Is Autism Over-diagnosed?

By: Erin Thomas

The current incidence of autism in the U.S. is 1 in 50 children. While this alarming rate is prompting research into causes and treatments of autism, it has also caused many to raise eyebrows and propose a different idea…Is autism simply being over-diagnosed today? The answer is not so clear.

One study showed that incidence rates for autism in the U.K. increased fivefold in the 1990s, but incidence in 8 year olds reached a plateau in the early 2000s. The rate then stayed stable through 2010. It has not been determined whether this same trend applies for the U.S.

ASDs are often first detected around 18 months and even earlier in some cases. But the truth also remains that some diagnosed cases of autism are considered to be “outgrown” at later ages. This may be because ASDs share some neurodevelopmental symptoms with other conditions, leading to mistakes in diagnosis at a young age.

One study compared three cohorts of people diagnosed with ASDs: young children (3-5 years), children (6-11 years), and adolescents (12-17 years). Data was collected to identify conditions that distinguished individuals who had a current diagnosis of an ASD from those who had a past but not current diagnosis of an ASD. The symptoms in the young children 3-5 years old who currently had an ASD diagnosis were moderate/severe learning disability and moderate/severe developmental delay. In children 6-11 years old the distinguishing symptoms were past speech problem, past hearing difficulties, and current moderate/severe anxiety. In adolescents, the distinguishing symptoms were past hearing difficulties, current moderate/severe speech problems, and current mild seizures or epilepsy. Overall, the study suggested that co-occurring neurodevelopmental and psychiatric syndromes could be associated with a change in ASD diagnosis.

Another claim regarding the over-diagnosis of ASDs is that the spectrum has become too wide and inclusive, making it difficult to distinguish Asperger’s and high functioning parts of the spectrum from pure social disabilities. Some physicians argue that a few socially odd tendencies or repetitive behaviors may be enough to label a child as autistic today, whereas just a few decades ago these children would not have been included on the spectrum. Physicians such as Paul Steinberg argue that more biological markers are necessary to separate ASDs from social disabilities. He warns that because Asperger’s syndrome is so loosely defined today, we put children who are introverted, quirky, or challenged when it comes to relating with their peers in danger of being wrongly diagnosed as having Asperger’s. Steinberg says that with the erroneous diagnosis comes lower self-esteem and poorer social development when they are placed in classrooms with children who actually have an Autism Spectrum Disorder. For an adult with a social disability, a misdiagnosis of Asperger’s on his or her permanent medical record can be a hurdle when searching for employment. Ultimately, there is a concern that as a society we are pathologizing quirks while undermining the severity of classic autism symptoms, such as difficulties in language acquisition and development.

Nordqvist, C. (2012, January 23). "Autism Overdiagnosed? Possibly, Because Many

Children Seem To "Outgrow" It."Medical News Today. Retrieved from

http://www.medicalnewstoday.com/articles/240649.

Steinberg, P. (2012). Asperger’s history of over-diagnosis. Retrieved from

http://www.nytimes.com/2012/02/01/opinion/aspergers-history-of-over-diagnosis.html?_r=0.

Taylor B, Jick H, MacLaughlin D. Prevalence and incidence rates of autism in the UK: time

trend from 2004–2010 in children aged 8 years. BMJ Open 2013;3:e003219. doi:10.1136/bmjopen-2013- 003219. 

New Study: Increased Immune Activation During Pregnancy May Lead To Higher Risk of Autism and Schizophrenia

By: Erin Thomas

A new study by researchers at the UC Davis Center for Neuroscience and Department of Neurology found that viral infection during pregnancy may cause a higher chance of autism onset as well as schizophrenia. This is the first evidence that levels of major histocompatibility complex class I molecules (MHC1), cells involved in regulating immunity, are altered on the surface of neurons in an offspring’s brain if the mother’s immune system is activated. The study showed that MHC1 levels are doubled on the surface of neurons in the newborn offspring of mothers whose immune systems are activated. This suggests that MHC1 levels are very responsive to a peripheral immune response in the mother (Elmer, 2013). This is significant because maternal immune activation is a risk factor for Autism Spectrum Disorders and schizophrenia in humans. Mouse models have shown that offspring of mothers with immune activation show symptoms of both ASD and schizophrenia. This study demonstrated that maternal immune activation causes MHC1 signaling to limit the capability of neurons to form synapses, which are connections between neurons. When MHC1 levels in the newborns were made to return to normal, synaptic densities also returned to normal levels. Future experiments will seek to determine how the MHC1 signaling pathway is specifically affected by maternal immune activation.

