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What's in a Name?  The Disorderly World of PDD Labels

By Richard Irwin and B.C.  (Members of CTFEAT)

“Autistic Disorder.” “PDD.” “Asperger’s Syndrome.” “Infantile Autism.” These are just a few of the many labels commonly seen and sometimes misused in the world of autism and its related developmental disorders. Some of these labels are actual diagnostic labels, while others are “unofficial” or “popular” terms with less precise definitions.
As a parent, this myriad of labels can cause a great deal of confusion. Do labels such as “autism,” “infantile autism” and “autistic disorder” refer to the same disorder? Are there nuances that differentiate one disorder from another? How does a label of Pervasive Developmental Disorder Not Otherwise Specified (PDD-NOS) relate to autism? Should the treatment and education of a child with a diagnosis of PDD-NOS be any different from that of a child diagnosed with autistic disorder?

The common practice of ranking children as "mildly," "moderately" or "severely" autistic is also confusing. Does the severity have implications for treatments and outcomes? These are the type of questions that need to be answered in your quest for information and help for your child.
Diagnostic Categories. Though it can make for somewhat intimidating reading, the essential place to start untangling this web of labels and terms is in the fourth edition of the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders (DSM-IV; 1994). Qualified diagnosticians use the DSM-IV guidelines when diagnosing children. The DSM-IV describes a class of disorders, called "Pervasive Developmental Disorders" (PDD), under which there are five diagnostic categories:

Autistic Disorder
Asperger’s Disorder
Pervasive Developmental Disorder - Not Otherwise Specified (PDD-NOS)
Childhood Disintegrative Disorder
Rett’s Syndrome

Note that there is no such thing as a singular diagnosis of "PDD." This has been a source of great confusion, as the label PDD is regularly discussed and applied to children. But, in fact, PDD is simply the umbrella under which the five disorders listed above fall.
A Better Way of Thinking. It is helpful to understand the relationship of the five disorders to one another. In a 1997 report sponsored by the California Departments of Education and Developmental Services, which looked at best practices in the field of autism, the authors used the term “autistic spectrum disorders” (also referred to as "autism spectrum disorders or "ASD") to refer to the five disorders classified in DSM-IV:

“The term ”spectrum,” used in the context of ASD, suggests a range of related qualities or activities.... Autistic spectrum disorders implies a class of related developmental disorders that overlap but are clinically distinct and separately diagnosed. These disorders overlap in the sense that a portion of their clinical features are shared.... The assumption is that with careful assessment the PDDs can be differentially diagnosed.” (from Best Practices for Designing and Delivering Effective Programs for Individuals with Autistic Spectrum Disorders, page 17)

The term ASD makes it clear that the five Pervasive Developmental Disorders share important similarities, despite some differences in the areas affected (e.g., language, cognitive, etc.) or the relative degree of impairment (e.g. mild to severe). For instance, one important “common denominator” among the PDDs is the presence of a significant disturbance in the child’s ability to relate to others. This disturbance, which may be present in varying levels of severity, has important implications for the child’s ability to learn from the environment.

DIAGNOSTIC CRITERIA. The following are the diagnostic criteria for Autistic Disorder, Asperger’s Disorder and Pervasive Developmental Disorder, Not Otherwise Specified (PDD-NOS), as taken from the DSM-IV. Both Rett’s Syndrome and Childhood Disintegrative Disorder are very rare and will not be discussed here. The diagnostic criteria provide a roadmap to understanding the similarities and differences among these three ASDs.  

Autistic Disorder. Autistic Disorder has been referred to simply as “autism,” “classical autism,” “infantile autism” and “Kanner’s autism.” All are one in the same. There are no formal diagnostic categories for the popular terms “mild,” “moderate,” and “severe” autism. Rather, these terms probably have their origins in a widely used diagnostic assessment tool called the Childhood Autism Rating Scale (CARS) that does divide children into the two categories “mild-to-moderate” and “severe.” Many children who are initially categorized as being “severely” affected by autism, become only “mildly” so after appropriate treatment.

There is also no diagnostic category, and no commonly accepted definition, for the label “high functioning” autism. It is sometimes associated with those children who rank in the “mild-to-moderate” range on the CARS test, or who have autism unaccompanied by mental retardation. This vague "high functioning" label draws its meaning, presumably, by being contrasted with the label “low functioning." Like "high functioning autism," "low functioning autismi" has no concrete definition. The term is offensive to many parents since it can be very damaging to the children labeled with it. That's because "low functioning" too often connotes “low expectations," which can become a self-fulfilling prophecy when children are denied effective treatment based on “low expectations." Unfortunately, even the Autism Society of America contributes to this confusion regarding “high vs. low functioning" by using these terms in their information materials.  

