The Toolbox Study aims to explore whether certain types of intellectual or cognitive tests are reliable, valid and sensitive in evaluating treatment responses among individuals with intellectual disability. The NIH Toolbox Cognitive Battery has been shown to accurately measure various cognitive skills across a wide age range, but has yet to be widely adopted among individuals with intellectual disability. In 2015, the Toolbox Study began enrolling children, teens, and young adults with Down syndrome, fragile X syndrome, autism spectrum disorder, and intellectual disabilities from other causes. In 2021, the Toolbox Study received supplemental funding to enroll participants with Down syndrome and fragile X syndrome who are over 25 years old. The data collected from this study will provide insight into the natural aging trends of adults with intellectual disability, and motivate future research to focus on the cognitive projections for aging adults with neurocognitive disabilities. .

From the first phase of the study, we published a paper in the journal Neurology that detailed how well the battery performs in children and young adults with intellectual disability. Briefly, we proved that with some accommodations and adjustments, people with intellectual disabilities can provide scores on the test that are, in most ways, as reliable and valid as scores from typically developing people. This is a big achievement because it promotes inclusion in research for people with intellectual and developmental disabilities (IDD) who may have previously been excluded from such opportunities due to a misperception that they are not able to be assessed or participate in study activities. This good news led several investigators to choose the Toolbox test as an outcome measure in clinical trials, another important indicator of progress. This means, because the Toolbox test was successful in our study, it is being used to measure specific cognitive skills to track how well a treatment might be working.


Your child may be eligible to participate in the Toolbox Study if they:

  • Are over 25 years old at the time of enrollment
  • Have been diagnosed with intellectual or developmental disability caused by Down syndrome or fragile X syndrome

Families who enroll in the study will:

  • Come to the MIND Institute for a study visit lasting approximately 6 hours. Participants may also be eligible for an in-home assessment without having to travel to the MIND Institute
  • Participate in a variety of cognitive assessments, including the NIH Toolbox Cognitive Battery
  • Caregivers will be asked to answer questions about the participant’s home environment, behavior, and functioning
  • Participants will be invited back for a follow-up visit 2 years after their first study visit
  • Receive compensation for both travel and participation in the study, and receive detailed assessment results

If you are interested in learning more or participating in this study, please contact our Study Coordinator at or by phone at 916-734-1541.


Dana Glassman
Study Coordinator 

For interested individuals with intellectual disability caused by Down syndrome, fragile X syndrome, or other causes under 25 years old, please see the Toolbox Study for more information.