AsianScientist (Oct. 2, 2014) – Scientists now have a better understanding of the brain processes underlying the inability of children with attention-deficit/hyperactivity disorder (ADHD) to recognize facial expressions. This research has been published in Neuropsychologia.
ADHD is one of the most commonly diagnosed developmental disorders in children. Inattention, hyperactivity and impulsive behavior in children with ADHD can result in social problems and cause them to be excluded from peer activities. One of the symptoms of ADHD is the inability to correctly read emotions in the facial expressions of other people, adding to the distress that ADHD children may face in social situations.
A team of researchers including Professor Ryusuke Kakigi of the National Institute for Physiological Sciences under Japan’s National Institutes of Natural Sciences, in collaboration with Professor Masami K. Yamaguchi and Assistant Professor Hiroko Ichikawa of Chuo University conducted a study to investigate the neurological basis of ADHD children’s processing of facial expressions.
Using a technique known as non-invasive near-infrared spectroscopy (NIRS), they first identified the characteristics of facial expression recognition of children with ADHD by measuring hemodynamic response in the brain. Near-infrared light, which is likely to go through the body, was projected through the skull and the absorbed or scattered light was measured. The strength of the light absorbed depends on the concentration of oxyhemoglobin in the blood vessels of the brain.
The researchers showed showed images of a happy expression or an angry expression to 13 children with ADHD and 13 typically developing children and identified the location of the brain activated at that time. They found that typically developing children showed significant hemodynamic response to both the happy expression and angry expression in the right hemisphere of the brain.
On the other hand, children with ADHD showed significant hemodynamic response only to the happy expression but brain activity specific for the angry expression was not observed. This difference in the neural basis for the recognition of facial expression might be responsible for impairment in social recognition and the establishment of peer-relationships.
Source: National Institutes of Natural Sciences.
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