The investigators looked at the entropy of each EEG channel, which is believed to contain information about the density of neural connections in the brain region near that electrode.
"Many neuroscientists believe that autism reflects a 'disconnection syndrome,' by which distributed populations of neurons fail to communicate efficiently with one another," explains Nelson. "The current paper supports this hypothesis by suggesting that the brains of infants at high risk for developing autism exhibit different patterns of neural connectivity, though the relationship between entropy and the density of neural arbors remains to be explored." (Neural arbors are projections of neurons that form synapses or connections with other neurons.)
On average, the greatest difference was seen at 9 months of age. The researchers note that at 9 months, babies undergo important changes in their brain function that are critical for the emergence of higher-level social and communication skills -- skills often impaired in ASDs.
For reasons that still need to be explored, there was a gender difference: classification accuracy was greatest for girls at 6 months and remained high for boys at 12 and 18 months.
Overall, however, the distinction between the high-risk group and controls was smaller when infants were tested at 12 to 24 months. The authors speculate that the high-risk group may have a genetic vulnerability to autism that can be influenced and sometimes mitigated by environmental fact
|Contact: Keri Stedman|
Children's Hospital Boston