Autism Spectrum Disorders

By Stephen Brian Sulkes, MD, Golisano Children's Hospital in Strong, University of Rochester School of Medicine and Dentistry Clinically evaluated Feb 2022 PATIENT EDUCATION VISION Etiology Signs and symptoms diagnosis Treatment key points

Additional Information Autism spectrum disorders are neurodevelopmental disorders characterized by impaired interaction and social communication, stereotyped and repetitive patterns of behavior, and irregular intellectual development, often with mental retardation. Symptoms begin early in childhood. In most children, the cause is unknown, although there is evidence of a genetic component; in some patients, as the illnesses may be associated with a medical cause. Diagnosis is based on developmental history and observation. Treatment consists of behavioral control and sometimes drug treatment. Autism spectrum disorders represent a range of neurodevelopmental differences that are considered disorders of psychological development.

Neurodevelopmental disorders are neurological conditions that appear early in childhood, usually before school age, and affect the development of personal, social, academic, and/or professional functioning. They typically involve difficulties in acquiring, retaining, or applying specific skills or information sets. Neurodevelopmental disorders can involve disturbances in attention, memory, perception, language, problem solving, or social interaction. Other common neurodevelopmental disorders include attention-deficit/hyperactivity disorder, learning disorders (eg, dyslexia), and intellectual disability. Current estimates of the prevalence of autism spectrum disorders are in the range of 1/54 in the US, with similar ranges in other countries. Autism is about 4 times more frequent among boys. In the last decade there has been an increase in the diagnosis of autism spectrum disorders, partially due to changes in diagnostic criteria. Etiology of autism spectrum disorders The specific cause, for the most part, of autism spectrum disorders remains elusive. However, some cases occur with congenital rubella syndrome, cytomegalic inclusion disease, phenylketonuria, tuberous sclerosis complex, or fragile X syndrome. Strong evidence points to genetic components. For parents of a child with an autism spectrum disorder, the risk of having another child with an autism spectrum disorder is about 3 to 10%. The risk is higher (about 7%) if the affected child is female and lower (about 4%) if the child is male. The concordance rate in monozygotic twins of autism is high. Research on families has suggested several potential gene target areas, including those related to neurotransmitter receptors (serotonin and gamma-aminobutyric acid [GABA]) and structural control of the central nervous system (HOX genes). Environmental causes were suspected, but they have not been proven. There is strong evidence that vaccines do not cause autism, and the preliminary study that suggested this association was disregarded because its author falsified data [see also measles, mumps, and rubella (SCR) vaccine].

Differences in brain structure and function likely underlie the etiology of autism spectrum disorders. Differences were identified in the cerebellum, cerebellar tonsil, hippocampus, frontal cortex and brainstem nuclei (1). Recent research suggests that the incidence of autism spectrum disorders is directly proportional to prematurity (2). References on etiology 1. Donovan APA, Basson MA: The neuroanatomy of autism—A developmental perspective. J Anat 230(1): 4–15, 2017. doi: 10.1111/joa.12542 2. Crump C, Sundquist J, Sundquist K: Preterm or early term birth and risk of autism. Pediatrics 148(3):e2020032300, 2021. doi: 10.1542/peds.2020-032300

Signs and symptoms of autism spectrum disorders Autism spectrum disorders can manifest during the first year of life, but depending on the severity of symptoms, the diagnosis may not be clear until school age.

Two main characteristics define autism spectrum disorders:

• Persistent deficits in communication and social interaction

• Restricted repetitive patterns of behavior, interests, and/or activities
  

These two features must be present at a young age (although they may not be recognized at that time) and must be severe enough to significantly impair the child's ability to function at home, school, or in other situations. Manifestations should be more pronounced than expected for the child's developmental level and fit the norms in different cultures.

