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Exploring Sympathetic Nervous System Function in Individuals With Down Syndrome
Sponsor: University of Colorado, Denver
Summary
Down syndrome (DS), the most common genetic cause of intellectual disability, is associated with widespread organ dysfunction, including abnormalities in the autonomic nervous system (ANS). The ANS regulates critical functions such as heart rate (HR) and blood pressure (BP), both essential for maintaining homeostasis and supporting physical activity. Individuals with DS often exhibit blunted HR responses to exercise-typically \~30 beats per minute below expected levels-suggesting reduced sympathetic nervous system (SNS) activity. The SNS governs rapid changes in HR and BP during stress by releasing catecholamines: epinephrine (from the adrenal medulla) and norepinephrine (from sympathetic nerve endings). Despite its importance, SNS function has not been comprehensively assessed among individuals with DS. This study addresses a critical knowledge gap by evaluating SNS responses to physiological stressors in individuals with DS. The investigators will measure beat-to-beat HR and BP, along with plasma catecholamine levels, in response to sympathetic activation, comparing individuals with DS to age- and sex-matched controls. Understanding the mechanisms of SNS dysfunction in DS is vital, as it likely underlies reduced exercise capacity and contributes to broader clinical challenges. These insights may guide targeted interventions to improve cardiovascular function, physical capacity, and overall quality of life in this understudied population.
Official title: Dysautonomia InVestigation in Individuals With Down SyndromE: DIVE Study
Key Details
Gender
All
Age Range
18 Years - 50 Years
Study Type
INTERVENTIONAL
Enrollment
200
Start Date
2025-12
Completion Date
2029-12
Last Updated
2025-11-20
Healthy Volunteers
Yes
Conditions
Interventions
Fear Response
Fear triggers the sympathetic nervous system, known as the 'fight-or-flight' response, which prepares the body to respond to a perceived threat by increasing heart rate, blood pressure, and releasing catecholamines. These measurements will be taken to examine the cardiovascular physiology of how individuals with DS will respond during a scary simulation. The investigators are looking at how plasma catecholamines (i.e., Epinephrine, Norepinephrine, and Dopamine), blood pressure, and heart rate are expressed during a fear simulation using virtual reality goggles in individuals with Down syndrome, who have proposed autonomic dysfunction. This study will compare responses among individuals with Down syndrome to a control group without Down syndrome.
Cold Stress
Cold triggers the sympathetic nervous system, known as the 'fight-or-flight' response, which prepares the body to respond to a perceived threat by increasing heart rate, blood pressure, and releasing catecholamines. These measurements will be taken to examine how individuals with DS will respond during a cold stress test. The investigators are looking at how plasma catecholamines (i.e., Epinephrine, Norepinephrine, and Dopamine), blood pressure, and heart rate are expressed during a cold stress test in individuals with Down syndrome, who have proposed autonomic dysfunction. This study will compare responses among individuals with Down syndrome to a control group without Down syndrome.
Pain Response
Pain triggers the sympathetic nervous system, known as the 'fight-or-flight' response, which prepares the body to respond to the perceived threat (i.e., hurt) by increasing heart rate, blood pressure, and releasing catecholamines. These measurements will be taken to examine how individuals with DS will respond during application of a painful patch. The investigators are looking at how plasma catecholamines (i.e., Epinephrine, Norepinephrine, and Dopamine), blood pressure, and heart rate are expressed during application of a pain patch in individuals with Down syndrome, who have proposed autonomic dysfunction. This pain patch is similar to what someone would buy at the drug store for sore muscles. This study will compare responses among individuals with Down syndrome to a control group without Down syndrome.
Caffeine
Caffeine acts as a stimulant to the sympathetic nervous system leading to an increase in blood pressure, heart rate, and release of catecholamines. The investigators are looking at how plasma catecholamines (i.e., Epinephrine, Norepinephrine, and Dopamine), blood pressure, and heart rate are expressed following ingestion of a caffeine pill (similar to \~2 cups of coffee) in individuals with Down syndrome, who have proposed autonomic dysfunction. This study will compare responses among individuals with Down syndrome to a control group without Down syndrome.
12-Hour Fast
Fasting-induced hypoglycemia triggers a 'fight-or-flight' response as the body attempts to raise low blood glucose levels to bring them back to 'normal'. These measurements will be taken to examine how individuals with DS will respond following a 12-hour abstinence from food, inducing low blood sugar. The investigators are looking at how plasma catecholamines (i.e., Epinephrine, Norepinephrine, and Dopamine), blood pressure, and heart rate are expressed following a 12-hour fast in individuals with Down syndrome, who have proposed autonomic dysfunction. This study will compare responses among individuals with Down syndrome to a control group without Down syndrome.
Maximal Dynamic Exercise
The investigators are looking at how plasma catecholamines (i.e., Epinephrine, Norepinephrine, and Dopamine), blood pressure, and heart rate are expressed during a treadmill maximal exercise test in individuals with Down syndrome, who have proposed autonomic dysfunction. This study will compare responses among individuals with Down syndrome to a control group without Down syndrome.
Locations (1)
Linda Crnic Institute for Down Syndrome, University of Colorado Anschutz Medical Campus
Aurora, Colorado, United States