Individuals with five neurodevelopmental disorders — autism spectrum disorder, obsessive-compulsive disorder, Tourette syndrome, dyslexia, and specific language impairment (SLI) — appear to compensate for dysfunction by relying on a single powerful and nimble system in the brain known as declarative memory, according to a Georgetown University Medical Center neuroscientist.
The proposed compensation allows individuals with autism to learn scripts for navigating social situations; helps people with obsessive-compulsive disorder or Tourette syndrome to control tics and compulsions; and provides strategies to overcome reading and language difficulties in those diagnosed with dyslexia, autism, or SLI.
‘There are multiple learning and memory systems in the brain, but declarative memory is the superstar,’
says Michael Ullman, PhD, professor of neuroscience at Georgetown and director of the Brain and Language Laboratory. He explains that declarative memory can learn explicitly (consciously) as well as implicitly (non-consciously).
‘It is extremely flexible, in that it can learn just about anything. Therefore it can learn all kinds of compensatory strategies, and can even take over for impaired systems,’
says Ullman. Nevertheless, in most circumstances, declarative memory won’t do as good a job as these systems normally do, he adds.
Knowing that individuals with these disorders can rely on declarative memory leads to insights on how to improve diagnosis and treatment of these conditions. It may also help explain an observation that has long puzzled scientists — the fact that boys are diagnosed with these disorders more frequently than girls.
‘Studies suggest that girls and women are better than boys and men, on average, in their use of declarative memory. Therefore females are likely to compensate more successfully than males, even to the point of compensating themselves out of diagnosis more often than males,’
Ullman says. The study was published online and in the April issue of Neuroscience and Biobehavioral Reviews.