Autism Spectrum Disorders - Ongoing Assessment

Page Contents

• Overview
• Screening
• Diagnostic Criteria
• Pearls And Alerts
• History And Examination
• Clinical Classification
• Medical Conditions Causing Diagnosis
• Comorbid Conditions
• Resources

Overview

Ongoing assessment of the child with an autism spectrum disorder (ASD) should include monitoring for medical and behavioral/psychiatric comorbidities. Assessment of adaptive and educational progress should be performed and attention paid to family stress and function. Referral to appropriate services and resources should be provided as needed.

Screening

The American Academy of Pediatrics has recommended that all children be screened for autism spectrum disorders with an autism-specific tool at the 18 month and the 24 or 30 month well-child assessments. While recent evidence suggests that earlier identification and diagnosis is possible, autism-specific screening tools have not been validated for children younger than 18 months. While none of the readily available screening measures combine high sensitivity, specificity, and positive predictive value, some can be useful. Screening tools are not diagnositic tests – concerning results on a screening test must be confirmed with a formal evaluation.

The M-CHAT: The Modified Checklist for Autism in Toddlers was created to screen for autism from 16-30 months of age. Because the M-CHAT is not highly specific, it is recommended that children who screen positive be screened again one month later. The positive predictive value of a "fail" score on the M-CHAT is only 6%. The M-CHAT Follow-up Interview and Algorithm may be used to improve the positive predictive value (and therefore its specificity) to 57%.

• M-CHAT (Modified Checklist for Autism in Toddlers) ( 117 KB)
• M-CHAT Scoring Instructions ( 74 KB)
• M-CHAT Scoring Overlay ( 52 KB)
• M-CHAT Follow-up Interview and Algorithm ( 310 KB)

The Infant/Toddler Checklist from the Communication and Symbolic Behavior Scales Developmental Profile ( 56 KB) focuses on social and communication skills and may be useful in screening children from 6-24 months of age.

Consider using the SCQ: Social Communication Questionnaire for individuals over 4 years of age. This tool may be used for individuals with or without ID/MR.

• The SCQ was originally designed for epidemiologic research.
• It takes about 10 minutes to complete and can be used in the primary care setting or mailed to and completed by parents at home. The SCQ is a cost-effective screening tool to determine whether an individual should be referred for a comprehensive evaluation.
• The SCQ is available from Western Psychological Services at a cost of approximately $1.50 each when ordered in packs of 20. Western Psychological Services/Social Communication Questionnaire

Diagnostic Criteria

• DSM-IV Diagnostic Criteria for Autism ( 970 KB)
• DSM-IV Diagnostic Criteria for Asperger Syndrome ( 968 KB)
• The diagnosis of PDD-NOS should be used when there is a severe and pervasive impairment in the development of reciprocal social interaction associated with impairment in either verbal or nonverbal communication skills or with the presence of stereotyped behavior, interests, and activities, but the criteria are not met for a specific Pervasive Developmental Disorder (e.g., autism or Asperger syndrome), Schizophrenia, Schizotypal Personality Disorder, or Avoidant Personality Disorder.

For more information see Autism Spectrum Disorders, Initial Diagnosis.

Pearls And Alerts

A score of "fail" on the M-CHAT or other screening tool is not diagnostic for an autism spectrum disorder. A child who receives a concerning score during screening should be referred for a formal developmental evaluation.

History And Examination

Clinical Classification

Most children on the autism spectrum will fall into one one of the categories below:

Autistic disorder: Involves significant impairment in all three domains with onset before 3 years of age. Alternative names are autism, infantile autism, primary autism. A subtype is "high-functioning autism," in which cognitive functioning is in the normal to superior range. Cognitive functioning in children with autism can range from profound mental retardation to superior intelligence and verbal ability can range from absent to articulate speech.

Asperger syndrome: Involves significant impairment in social interaction and range of interests and activities, similar to a child with autism. Children with Asperger syndrome, however, do not experience delayed onset of language. Their communication may be impaired by an inability to read social cues, making socially inappropriate comments, or having a narrow focus of interest. Cognitive function is within the normal range.

