Finding precise measures to gauge whether an intervention or medicine is effective is a significant difficulty when testing new therapies for people with intellectual disabilities. The NIH Toolbox Cognition Battery (NIHTB-CB) is a promising alternative, according to a recent study by scientists at the UC Davis MIND Institute and other universities. According to the study, the exam is sensitive to changes in development in kids, teens, and young adults.
David Hessl, professor in the Department of Psychiatry and Behavioral Sciences and corresponding author of the report, said that “those with poorer developmental capacities are frequently excluded from research investigations and clinical trials.” That implies that not everyone can benefit from the findings of those studies, and the entire group is excluded from the possible advantages of a treatment.
An IQ of 70 or less is considered intellectually disabled. It can occur with diseases such as fragile X syndrome, autism, and Down syndrome and affects 1.8–3.2% of people worldwide.
The challenges of adaptive behavior are also apparent in intellectual disability. It has an impact on many facets of daily life, including independence and academic performance.
What is the NIH Toolbox Cognition Battery?
The NIHTB-CB is a test that can be taken on a computer or tablet. It includes a number of quick tests to evaluate cognitive abilities like language, working memory, and attention.
For instance, in one segment, participants must assess whether two images are similar or distinct, while in another, they must listen to a word and then point to the image that corresponds to it. Another segment asks students to listen to a story and then arrange the visuals it contains.
Measuring developmental change in young people
The team analyzed young people during childhood and early adulthood, when kids and teens are typically developing cognitive skills and gaining capacities, to determine whether the NIHTB-CB is responsive to developmental change.
Hessl, who is also a faculty member at the MIND Institute, stated, “We knew that a significant fraction of young people would be making advances in cognition during this period, and we could use that chance to see if the Toolbox picked up on those developmental changes.” It is crucial to determine a measure’s sensitivity to change before employing it in clinical studies.
256 people received the NIHTB-CB from the researchers. People with fragile X syndrome, people with Down syndrome, and people with additional intellectual disabilities were divided into one of three groups. The participants’ ages ranged from 6 to 27. The team retested 197 of the individuals after two years.
The Stanford-Binet Intelligence Scales, Fifth Edition (SB5) were also administered by the researchers at both time periods in order to cross-validate the NIHTB-CB. An IQ test with a lengthy history is the SB5.
Results very promising
Overall, the NIHTB-CB assays revealed developmental growth that was comparable to—oor greater than—tthat of the SB5. The NIHTB-CB growth pattern in each group matched the SB5 growth pattern.
Participants with various intellectual disabilities showed considerable improvements in almost all categories according to the NIHTB-CB at age 10, maintained improvements at age 16, and stabilized development at age 22.
When compared to the group with other intellectual disabilities, the participants with fragile X syndrome showed delayed improvements in attention and inhibitory control. Comparing the group with additional intellectual disabilities to the people with Down syndrome, the latter group showed delayed gains in receptive vocabulary.
Participants with Down syndrome experienced significant progress in early adulthood in the domains of attention, inhibitory control, and working memory, in contrast to the other groups.
Cognitive flexibility, or the capacity to adjust to a new rule or situation, showed relatively little development across all three groups.
According to Hessl, “These results may assist in leading us in terms of where intervention would be the most effective or advantageous.”
A new measurement tool for clinical trials?
The SB5 IQ test must frequently be repeated over a brief period of time for treatment trials, which many researchers find tedious.
Hessl stated that there may be “practice effects” for some IQ test elements as well as an emphasis on questions requiring learned knowledge. “You want something like the NIHTB-CB for an outcome measure since its components are more flexible and easily modifiable.”
The NIHTB-CB is already being used in some therapy studies to gauge cognitive development. This includes a modest but well-publicized trial that showed adult males with fragile X syndrome had higher cognitive scores after taking an Alzheimer’s medication. Now, a bigger trial is anticipated. Hessl is a consultant for Tetra Therapeutics, the pharmaceutical company that is conducting the study.
Hessl points out that the NIHTB-CB might also be modified for use in clinics or schools to evaluate patients or students.
“The NIH Toolbox Cognition Battery does, in my opinion, show evidence of changes in cognition across time.” There is enough evidence across the groups and tests to suggest that, while it may not be universal—not for every single subtest with all of the groups we tested—it is detecting some significant aspects of the change Hessl mentioned.
The study’s findings were posted online in Neurology®, the medical journal of the American Academy of Neurology, on December 2.
