An observational study in Urea Cycle Disorder, sponsored by St. Jude Children's Research Hospital. Recruiting at 1 site in United States. Open to participants aged 16 Years to 40 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-07-31.
Sponsored by St. Jude Children's Research Hospital · Observational
This study is being done to understand how the brain works while people with urea cycle disorder (UCD) perform driving tasks that range from easy to difficult and to look at how that compares to traditional tests of thinking and attention.
Primary Objective
Secondary Objective
This is a non-therapeutic, non-interventional study in which brain fNIRS (functional near-infrared spectroscopy) measures will be compared under simulated driving conditions between patients with UCD vs. age and sex-matched control participants.
Participants who agree to participate will have Information about their medical history collected, have a basic neurological exam and answer questions about their health, diet, and driving habits. They will complete some simple thinking and memory tests. These tests will help investigators understand skills like memory, attention, and problem-solving. Participants will also wear a soft cap with small sensors called an fNIRS (functional near-infrared spectroscopy) device while they complete a driving simulator activity. This cap is noninvasive and measures how the brain uses oxygen while they drive in the simulator.
All study activities will be completed on the day of enrollment.
Individuals who meet the Eligibility Criteria and agree to participate.
Exclusion Criteria:
Participants with urea cycle disorders (UCD) who meet the Eligibility Criteria and consent to participate
Healthy controls who meet the Eligibility Criteria and consent to participate
Changes in Oxyhemoglobin (HbO), Deoxyhemoglobin (HbR) and Total Hemoglobin (HbT) concentrations in the right and left prefrontal cortex in participants with urea cycle disorders (UCD) compared to healthy control volunteers
Investigators will compare prefrontal cortex hemoglobin concentrations during low cognitive load between patients with UCD and healthy age and sex matched control participants using functional near-infrared spectroscopy (fNIRS). Mean values of hemoglobin concentration differences on the right and left prefrontal cortex between individuals, with and without UCD, during the low cognitive load task will be calculated and compared using two sample t-tests (for normally distributed data) or Wilcoxon rank sum tests (for nonnormally distributed data). P values will be adjusted for multiple comparisons using the Bonferroni method.
Time frame: Day 1, during driving simulator task
Changes in HbO, HbR and HbT concentrations in the left and right parietal and occipital brain regions in participants with urea cycle disorders (UCD) compared to healthy control volunteers
Investigators will compare left and right parietal and occipital regions hemoglobin concentrations during low cognitive load between patients with UCD and healthy age and sex matched control participants using functional near-infrared spectroscopy (fNIRS). Mean values of hemoglobin concentration differences on the left and right parietal and occipital regions between individuals, with and without UCD, during the low cognitive load task will be calculated and compared using two sample t-tests (for normally distributed data) or Wilcoxon rank sum tests (for nonnormally distributed data). P values will be adjusted for multiple comparisons using the Bonferroni method.
Time frame: Day 1, during driving simulator task
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
Contact study teamGet an email when the registry record changes — status, dates, results — or when someone posts here.
Sign in to followQuestions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.
Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.
Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.
St. Jude Children's Research Hospital