How is Autism Diagnosed?

The following information is being used with permission from the Autism Speaks web site.

Presently, we don’t have a medical test that can diagnose autism. Instead, specially trained physicians and psychologists administer autism-specific behavioral evaluations.

Often parents are the first to notice that their child is showing unusual behaviors such as failing to make eye contact, not responding to his or her name or playing with toys in unusual, repetitive ways.  For a description of early indicators of autism, see Learn the Signs.

The Modified Checklist of Autism in Toddlers (M-CHAT) is a list of informative questions about your child. The answers can indicate whether he or she should be further evaluated by a specialist such as a developmental pediatrician, neurologist, psychiatrist or psychologist.

We encourage parents to trust their instincts and find a doctor who will listen and refer their child to appropriate specialists for diagnosis. Unfortunately, doctors unfamiliar with diagnosing autism sometimes dismiss parent concerns, delaying diagnosis and the opportunity for early intervention therapies. Autism Speaks and other autism organizations are working hard to raise awareness of early signs among physicians as well as parents.

From birth to at least 36 months of age, every child should be screened for developmental milestones during routine well visits. When such a screening—or a parent—raises concerns about a child’s development, the doctor should refer the child to a specialist in developmental evaluation and early intervention. These evaluations should include hearing and lead exposure tests as well as an autism-specific screening tool such as the M-CHAT. Among these screening tools are several geared to older children and/or specific autism spectrum disorders.

A typical diagnostic evaluation involves a multi-disciplinary team of doctors including a pediatrician, psychologist, speech and language pathologist and occupational therapist. Genetic testing may likewise be recommended, as well as screening for related medical issues such as sleep difficulties. This type of comprehensive helps parents understand as much as possible about their child’s strengths and needs.

Sometimes an autism spectrum disorder is diagnosed later in life, often in relation to learning, social or emotional difficulties. As with young children, diagnosis of adolescents and adults involves personal observation and interview by a trained specialist. Often, a diagnosis brings relief to those who have long struggled with difficulties in relating socially while not understanding the source of their difficulties. A diagnosis can also open access to therapies and assistive technologies that can improve function in areas of difficulty and, so, improve overall quality of life.

DSM-IV (DSM-4) criteria for a diagnosis of autism

Physicians use the Diagnostic and Statistical Manual (DSM) for Mental Disorders to determine whether a person has an autism spectrum disorder. The latest version of this manual is the DSM-IV. Its criteria for autism include the following:

I. A total of six (or more) items from heading (A), (B) and (C) with at least two from (A) and one each from (B) and (C):

(A) Qualitative impairment in social interaction as manifested by at least two of the following:

• Marked impairments in the use of multiple nonverbal behaviors such as eye-to-eye gaze, facial expression, body posture and gestures to regulate social interaction.
• Failure to develop peer relationships appropriate to developmental level.
• A lack of spontaneous seeking to share enjoyment, interests or achievements with other people, (e.g. a lack of showing, bringing or pointing out objects of interest to other people).
• A lack of social or emotional reciprocity.

(B) Qualitative impairments in communication as manifested by at least one of the following:

• Delay in or total lack of the development of spoken language (not accompanied by an attempt to compensate through alternative modes of communication such as gesture or mime).
• In individuals with adequate speech, marked impairment in the ability to initiate or sustain a conversation with others.
• Stereotyped and repetitive use of language or idiosyncratic language.
• Lack of varied, spontaneous make-believe play or social imitative play appropriate to developmental level.

(C) Restricted repetitive and stereotyped patterns of behavior, interests and activities as manifested by at least two of the following:

• Encompassing preoccupation with one or more stereotyped and restricted patterns of interest that is abnormal either in intensity or focus.
• Apparently inflexible adherence to specific nonfunctional routines or rituals.
• Stereotyped and repetitive motor mannerisms (e.g. hand or finger flapping or twisting, or complex whole-body movements).
• Persistent preoccupation with parts of objects.

II. Delays or abnormal functioning in at least one of the following areas, with onset prior to age 3 years:

(A) Social interaction
(B) Language used in social communication
(C) Symbolic or imaginative play