B. M. Elmer, M. L. Estes, S. L. Barrow, A. K. McAllister. MHCI Requires MEF2 Transcription Factors to Negatively Regulate Synapse Density during Development and in Disease. Journal of Neuroscience, 2013; 33 (34): 13791 DOI:10.1523/%u200BJNEUROSCI.2366-13.2013

Image: http://www.natcom.org/uploadedImages/CommunicationCurrents_Articles/Volume_2/neuron.jpg

Something in the Air?

By: Erin Thomas

While it is suspected that autism has a genetic component, recent research has been minimizing the role of genetics in the onset of autism and maximizing the role of environmental factors. Until now, twin studies have lead us to believe genes are involved in causing autism. One study reported that when one sibling has an ASD, the other sibling also has an ASD twice as often in identical twins than in non-twin siblings (Bohm, 2013).  Another study in Denmark using data from 1980 to 2004 reported that the concordance risk of ASDs was 6.9 in siblings, 2.4 in maternal half siblings, and 1.5 in paternal half siblings (Gronborg, 2013). This shows that the risk is higher in full siblings than half siblings, further intimating the genetic component of autism.  The risk is also higher in maternal half siblings than paternal half siblings, suggesting that issues during pregnancy may have an effect.

Because these concordance rates in twins and siblings are smaller than previously thought, there has been increasing research into environmental-gene interactions and exposure to harmful chemicals during the first trimester of pregnancy.

Epidemiological studies have pointed to thalidomide and valproic acid as possible teratogens, agents that cause malformation of the embryo (Matsuzaki, 2012). In the 1960s, children of women who used thalidomide during pregnancy were born with developmental disabilities, most notably shortness of the limbs. 5% of these children also had autism. However, autistic children usually only have malformed ears, not shortness of the limbs. This led to the assumption that the developmental issues associated with autism occurred in the first trimester, when the brainstem is formed. In addition, children born to women who took valproic acid (VPA) during pregnancy developed a condition known as fetal VPA syndrome. Children with this syndrome also had a high probability of having autism. A study of the postmortem brain of an autistic patient revealed a decrease in nerve cells in certain areas that led researchers to believe that the onset of autism occurred immediately after the neural tube of the fetus was closed in the first trimester of pregnancy. Valproic acid-exposed animal (rat) models have also been shown to present the symptoms of autism, and they have been used frequently as autistic models of environmental factors (Matsuzaki, 2012).

There is also ongoing research into the effects of pollution on autism onset. One study conducted in Los Angeles, California from 1998 to 2009 revealed that there was a 12-15% increase in odds of being diagnosed with autism after increasing exposure to ozone and particulate matter, and a 3-9% odds increase with increasing exposure to nitric oxide and nitrogen dioxide (Becerra, 2013). The data suggested that there may be an association between autism and exposure to air pollutants during pregnancy, primarily in relation to traffic sources. Most recently, a study into the effects of air pollution was conducted on a national scale. The study looked for correlations between the level of air pollutants at the time and place a woman was pregnant and the presence of an ASD in her child. The results showed that women living in areas that were most polluted, areas with the highest levels of diesel particulates or mercury, were twice as likely to have a child with autism (Roberts, 2013). Women exposed to other pollution, such as lead, manganese, and hard metals also had a higher risk of having a child with autism. However, the researchers of this study warn that it is not conclusive as to what causes the autism. Previous studies have shown that there is no relationship between mercury in vaccines and autism onset. The next step would be to study the blood samples of mothers and children with autism to see which toxin specifically is being transmitted (Roberts, 2013).

So is there something in the air causing autism rates to soar? Not necessarily. As you can see, the research is far from conclusive. However, scientists do have strong reason to believe that environmental factors play a larger role than previously thought, and this knowledge is crucial for finding effective treatments.

