What is Post-Concussive Dysautonomia?
Post-Concussive Dysautonomia
Post-concussive dysautonomia is a problem with the autonomic nervous system that develops after a concussion or traumatic brain injury (1). The autonomic nervous system controls vital automatic functions such as heart rate, blood pressure, breathing, digestion and many other reflexes the body depends on. Dysautonomia can make it hard for your body to make the automatic adjustments needed when you change position.
Symptoms like these should also be checked by your physician, since heart and other medical conditions can cause similar problems. Call 911 if you have chest pain, severe shortness of breath, fainting with an injury, or fainting during exercise. After any head injury, get emergency care for a headache that keeps getting worse, repeated vomiting, confusion, slurred speech, weakness or a seizure.
How Common Is Post-Concussive Dysautonomia?
An estimated 1.8 to 3.8 million concussions happen each year in the U.S., and many more likely go unreported. Post-concussive dysautonomia is not widely recognized, and researchers believe it may be more common than it appears (2).
What Causes Post-Concussive Dysautonomia?
Post-concussive dysautonomia happens when the body has trouble managing blood flow during changes in position. The reason is different from person to person, and many people have more than one contributing factor. Because the right approach depends on the cause, it’s important for each person to have a thorough evaluation, including a neurological assessment.
Many areas of the brain help control the autonomic nervous system, including the insular cortex, the medial prefrontal cortex, the amygdala, the hypothalamus and the brainstem (1). Your inner ear’s balance system also tells your brain where your head is in relation to the rest of your body. That information travels to the brainstem, where it combines with information from the cortex about where you are in space, so the brainstem can signal your blood vessels to tighten and keep blood flowing to your brain (3). A concussion can disrupt one or more of the systems involved in this process.
What Are the Symptoms of Post-Concussive Dysautonomia?
Symptoms vary from person to person. They may include severe, long-lasting fatigue; sleep problems; lightheadedness or dizziness when changing position; fainting; nausea and vomiting; headaches; “brain fog,” or trouble thinking and focusing; heavy sweating; neck muscle tension; a pounding or irregular heartbeat; and pale skin or discolored hands and feet.
Not everyone has every symptom, and other symptoms are possible. Symptoms often get worse in warm environments, such as a hot shower, when you haven’t had enough fluids, or after standing for a long time (4).
What Happens in the Brain With Post-Concussive Dysautonomia?
When you go from lying down to standing, gravity pulls blood toward your feet. Normally, the autonomic nervous system tightens blood vessels so blood keeps flowing back up to the brain. In dysautonomia, these reflexes don’t work well, and blood flow to the brain can drop.
The body normally speeds up the heart to make up for this. In some types of dysautonomia, the heart rate rises much more than normal. A very fast heart rate may give the heart less time to fill between beats, which can reduce blood flow to the brain even more. Some people feel dizzy or faint and may be injured in falls. Others have constant headaches, brain fog, light and sound sensitivity or lightheadedness. Research also suggests that ongoing strain on the sympathetic nervous system may affect organs such as the heart and kidneys over time (5).
When the brain doesn’t get enough blood flow, many symptoms can appear. Your brain uses a great deal of energy, and when its supply is disrupted, many brain functions can be affected. Simple thinking tasks can feel like huge challenges, and simple physical tasks can be exhausting. Managing emotions can become very difficult. Nearly everything your brain does depends on steady blood flow, so when that system struggles, almost everything can feel like a struggle (4).
The Inner Ear’s Role in Blood Pressure
Your inner ear does more than help you balance. Through a reflex called the vestibulosympathetic reflex, signals from your inner ear reach blood pressure control centers in the brainstem and help adjust blood pressure and heart rate when you change position. This reflex responds to head movement before blood pressure has a chance to fall, while the baroreceptor reflex, which senses blood pressure in the large arteries, takes a second or two to catch up. That head start matters when you stand up quickly (6).
To use inner ear signals well, the brain has to clean them up. The inner ear’s motion sensors, the semicircular canals, give an imperfect signal, and its gravity sensors, the otoliths, can’t tell the difference between tilting your head and moving in a straight line. The brainstem and cerebellum solve these problems with a process called velocity storage, which combines and smooths these signals to estimate how your head is really moving and which way is down (6).
