Autism Spectrum Disorders - Initial Diagnosis

Page Contents

• Overview
• Presentations
• Diagnostic Criteria
• Pearls And Alerts
• Practice Guidelines
• Differential Diagnosis
• History And Examination
• Resources

Overview

Each child undergoing evaluation for autism or other developmental delay requires an individualized assessment. The manifestations of the core features of autism vary between individuals and within the same individual at different developmental stages. Variation in associated cognitive, neurological, and psychiatric features is extensive.

The goals of assessment are to:

• Recognize children who have developmental signs that could result from autism
• Determine if the child meets criteria for autism or another ASD, while considering other diagnoses
• Rule out possible causal medical or genetic factors
• Describe the child's unique pattern of cognitive strengths and weaknesses
• Identify any associated impairing neurological or psychiatric problems
• Understand how all of the child's difficulties come together to impair the adaptive functioning of the child and impact his or her family

Presentations

Speech and language delay. Children on the autism spectrum often come to medical attention with parental concern of language delay between 15 and 18 months of age. About 25% of children with ASDs begin saying a few words but then undergo a regression in language skills between the ages of 15-24 months. In addition to delayed speech, children on the autism spectrum typically display a lack of desire to communicate and a lack of compensatory non-verbal gestures. Some children, particularly those with normal cognitive functioning, may gesture toward a desired object but do not look to the caregiver's face while gesturing to communicate their need or desire. Some children on the autism spectrum will develop speech at an early age but it may be nonfluent, rote, or characterized by echolalia.

Social skills deficits. While social skills deficits are more specific than language deficits for an ASD, they often go unrecognized by parents and clinicians during the first two years of life. In the very young child, deficits in social skills are manifested by a lack of normal joint attention, during which an infant or young child participates with a caregiver in a back-and-forth manner as a means of sharing an enjoyable experience. Typically-developing children begin to point at objects by 14-16 months of age to comment or indicate an interest. Children with ASDs may gesture to indicate a need or desire but consistently fail to point to "comment" on objects or events. Social referencing refers to a child's seeking out and recognizing the emotional state of others as they respond to new events or stimuli in their environment. A typically developing child will look to his caregiver when faced with a novel situation to detect their emotional state, something children on the autism spectrum generally do not do. Lacking these social skills, children with ASDs usually have great difficulty engaging in age-appropriate social behavior and are less likely to develop appropriate relationships with their peers.

Repetitive/stereotypic patterns of behavior, restricted interests. Stereotypies are repetitive, atypical, nonfunctional behaviors, such as hand flapping, unusual eye gaze, repetitive toe-walking, and pacing. These behaviors show much variation between individuals and can change over time within the same person. Stereotypies themselves are usually harmless, although they may impair the ability to acquire new skills and function in social settings. Some repetitive behaviors such as hand flapping and jumping may be seen in normal toddlers as an expression of excitement or anxiety. Other unusual behaviors, particularly those involving visual stimulation (e.g., fixation on visual patterns, looking at objects out of the corner of the eye, staring at objects up close) are more likely to represent a neurodevelopmental disorder such as ASD.

Some stereotypies are self-injurious (head banging, self-biting, picking at skin) and occur more commonly in those with global developmental delay or intellectual disability.

Atypical play skills. ASDs are characterized by lack of or delayed imaginative play skills. These children may engage in ritualistic or persistent sensorimotor play. For example, they may prefer to repetitively line up or spin the wheels of toy trains rather than driving them. They may learn to engage in some forms of pretend play, but this typically involves the rote learning of limited play scenarios that are repeated. Children on the autism spectrum may prefer sensorimotor play, such as rough-and-tumble play, or playing computer and puzzle-type games.

Diagnostic Criteria

• DSM-IV Diagnostic Criteria for Autism ( 970 KB)
• DSM-IV Diagnostic Criteria for Asperger Syndrome ( 968 KB)
• The diagnosis of PDD-NOS may 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 (such as autism or Asperger syndrome), Schizophrenia, Schizotypal Personality Disorder, or Avoidant Personality Disorder.

Pearls And Alerts

The American Academy of Neurology and Child Neurology Society suggest that the following "red flags" are absolute indications for an immediate evaluation for autism:

• No babbling or pointing or other gesture by 12 months
• No single words by 16 months
• No 2-word spontaneous (not echolalic) phrases by 24 months
• ANY loss of ANY language or social skills at ANY age
  [Filipek: 2000]

The following signs may indicate the presence of an autism spectrum disorder in a child less than 18 months of age:

• Lack of appropriate gaze
• Lack of warm, joyful expression with gaze
• Lack of alternating patterns of vocalizations between infant and caregiver that usually begins at approximately 6 months of age
• Lack of recognition of consistent caregiver's voice
• Disregard for vocalizations (such as lack of response to name), yet keen awareness of environmental sounds
• Onset of babbling delayed beyond 9 months of age
• Decreased use of pre-speech gestures (pointing, waving, showing)
• Lack of expressions such as "uh-oh" [Johnson: 2007]

For children with ASD who develop seizures (5-38%), there is a bimodal distribution in their onset – some with peak incidence in early childhood and others in adolescence. Consider new-onset of seizure activity as a cause of acute behavior changes in the adolescent, particularly in those with intellectual disability.

