Functional Evaluation in Patients With Urea Cycle Disorders (UCD) During a Driving Task

Primary Objective * To use fNIRS to study brain functional behavior in subjects with UCD by measuring the changes in HbO, HbR and HbT concentrations versus healthy control volunteers during the baseline driving task on the left and right prefrontal cortex (LPFC, RPFC). Secondary Objective * To include other cortical regions such as temporal and occipital regions, to investigate the neurocognitive changes in these regions which may or may not change with driving. Thus, we will measure changes in HbO, HbR and HbT concentrations during the baseline driving task in four more brain regions (left and right parietal and occipital regions, LPA, RPA, LOL, ROL). 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.