Dr. Schweitzer showed in a previous PET and regional cerebral blood flow (rCBF) study (Schweitzer et al., 1997) a dysfunction in the same right frontal medial region in patients with ADHD when asked to perform a working memory task.
Working memory is a fairly new term that replaces and expands upon the concept of short-term memory. Researchers have theorized that working memory serves not only as temporary storage for new information, but also the active manipulation of this information. Part of the active process may involve inhibiting -- or forgetting -- certain knowledge.
Disruption of working memory may explain many of the everyday difficulties individuals with ADHD encounter, from coping with laborious reading to never remembering to complete one of multiple unfinished tasks, Dr. Schweitzer says. "These findings expand upon earlier data on AD/HD that suggested there was underactivity in AD/HD and show us that there are also areas that are overactive," says Dr. Schweitzer, who is assistant professor of Psychiatry and Behavioral Sciences at the Emory University School of Medicine. "These data provide us with novel clues in regard to developing more specific drug treatment for individuals with ADHD."
Other Emory collaborators on the study included Doug O. Lee, M.D.; Tim D. Ely, B.S.; Matt Ostrowitz; Russell B. Hanford, M.A.; and Scott T. Grafton, M.D.; John M. Hoffman, M.D., of the Department of Neurology and Emory PET Center and Clint D. Kilts, Ph.D., of the Department of Psychiatry and Behavioral Sciences. The study was supported by the National Institute of Mental Health. (Abstract 375.12)