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Pervasive Developmental Disorder


Common symptoms include:


- delays in the development of socialization and communications skills,

- problems with using and understanding language,

- difficulty relating to people, objects and events,

- unusual play with toys and other objects,

- difficulty with changes in routine or familiar surroundings,

- repetitive body movements or behaviour patterns,

- impaired social interaction and communication skills,

- a limited range of activities and interests, and

- unusual responses to sensory information, such as loud noises and lights.


Children with PDD vary widely in abilities, intelligence and behaviours.


Some children do not speak at all, others in limited phrases or conversations and some have relatively normal language development.


Pervasive Development Disorders include:


- Autism,

- Asperger’s Syndrome,

- Childhood Disintegrative Disorder, and

- Rett’s Syndrome.


Perseveration, stereotypic behaviour and obsessive compulsive behaviours are common in children with PDD.  Some children may also have tics and possibly a diagnosis of TS.  Distinguishing PDD behaviours from motor tics and OCD compulsions can be difficult.


Social deficits are a conspicuous feature of PDD.  These children frequently miss the nonverbal cues that are crucial to social interactions.  They may want to talk endlessly about a topic that has captured their interest and are oblivious to cues that others are disinterested or are displaying frustration and anger toward their verbosity.


Children with PDD tend to interpret conversation and instruction literally, eg “don’t pinch your brother’s friends when they come to the door” doesn’t generalize to “don’t pinch your brother’s friends.”  They have difficulty detecting sarcasm or may be unable to do so at all, often have impaired dexterity and may have sensory dysfunction.


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