The following are the diagnostic criteria for Autistic Disorder:
A.  A total of six (or more) items from sections 1, 2, and 3, with at least two from section 1, and one each from sections 2 and 3:
1) Qualitative impairment in social interaction, as manifested by at least two of the following:

a) Marked impairment in the use of multiple, nonverbal behaviors, such as eye-to-eye gaze, facial expression, body postures, and gestures to regulate social interaction;

b) Failure to develop peer relationships appropriate to developmental level;

c) A lack of spontaneous seeking to share enjoyment, interests, or achievements with other people (e.g., by a lack of showing, bringing, or pointing out objects of interest);

d) Lack of social or emotional reciprocity.

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

a) Delay in, or total lack of, development of spoken language (not accompanied by an attempt to compensate through alternative modes of communication, such as gesture or mime);

b) In individuals with adequate speech, marked impairment in the ability to initiate or sustain a conversation with others;

c) Stereotyped and repetitive use of language or idiosyncratic language;

d) Lack of varied, spontaneous make-believe play or social imitative play appropriate to developmental level.

3) Restricted repetitive and stereotyped patterns of behavior, interests, and activities, as manifested by at least one of the following:

a) Encompassing preoccupation with one or more stereotyped and restricted patterns of interest that is abnormal either in intensity or focus;

b) Apparently inflexible adherence to specific, nonfunctional routines or rituals;

c) Stereotyped and repetitive motor mannerisms (e.g., hand or finger flapping, twisting, or complex whole-body movements);

d) Persistent preoccupation with parts of objects.

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

1) Social interaction;
2) Language as used in social communication;
3) Symbolic or imaginative play

C. The disturbance is not better accounted for by Rett’s Disorder or Childhood Disintegrative Disorder. If the criteria for Autistic Disorder are not met and the child has autistic features, the PDD-NOS diagnostic label can be used.

Asperger’s Disorder. Asperger’s Disorder is also often referred to as Asperger’s Syndrome. Children with Asperger’s Disorder are sometimes mislabeled as having “high functioning” autism, because their language and cognitive skills are generally better than children with Autistic Disorder. This exemplifies the problem with the very imprecise term “high functioning autism,” since it is often used to describe individuals from two entirely separate diagnostic categories.  

According to the Handbook of Autism and Pervasive Developmental Disorders (Edited by Donald J. Cohen and Fred R. Volkmar, 1997, p. 113), Asperger's Disorder differs from Autistic Disorder and PDD-NOS in that "the onset is usually later and the outcome is more positive. In addition, social and communication deficits are less severe, motor mannerisms are usually absent, and circumscribed interest is more conspicuous. Motor 'clumsiness' is more frequently seen…and family history of similar problems is more frequently ascertained…" The following are the diagnostic criteria for Asperger’s Disorder:  

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

1) marked impairment in the use of multiple nonverbal behaviors such as eye-to-eye gaze, facial expression, body postures, and gestures to regulate social interaction;

2) failure to develop peer relationships appropriate to developmental level;

3) lack of spontaneous seeking to share enjoyment, interests, or achievements with other people (e.g., by a lack of showing, bringing, or pointing out objects of interest to other people);

4) a lack of social or emotional reciprocity.

B. Restricted repetitive and stereotyped patterns of behavior, interests, and activities, as manifested by at least one of the following:
1) encompassing preoccupation with one or more stereotyped and restricted patterns of interest that is abnormal either in intensity or focus;

2) apparently inflexible adherence to specific, non-functional routines or rituals;

3) stereotyped and repetitive motor mannerisms (e.g., hand or finger flapping or twisting, or complex whole-body movements);

4) persistent preoccupation with parts of objects
C. The disturbance causes clinically significant impairment in social, occupational, or other important areas of functioning.

D. There is no clinically significant general delay in language (e.g., single words used by age 2 years, communicative phrases used by age 3 years)

E. There is no clinically significant delay in cognitive development or in the development of age-appropriate self-help skills, adaptive behavior (other than in social interaction), and curiosity about the environment in childhood.

F. Criteria are not met for another specific Pervasive Developmental Disorder or Schizophrenia.  
Pervasive Developmental Disorder, Not Otherwise Specified (PDD-NOS). PDD-NOS is often incorrectly referred to as simply “PDD” and sometimes as “atypical” autism. In some respects, PDD-NOS is a "default" diagnosis, to be applied where a child fails to meet full diagnostic criteria for one of the other pervasive developmental disorders. According to the Handbook of Autism and Pervasive Developmental Disorders (cited above,. page 128) it can be difficult to reliably distinguish PDD-NOS from autistic disorder or Asperger's Disorder . "Current criteria offer little direction or guidance for separating PDD-NOS from Asperger's syndrome…determining whether an individual has autism or PDD-NOS can be most perplexing…The absence of measurable standards and of specific cut points that define the levels of impairment within domains is particularly problematic."
The following are the diagnostic criteria for PDD-NOS:

