |pages=16–25 |title= Early communication development and intervention for children with autism |author= Landa R |doi=10.1002/mrdd.20134 |pmid=17326115}}</ref><ref name=Tager-Flusberg>{{cite journal |journal= Pediatr Clin North Am |year=2007 |volume=54 |issue=3 |pages=469–81 |title= Language disorders: autism and other pervasive developmental disorders |author= Tager-Flusberg H, Caronna E |doi=10.1016/j.pcl.2007.02.011 |pmid=17543905}}</ref>
| | * Children may only exhibit abnormal sounds. These are considered persistent if seen beyond 3 y.ears: |
| | ** Meaningless speech |
| | ** Echolalia (repetitive speech) |
| | ** Neologisms (word substitution by sounds) |
| | * Reduced ability to hold conversations |
| | * Inability or difficulty in understanding sarcasm, jokes or indirect speech. |
| | * Excessive inqusitiveness or talking only about restricted topics. |
| | '''Non-verbal communication''' |
| | * Reduced ability to understand gestures |
| | * Absence of or decreased pointing (either for expressing desire or sharing interest). They may keep crying without pointing or go to great extents to obtain something in order to avoid asking for assistance |
| | * Forcefully ask someone to help indicate something (even trying to drag them) |
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| In a pair of studies, high-functioning autistic children aged 8–15 performed equally well, and adults better than individually matched controls at basic language tasks involving vocabulary and spelling. Both autistic groups performed worse than controls at complex language tasks such as figurative language, comprehension and inference. As people are often sized up initially from their basic language skills, these studies suggest that people speaking to autistic individuals are more likely to overestimate what their audience comprehends.
| | === Repetitive behaviors === |
| | It is not uncommon for children with ASD being brought for concerns related to co-morbid conditions. These include: |
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| ===Repetitive Behavior=== | | === Neurological symptoms === |
| [[Image:Autistic-sweetiepie-boy-with-ducksinarow.jpg|thumb|left|A young boy with autism, and the precise line of toys he made]] | | '''(a) Cognitive Impairment [Global developmental delay (GDD) or Intellectual disability (ID)]:''' |
| Autistic individuals display many forms of repetitive or restricted behavior, which the Repetitive Behavior Scale-Revised (RBS-R) categorizes as follows.
| | * This has been reported in 50–70% individuals. The wide variability is due to difference in evaluation methods. Assessment should be done by tools that rely predominantly on non-verbal based skills. |
| *''[[Stereotypy]]'' is apparently purposeless movement, such as hand flapping, head rolling, or body rocking. Some may also nurture a complex habitual movement (termed "[[stimming]]") at which they become adept, for example, pen spinning, while otherwise being prone to clumsiness.
| | '''(b) Epilepsy:''' |
| *''[[Compulsive behavior]]'' is intended and appears to follow rules, such as arranging objects in a certain way. | | * All types of seizures are seen in 25–30% with bimodal presentation (infancy and adolescence). |
| *''Sameness'' is resistance to change. As with people elsewhere on the autistic spectrum, people with high-functioning autism generally prefer routine and order, and this usually begins in early childhood. They may, for example, write an alphabetized index of their [[comic book]] collection, stick to a limited wardrobe, insist that the furniture not be moved or refusing to be interrupted.
| | '''(c) Psychiatric Illnesses:''' |
| *''Ritualistic behavior'' involves the performance of daily activities the same way each time, such as an unvarying menu or dressing ritual. This is closely associated with sameness and an independent validation has suggested combining the two factors.<ref>{{cite journal |journal= J Autism Dev Disord |date=2007 |volume=37 |issue=5 |pages=855–66 |title= The Repetitive Behavior Scale-Revised: independent validation in individuals with autism spectrum disorders |author= Lam KSL, Aman MG |doi=10.1007/s10803-006-0213-z |pmid=17048092 |url=http://springerlink.com/content/v03747x60562638m/fulltext.html}}</ref>
| | * Attention Deficit Hyperactivity disorder |
| *''Restricted behavior'' is limited in focus, interest, or activity, such as preoccupation with a single television program. They do not lack empathy (although they may have difficulty expressing it), and can thus enjoy films and stories with emotional content. Some may gain the bulk of their insight into why people behave the way they do through watching movies that provide a forceful and musically-cued "capsule lesson" in human emotions (e.g. [[melodrama]]s).
