Signs and Symptoms
ASD signs and symptoms are evident as early as twelve months and the diagnosis can reliably be made by experts by two years old. Early symptoms of ASD include inconsistent or lack of response to name, poor eye contact and impaired joint attention. Research in Molecular Autism has confirmed that infant neurocognitive ASD markers relate to the disease in mid-childhood, having implications for understanding the neurodevelopmental mechanisms that lead from risk to disorder and for identification of potential targets of pre-emptive intervention.
Social and language deficits
Children with ASD demonstrate significant social deficits and have limited imaginary play, less interest in other children, and significant difficulty with reciprocal play as they get older. Language deficits include delays in achieving phrase speech, or later, engaging in reciprocal conversation.
Repetitive and unusual behaviors
Repetitive behaviors are also criteria for diagnosing autism. Children with ASD may rigidly adhere to routines, have difficulty transitioning between activities or environments, and engage in repetitive movements like hand-flapping, toe-walking, or rocking.
An important change in the DSM-5 criteria for ASD is the addition of atypical reactivity to sensory input, sensory seeking behaviour, or unusual interest in sensory stimuli in the environment, such as light, sound, or textures. The DSM-5 criteria refers to the Diagnostic and Statistical Manual of Mental Disorders, serving as a universal authority for psychiatric diagnoses but is this a good enough measure for diagnosis? Read the views of leading researchers in the field in this collection published in Molecular Autism.
ASD is primarily a genetic disorder; more than 100 genes that cause ASD have been identified to date and perhaps 1000 more are implicated based on large scale genetic studies, regularly showing overlap with other psychiatric diseases. Research published in Molecular Autism demonstrates that common genetic variations exert substantial additive genetic effects on ASD occurrence.
For more papers on the potential genetic contributors to the disease click here.
There is also a group of factors that likely act on the genetic vulnerability to increase the risk of ASD. These risk factors include very low birth weight, preterm birth, older parental age, and exposure to several toxins during pregnancy.
While the prevalence of ASD is increasing, the diagnostic criteria have also been changing and it is still not entirely clear exactly how common ASD is. The Center for Disease Control (CDC) does monitoring studies and the latest numbers reported in 2012 suggest that 1 in every 68 children is affected. However, studies that use gold standard diagnostic procedures and observe children directly find rates closer to 1 in 150. ASD is prevalent in all different populations and across racial, ethnic, and socioeconomic lines. Yet boys are four to five times more likely to be affected than girls. Research in Molecular Autism investigated potential sex specific factors which may influence the high prevalence in males.
They examined three markers, previously shown to be associated with later autistic social-communication symptoms, to test whether sex differences were already present in these markers at 1 year of age, which would suggest sex-specific mechanisms of risk or protection. While no sex differences were found in any of the three markers investigated, researchers found sex differences in their relationship to 3-year autism traits; all three markers significantly predicted later autism traits only in the boys.
The American Academy of Pediatrics recommends that all children should be screened for ASD at 18 and 24 months using a specific screening tool like the Modified Checklist for Autism in Toddlers. If there are red flags, the next step is a gold-standard evaluation for ASD, which consists of direct observation of the child (e.g. using the Autism Diagnostic Observation Schedule) and an in-depth parent interview done by specialists. For all children suspected of having ASD, genetic testing is also now recommended. The current standard of evaluation is to use chromosomal microarray testing but soon even higher resolution genetic testing (e.g. whole exome sequencing) will be routine.
Treatment usually includes speech therapy, occupational therapy, physical therapy, and behavioral therapy. The most commonly prescribed behavioral therapy in ASD, and the one with the most evidence to support its use, is applied behavioral analysis (ABA). ABA teaches children skills using positive reinforcement. It is now well accepted that the earlier and more intensively you intervene, the more robust the gains. Medications can also be used to target associated symptoms commonly seen in children and adults with ASD, like anxiety, attention deficit, hyperactivity, irritability, and aggression.
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To learn more about the Seaver Autism Center: www.seaverautismcenter.org
Discover more of the current research ongoing in this field and related blogs here.