Autism spectrum disorders (referred to as pervasive developmental disorders in the Diagnostic and Statistical Manual) are comprised of a number of distinct disorders including: autistic disorder, asperger’s, PDD-NOS, Rett’s Disorder and Childhood Disintegrative Disorder. Each of these disorders has a distinct set of characteristics by which a diagnosis is made. In order to provide a diagnosis within the autism spectrum the diagnostician must use differential diagnosis and determine which of the autism spectrum disorders a person has as well as ruling out any other possible diagnosis outside of the autism spectrum.
Autistic Disorder as a Diagnosis
In order for someone to receive an autism diagnosis the individual must exhibit a total of 6 or more characteristics. They must present with a minimum of two characteristics from the area of socialization and one from each of the areas of communication and behavior.
Characteristics in the area of socialization include: impairment in the use of non-verbal behaviors (e.g., facial expressions, gestures), failure to develop peer relationships, lack of spontaneous seeking to share enjoyment and lack of social or emotional reciprocity.
Characteristics in the area of communication include: a delay or lack of spoken language, impairment in the ability to initiate or sustain conversation, repetitive language and lack of spontaneous pretend play.
Characteristics in the area of behavior include: a preoccupation with one or more stereotyped and restricted patterns of interest that is abnormal either in intensity or focus, inflexible adherence to nonfunctional routines, stereotyped and repetitive motor mannerisms (e.g., hand or finger flapping or twisting) and persistent preoccupation with parts of objects
In addition, the onset must occur prior to age 3. Differential diagnosis is used to assure that the disorder is not better accounted for by Rett's disorder or childhood disintegrative disorder.
Asperger’s Disorder as a Diagnosis
An Asperger’s diagnosis is based on the same characteristics as an autistic disorder diagnosis in relation to socialization and behavior.
There are a number of additional factors that must be considered when making a diagnosis of Asperger’s Disorder. The disorder must cause clinically significant impairment in social, occupational, or other important areas of functioning, There is no clinically significant general delay in language, cognitive development or self-help skills. Lastly, criteria are not met for another specific pervasive developmental disorder or schizophrenia.
PDD-NOS as a Diagnosis
PDD-NOS is provided as a diagnosis when there is impairment in the development of social interaction or communication skills, or when stereotyped behavior, interests, and activities are present and the criteria are not met for a specific pervasive developmental disorder. PDD-NOS encompasses cases of "atypical autism," specifically those clinical presentations that do not meet the criteria for autistic disorder because of late age of onset, atypical symptomatology, or subthreshold symptomatology, or all of these. In addition differential diagnosis is conducted to account for schizophrenia, schizotypal personality disorder, or avoidant personality disorder.
Rett’s Disorder as a Diagnosis
A diagnosis of Rett’s Disorder can only be made if there is normal development in a number of areas including: prenatal and perinatal development, psychomotor development through the first 5 months after birth, head circumference at birth.
After the period of normal development the individual then exhibits deceleration of head growth between ages 5 and 48 months, loss of previously acquired purposeful hand skills between ages 5 and 30 months with the subsequent development of stereotyped hand movements (i.e., hand-wringing), loss of social engagement early in the course (although often social interaction develops later), appearance of poorly coordinated gait or trunk movements, severely impaired expressive and receptive language development with severe psychomotor retardation
Childhood Disintegrative Disorder
A diagnosis of Childhood Disintegrative Disorder can only be made if the individual exhibited normal development for at least the first 2 years after birth as manifested by the presence of age-appropriate verbal and nonverbal communication, social relationships, play, and adaptive behavior. The individual must exhibit a clinically significant loss of previously acquired skills (before age 10 years) in at least two of the following areas: expressive or receptive language, social skills or adaptive behavior, bowel or bladder control, play and motor skills.
Additionally they must present with abnormalities of functioning in at least two of the following areas: impairment in social interaction, impairments in communication and restricted, repetitive, or stereotyped patterns of behavior, interests, and activities, including motor stereotypies and mannerisms. The disorder cannot be better accounted for by another specific pervasive developmental disorder or by schizophrenia.
The Importance of an Accurate Diagnosis
Autism spectrum disorders are comprised of a variety of different disorders each with their own unique set of characteristics. It is important for children to receive a diagnosis that is accurate and timely. When an individual receives a diagnosis they can they qualify for necessary services.
References
American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders (4th ed.). Washington, D.C., 1994.
Mary McDonald - Dr. McDonald is an Assistant Professor in the CRSR Department (Counseling, Research, Special Education and Rehabilitation) and teaches in ...
Join the Conversation