Details

Autor(en) / Beteiligte

• Nalty, Theresa

Titel

Neurodevelopmental theory of autism

Ort / Verlag

ProQuest Dissertations & Theses

Erscheinungsjahr

2005

Quelle

ProQuest Dissertations & Theses A&I

Beschreibungen/Notizen

• A neurodevelopmental theory of autism is proposed with a focus on the role of serotonin on brainstem and cerebellum function. Using a neurodevelopmental approach, it is theorized that disruption of neuropathways routing through the brainstem and cerebellum impair further development of higher order functions, resulting in many of the signs and symptoms associated with autism. Children consistently diagnosed with autism on three measures (ADOS, ADI, and DSM-IV), children with developmental delay (DD), and typically developing children were included in this study. The groups were age-equivalent matched on fine motor performance using the Mullen Scales of Early Learning at 25 months of age. Scales were composed to assess specific functions of the brainstem and cerebellum (sensory, vestibular, visual, and eye hand coordination). Brain growth was assessed by head circumference (HC) at approximately 18 months of age. HC was significantly different in the autism group when compared with the DD group. In addition, both diagnosis groups significantly differed from the CDC norms for typically developing age-matched children. Significant differences were found between the autism and DD groups on the sensory, visual, and vestibular scales. No differences were expected for the eye hand coordination scale, as this was comprised of items for which the children were matched on fine motor skills. Significant differences were found between the autism group (44 months of age) and the typically developing children (24 months of age) on both the sensory and vestibular scales even though both were age-equivalent matched on fine motor skills at 25 months. To determine if the vestibular scale, a measure of brainstem function, could differentiate the autism and typically developing groups, structural equation modeling was used. Constraining the path between the vestibular and visual scales, the LaGrange Multiplier test found significant differences between the two groups. This is consistent with impaired function at the brainstem level of development in the autism group (mean age 44 months), but not in the younger typically developing children (mean age 24 months) despite age equivalent scores on fine motor skills at 25 months. Implications for earlier identification of children at risk for autism are discussed.