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Early Detection of Autism

by Steven Novella, Jan 30 2012

Autism is a spectrum of neurological disorders that involve, primarily, reduced social aptitude. People with autism tend to make less eye contact, they have less of a response to viewing a human face, and they are less verbal. Half a century ago autism was blamed on bad parenting, but that view is now considered outdated and even cruel.

Autism is a brain disorder. Neuroscientists are learning more and more about what is different about autistic brains from more typical brains. One feature seems to be reduced communication among neurons in the brain. Autism is diagnosed clinically. It is usually first recognized by the parents, who then bring their child to medical attention and after an evaluation the diagnosis is made. At present there are no supporting laboratory tests – we don’t diagnose autism by an MRI scan, EEG, or blood test. It is diagnosed by clinical observation and some standardized questionnaires and cognitive tests. At the more subtle end of the spectrum the diagnosis may not be made right away, not until the child is a bit older and can be more thoroughly evaluated.

The median age at diagnosis was 4.4 years in 1992. This has steadily decreased, to less than 3.4 years by 2001. This effect is greater in higher socioeconomic status (SES) groups. Low SES children are diagnosed later than higher SES children, and this gap has widened in the last 20 years. There has also been a linear increase in the number of autism diagnoses since 1992, aggregating in birth cohorts, with a greater effect for higher functioning children with autism. This suggests that more diagnoses are being made at the milder end of the autism spectrum, and at a younger age, with a strong social influence.

The current dominant interpretation among experts (I’m not sure it’s robust enough to call it a consensus) is that the increase in autism diagnoses over the last 20 years is due to increased surveillance, widening the definition, diagnosing children at younger ages, and diagnosing milder cases. A number of studies have also looked for signs of autism at younger and younger ages, with several showing differences between children who will go on to be clinically diagnosed on the autism spectrum from other children as early at 6 months of age.

Now another study has been published also demonstrating these results. Researchers looked at infants aged 6-10 months old and showed them pictures of faces with the eyes either looking toward or away from the infant. The researchers recorded brain wave activity with EEG, looking for differences in brain response between these two stimuli. A typical child should respond differently to the two images, as a human face looking toward the infant should evoke more of a response.

They found that there was indeed a difference in brain response between the two stimuli, but in those children who would later be confirmed to have autism the response was generally diminished compared to children who were not later diagnosed (at 36 months). The effect was robust, but not with sufficient sensitivity and specificity to be very useful clinically. This is an important distinction to make. The results were statistically significant, meaning that there is very likely a real effect here.

In other words, even as early as 6 months the brains of children with autism respond differently than children without autism in a way that one might predict from the symptoms of autism (diminished social responsiveness). But there were still false positives and false negatives, limiting such a test’s usefulness when applied to an individual child. The false positives and negatives may be due to the heterogeneity of autism as a spectrum of disorders, or to limitations of the diagnostic technique itself. Probably this technique (in addition to being refined) will have to be combined with other methods of early diagnosis before application to the individual will be practical.

There are several implications of this research worth discussing. The first is that early diagnosis of autism will improve early access to intervention, which seems to make a difference in outcome. Laboratory confirmation can help to reduce doubt or confusion as to the proper diagnosis, and lead more quickly to services for young children. There are also implications for our understanding of autism as a brain disorder. What, exactly, is happening in the brain of children with autism? This study has indirect implications for this question, but still adds to our pathophysiological knowledge of autism as a disorder.

Finally, there are implications from this research regarding the ongoing social (but not scientific) controversy of the role of vaccines and other environmental factors in autism. If the signs of autism are present at 6 months of age, then vaccines that are given after 6 months cannot be implicated as a cause of autism. This unavoidable implication, however, is unlikely to move the anti-vaccine community.

As with any single study, this new study is not definitive. Follow up research is required, and it seems that this technique will likely have to be combined with other techniques to be clinically useful. It adds to existing research, however, increasingly pointing to the detection of differences in the brains of children with autism as early as 6 months of age.

