IDEA Definition:

"a developmental disability significantly affecting verbal and nonverbal communication and social interaction, generally evident before age 3, that adversely affects a child's educational performance" (Hall pg. 4). 

Prevalence:
Rates & Influences

 Since the 1940s, the prevalence of autism has significantly increased.  A CDC report indicates the number of cases of autism spectrum disorders (ASD) to be 1 in 110 (2009).  In addition, more boys than girls are identified as having ASD.  Factors affecting the prevalence increase include: (1) an increased awareness by the public and by physicians and psychologist who make the diagnosis; (2) the broadening of the classification to include pervasive developmental disorder that requires minimum criteria for classification; (3) different methods for case findings; and (4) service availability (Hall, pg. 4-5)

Physiological Interventions

1.) Medication Treatment
2.) Diets
3.) Sensory Activities
(Hall, pg. 10-16)

ASD Influences

1.) Genetic Influences--research reports ASD is caused by 2 to 20 susceptible genes across various chromosomes acting in unison, producing significant heterogeneity in both genes involved and the mode of inheritance (Hall, pg. 6).
2.) Differences in Structure & Function of the Brain--"Autism is undeniably due to abnormal brain development beginning in early life"; ASD occurs as a result of abnormalities in multiple neural systems and cortical systems (Hall, pg. 9-10).
3.) Environmental Toxins--remains controversial; possibly toxic influences, with no substantial evidence; measles, mumps, and rubella (MMR) vaccine; "The environmental factors identified thus far account for a very small proportion of autism cases, but that does not diminish the importance of their contribution to our understanding of ASDs" (Hall pg. 11).