Practice Guidelines

Johnson CP, Myers SM.
Identification and evaluation of children with autism spectrum disorders.
Pediatrics. 2007;120(5):1183-215. PubMed abstract / Full Text

Differential Diagnosis

• Mental retardation/intellectual disability (MR/ID) without autism. Some children meet criteria for both MR/ID and autism or PDD-NOS. Most children with MR/ID, however, do not have autism.
• Specific language disorder. These children have a significant delay in language development and may have difficulty learning how to read. Impaired language development can also affect a child's social functioning. Children with isolated language delay do not have the triad of impairments characteristic of ASDs.
• Deafness. Though deaf children may have great difficulty learning to talk, they are usually normal in their use of non-verbal behaviors (gestures, mime, facial expression) to communicate.
• Selective mutism. Children with selective mutism speak and behave normally at home with their families but are functionally mute in other environments.
• Reactive attachment disorder. Children who have experienced social/emotional neglect and maltreatment may develop some of the clinical features of ASDs. When they are placed in a nurturing, stimulating environment and are well cared for, the "autistic" features spontaneously improve.
• Childhood disintegrative disorder. Children with this rare disorder develop normally until approximately 2 years of age or older, but then experience a major deterioration in functioning. The deterioration may involve language, social, and play as in autism, but the deterioration is more severe than in autism and also involves adaptive and motor skills.
• Rett syndrome. Rett syndrome occurs predominantly in girls and is characterized by normal development until about 5 months of age. At that time, affected children show a decline in the rate of head and brain growth and severe developmental regression. The regression involves motor functioning, language and social functioning, and adaptive skills. These children become unsteady when they walk or sit, lose purposeful hand movements, and develop stereotypic midline hand movements. Mental retardation/intellectual disability and seizures usually develop.
• Dementia. Children with isolated dementia have a significant decline in intellectual functioning, usually due to head trauma or some other serious medical disorder.
• Obsessive compulsive disorder. Many children and adults with ASDs meet criteria for obsessive compulsive disorder (OCD), particularly when they are older. Most children with OCD, however, do not meet criteria for an ASD.
• Stereotypy habit disorder. This disorder describes children affected by MR/ID who have impairing stereotypic motor mannerisms but do not meet other criteria for an ASD.
• Landau-Kleffner syndrome (LKS). This syndrome, also called acquired epileptic dysphasia, is characterized by normal language development followed by loss of language. The loss of language in Landau-Kleffner Syndrome typically occurs after 3 years of age and is associated with a relative sparing of social skills. This deterioration in language is associated with characteristic seizure activity in the temporal lobe of the brain. Children with isolated LKS do not meet criteria for an ASD.
• Schizophrenia. Schizophrenia, like autism, is a developmental disorder in which impairments in social and emotional functioning, changes in language functioning, and stereotypies and other unusual behaviors may occur. The onset of schizophrenia is later than autism and usually later than other ASDs. Onset of schizophrenia is rare during childhood and usually occurs during late adolescence or adulthood. The hallmark clinical signs are hallucinations and delusions. Schizophrenia occurs in about 1% of the general population and rarely in older individuals with ASD.
• Schizoid, schizotypal, and avoidant personality disorder. Individuals with these disorders, in isolation, may have some of the social and emotional features seen in some individuals with ASDs (social avoidance, social anxiety, lack of social interest). They do not typically meet diagnostic criteria for ASD.

History And Examination

Resources

Authors

Page Bibliography

Bouma R, Schweitzer R.
The impact of chronic childhood illness on family stress: a comparison between autism and cystic fibrosis.
J Clin Psychol. 1990;46(6):722-30. PubMed abstract

Filipek PA, Accardo PJ, Ashwal S, Baranek GT, Cook EH Jr, Dawson G, Gordon B, Gravel JS, Johnson CP, Kallen RJ, Levy SE, Minshew NJ, Ozonoff S, Prizant BM, Rapin I, Rogers SJ, Stone WL, Teplin SW, Tuchman RF, Volkmar FR.
Practice parameter: screening and diagnosis of autism: report of the Quality Standards Subcommittee of the American Academy of Neurology and the Child Neurology Society.
Neurology. 2000;55(4):468-79. PubMed abstract / Full Text

Johnson CP, Myers SM.
Identification and evaluation of children with autism spectrum disorders.
Pediatrics. 2007;120(5):1183-215. PubMed abstract / Full Text
Comprehensive clinical report addressing the definition, history, epidemiology, diagnostic criteria, early signs, neuropathologic aspects, and etiologic possibilities in autism spectrum disorders. This report also provides the primary care provider with an algorithm for assistance in the early identification of children with autism spectrum disorders.

Schieve LA, Blumberg SJ, Rice C, Visser SN, Boyle C.
The relationship between autism and parenting stress.
Pediatrics. 2007;119 Suppl 1:S114-21. PubMed abstract