| | * Depression |
| *''[[Self-injury]]'' includes movements that injure or can injure the person, such as biting oneself. Dominick ''et al.'' reported that self-injury at some point affected about 30% of children with ASD.<ref name=Dominick/>
| | * Anxiety |
| No single repetitive behavior seems to be specific to autism, but only autism appears to have an elevated pattern of occurrence and severity of these behaviors.<ref name=RBS-R>{{cite journal |journal= J Autism Dev Disord |date=2000 |volume=30 |issue=3 |pages=237–43 |title= Varieties of repetitive behavior in autism: comparisons to mental retardation |author= Bodfish JW, Symons FJ, Parker DE, Lewis MH |doi=10.1023/A:1005596502855 |pmid=11055459}}</ref>
| | * Obsessive-Compulsive disorders. |
| | '''(d) Feeding Disturbances:''' |
| | * Decreased chewing |
| | * Poor food acceptance |
| | * Picky eater |
| | * Food aversion |
| | * Meal time misbehavior |
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| ==Other Symptoms== | | === Gastrointestinal symptoms === |
| Autistic individuals may have symptoms that are independent of the diagnosis, but that can affect the individual or the family.<ref name=Filipek>{{cite journal |author= Filipek PA, Accardo PJ, Baranek GT ''et al.'' |title= The screening and diagnosis of autistic spectrum disorders |journal= J Autism Dev Disord |date=1999 |volume=29 |issue=6 |pages=439–84 |doi=10.1023/A:1021943802493}} {{cite journal |title=Erratum |quotes=no |date=2000 |journal= J Autism Dev Disord |volume=30 |issue=1 |pages=81 |doi=10.1023/A:1017256313409 |pmid=10638459}} This paper represents a consensus of representatives from nine professional and four parent organizations in the U.S.</ref> Unusual responses to [[Stimulus (physiology)|sensory stimuli]] are more common and prominent in autistic children, although there is no good evidence that sensory symptoms differentiate autism from other developmental disorders.<ref>{{cite journal|journal=J Child Psychol Psychiatry|date=2005|volume=46|issue=12|pages=1255–68|title=Annotation: what do we know about sensory dysfunction in autism? A critical review of the empirical evidence|author=Rogers SJ, Ozonoff S|doi=10.1111/j.1469-7610.2005.01431.x|pmid=16313426}}</ref> Differences are greater for under-responsivity (for example, walking into things) than for over-responsivity (for example, distress from loud noises) or for seeking (for example, rhythmic movements).<ref>{{cite journal |journal= J Autism Dev Disord |date=2008 |title= A meta-analysis of sensory modulation symptoms in individuals with autism spectrum disorders |author= Ben-Sasson A, Hen L, Fluss R, Cermak SA, Engel-Yeger B, Gal E |doi=10.1007/s10803-008-0593-3 |pmid=18512135}}</ref>
| | * Frequent vomiting |
| Several studies have reported associated motor problems that include [[poor muscle tone]], [[Apraxia|poor motor planning]], and [[toe walking]]; ASD is not associated with severe motor disturbances.<ref>{{cite journal |journal= Brain Dev |date=2007 |volume=29 |issue=9 |pages=565–70 |title= Prevalence of motor impairment in autism spectrum disorders |author= Ming X, Brimacombe M, Wagner GC |doi=10.1016/j.braindev.2007.03.002 |pmid=17467940}}</ref>
| | * Gastro-esophageal reflux |
| | * Recurrent diarrhea |
| | * Chronic constipation |
| | * Recurrent abdominal pain |
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| Atypical eating behavior occurs in about three-quarters of children with ASD, to the extent that it was formerly a diagnostic indicator. Selectivity is the most common problem, although eating rituals and food refusal also occur;<ref name=Dominick/> this does not appear to result in [[malnutrition]]. Although some children with autism also have [[gastrointestinal]] (GI) symptoms, there is a lack of published rigorous data to support the theory that autistic children have more or different GI symptoms than usual;<ref>{{cite journal|journal=J Autism Dev Disord|date=2005|volume=35|issue=6|pages=713–27|title=Gastrointestinal factors in autistic disorder: a critical review|author=Erickson CA, Stigler KA, Corkins MR, Posey DJ, Fitzgerald JF, McDougle CJ|doi=10.1007/s10803-005-0019-4|pmid=16267642}}</ref> studies report conflicting results, and the relationship between GI problems and ASD is unclear.