This also fits with the dominant view that autism is likely a complex set of genetic disorders. Environmental factors cannot be entirely ruled out, but genes seem to be playing a dominant role in autism. If this is true it may be theoretically possible to push early detection of autism to even younger ages. Then again, perhaps not – perhaps the brain has to develop to a certain point before the differences in brain function are there. Six months, so far, seems to be the point of earliest detection, and this new study supports that (although they did not study younger children).

It would be interesting to apply these techniques to 2-6 month olds to see if the differences continue to show. In any case – this and other studies like it are pointing the way toward much earlier diagnosis of autism spectrum disorders.

Recommended Reading

36 Responses to “Early Detection of Autism”

  1. Trimegistus says:

    You cannot use scientific evidence to argue people out of a position they did not arrive at by scientific reasoning.

    The antivaxers “want” autism to be caused by “chemicals” because that makes it the fault of corporations or other agents rather than random chance or parental genetics. The parents, of course, are desperate to hear it’s not their fault. Other leeches love the idea of suing pharmaceutical makers for billions, and of course it fits with the current political project of expanding government control of business, especially in the health field.

    When emotional need, greed, lust for power, and ideology all pull together, facts can’t stand against them. We are very fortunate that the fraud at the core of the antivax movement came out before more damage could be done.

  2. CountryGirl says:

    “the increase in autism diagnoses over the last 20 years is due” to increased money to schools, parents and health care providers for autism. It’s as simple as that. For some having an autistic child is a badge of honor which allows them sympathy and a degree of attention they need and seek. It is a form of Munchausen by Proxy syndrome. What is and should be important to legitimate mental health care providers is the harm done to children labeled as autistic who are not. But that is not the case. An “autistic” child is “mined” like a goldmine for $150 an hour therapy sessions, more union jobs in schools, more federal money to the states and communities and more attention to the parents. The “boom” in mining for autism is a result of a kind of “fracking” were self declared experts identify autism that cannot be disproven which produces a greater flow of the “gold” for all.

    What a great title for a new book; “Fracking For Autism”.

    • Max says:

      It’s almost as bad as self declared experts diagnosing Munchausen by Proxy syndrome.

    • Donald Prothero says:

      “Country Girl”–I have two children on the spectrum and I resent your accusation that my children or my family are a bunch of gold-diggers. Autism and ASD are awful, family-destroying conditions that have turned our lives upside down, and any day can be a living hell if the ASD child is having one of their “problems”. It is NO fucking “badge of honor”–we ASD parents would much rather do without it if we could! I struggled for 20 years to get my eldest son through school, and he would be up shit creek without the state and federal requirements that the schools make accommodations for ASD kids. I now have to live with the tantrums and social problems from my youngest, also Asperger’s. I know many more families with much more severe autism than my family suffers, and their lives ARE a living hell. NONE of us WANT to suffer through this, and would GLADLY get rid of ASD if it were curable.
      Apparently, you don’t know anyone with ASD kids or you would not have made such callous, cruel remarks. In the past, there WAS nothing to help ASD parents with this debilitating condition that made it impossible for their kids to learn normally at school. I am grateful every day for the laws which are now in place for all disadvantaged and special-needs kids. WIth these accommodations, they can become productive tax-paying members of society, rather than permanently on disability. And ALL of the therapists and doctors we’ve dealt with are caring, self-sacrificing individuals who are not “gold mining” the system but doing their best to help a bad situation. They are not “self-declared experts” but doctors and psychiatrists with years of medical training who clearly know more about ASD than your ignorant comments reveal.
      I can only conclude from your cruel and thoughtless comments that you have never had to deal with ASD. If you had, you would not want to experience this living hell that ASD families suffer. I think an apology is in order to all of us who are not as lucky as you are…

      • hardindr says:

        Autism and ASD are awful, family-destroying conditions that have turned our lives upside down, and any day can be a living hell if the ASD child is having one of their “problems”.

        While I think you are entitled to this opinion, I think many parents of children who have ASD would disagree with you.

      • Donald Prothero says:

        I have seen many families torn apart by the stresses of dealing with ASD in a kid, and others that just barely hang on because the demands can be so great. Some ASD are milder than others and may not be as difficult to deal with, but when an Asperger’s or autistic kid goes into one of their tantrums, it IS hell!

