Diagnostic Classification Of Autism Essay

Autism is a pervasive developmental disorder characterized by deficits in social behavior, communication and by restricted and repetitive behavior and interests (American Psychiatric Association, 1994). Although an individual must show impairment in all three autistic ‘domains’ to receive a diagnosis of autism, there is considerable phenotypic heterogeneity in this population. This variability has led to the claim that the diagnostic classification of autism incorporates a number of subtypes (Fein et al., 1999; TagerFlusberg & Joseph, 2003).
It is difficult to know which treatment components directly affected language use. Contingent verbal imitation (Gazdag & Warren, 2000) and linguistic mapping (Yoder, Kaiser, Goldstein, & Alpert, 1995) have both been shown to increase children’s language use. Research has not documented that non-verbal imitation training increases language although verbal imitation
training has been shown to increase speech production (e.g., Lovaas et al., 1977). It is likely that all three components (contingent verbal imitation, linguistic mapping, and non-verbal imitation training) contributed to the children’s increase in verbal communication, although different components may have contributed to different forms of language. Speech deficits are common to children with autism (American Psychiatric Association, 2000). Approximately 50% of children diagnosed with autism will remain functionally mute in adulthood (Peeters & Gillberg, 1999). Even with early intensive intervention including speech instruction, some children may fail to acquire useful speech (e.g., Lovaas, 1987).
Autism research has benefited from opportunities to define samples by diagnostic instruments such as the Autism Diagnostic Interview-Revised (ADI-R; Rutter et al., 2003) and the Autism Diagnostic Observation Schedule (ADOS; Lord et al., 1999). Standardized methods of collecting, coding, and summarizing information result in categorical diagnoses of autism or not autism on the ADI-R, a caregiver interview, and in classifications of autism, broader autism spectrum disorders (ASDs) or nonspectrum on the ADOS, a semistructured observation. These two instruments were intended to be used together, yet there has been no systematic attempt to evaluate how information from the instruments should be combined for diagnosis.
Neurodevelopmental disorders have diverse causes and some have a genetic basis.
Autism and specific language difficulties may show genetic linkage, although the pathological basis for these conditions is not clear (reviewed in Rapin and Katzman, Lord and colleagues, and Poustka). An increased incidence of immunological abnormalities, in the children or their families (see Adinolfi), also has been reported and a role for maternal antibodies suggested.
Children with autism display many abnormal behaviors that, while not essential to the diagnosis, cause serious distress for both the child and the family. Unusual eating habits, abnormal sleep patterns, temper tantrums, and aggression to self and to others are among the most common of these abnormal behaviors. In order to achieve a greater understanding of abnormal behaviors in the context of autism, it is important to better characterize their frequency and course as well as to explore their relationship to other aspects of children’s functioning including language, intelligence, and severity of autistic
symptoms.