Body Size and Neurological Abnormalities in Jamaican Children with Autism

Background:

Autism is a complex lifelong neurodevelopmental and behavioral disorder manifesting in infancy or early childhood. The prevalence of neuromotor abnormalities in children with autism has been widely studied. Studies have shown that neurologic abnormalities including hyporeflexia, stereotypies, and hypotonia are more prevalent in children with autism. This has not previously been documented in Jamaican children.

Objectives:  

To determine the prevalence of abnormal neurologic findings on standard examination of Jamaican children with autism and autistic spectrum disorder (ASD) and to describe the associated factors.

Methods:  

Forty-three children with autism/ASD age 2-8 years were invited to participate. Each child with autism/ASD was matched with a peer for age and gender. Informed consent was obtained. Parents and caregivers were interviewed to obtain information on demographics and the medical records were reviewed. The diagnosis of autism/ ASD was established according to DSM IV criteria, the Childhood Autism Rating Scale (CARS) and the Autism Diagnostic Observation Schedule (ADOS). The height, weight and head circumference were measured by one trained research assistant. A standardised neurological examination was performed on all children by one of three paediatric neurologists. Joint hypermobility was evaluated using the Beighton score. Ethical approval was obtained. Data were analysed to determine the association of growth characteristics with neurologic abnormalities and factors predictive of neurologic abnormalities.

Results:  

The mean age was 5.50 years (S.D. 1.57 years). There were significant differences in the prevalence of joint hypermobility and incoordination between the two groups. Joint hypermobility was found in 41.8% and motor coordination abnormalities in 30% of children with autism/ASD (P=0.00, 0.04 respectively). The prevalence of these findings was not significantly different among autism subgroups. In children with autism/ASD, tall stature and macrocephaly were significantly associated with the finding of abnormal motor coordination (P=0.00, 0.04 respectively) and a BMI > 85^th centile was significantly associated with the finding of joint hypermobility (P=0.02). Tall stature was significantly associated with hypotonia (P= 0.036). Logistic regression analysis determined that controlling for age and gender, head circumference (B=0.63, P=0.02) and height (B=0.16, P= 0.03) were significantly associated with abnormal motor coordination in children with autism/ASD.

Conclusions:  

The prevalence of motor coordination abnormalities and joint hypermobility is higher in Jamaican children with ASD/ autism than their peers. Growth dysregulation is significantly associated with motor coordination abnormalities. The association with height has not been widely reported. Dysregulated growth in height and head circumference may represent the physical manifestations of a subtype of autism/ASD with significant motor coordination abnormalities.