Autism & Autism-Spectrum Disorders

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This topic has several video links to provide you with real examples of these disorders.  Click on them to view in another window.


 

Background  

 

Broadly speaking, autism spectrum disorders (ASD) are a hetergenous group of disorders characterized by deficits in socilization, communication, and behavior. 75% of persons with autism are mentally retarted and their cognitive ability is directly predictive of the severity of their autism.

  1.  Socialization
    1. Limited eye contact and facial expression
    2. Difficulty developing peer relationships
    3. Indifference to social overtures
    4. Lack of social reciprocity
    5. Inflexibility
    6. No engagement in pretend play
  2. Communication
    1.  Impaired reciprocal communication
    2. Language development deviant
    3.  Echolalia, perseverative speech
  3. Behavior
    1. Restrictive, stereotyped patterns of behavior
    2. Repetitive self-stimulatory behaviors
    3. Preoccupation or fascination with a single object or subject

 

Epidemiology    

The prevalence of autism has risen over the past 20 years (10-15:1000 with male to female 4:1); however, this is thought to be a direct result of improved diagnosis and reporting. The diagnosis of autism typically occurs around 18 months to 3 years of age when the child fails to develop normal milestones in the categories listed above. It is imperative to recognize that this critical time in development when autism is typically diagnosed coincides with the MMR vaccine; however, NO long-term epidemiologic studies have found any association suggesting a link between the vaccine and the development of autism. 

 

Etiology

Given the multifaceted nature of autism, no single cause has been elucidated, However, there is a genetic predisposition as there is a 36% observed concordance rate in monozygotic twins and a 0% observed concordance rate in dizygotic twins. Furthermore, prenatal neurologic insult, biochemical, and immunological factors have been attributed as causes of autism. There is a significant comorbidity with fragile X syndrome, tuberous sclerosis, mental retardation, and seizure disorders. CT/MRI in autistic disorders commonly show ventricular enlargement and small, densely packed, immature cells in the limbic system and cerebellum.

 

Autistic Spectrum Disorders (ASD)

1. Autistic Disorder                     Example of a child with Autism at play

  • Qualitative impairment in social interactions
  • Qualitative impairment in communication
  • Restricted repetitive and stereotyped patterns of behavior, interests, and activities
  • Abnormalities not otherwise explained by other disorders
  • Onset prior to 3 years of age
         

2.  Asperger's Disorder- (High-functioning form of autism)          Examples

  • Social ineptness and difficulty making friends
  • Often normal or above normal scores on standardized tests
  • No speech difficulties
  • Narrow range of interests and often clumsy
       

3. Pervasive Developmental Disorder not otherwise specified (PDD-NOS)

  • Less severely disabled children who do not meet criteria for autistic disorder or Asperger's
       

4. Disintegrative disorder

  • Early development is normal and then between 2-10 years of age there is regression affecting language, sociability, intelligence, skills of daily life.
        

5. Rett's syndrome         Video of children with Rett's & their families 

  • Usually girls who develop normally and then have with severe global regression.  
  • Accompanied by other neurological deficits.
  • Often have characteristic hand movements.   Example 1   Example 2

   
Characteristics of Autism

  • Severe language delays or peculiar speech patterns.  Video Example 
          
  • Social delays - poor eye contact, resists touching, appears "tuned out", poor interactions and lack of interest in peers and family members.  
             
            Video Example of social delays & integrated play therapy
        
  • Unusual response to sensory stimuli.  Video Example & therapy
            
  • Intellectual functioning is often uneven with being exceptional at certain skills such as drawing, music, mathematical computations, and memorization. While mental retardation is often associated with ASDs, some studies have shown global developmental delay or mental reatardation occurs in asa few as 26% of patients.
         
  • Ritualistic movements and obsessive compulsive behaviors
        
  • Extreme hyperactivity or passivity. May demonstrate risky-dangerous behaviors.
         
  • Most children have a normal physical appearance and examination
     

 

Diagnosis

  • Because there are no pathognomonic signs, physical findings. or laboratory tests to detect ASD, the physician must be suspicious after a careful evaluation.
       
  • If appropriate screening suggests autism, the family and child should be fully evaluated by professionals that are experts in autism.  The AAP currently recomends that all children be screened for ASDs between 18 and 24 mnonths of age.  Several screening tools exist to make this assessment.
         
    • The Checklist for Autism in Toddlers (CHAT) is the only ASD screening tool with long-term follow-up  in both screen posituve and screen-negative patients.  Very low sensitivity in children < 18 months old.
         
    • The Modified Checklist for Autism in Toddlers (M-CHAT) is a broader screening tool than the CHAT.  If used correctly, with follow-up interview with the parents, the sensitivity of this tool is estimated to b about 85%.
          
    • Screening Tool for Autism in Two-year -olds (STAT) is a useful tool for autism screening and has been cited in one study ashaving a sensitivity and specificity of 95% and 73% respeectively.
         
  • Absolute indications for immediate evaluation include:
    • No babbling by 12 months of age
    • No pointing or gestures by 12 months
    • No single words by 18 months
    •  No two word phrases by 2 years of age
    •  Any deterioration of language or social skills
         

 

References

1. American Academy of Pediatrics. The Pediatrician's Role in the Diagnosis and Management of Autistic Spectrum Disorder in Children. Pediatrics Vol. 107 No. 5 May 2001

2. American Academy of Pediatrics. Technical Report: The Pediatrician's Role in the Diagnosis and Management of Autistic Disorder in Children. Pediatrics Vol. 107 No. 5 May 2001

3. Rapin Isabelle. The Autistic Spectrum Disorders. NEJM Vol. 347 No.5 August 1, 2002

4. Madsen Kreesten Meldgaard, Hvid Anders, et al. A Population-Based Study of Mesles, Mumps, and Rubeela Vaccination and Autism.  NEJM Vol 347 No. 19 Nov. 7, 2002

5. Practice Parameter.  Screening and diagnosis of autism: Report of the Quality Standard Sub-Committee of the American Academy of Neurology and the Child Neurology Society.  Neurology Vol. 55(4) August 22, 2000

6. Chouieri R. and Bridgemohan C.  To make the biggest difference, screen early for autism spectrum disorders.  Contemporary Pediatrics October 2005

7. Johnson C. Autism Pediatrics in Review March 2008

8 . American Academy of Pediatrics. Identification and evaluation of children with Autism spectrum disorders.  Pediatrics 2007; 120(5) 1183

9. Zwaigenbaum L et al.  Clinical Assessment and Mangement of Toddlers with Suspected Autism Spectrum Disorder: Insights from Studies of High-Risk Infants.  Pediatrics May 2009

10. DoveD et al. Medications for Adolescents with Autism Spectrum.  Pediatrics October 2012

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