WEDNESDAY, May 29 (HealthDay News) -- Parts of the brain thought to support consolidation of emotional memories during sleep are less active in children with attention-deficit hyperactivity disorder (ADHD), according to a new study.
This deficit in sleep-related emotional processing may worsen the emotional problems of children with this condition, researchers in Germany report.
Children with ADHD have difficulty sustaining attention, and often display hyperactivity and impulsive behavior. The neurobehavioral disorder affects 3 percent to 5 percent of U.S. children, more of them boys than girls.
For the study, published May 29 in the journal PLOS ONE, children with ADHD were shown pictures that evoked emotion, such as a scary animal, before they went to bed. They also viewed neutral pictures, such an image of an umbrella or lamp. Their brain activity was then monitored as they slept. When the kids woke up the next morning, the researchers also tested them about what they remembered. The same process was repeated with healthy children and adults.
During sleep, regions of the brain believed to be involved in consolidation of emotional memories were most active among the healthy children. The researchers noted there was less activity in this part of the brain among the healthy adults, and the least activity was noted in the children with ADHD.
The researchers concluded that sleep consolidates emotional memories in healthy children but not in those with ADHD.
"While several studies reported a benefit from sleep with respect to emotional memory in healthy individuals, our results showed for the first time that healthy children outperform healthy adults," the study authors, led by Alexander Prehn-Kristensen from University Hospital Schleswig-Holstein, said in a journal news release. They added, however, that the child-oriented pictures used in the study may have influenced this finding.
More research is needed to determine if this issues resolves over time, or if it continues to affect people of all ages with ADHD, the study authors added.
The U.S. Centers for Disease Control and Prevention provides more information on ADHD.