      • Janet Camp says:

        @Donaldl Prothero

        It’s not a contest at all, but you should try a week with my son who has childhood onset bipolar disorder (it’s going to be called something a bit different in the new DSM). This condition is even less understood than autism and almost always brings comments of “he just needs a good spanking” and “WHY are you drugging your child?”, among others that are even more devoid of any medical knowledge on the subject.

        Interestingly, in some ways he seems very “Asperger-y”, except that he becomes extremely verbal when manic!

        Congratulations on getting your eldest through school and for utilizing available resources–very little was available in our small town (including medical experts) so we really struggled and ended up home schooling (not the kind that fundies do) and commuting long hours to larger cities. Thanks for responding to the ignorant and insensitive statements of CountryGirl–I know her well.

      • CountryGirl says:

        So are you saying it does not exist? That we have not in fact quadrupled the diagnoses because of the push to get the money provided? If what I said was true how does that hurt you or take anything away from you or your children. On the contrary you have proved my point, i.e. that you quickly trot out your children to make yourself important. I have seen remarkably normal children in kindergarten and elementary school who have been “labeled” having the autism spectrum disorder. They are then treated differently by the school and thus suffer an abnormal childhood. How do you suppose this affects the reat of their lives? Don’t demand an apology from others who are not on your bandwagon; instead take action to treat your children as “normal” and to require the schools to treat your children as normal so that some day in the future you aren’t the one having to apologize to your adult children. The attention and being treated as “special” is harmful to children. Worse if it is a result of the parents need for attention. The least safe place in the world is between a microphone and a hollywood actress who’s child has been diagnosed with autism, Asperger’s or a related disorder. Don’t let the media and the government seduce you into destroying your family and turning your lives upside down and become a living hell. stop competing to be the most unlucky parent alive. Stop letting the unholy alliance of the public service unions and politicians make your problems worse so they can benefit from it. It is unlikely that the frequency of autism, Asperger’s or related disorders is increasing; what is far more likely is that the diagnoses is increasing. This is very much like the explosion ADHD as a result of nothing more then increased attentionto the “problem”.

      • Chris says:

        I see you don’t actually read what anyone writes in response to your fact free comments. The inside of your head must be a nice safe environment with all the locks you have placed on it to keep all new information out.

      • Donald Prothero says:

        Apparently you don’t actually read what people have said, so you just dug your hole of shame deeper and further demonstrated your ignorance. There may be a few kids in your experience who appear “normal” to you (but you’ve never had to supervise them through a 6-hour school day, or take care of them at home), but believe me, we TRIED to treat our eldest as normally as possible, avoiding special ed classes through most of his schooling and trying to “mainstream” him instead. But he could not have survived without a 1-on-1 through his early years, and constant monitoring by a specialist right up to his high school graduation. Still there are MANY aspects of ASD and how it affects their ability to learn in school of which you are clearly ignorant. Since you continue to spout out further ignorant statements that are a waste of everyone’s time, I’m done with you and your cruelty and heartlessness.

      • CountryGirl says:

        You keep acting as though this is about you. If your child has autism or some degree of the autism spectrum then nothing I have said should either affect you or anger you. The point remains; we don’t suddenly have MORE autism we have more diagnoses of autism (or something we will call the autism spectrum). It is undeniable that the push for greater diagnoses was money. THAT!! Is the sole reason we have a greater diagnoses. To look for some environmental scapegoat reason for the greater diagnoses and ignore the obvious is naive at best. Methinks thou protest too much. If you did not seek greater responsibility by the school for your children or demand special care and treatment at the taxpayers expense then you would NOT have seen yourself in my comments and not been offended. Just as I am not offended by your rude comments because youa re simply incorrect.

      • Beelzebud says:

        The end-result of a diet of right-wing talk radio, and Fox News. If anyone wonders why right-wingers are hated by a lot of rational people, look no further than this…

      • CountryGirl says:

        Did a “right wing” radio talk show host say something that you think is connected to this issue. Please share as I never listen to the radio.