Becerra, T et. al. (2013). Ambient air pollution and autism in Los Angeles County, California. Environ Health Perspect. 121(3): 380–386

Bohm, H.V. et. al. (2013). On the autism spectrum disorder concordance rates of twins and non-twin siblings. Med Hypotheses. pii: S0306-9877(13)00408-8. 

Gronborg, TK et. al. (2013). Recurrence of Autism Spectrum Disorders in full- and half- siblings and trends over time: A population-based cohort study. JAMA Pediatr. 167(10):947-953.

Roberts, A et al. (2013). Perinatal air pollutant exposures and Autism Spectrum Disorder in the children of Nurses’ Health Study II participants. Environ Health Perspect 121:978–984. http://dx.doi.org/10.1289/ehp.1206187 [Online 18 June 2013]

Image: http://us.123rf.com/400wm/400/400/elwynn/elwynn1104/elwynn110400218/9410034-sunset-cityscape-of-highway-and-buildings-with-bad-weather-and-air-pollution-city-scenery-in-taipei-.jpg

Moving Forward

By: Erin Thomas

Just tell me what I have to do to help my child and I will do it. –the heart- cry of every parent who hears that daunting autism diagnosis.

The bad news: It can sometimes be a grueling process to find what works.

The good news: There are a multitude of resources available today, that were not available just over a decade ago, to help you find your path.

The therapies for Autism Spectrum Disorders are plentiful and varied. It is crucial that parents work to craft a personalized therapy for their child. While the process of trial and error can certainly be disheartening, it is often the case that what is therapeutic for one child, for example pet therapy, may be too stimulating or ineffective for another child on the Spectrum. There is no elixir for ASDs, and that can be frustrating for parents who simply want their child to live to his or her full potential. It is important to remember that each small step of improvement along the way is integral for the journey and should be celebrated.

Generally, there are two models of early intervention behavioral treatments. One model is the Lovaas Model using Applied Behavior Analysis (ABA). ABA is widely used today as an early intervention method to improve cognitive skills, language, and behavior. As of yet, it is the therapy with the most scientific support (Geschwind, 2009). ABA aims to cultivate basic skills such as looking, listening, and imitating as well as language skills, sociability, motor development, and academic skills (Autism Speaks, 2013). It has also been shown to improve skills in teens and adults with autism, and is useful for those trying to live more independent lives or find employment. However, the use of ABA has been less studied in teens and adults than in children.

The other model of early intervention therapy is the Early Start Denver Model for children ages 12 months to 4 years. This approach incorporates the principles of the ABA method but is more relationship-centered. Parents play an integral role in the execution of this model, and it is play-based to increase social and communicative skills.

Here a few more early intervention behavioral therapies that some parents have found effective:

• Floortime, in which the parents engage their child for 20 to 30 minute sessions of playtime on the floor. Parents implement activities based on their child’s interests, and they are in effect meeting the child at his or her “level”. Parents allow their child to take the lead but challenge them to interact more or use language. For example, if a child is playing with a doll, a parent may use another doll to imitate what the child is doing and then add language to the game. Systematic studies regarding the efficacy of this approach have been very limited, but case studies have reported improvement in communication skills (Martinex-Pedraza, 2009).
• Pivotal Response Treatment (PRT) shares the core principles of ABA and the Early Start Denver Model, but it focuses on pivotal areas that may affect broad functioning. For example, PRT uses certain behavioral methods to target the “pivotal area” of motivation and fosters social motivation by using rewards (Steiner, 2013).
• Verbal Behavior Therapy is a method that aims to teach individuals with ASDs how to communicate effectively using language. Instead of regarding words as mere labels for objects, it trains people to think of language as a means to obtain things they want or to relay ideas (Autism Speaks, 2013). For example, it conditions children to realize that if they say ice cream then their parent or therapist will produce ice cream for them.

This is just a sampling of the multitude of treatments available for individuals with ASDs, and the focus here was on early intervention methods. In some cases medication may be used to treat certain auxiliary symptoms of autism, such as high energy levels, inability to focus, tantrums, and depression (CDC, 2013). Unfortunately, there is no cookie cutter approach that guarantees results in all individuals with ASDs. However, there is an abundance of resources and information relating to autism treatment available, and this blog hopes to keep you informed about the various options.

