Low-birth-weight infants with a specific brain disorder are at greater risk for autism, according to new imaging findings that could provide clinicians with new indications for early detection of the still little known disorder.

Led by Michigan State University (MSU; East Lansing, USA) investigators, the research demonstrated that low-birth-weight newborns were seven times more apt to be diagnosed with autism later in life if an ultrasound captured just after birth revealed they had enlarged ventricles (cavities in the brain that store spinal fluid). The study’s findings were published February 13, 2013, in the Journal of Pediatrics.

“For many years there’s been a lot of controversy about whether vaccinations or environmental factors influence the development of autism, and there’s always the question of at what age a child begins to develop the disorder,” said lead author Dr. Tammy Movsas, clinical assistant professor of pediatrics at MSU and medical director of the Midland County Department of Public Health. “What this study shows us is that an ultrasound scan within the first few days of life may already be able to detect brain abnormalities that indicate a higher risk of developing autism.”

Dr. Movsas and coworkers reached that conclusion by analyzing data from a cohort of 1,105 low-birth-weight infants born in the mid-1980s. The babies had cranial ultrasound scans right after birth, thus the researchers could search for relationships between brain abnormalities in infancy and health disorders that showed up later. Participants also were screened for autism when they were 16 years old, and a subset of them had a more rigorous test at 21, which turned up 14 positive diagnoses.

In premature infants, ventricular enlargement is identified more frequently and it may indicate loss of a type of brain tissue called white matter. “This study suggests further research is needed to better understand what it is about loss of white matter that interferes with the neurological processes that determine autism,” said coauthor Nigel Paneth, an MSU epidemiologist who helped organize the cohort. “This is an important clue to the underlying brain issues in autism.”

Earlier research had demonstrated an increased rate of autism in low-birth-weight and premature babies, and earlier research by Drs. Movsas and Paneth found a slight increase in symptoms among autistic children born early or late.

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