February 18, 2012
Study Suggests Pre-Autism Brain Differences In Six Month Olds
Brain changes in infants as young as six months of age suggest that MRIs could be used to detect autism in children at least half a year before the emergence of other symptoms, according to a new study published online Friday in the American Journal of Psychiatry.
According to Lara Salahi of ABC News, Dr. Joe Piven, director of the University of North Carolina´s (UNC) Carolina Institute for Developmental Disabilities and senior author of the study, and colleagues studied 92 infants who had already been considered to be high-risk of developing autism-spectrum disorders (ASDs) because of siblings who had already been diagnosed with the ailment.
Piven's team tracked brain changes in those infants at the six-month, one-year, and two-year points, then formally tested each for autism using the standard diagnostic test at the age of two -- which according to ABC News is the typical age when ASDs are diagnosed.
Of the 92 subjects, 28 of them whose MRI results showed slower than normal brain connections went on to be diagnosed with autism or a similar disorder, "suggesting the condition has a stronger genetic and biological root" than previously believed, Salahi wrote. The researchers report that this is the first study to track brain changes in infants as young as a half-year old, she added.
“These results offer promise that we may one day be able to identify infants at risk for autism before the behavioral symptoms are present,” Dr. Geri Dawson, Chief Science Officer of Autism Speaks, an ASD fund-raising and advocacy group, and co-author of the study, said in a statement on Friday. "The goal is to intervene as early as possible to prevent or reduce the onset of disabling symptoms."
In a press release issued by the UNC School of Medicine, the researchers said that the results come from the ongoing Infant Brain Imaging Study (IBIS) Network study, which is headquartered at the university and funded by the National Institutes of Health (NIH). The results discovered that at the 24 month point, 30% of the infants met the criteria for ASD while 70% (64 infants) did not.
"The two groups differed in white matter fiber tract development -- pathways that connect brain regions -- as measured by fractional anisotropy (FA). FA measures white matter organization and development, based on the movement of water molecules through brain tissue," the UNC media advisory said.
"This study examined 15 separate fiber tracts, and found significant differences in FA growth trajectories in 12 of the 15 tracts between infants who did develop autism versus infants who did not. Infants who later developed autism had elevated FA at six months but then experienced slower development over time. By 24 months of age, infants with autism had lower FA values than infants without autism," the Children's Hospital of Philadelphia, which was represented on the research team, added in a separate press release.
While autism researcher Christine Wu Nordahl of the University of California-Davis MIND Institute, who was not involved in the study, told USA Today's Liz Szabo that the study was "remarkable" and a "great first step," she noted that the other researchers needed to reproduce the findings before doctors can begin work on a trustworthy early detection system for autism and autism-spectrum disorders.
Likewise, Harvard Medical School Pediatrics and Neuroscience Professor Charles Nelson told Szabo that the study results suffer because the researchers did not compare the children from high-risk families to a group of normal-risk infants who do not have autistic siblings. Szabo added that Nelson "questioned why 30% of the high-risk children were diagnosed with autism, a rate that's 50% higher than expected."
On the Net:
- University of North Carolina (UNC)
- Autism Speaks
- National Institutes of Health (NIH)
- Children's Hospital of Philadelphia
- University of California-Davis MIND Institute
- Harvard Medical School