A 2022 study in the Annals of Clinical and Translational Neurology looked at 53 people with vestibular syncope, meaning fainting triggered by vertigo (7). More than a third had repeated episodes, and about 13% had potentially life-threatening injuries from falls. Abnormal inner ear tests were common, including abnormal head impulse tests in 31%, and about 1 in 5 also had orthostatic hypotension. The researchers proposed that when velocity storage produces a false sense of motion, the brain may adjust blood pressure for a position change that never happened. The baroreceptor reflex can then overcorrect, slowing the heart and dropping blood pressure, which can lead to fainting (7, 8).
A concussion can affect the inner ear, the brainstem and the cerebellum, the same systems involved in velocity storage and the vestibulosympathetic reflex. This research helps explain how problems in how the brain processes motion and gravity after a concussion may contribute to autonomic symptoms, and it is a core part of how we approach post-concussive dysautonomia.
That’s why we measure these systems so carefully. Videonystagmography (VNG) records eye movements that reflect how the brainstem and cerebellum are processing inner ear signals, including velocity storage. The video head impulse test (vHIT) measures how well each semicircular canal is working. CAPS computerized posturography shows how well your brain uses inner ear, visual and body-position information to stay upright.
How Is Post-Concussive Dysautonomia Usually Treated?
There is no established cure for post-concussive dysautonomia. It is usually managed with lifestyle changes, diet and a gradual exercise program (9, 10). Some people benefit from medications that help the body hold on to salt and increase blood volume, or medications that calm the sympathetic nervous system (2, 11). These treatments can help many people manage their symptoms.
How the NeuroRescue Program Can Help
Our care is designed to work alongside your physician, cardiologist and other providers, never in place of them. Please don’t change or stop any medication, or make changes to salt or fluid intake, without talking with your medical provider.
One of the brain’s most important jobs is figuring out where you are in the world. It uses your inner ear to sense where your head is in relation to gravity and how it’s moving, your muscles and joints to sense where your body is and what it’s doing, and your eyes to sense where you are in relation to everything around you. Your brain combines all of this into a picture of where you are, so you can respond to the world around you.
Your brain organizes this information as a set of maps: a vestibular map from your inner ear, a body map from your muscles and joints, a visual map from your eyes, and others. These maps need to agree with each other about where you are.
After a concussion, these maps may not match. Your eyes, inner ear and body may be sending different messages about where your head is in relation to gravity. Your inner ear also helps your body adjust blood pressure when you change position (6). When you go from lying down to sitting or standing, mismatched signals may make it harder for your brain to adjust blood flow to your head. Eye movement exercises can activate brain and brainstem areas involved in autonomic control (12).
Our approach is to first work on improving how your visual, vestibular and body-position systems function on their own. Then we gradually train them together in different positions relative to gravity, with the goal of helping your nervous system respond more appropriately when you change position.
Depending on your needs and test results, your program may include specific eye exercises (13), vestibular therapy (14), electrical stimulation (15), light therapy, also called photobiomodulation (16), and exercises in a virtual reality environment (17). The therapies we recommend are always chosen based on your testing and exam findings.
How the NeuroRescue Program Works
Your NeuroRescue Program begins with your Discovery Day. We start with a detailed history of your condition and your life on a timeline. This helps us understand the factors that may have contributed to where you are now, and identify related conditions that may be making it harder to move forward.
We measure how your visual, vestibular and balance systems are working through computerized analysis of your eye movements, inner ear reflexes and balance under different conditions. Our testing includes videonystagmography and saccadometry to measure several types of eye movements, the video head impulse test to measure inner ear reflexes, and CAPS computerized posturography to assess your balance under different sensory conditions. We also use NeuroSensoryMotor Integration testing to evaluate hand-eye coordination and cognition, and Virtualis testing to assess dynamic eye tracking and your perception of vertical in a virtual reality environment.
We combine this with a thorough physical and neurological exam of your sensory, motor, autonomic and cognitive systems, including a passive tilt table test to see how your heart rate and blood pressure respond when you’re tilted upright (18). We also review any relevant lab work, imaging and prior testing, and integrate it with our findings.
Together, this helps us understand which parts of your nervous system are working well, which are struggling, and how quickly they tire. We use that information to design your personal NeuroRescue Program, aimed at improving function in the systems that need support and helping them work together. Our testing also helps us decide when to push and when to let you rest, which matters when pushing too hard can leave you wiped out for days.
Our goal is to help you build tolerance for being upright, so you can stand, think and get through your day with more energy and less dizziness.
Your Next Step
Living with dysautonomia after a concussion can be exhausting, and it’s often invisible to the people around you. You don’t have to keep pushing through alone. To find out if the NeuroRescue Program is right for you, contact one of our patient care coordinators to schedule your Discovery Day.
It’s never too late to take the next step.
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