The next post will take a more in depth look into one of the popular treatment options, Applied Behavior Therapy. Stay tuned!

Autism Speaks. 2013. How is autism treated? Retrieved from http://www.autismspeaks.org/what-autism/treatment

Centers for Disease Control and Prevention. 2013. Treatment. Retrieved from http://www.cdc.gov/ncbddd/autism/treatment.html.

Geschwind. Advances in Autism. Annu Rev Med. 2009; 60: 367–380. [PubMed].

Martinez-Pedraza. Autism spectrum disorders in young children. Child Adolesc Psychiatr Clin N Am. 2009 July; 18(3): 645–663. [PubMed].

Steiner, A et al. Pivotal response treatment for infants at risk for autism spectrum disorders: A pilot study. J Autism Dev Disord. 2013 January; 43(1): 91–102. [PubMed].

Dispelling the Myth

By: Erin Thomas

The question on everyone’s minds…

With an astounding incidence of autism in the U.S. today that only seems to be growing, it is even more astounding that a definite cause has yet to be found.  Autism has done a successful job of leaping into the public eye and vernacular; fifteen years ago, talk about having an autistic child likely would have been met with confused gazes. It is understandable that the lack of an explicit cause is a frustrating reality for so many individuals on the Autism Spectrum and their families. Without a cause, it becomes all the more difficult to target a treatment for an individual, and families are often left shooting in the dark for therapies.

One school of thought that has pervaded the media is the connection between the Measles-Mumps-Rubella (MMR) vaccine and autism. You may have heard public figures, most notably Jenny McCarthy, promoting the culpability of MMR as a cause of autism. Well, from a scientific standpoint, you may be surprised to hear that there has been NO scientific evidence to support this claim. Not one. So how did this idea gain fuel and become so embedded in the public perception of autism?

Quick history break- Well in 1998, a gastroenterologist named Andrew Wakefield published a paper in Britain describing 8 children who apparently experienced the onset of autism one month after receiving the MMR vaccine. Wakefield claimed that the MMR vaccine caused intestinal inflammation that allowed certain peptides (chains of two or more amino acids, similar to proteins but normally smaller) to enter the bloodstream and thus make their way to the brain where they affected development (Gerber, Offit, 2009). Wakefield was eventually prompted to take down his paper because of the

•  lack of experimental controls to confirm that MMR was responsible for causing the autism
• the unsystematic method in which data was collected
•  the lack of connection between measles, mumps, or rubella to intestinal inflammation, and
• the fact that gastrointestinal issues did not even precede autism onset in some children. (Click here to read more about the issues nullifying the Wakefield paper.)

Since then, research has been conducted to further rule out MMR’s role in causing autism. For one, research has not determined that children with ASDs contain more of the genetic information of the measles vaccine virus than those without ASDs (Hornig, 2008). Moreover, the harmful peptides Wakefield suspected to have been invading the brain from the intestine have not been identified (Gerber, Offit, 2009). In fact, the proteins now believed to contribute to ASDs are endogenous, or have no external origins, and affect neuron activity (Sutcliffe, 2008). 

Studies have further severed the link between the MMR vaccine and autism by showing that the incidence of autism has not increased since people started becoming vaccinated against MMR.  An extensive study on 498 autistic children born from 1979-1992 in the UK is just one source of evidence that rates of autism did not increase after the introduction of the MMR vaccine in 1987. Nor did children who received the MMR vaccine or a second dose of the vaccine have higher onsets of autism than unvaccinated children (Farrington, 2001). Click here for an outline of more studies that have refuted the connection between MMR and autism. 

So if there is no scientific evidence supporting the link between the MMR vaccine and autism, and no logical scientific mechanism for how MMR could even lead to autism, why is the idea still lingering in the minds of parents taking their newborns to the pediatrician’s office?   