Examples of communication and social interaction deficits include

• Deficits in social and/or emotional reciprocity (eg, inability to initiate or respond to social interactions or conversations, no sharing of emotions)

• Non-verbal social communication deficits (eg, difficulty interpreting other people's body language, gestures, and expressions; reduction in facial expressions and gestures and/or eye contact)

• Deficits in developing and maintaining relationships (eg, establishing friendships, adjusting behavior to different situations)
  

The first manifestations noticed by parents may be delayed language development, not pointing at things from a distance, and lack of interest in parents or in typical play. Examples of repetitive, restricted patterns of behavior, interests and/or activities include

• Stereotypical or repetitive speech or movements (eg, repeatedly flapping hands or snapping fingers, repeating idiosyncratic phrases or echolalia, lining up toys)

• Inflexible adherence to routines and/or rituals (e.g., feeling extreme distress at minor changes in meals or clothing, having stereotyped greeting rituals)

• Abnormally fixed very narrow interests (eg, preoccupation with vacuum cleaners, older patients who write down flight times)

• Overreaction or lack of reaction to sensory stimuli (eg, extreme aversion to specific smells, aromas, or textures; apparent indifference to pain or temperature)

Some children self-harm. About 25% of those affected have lost previously acquired skills.

All children with an autism spectrum disorder have at least some difficulty with interaction, behavior, and communication; however, the severity of problems varies significantly. One of the current commonly held theories states that the fundamental problem of the autism spectrum disorder is "mind blindness", that is, the inability to imagine what the other person might be thinking. It is assumed that this difficulty results in anomalous interactions, which, in turn, lead to abnormal language development. One of the earliest and most sensitive markers for autism is a 1-year-old's inability to communicatively point to objects at a distance. The hypothesis is that the child cannot imagine that another person understands what is being indicated; instead, the child indicates the desired object only by physical touch or using the adult's hand as a tool. Recent research also suggests that differences in sensory processing underlie differences in social interaction and communication in young children with autism spectrum disorders. Comorbid conditions are common, particularly intellectual disability and learning disorders. Non-focal neurological features include uncoordinated walking and stereotyped motor movements. Seizures occur in 20 to 40% of these children (particularly those with IQ IQ < 50).

Diagnosis of autism spectrum disorders

• Clinical evaluation

Diagnosis of autism spectrum disorders is clinical and based on criteria from the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5), and requires evidence of impaired social interaction and communication and the presence of ≥ 2 behaviors or stereotyped, repetitive, and restricted interests (as described earlier in Signs and Symptoms of Autism Spectrum Disorders). Although the manifestations of autism spectrum disorders can vary significantly in terms of extent and severity, former categorizations such as Asperger syndrome, childhood disintegrative disorder, and pervasive developmental disorder are grouped under autism spectrum disorders and are no longer distinguished. Screening tests include the Social Communication Questionnaire (1) and the Modified Checklist for Autism in Toddlers, Revised, with Follow-Up (M-CHAT-R/F) (2). (See also the American Academy of Pediatrics' 2020 clinical report Identification, Evaluation, and Management of Children with Autism Spectrum Disorder.) Formal standard diagnostic tests, such as the Autism Diagnostic Observation Schedule-Second Edition (ADOS-2), based on DSM-5 criteria, are typically administered by developmental and behavioral psychologists or pediatricians. Another commonly used tool is the Childhood Autism Rating Scale-Second Edition (CARS2;3), which also has a version for testing people with high functioning. Children with autism spectrum disorders are difficult to test and generally do better on performance items than on IQ tests, and may show examples of age-appropriate performance despite delays on most other tests. However, reliable diagnosis of autism spectrum disorders is becoming increasingly available at younger ages. A well-administered IQ test by an experienced examiner can provide useful prognoses.

In addition to standardized tests, metabolic and genetic testing is recommended to help identify treatable or inherited disorders such as inherited metabolic disorders and fragile X syndrome. Diagnosis References 1. Chandler S, Charman T, Baird G, et al: Validation of the social communication questionnaire in a population cohort of children with autism spectrum disorders. J Am Acad Child Adolesc Psychiatry 46(10):1324-1332, 2007. doi: 10.1097/chi.0b013e31812f7d8d 2. Robins DL, Casagrande K, Barton M, et al: Validation of the modified checklist for Autism in toddlers, revised with follow-up (M-CHAT-R/F). Pediatrics 133(1):37–45, 2014. doi: 10.1542/peds.2013-1813 3. McConachie H, Parr JR, Glod M, et al: Systematic review of tools to measure outcomes for young children with autism spectrum disorder. Health Technol Assess 19(41):1–506, 2015. doi: 10.3310/hta19410

Treatment of autism spectrum disorders

• Applied behavioral analysis

• Speech therapy

• Occasionally physical and occupational therapy

• Drug therapy Treatment of autism spectrum disorders is generally multidisciplinary, and recent studies show measurable benefits of behavior-based approaches that encourage interaction and understanding of communication. Psychologists and educators emphasize a behavior analysis and then match behavioral guidance strategies with the person's specific behavior problems at home or at school. See also the American Academy of Pediatrics' 2020 clinical report Identification, Evaluation, and Management of Children with Autism Spectrum Disorder.