    • Chris says:

      So Country Girl, so we get a pass on your opinions because my son was never diagnosed with autism? When he three years old was diagnosed with other labels in 1991 due to his total lack of speech. You will notice that was before the DSM IV (oh, and the DSM V removes some criteria, so the numbers will go down).

      My son did receive special ed. services in the public school from age three until he graduated from high school. He gets disability services from the community college he attends. While insurance covered some speech therapy when he was younger, we spent plenty of money on private speech therapy (he has a few appointments this and next month). We never qualified for services from the Department of Developmental Disabilities due to having to high an income.

      So is it all okay dokay with you because he has never diagnosed with autism? Though the high school psychologist did say he seemed autistic when he was in 12th grade. She then admitted that if he had the “autism” label he would lose special ed. services if he was put into the high school autism program. At that time he was only in two special ed. classes (English and Social Studies), the other four classes were in the regular program. He stopped getting a half hour of school speech therapy when he was in eighth grade.

      So please stop pontificating on subjects that you know nothing about. Though you might find these graphs interesting, especially this one.

      • Max says:

        Do you think reclassifying mental retardation as autism accounts for most of the growth of autism in the last 20 years?

      • Chris says:

        No. Those charts are from only one dataset. There are also other kids like mine who were put into the autism bucket.

      • Chris says:

        As an explanation, I was assured that my son was not autistic by a neurologist when he was three years old, that was in 1991. The DSM IV came out in 1994, under which he may have been given an autism diagnosis. It looks like he would not get an autism diagnosis with the DSM V criteria.

        As it was, my son received special ed. services based on his needs, not a label (which was “Other Health Impaired”).

        Also, check out what the numbers on the vertical axis represent. The combined percentage of both autism and mental retardation maxes out at 12% of all IDEA (Individuals with Disabilities Education Act) disabilities. My son would have been lumped into the 88% during all the time he was educated under IDEA (1991 to 2007). Though if he were younger and been diagnosed after 1994 he may have added to the 12%.

    • Janet Camp says:

      What difference does it make if increased school jobs are or are not union? Have you got some political axe to grind that has no bearing on the subject at hand?

      • Janet Camp says:

        That was in response to CountryGirl, not Chris–it ended up way below her post.

      • Chris says:

        No problem, I understood that the threading did not seem obvious.

        I will say that your comment about having a bipolar child reminded me of college friends who have a super smart son with with autism, and other issues.

        When I last talked to the mom she said that their son was no longer suicidal. A couple of years before she told me her middle school aged son was just released from a state mental hospital.

        The issues they have with their son pale in comparison to our own.

        They live a couple of hours from us, and we get to see them at a quarterly dinner gathering at a restaurant of several of our college friends. We missed seeing them last week because our son had a migraine.

        He gets migraines about two or three times a year, but the one he had in early January mimicked a stroke (his speech became very disordered). That meant two days in a hospital (he would have been released earlier if it was not for his genetic heart condition).

        On the night we were to have dinner with our college friends he had another migraine, which included weird feelings in his arms, but at least his speech was normal. We had him take more over-the-counter pain meds (his heart condition prevents him from taking Imitrex, or anything stronger than ibuprofen or naproxen). He still panicked, so he took a small dosage of anti-anxiety medication and went to sleep.

        It was a very trying day to try to keep him calm, and make him actually rest. We really wanted to avoid him going to the hospital again. Because not only is it expensive, but he really hates it. Which is something I reminded him each time he came downstairs instead of going to sleep.

        The anti-anxiety medication worked. He finally was able to sleep, and wake up without a migraine. The last two days have been extremely normal and drama free.

        Still, he has never spent time in the state mental hospital, nor has he ever tried to kill himself. That continuum is very broad. I only understand a small portion of what you are going through. But I know it is very real, and there can always be hope.