| | === '''Sleep Disturbances:''' === |
| [[Sleep]] problems are known to be more common in children with developmental disabilities, and there is some evidence that children with ASD are more likely to have even more sleep problems than those with other developmental disabilities; autistic children may experience problems including difficulty in falling asleep, frequent nocturnal [[Wakefulness|awakenings]], and early morning awakenings. Dominick ''et al.'' found that about two-thirds of children with ASD had a history of sleep problems.<ref name=Dominick>{{cite journal|journal=Res Dev Disabil|year=2007|volume=28|issue=2|pages=145–62|title=Atypical behaviors in children with autism and children with a history of language impairment|author=Dominick KC, Davis NO, Lainhart J, Tager-Flusberg H, Folstein S|doi=10.1016/j.ridd.2006.02.003|pmid=16581226}}</ref>
| | Difficulty in falling asleep, repeated nocturnal awakenings, unusual bedtime routines lead to increased daytime behavioral issues and parental stress. |
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| Parents of children with ASD have higher levels of stress.<ref>{{cite journal |journal=Pediatrics |date=2007 |volume=119 |issue=5 |pages=e1040–6 |title= Psychological functioning and coping among mothers of children with autism: a population-based study |author= Montes G, Halterman JS |doi=10.1542/peds.2006-2819 |pmid=17473077 |url=http://pediatrics.aappublications.org/cgi/content/full/119/5/e1040}}</ref> Siblings of children with ASD report greater admiration of and less conflict with the affected sibling; siblings of individuals with ASD have greater risk of negative well-being and poorer sibling relationships as adults.<ref>{{cite journal |journal= Ment Retard Dev Disabil Res Rev |date=2007 |volume=13 |issue=4 |pages=313–20 |title= Siblings of individuals with autism spectrum disorders across the life course |author= Orsmond GI, Seltzer MM |doi=10.1002/mrdd.20171 |pmid=17979200 |url=http://waisman.wisc.edu/family/pdf/MRDDRR-OrsmondSeltzer2007.pdf |format=PDF |accessdate=2008-04-17}}</ref>
| | === '''Dysmorphism''': === |
| | This is observed in 18–20% individuals (syndromic or non-specific dysmorphic features). |
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| Behaviorally, certain characteristics identify the autism spectrum. The type, severity and/or number of autistic traits present determines the severity of [[autism]] in the individual. These autistic traits may be beneficial for some disciplines like [[science]], [[mathematics]], [[engineering]] and [[computer programming]]. Some autistic individuals might show a marked proficiency in rote memorization which may help learn the foundation of these subjects; however, the exceptionally good aptitude (in these subjects) of high functioning autistic spectrum persons may be due to their ability to readily identify patterns and apply them consistently to new situations outside of established knowledge or teaching. These [[autistic savant|savant]] skills, although popularly considered to be a major part of autistic disorders, are evident only in a small fraction of autistic individuals, with estimates of the fraction ranging from 0.5% to 10%.<ref>{{cite web |author= Treffert DA |title= Savant syndrome: an extraordinary condition—a synopsis: past, present, future |publisher= Wisconsin Medical Society |date=2007 |url=http://www.wisconsinmedicalsociety.org/savant_syndrome/overview_of_savant_syndrome/synopsis |accessdate=2007-09-19}}</ref>
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| ==References== | | ==References== |
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