New research suggests our brain can compensate for a variety of neurodevelopmental issues by relying on a system in the brain known as declarative memory.
Researchers from Georgetown University Medical Center propose that individuals diagnosed with autism spectrum disorder, obsessive-compulsive disorder, Tourette syndrome, dyslexia, and specific language impairment (SLI) use declarative memory to help them overcome behavioral issues.
Investigators say this hypothesis is based on decades of research. Research findings are published in online and will be in a forthcoming issue of the journal Neuroscience and Biobehavioral Reviews.
Researchers believe the compensatory mechanism allows individuals with autism to learn scripts for navigating social situations.
Further, the system 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 other developmental disorders of language.
“There are multiple learning and memory systems in the brain, but declarative memory is the superstar,” says Michael Ullman, Ph.D., 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, which is an important reason why individuals with the disorders generally still have noticeable problems despite the compensation,” 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 could improve treatment in two ways,” Ullman says. “First, designing treatments that rely on declarative memory, or that improve learning in this system, could enhance compensation.”
Conversely, treatments that are designed to avoid compensation by declarative memory may strengthen the dysfunctional systems.
Ullman says compensation by declarative memory 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.
Declarative memory may also compensate for dysfunctions in other disorders, he adds, including attention deficit hyperactivity disorder (ADHD) and even adult-onset disorders such as aphasia or Parkinson’s disease.
The hypothesis may thus have powerful clinical and other implications for a wide variety of disorders, Ullman says.