Applied Behavioral Analysis (ACA) is a therapeutic approach in which children gradually learn specific cognitive, social, or behavioral skills. Small improvements are reinforced and progressively encouraged to improve, change or develop specific behaviors in children with ASD. These behaviors include social skills, language and communication skills, reading and academic skills, as well as learned skills such as self-care skills (eg, showering, grooming), daily living skills, punctuality, and professional competence. This therapy is also used to help children minimize behaviors (eg, aggression) that may interfere with their progress. Adapts applied behavior analysis therapy to meet the needs of each child; in general, therapy is designed and supervised by professionals certified in behavioral analysis. In the US, ACA may be available as part of an Individualized Educational Plan (IEP) through schools, and in some states it is covered by health insurance. The Developmental, Individual-differences, Relationship-based (DIR®) model, also called Floortime, is another behavior-intensive approach. DIR® is based on a child's preferred interests and activities to help build social interaction and other skills. Currently, there is less evidence supporting DIR/Floortime than ACA, but both therapies can be effective.

Speech and language therapy should start early and use a variety of methods, including signs, exchanging pictures, and enhanced communication devices such as those that generate speech based on signs the child selects on a tablet or handheld device, as well as speech . Physical therapists and occupational therapists plan and implement strategies to help children compensate for specific deficits in motor function and sensory processing. Drug treatment can help relieve symptoms. There is evidence that atypical antipsychotic drugs (eg, risperidone, aripiprazole) help alleviate behavioral problems such as ritualistic, self-injurious, and aggressive behavior. Other drugs are sometimes used to control specific symptoms, including selective serotonin reuptake inhibitors (SSRIs) for ritualistic behaviors, mood stabilizers (eg, valproate) for disruptive and self-injurious behaviors, and stimulants and other drugs for mood disorder. attention-deficit/hyperactivity disorder (ADHD) to inattention, impulsivity, and hyperactivity. Dietary interventions, including some vitamin supplements and a gluten-free, casein-free diet, are not helpful enough to be recommended; but many families choose to use them, leading to the need to monitor dietary insufficiencies and excesses. Other supplemental and investigative approaches (eg, communicability facilitation, chelation therapy, auditory integration training, hyperbaric oxygen therapy) have not been shown to be effective.

Key points

• Children have some combination characterized by poor interaction and social communication, stereotyped and repetitive patterns of behavior, and uneven intellectual development, often with mental retardation.

• The cause is generally unknown, but there appears to be a genetic component; vaccines are not causative.

• Screening tests include the Modified Checklist for Autism in Toddlers, Revised, with Follow-up (M-CHAT-R/F) and, for older children, the Social Communication Questionnaire.

• Formal diagnostic tests are usually done by psychologists or pediatricians who specialize in development and behavior.

• Treatment is generally multidisciplinary and uses behavior-based approaches that encourage interaction and communication.

• Drugs (eg, atypical antipsychotics) may help with severe behavioral disorders (eg, self-injury, aggression).

Additional Information The following English resources may be helpful. Please note that The Manual is not responsible for the content of these resources. Modified Checklist for Autism in Toddlers, Revised, with Follow-Up (M-CHAT-R/F) American Academy of Pediatrics: Identification, Evaluation, and Management of Children With Autism Spectrum Disorder (2020)

Learning Disabilities Association of America (LDA): an organization that provides educational, supportive, and advocacy resources for people with learning disabilities These organizations provide community and educational support and resources for people with autism and their caregivers: Autism Research Institute Autism Society Autism Speaks National Autism Association

https://www.msdmanuals.com/pt-br/professional/pediatrics/dist%C3%BArbios-de-aprendizagem-e-desenvolvimento/distornos-do-spectro-autista