The MMR vaccine is administered in babies at 18 months…right around the time when autism is typically first detected (although in some cases it can now be detected earlier). Scientists have coined the term “correlation vs. causation” to illustrate an important fallacy associated with the connection being made here. For example, if I notice that the number of sick people in the U.S. increases as the consumption of hot chocolate in the country increases, is it safe to say that drinking a sweet cup of Swiss Miss causes people to fall ill? Of course not! The two are simply correlated because people happen to consume more hot chocolate in the winter, which is when flu season is at its peak. Similarly, the correlation between the administration of MMR vaccines at 18 months and the subsequent diagnoses of autism around that time does not necessarily link the vaccine to the cause of autism. This correlation vs. causation issue is something we will keep in mind as we continue to assess ongoing autism research. 

Farrington CP, Miller E, Taylor B. MMR and autism: further evidence against a causal association. Vaccine. 2001;19:3632–5. [PubMed]

Gerber J, Offitt P. Vaccines and autism: a tale of shifting hypotheses. Clinical Infectious Diseases. 2009;48:456–461 [PubMed]

Hornig M, Briese T, Buie T, et al. Lack of association between measles virus vaccine and autism with enteropathy: a case-control study. PLoS ONE. 2008;3:e3140.

Sutcliffe JS. Genetics: insights into the pathogenesis of autism. Science. 2008;321:208–9. [PubMed]

So What's the Buzz About?

By: Erin Thomas     

Autism has increasingly been making headlines in recent years and has sometimes found itself in the center of hot debate. How can the mere mention of a disorder stir so much controversy? Well, it is reported that today one in 50 children, aged 6-17, has an Autism Spectrum Disorder (CDC, 2013)- that is an alarming rate, and the incidence seems to be increasing.

So with such a high prevalence, the next thing you are probably wondering is what the culprit is. And here lies the problem at the center of disputes- a single cause of autism has yet to be pinpointed. As of now, researchers believe a combination of genetic and environmental factors are at play. There is a plethora of ongoing  research into the causes and treatments of autism. It is the goal of this blog to keep you informed   as well as clear up common misconceptions as best as we can.

 To start, there is often a  misunderstanding in the public of what autism is and whom it affects. Autism  is actually a general term used to refer to a group of five Autism Spectrum  Disorders, or ASDs, which affect brain development. Individuals with ASDs   process sensory information differently than those with normal brain development. Autism spans all races, ethnicities, and social groups (Autism Science Foundation, 2013).

What are the different types of ASDs? Well a “spectrum  disorder” means that symptoms can range from mild to severe (American Autism   Association, 2013).

• “Classic autism” is known as autistic disorder, in which a child may have delays in the development of language, have problems communicating, lack social ability, have intellectual disabilities, or have unusual behaviors and interests.
• Asperger’s Syndrome presents itself with milder symptoms than autistic disorder and is characterized by unusual behaviors or interests as well as a lack of social skills. Those living with Asperger’s do not normally have intellectual deficits or communication issues.
• Pervasive Developmental Disorder- Not Otherwise Specified (PDD-NOS)   is when an individual shows some but not all of the symptoms of autistic disorder or Asperger’s Syndrome (American Autism Association, 2013). People with PDD-NOS may only lack social and communication skills.
• Rett syndrome is a very rare and severe form of autism occurring only in girls. It is caused by a mutation on the X chromosome.
• Child disintegrative disorder is another very rare and severe condition in which a child regresses in development after at least two years of completely normal development (Mayo Clinic, 2013).

At the heart of the attention towards ASDs is, of course, the people who live with them and endure the symptoms each and every day- and we want to keep it that way. There is no cure for ASDs, but there is an array of therapies available to help treat the symptoms. Treatments play a large role in allowing individuals to overcome certain symptoms and thrive in society. This blog hopes to be a source of valuable information and resources in an effort to shed light on the ongoing research. We all have a lot to learn about Autism Spectrum Disorders, so let's use this space to learn together. 

References:

American Autism   Association. (2013). “What is autism?”[Handout]. New York, NY. Autism Science   Foundation. (2013). “What is autism?” Retrieved fromhttp://www.autismsciencefoundation.org/what-is-autism

Centers for Disease   Control and Prevention. (2013). “Autism spectrum disorders.”  Retrieved from http://www.cdc.gov/nchs/data/nhsr/nhsr065.pdf.

Mayo Clinic staff.   (2013). “Childhood disintegrative disorder.” Retrieved from http://www.mayoclinic.com/health/childhood-disintegrative-disorder/DS00801