Researchers with the UC Davis MIND Institute will develop and evaluate tests designed to measure and track changes in the cognitive functioning of people who typically are difficult to assess accurately: those with an intellectual disability, formerly termed mental retardation. The research will be funded through a new, five-year, $3.2 million grant from the National Institutes of Health (NIH).
The effort will be paired with other research conducted at the MIND Institute and elsewhere, which seeks to evaluate the efficacy of new, investigational treatments for people with intellectual disability. The tests will eventually be used to ascertain the effectiveness of medications and other treatments, specifically for people with fragile X and Down syndromes and other intellectual disabilities. Fragile X and Down syndromes are among the leading causes of intellectual disability in the United States and around the world. Fragile X syndrome also is the leading single-gene cause of autism spectrum disorder.
At the MIND Institute, the research will be led by principal investigator David Hessl, professor in the Department of Psychiatry and Behavioral Sciences and director of the Translational Psychophysiology and Assessment Laboratory, and co-investigator Leonard Abbeduto, director of the MIND Institute and Tsakopoulos-Vismara Endowed Chair of Psychiatry and Behavioral Sciences.
“There are virtually no comprehensive and developmentally appropriate, well-validated and reliable cognitive measures suitable for tracking treatment responses in people with intellectual disability,” Hessl said, “but there are exciting new therapies being evaluated now and more on the horizon, which suggests that substantial gains in cognitive functioning are possible, even for adults with lifelong cognitive deficits.”
"Most currently available standardized tests have been developed mainly for the general population and are not well-suited for people with intellectual disabilities,” he said. “They just weren’t designed for people with the level of functioning we typically see in fragile X and Down syndromes. What we will be working to do is modify and then validate the NIH Toolbox Cognition Battery so that it works well for individuals with intellectual disability.”
The NIH Toolbox is a multidimensional set of brief measures assessing cognitive, emotional, motor and sensory function from ages 3 to 85, meeting the need for a standard set of measures that can be used as a common currency across diverse study designs and settings. The cognitive test battery used in the study is a computer-based set of tests tapping processing speed, memory, attention and language.
The research will be conducted in concert with three other leading research institutions with robust programs in intellectual disabilities. In addition to the MIND Institute researchers, investigators at three other universities are involved:
- Karen Riley, dean and associate professor, Morgridge College of Education, The University of Denver;
- Richard Gershon, associate professor, medical social sciences and preventive medicine-health, Northwestern University School of Medicine;
- Elizabeth Berry-Kravis, professor, biochemistry, neurological sciences, pediatrics, Rush University Medical Center, Chicago.
“This project will help address a critical problem that is one of the largest barriers to development of new treatments to modify the underlying disease in developmental disabilities — the lack of good measures to document improvement in thinking that are appropriate, valid and measure change in children and young adults with intellectual disabilities,” Berry-Kravis said.
The research will benefit a wide range of studies aiming to assess or improve specific areas of cognition in persons with intellectual disability, Hessl said.
To evaluate the reliability, validity and sensitivity of the battery, over a five-year period the MIND Institute, Rush University and The University of Denver each will enroll 150 individuals with intellectual disability between the ages of 6 and 25 years with either fragile X syndrome, Down syndrome, or intellectual disability of unknown cause. The participants will undergo one round of testing and a second round four weeks later. The overall growth in the participants’ intellectual skills will be tested again after two years.
The Northwestern University team, which is responsible for the development, maintenance and training of the NIH Toolbox, will assist with making modifications to the tests to suit this unique population, maintain the data generated from the study, and participate in interpreting and disseminating the study findings.
“The holy grail of intellectual disabilities research is to find a treatment that raises a person’s cognitive capacity, and consequently their ability to function better on a day-to-day basis” Hessl said. “To prove that a treatment does that, you have to have tests that are sensitive to actual changes, including those associated with treatment.”