Pervasive developmental disorder, NOS: This diagnosis is applied to the child with some characteristics of an ASD, but who does not meet full criteria for Autistic Disorder or Asperger Syndrome. They may meet criteria for autism in the social or communication domain and may show some impairment in the other domains. It could also apply to a child with global developmental delay who demonstrates impairment in some, but not all, of the three developmental domains involved in ASD.

The term high-functioning autism is sometimes used to describe a child with autistic disorder that has average or above-average cognitive functioning.

Medical Conditions Causing Diagnosis

Genetic syndromes that may be associated with ASDs:

• Fragile X syndrome is associated with features of ASDs in 30-50% of individuals with the fragile X mutation. In contrast, 3-4% of individuals with autism and normal cognitive functioning will have that mutation. In those on the autism spectrum with comorbid intellectual disability/mental retardation, the incidence of the fragile X mutation rises to 8%. Features suggestive of fragile X include ID/MR, macrocephaly, protuberant ears, hyperextensible joints, hypotonia, and post-pubertal macroorchidism.
• Tuberous sclerosis is a neurocutaneous disorder characterized by ash-leaf spots (hypopigmented macules), fibroangiomata, mental retardation, renal and CNS hamartoma, and seizures. Greater than 50% of individuals with tuberous sclerosis will show features suggestive of an ASD, particularly if cortical tubers are present in the temporal lobe of the brain. Examination with a Wood's lamp may be necessary to detect cutaneous markers.
• Neurofibromatosis is characterized by cafe-au-lait macules, axillary and inguinal freckling, ocular Lisch nodules, and neurofibromas. Unlike tuberous sclerosis, a minority of individuals with Neurofibromatosis display features of autism.
• Phenylketonuria historically was associated with a significant number of cases of ASDs and MR/ID. With newborn screening and dietary intervention, this is a currently a rare disorder.
• Angelman's syndrome is associated with global developmental delay in early childhood with initial hypotonia, progressive spasticity, and seizures. These children are often non-verbal and may display social and behavioral characteristics suggestive of an ASD.
• Fetal alcohol syndrome. In-utero exposure to alcohol is associated with ASDs, as well as other neurodevelopmental complications.
• Rett syndrome is characterized by microcephaly, seizures, autistic-like regression, and stereotypic hand movement. It is much more common in females. When males are affected, their presentation may be more variable.
• Down syndrome. It is estimated that 6-7% of children with Down syndrome meet criteria for an ASD.

For more detail, see the Differential Diagnosis section on the Initial Diagnosis page.

Comorbid Conditions

• Epilepsy. The prevalence of seizure disorders in individuals on the autism spectrum is estimated to be 5-39%. The risk for developing seizures is higher in individuals with severe intellectual disability/mental retardation. In those with normal or borderline cognition, no associated medical disorder, and no family history of epilepsy, only 6-8% will develop seizures.
• Sleep disturbances are very common in individuals on the autism spectrum, regardless of level of cognitive ability. Medical causes of sleep disturbance, such as obstructive sleep apnea, periodic limb movement disorder, and gastroesophageal reflux should be sought. In the absence of an etiologic medical factor, management should focus on sleep hygiene, management of behaviors such as bedtime opposition, and limitation of daytime sleep. Sleep disorders in children with autism provides additional guidelines for the basic management of disordered sleep. If sleep difficulties persist or the etiology remains unclear, consider referral to a pediatric sleep specialist – see all Pediatric Sleep Medicine services providers (3) in our database.
• Gastrointestinal disorders. While the relationship between ASDs and gastrointestinal disorders is unclear, it has been shown that children on the autism spectrum suffer from gastrointestinal symptoms such as constipation, diarrhea, vomiting, and abdominal pain more often than do other children. While routine testing of children with ASDs for gastrointestinal disorders is not recommended, appropriate evaluation and management of symptoms should be performed. Abdominal pain or discomfort should be considered in any non-verbal child who presents with an acute onset of worsening behavior. Constipation is common and treatment is important for successful toileting skills, as well as for general comfort.

Resources

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