What is PDD-NOS, anyways?

"What is a developmental delay? As mentioned, healthy development follows along a predictable path. When a child is obtaining developmental skills along the predicted path but more slowly than expected, they are said to be delayed. For the purpose of illustration, let's look at a car ride. Our destination is 60 miles away and we can go between 45 and 60mph. That means our estimated time of arrival is somewhere between 1 and 1.5 hours. This represents normal development. In the case of delayed development, the car does not change its course, but arrives two to three hours after the expected time. Let us apply this concept to child development. If a child moved its total body as an infant, but was slow to sit independently, and did not walk until close to 16 months of age, one could say that this child is progressing at a slower pace than his/her peers. This progress is not different. It is just delayed.

What is a developmental disorder? When we speak of a difference in the pattern or nature of the developmental process, we are speaking of a disorder. Categorizing into groups those behaviours or differences that set some children apart from their peers defines a developmental disorder. A well-known developmental disorder is Attention Deficit Hyperactive Disorder (ADHD). Children with this disorder have in common the inability to focus their attention appropriately and they have a high degree of physical activity. They have a common group of characteristics that are different from their peers, yet similar to each other. Therefore, ADHD is said to be a developmental disorder.

Children with developmental disorders are not merely slow in obtaining skills. Applying this case to the concept above, children with developmental disorders are not travelling at a slower pace, they are travelling a different route altogether. They may arrive at the same point eventually, but they will need some help and guidance along the way. They either have a different way of acquiring appropriate developmental skills than expected, or they have a lessened capacity for acquiring certain skills.

What is Pervasive Developmental Disorder? Pervasive Developmental Disorder (PDD) is the diagnostic terminology for a group of individuals who present with an underlying impairment in the communication process and connectedness to the world around them. This impairment in turn pervades over all areas of development. The inability to fully connect, or relate appropriately to one's surroundings greatly influences learning and the pathway development. As mentioned previously, a developmental disorder entails a compilation of characteristics that set the group apart from their peers but in common with each other. In the case of PDD, the characteristics include impairments in the areas of language and communication, socialization, and use of imaginative play. The disorder is viewed as a spectrum disorder because there is a great deal of variability in the presentation of the disorder along a spectrum of severity. Therefore, the diagnostic terminology of Pervasive Developmental Disorder (PDD) is an umbrella term that encompasses a continuum of impairments in communication, socialization, and play repertoire." -Pervasive Developmental Disorder: An Altered Perspective, Barbara Quinn

PDD is a category of developmental disorders whose effects are pervasive. Within this category, there are five sub-categories: Autistic Disorder, Asperger's Disorder, Childhood Disintegrative Disorder, Rett's Disorder, and PDD Not Otherwise Specified, or PDD-NOS. The category of PDD has in the past been referred to as Autism Spectrum Disorders, or ASD. Each of these five sub-categories are characterized by the above-mentioned triad of areas of impairment, and are set apart from each other by how they rank in these three areas in relation to each other.

Autistic Disorder
A. Must have all three:
1. Qualitative, or measurable, impairments in social skills
2. Oualitative impairments in language development
3. Restricted and repetitive patterns of behaviour, interests, and activities
B. Usually accompanied by delays in cognitive development and testable IQ<70
C. Behavioral symptoms observed prior to three years of age

Asperger's Disorder
A. Must have both:
1. Qualitative, or measurable, impairments in social skills
2. Restricted and repetitive patterns of behaviour, interests, and activities
B. No delay in language development, although social language may be peculiar
C. No delay in cognitive development with an IQ>/=85
D. Symptoms can be rather subtle or even undetected until the child is over three years of age

Childhood Disintegrative Disorder (CDD)
A. Apparently normal development until at least age 2
B. Followed by a significant loss of skills in at least two of the following areas:
1. Expressive or receptive language
2. Social skills or adaptive behaviour
3. Bowel or bladder control
4. Play skills
5. Motor development
C. Regression resulting in the presence of at least two of the following:
1. Qualitative, or measurable, impairments in social skills
2. Oualitative impairments in language development
3. Restricted and repetitive patterns of behaviour, interests, and activities

Rett's Disorder
A. Must demonstrate ALL of the following:
1. Apparently normal early development during infancy
2. Normal head circumference at birth
3. Regression of motor and social skills that occurs between 5 months and 2.5 years
4. Deceleration of head circumference growth between the same time period
5. Repetitive hand motions such as hand-wringing or hand-washing actions
6. Poor motor coordination, especially gait and trunk (upper body) movements
7. Although has been able to use hands effectively as an infant, now has difficulty with any tasks that involve hands
8. Severely impaired expressive and receptive language development

PDD- Not Otherwise Specified (PDD-NOS)
A. Must show some degree of qualitative impairment in:
1. Social skills, OR
2. Language skills, OR
3. The presence of restricted and repetitive patterns of behaviour and interests

-Demystifying Autism Spectrum Disorders: A Guide to Diagnosis for Parents and Professionals, Carolyn Thorwarth Bruey, Psy.D

More on this triad of areas and what each functionally includes can be found at the link I posted yesterday, here. Ethan's problems are not merely a delay, but a disorder. He marches to the beat of his own little drum, learns things in a different way, with different perspectives, not limited ones. I just want to get inside his head and be able to at least imagine how he sees the world, learns from it, and uses it to go on the next intersection, mapping his way to grown-up.