NIH ToolboxA Study Funded by the National Institutes of Health

The purpose of this research is to explore whether certain types of intellectual or cognitive tests are reliable, valid and sensitive to improvement in evaluating treatment responses among individuals with intellectual disability. This newer cognitive test has been shown to accurately measure various cognitive skills across a wide age range, but has yet to be adapted and tested among individuals with intellectual disabilities.


Participants include individuals between the ages of 6-25 years old with a confirmed diagnosis of intellectual disability caused by fragile X syndrome, Down syndrome, or another cause.


Participation in the study involves three visits to a clinic. The first visit lasts approximately seven to eight hours and is scheduled over a two-day period. The second visit is scheduled approximately four weeks later and will be much shorter, only lasting about one hour.

Participants will be asked to return for a third visit. The schedule for the third visit is the same as the first visit and will take place approximately two years later. These visits will include cognitive testing for your son/daughter and parents/guardian will be asked to fill out questionnaires and participate in interview surveys.


This is a multi-site study with teams in Sacramento, Chicago, and Denver seeking participants.

This study is under the direction of Dr. David Hessl at UC Davis Mind Institute, Dr. Elizabeth Berry-Kravis at Rush University Medical Center, and Dr. Karen Riley at the University of Denver.

Contact information

Rebecca Shields
Study Coordinator
UC Davis MIND Institute
Department of Psychiatry & Behavioral Sciences
2825 50th Street
Sacramento, CA 95817
P: 916-703-0121.
F: 916-703-0340

Claire Michalak
Clinical Research Coordinator
Rush University Medical Center
Pediatric Neurology Fragile X Research
1725 W. Harrison St. Suite 718
Chicago, IL 60612
P: 312-563-4937
F: 312-942-4168

Jeanine Coleman, PhD
Clinical Assistant Professor
Morgridge College of Education
University of Denver
1999 East Evans Avenue
Denver, CO 80208
P: 303-871-2496