        (By the way, the way our college friends have been able to help their son through our state’s adoption of homeschool programs. The state actually facilitates and pays for their son’s homeschool program, which reduced his social issues immensely. On the other hand, it never would have worked for our son… but each person is different. Which is kind of the point of Individual Education Programs)

  3. Leonard Oestreicher says:

    Just yesterday, I took my 2 year old daughter to the park and there was a little boy, a bit over 2 years,who does not talk yet. He was clutching and inseparable from his toys cars. My impression, he may sit in the ASD spectrum. The father is telling me proudly that he already learned his numbers and colors from his Ipod. Anyone who thinks ASD is not increasing frightening rapidly is living in a dream. My advise, go to the park and start talking to the parents of little boys. We are raising a generation of boys who will have tons of problem assuming their roles as adults.

    There is a punishing burden of ASD on the family and the child is denied a life with normal social interactions, a fundamental part of human existence.

    The cause of this epidemic is not vaccines or a sudden change in our genetic makeup. It is the massive onslaught of video devices and distracting toys into the life of infants. The babies are drawn to and amused by these objects and thereby entranced away from the two-way communication they need in infancy to acquire the skills and interest for normal social development.

    Leonard Oestreicher MD
    Author: The Pied Piper’s of Autism
    How Television, Video and Toys in Infancy Cause ASD
    http://www.toystvautism.com

    • Chris says:

      My advise, go to the park and start talking to the parents of little boys. We are raising a generation of boys who will have tons of problem assuming their roles as adults.

      Because of a one conversation you had in a park with one parent. You may have an “MD” behind your name, but it seems to have missed the statistical analysis bit in your education. You also need to check out these five graphs.

      My son also could not talk when he was two years old, but he has never been diagnosed with autism. Plus many typical two year old children are possessive of their toys. They have not learned to share yet.

    • feralboy12 says:

      When I need critical information of a scientific, medical nature, I always look for books with punctuation mistakes in the title. So reassuring.

    • tmac57 says:

      So,would it be fair to say that you developed your ‘toys’ and autism hypothesis not from a deep academic study of the scientific literature,and specialization in autism treatment,but from just ‘things that you noticed’ over your career as a doctor and father?
      If that is the case,then I cannot understand your expression of certainty about ‘distracting toys’ as being the cause of autism.

    • gdave says:

      Personally, I’m not anti-TV, video games, and toys, I’m pro-safe TV, video games, and toys. A two year old who has an iPod AND toy cars? Clearly too much, too soon.

  4. gdave says:

    Dr. Novella wrote: “If the signs of autism are present at 6 months of age, then vaccines that are given after 6 months cannot be implicated as a cause of autism.”

    I don’t think that actually logically follows. It is at least logically possible that both vaccines and some as-yet undetermined genetic factors cause autism. Or that vaccines exacerbate an underlying condition, causing potential cases of autism to manifest as actual autism more often, or in more severe forms, or both.

    This finding does seem to point to factors other than vaccines as a cause of at least some cases of autism. It is also entirely consistent with the contention that vaccines do not cause autism. However, particularly since this test has so many false positives and negatives as to be useless as a predictor in any individual case, this study by itself does not really indicate anything as to whether vaccines cause autism.

    • Max says:

      It brings to mind celiac disease, which is caused by a reaction to gluten in genetically predisposed people.

    • gdave – You are partly correct, but what you say is not incompatible with my point. These studies do not just show a genetic predisposition, but that in many cases the brain is already in the process of developing into an autistic brain by 6 months. This is not compatible with any alleged cause of autism that does not occur until after six months. It does not eliminate anything as an exacerbating factor, but that is not the same thing as a cause.

      • gdave says:

        @Steven Novella:

        I think you missed my point. The study you discuss clearly indicates that many cases of autism are due to factors that occur prior vaccination – but the idea that SOME cases of autism are directly caused by vaccines is still compatible with these findings.

        And yes, “an exacerbating factor…is not the same thing as a cause,” at least technically. However, if a vaccine exacerbated a potential case of autism that otherwise would have remained undetected, into full-blown, severe autism, I think it would be fair to say the vaccine caused that case of autism.

        Please note, I don’t think any of the above is actually plausible. There is plenty of other evidence available that pretty thoroughly disproves any link between autism and vaccination. My objection here is that the particular study you are discussing isn’t actually evidence for this particular point.