This category should be used when there is a severe and pervasive impairment in the development of reciprocal social interaction or verbal and nonverbal communication skills, or when stereotyped behavior, interests, and activities are present. The criteria are not met for a specific Pervasive Developmental Disorder, Schizophrenia, Schizotypal Personality Disorder, or Avoidant Personality Disorder. For example, this category includes “atypical autism” – presentations that do not meet the criteria for Autistic Disorder because of late age at onset, atypical symptomatology, subthreshold symptomatology, or all of these.  
Treatment for Children with an ASD. There is only one treatment program scientifically proven to be effective for children with the Autistic Spectrum Disorders described here: an intensive intervention program based on the principles of Applied Behavior Analysis (ABA). As Doctors Sandra Harris and Mary Jane Weiss state in their 1998 book Right From the Start: Behavioral Intervention for Young Children With Autism, “Precise diagnosis of very young children is sometimes difficult, and for the purpose of this book it does not matter if your child is labeled as having autistic disorder, Asperger’s disorder, childhood disintegrative disorder or atypical autism (PDD-NOS). Although the long-term prognosis for children in these four groups may be somewhat different, their early treatment is similar.”

COMMON MISCONCEPTIONS. Widespread acceptance of intensive ABA programs as the treatment of choice for children with ASDs has been slow to happen for a variety of reasons. Among these are: confusion over the various labels and their implications for treatment; misconceptions about what intensive ABA treatment programs entail; long-standing allegiances to less effective treatments; and the comparatively greater expense involved in providing intensive ABA treatment. The following are a series of frequently held misconceptions surrounding the various labels in the world of autism and their implications for treatment.  

"My child has PDD, not autism, so an ABA program isn’t appropriate." The same argument is commonly made if a child has been labeled as “mildly” autistic or “high functioning.” Interestingly, one encounters this view almost as frequently as its opposite “ ABA programs are only for the most severely impaired.” A more balanced interpretation of the research indicates that intensive ABA programs help most children with autism spectrum disorders make the most progress towards reaching their potential - regardless of how “high” or “low” functioning they may be, or where they may fall on the autism spectrum.  

The landmark study on the effectiveness of intensive behavioral intervention was performed by Dr. O. Ivar Lovaas of UCLA (Lovaas, O.I. (1987) "Behavioral treatment and normal educational and intellectual functioning in young autistic children," Journal of Consulting and Clinical Psychology, 55, 3-9). It is true that the study was performed on children with autistic disorders, but subsequent data has been gathered on children with PDD-NOS and Asperger’s Disorder. A recent book on preschool programs for children with autism (Preschool Programs for Children with Autism,” Sandra L. Harris and Jan S. Handleman eds., Pro-Ed, 1994), listed intake and outcome data for several preschool programs based on intensive behavioral intervention. It showed that these preschool ABA programs successfully treated children with Autistic Disorder, PDD-NOS and Asperger’s Disorder.  

The New York State Department of Health Early Intervention Program recently released a report recommending intensive behavioral intervention as the most effective treatment for children with "autism," which was defined broadly to include "the entire range of pervasive developmental disorders as seen in young children." ( Clinical Practice Guideline: Autism/Pervasive Developmental Disorders, p. I-5, 1999).  

"My child is too advanced for discrete trial training." This is a really close relative of the “high-functioning” argument. Unfortunately, many uninformed people think of an ABA program as consisting only of discrete trial training and that ABA is not effective for teaching advanced skills such as social skills and the pragmatics of language. In fact, ABA is really more of a systematic approach to teaching, rather than one specific method. Discrete trial teaching is used very early on as an effective method of teaching certain fundamental skills. However, it is only one part of an ABA program. Quality ABA programs seek to teach all the skills a typical child acquires naturally, including the most sophisticated social, play and language skills.

It is helpful to remember that in the research study performed by Lovaas and his colleagues ("Long-term outcome for children with autism who received early intensive behavioral treatment," American Journal on Mental Retardation, 1993, Vol.97, No. 4, 359-372) a large number of the children (nine out of nineteen) achieved what was termed “normal functioning” status. This meant they were indistinguishable from their typical peers in every way. These children learned all the skills they needed to achieve this status in their intensive ABA programs.  

"Autism is a spectrum disorder and every child is different." This correct observation is usually invoked to support an “eclectic” treatment program. An eclectic program usually consists of a mix of interventions, such as speech/language training, school inclusion, sensory integration, special education, special diets, etc. Advocates of this "eclecticism" often imply that a program based on ABA is a rigid, one-size-fits-all approach.  

It is true that within the broad autism spectrum, every child is different. It is also true that ABA programs are extremely individualized. A great deal of data is taken on each child’s strengths and weaknesses, and likes and dislikes, so that the program can be specifically tailored to the child's learning style. It is not unusual to observe two children learning the same basic skill in very different ways. There also is a great emphasis put on parental participation and parents typically play a major role in every aspect of the intervention program.

In conclusion, the labels that are attached to our children are often a source of confusion and consternation. But there is hope. Other parents have waded through this experience and are willing to help. The families of CT FEAT are an excellent source of information. If you would like to learn from their experiences, please feel free to contact CT FEAT by phone at 860-571-3888 or by E-mail at info@ctfeat.org.
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