        Your second to last paragraph discusses these findings as part of a larger body of evidence, which I have no problem with. But the section I quoted in my original reply seems to argue this study alone disproves a vaccine-autism link, which I think is over-claiming, and is not only logically fallacious in itself (but perhaps a pedantic nit-pick to point out), but doesn’t help in arguing against anti-vaxxers. Skeptics are usually quick to jump on anti-vaxxers for over-claiming about the results of an individual study. I don’t think it’s helpful for skeptics to do the same.

  5. EJ says:

    Wow. I’m an autistic skeptic and long-time fan of this blog, and I am really disappointed by the level of anti-autistic rhetoric in these comments. Not all of us view our conditions as “life-destroying”! In fact, those types of statements are what turned me and countless others against the antivax movement and against quack-friendly autism support groups in the first place. Dr. Prothero, I really respect your work and writing, and I’m actually heartbroken by your words. My parents would not say their lives were “a living hell” when I was a kid and I certainly don’t see my life that way. No wonder skeptical groups are having such a hard time attracting diversity.

  6. Nathaniel Brottingham says:

    This is nice and all, but what we really need is a genetic test so we can simply abort them. Due to things I won’t go into, I’ve had to deal with more autistic people than average, and I think trying to cure autism, or teaching them to deal with it, is a waste of time and money.

    • Chris says:

      I have the same problem with trolls.

    • MadScientist says:

      I think it remains an interesting challenge – will we eventually learn enough to treat the disorder or at least learn enough to say it cannot possibly be treated? Even given the option, many people will not abort; the decision is usually a traumatic experience either way.

  7. Phil says:

    One aspect of autism seems to be playing by yourself and being quiet. I was like that as a kid but not because I was autistic! Because I had an active imagination and other kids were mean! I would be curious to see if other cultures have the same rate of autism.

  8. Ela says:

    I was always quiet and played by myself when I was a child and yes, in my case was too…because I have had an active imagination, I have always “created” stories in my mind (Some were more beautiful than the ones found in my books) and because I was writing poems…when others were playing with dolls. But I was living in Europe and nobody called me “autistic child”, and actually, me being as “nice” and “quiet” and “composed” as I was, it was a good thing. All my teachers/parents’ friends went on and on about how good of a kid I was. I went through school with great grades and although I was a quiet and “rather lonely” teenager, did not keep me from following my dreams and becoming a good person, a great worker, a great mother and a great wife (so my hubby says :). My “strangely quiet” behaviour did not keep me from moving across the world, on my own (it was my dream!), study, work, take care of myself and also helping my family back home. My daughter now seems to be just like me, quiet, taliking only with the people she likes and who are not mean, pushy or too loud and…she is almost three. But after a few weeks in her NEW daycare (new educator, new kids, new environment) her educator called me one day to tell me that “she thinks my kid is autistic” because instead of beating other kids up, fighting for toys and speaking loudly and eratically, she skips the insanity there and she prefers to flip books’ pages on her own or not talk “bad” to a child who was rough with her at some point. I wanted to give this lady the benefit of the doubt (although my daughter is very acive at home, talkative and very happy and yes, sometimes she prefers to “read” books on her own and I just let her be) I talked about this with her doctor. Mid-sentence,I was STOPPED!!! I couldnt even explained everything as I am explaining here and this doctor already filled a recomendation for me to take my not even 3 years old girl to speech therapy and other expensive tests. I just wanted an opinion, I wanted SOMEONE to tell me that IT IS NORMAL for my girl to be “quiet” and well behaved because this was a new daycare or maybejust because she is raised well at home by two educated parents who are not screaming, shouting or use crazy language or physical force/abuse….and what I got instead was a rushing advice to spend all this money on my “what seems to be autistic behaviour”. Thank God I was born and raised in a country where common-sense…makes sense and that I have it in my DNA. Otherwise I would have been now just another “paranoic” mother taking my daughter to a million other doctors trying to label her “as special” or “autistic” or some other crazy-money hungry label and most likely pumping her with drugs…I think that a lot of love, great attention, care and a great diet (As in raw, good food and water) “cures” these “autistic” children way better than drugs and “speech/behavioural therapists”. Best of luck and strength to all parents out there!