Hemiparesis is partial weakness and reduced control of movement on one side of the body and face. It can make it hard to balance, walk, grasp objects, move precisely and coordinate movements, and it can have a major impact on everyday activities.
Call 911 right away for any new stroke symptoms, such as sudden face drooping, arm or leg weakness, numbness, trouble speaking, vision loss, severe dizziness or a sudden severe headache. Fast treatment matters.
How Common Is Hemiparesis?
Hemiparesis is most often caused by a stroke. Hundreds of thousands of strokes happen in the U.S. each year, and about 80% of people who have a stroke have some degree of hemiparesis. About 1.7% of people in the U.S., more than 5 million, report living with some form of paralysis (1).
What Are the Symptoms of Hemiparesis?
The main symptom of hemiparesis is reduced control of movement on one side of the body. This can affect many parts of daily life (2):
Loss of balance
Trouble walking
Trouble grasping objects
Less precise movements
Muscle fatigue
Loss of coordination
Weakness on the right side of the body means the left side of the brain was injured. This can also affect speech and language, making it hard to speak or understand others, and it can affect the ability to tell left from right.
Weakness on the left side of the body means the right side of the brain was injured. This can affect attention, memory, awareness of the left side of the body and space, nonverbal communication and behavior. Some people also talk more than usual or have a shorter attention span (3).
Other short- and long-term complications can include (4):
Breathing problems
Muscle wasting
Trouble with bowel control
Trouble emptying the bladder, or loss of bladder control
Muscle stiffness and spasms (spasticity)
What Causes Hemiparesis?
Hemiparesis is usually caused by a stroke, but it can also result from a traumatic brain injury, a brain tumor, multiple sclerosis, cerebral palsy, a brain infection and other conditions. Where the injury happens determines where the weakness occurs and how severe it is (2).
What Happens in the Brain With Hemiparesis?
The brain is made of many types of cells. The ones we usually think of as brain cells are neurons. To survive, neurons need a constant blood supply to deliver oxygen and glucose.
A stroke disrupts this blood supply. This can set off a chain reaction called the ischemic cascade. Without enough oxygen, the cell’s energy production fails, and a flood of a brain chemical called glutamate pushes neurons to fire faster than they can keep up with. This produces damaging molecules called free radicals and lets calcium rush into the cell, breaking down its proteins and eventually killing the neuron (4).
The walls of blood vessels can also break down from enzymes released by damaged cells. This can damage the blood-brain barrier and cause brain swelling, which can lead to further injury (5).
The main pathway affected in hemiparesis is the corticospinal tract. This long pathway starts in the brain’s motor cortex, runs down through the brainstem, crosses to the other side in the lower brainstem and continues down the spinal cord to control the arm and leg. An injury anywhere along this path can cause hemiparesis. In hemiparesis, the pathway is partly damaged, while in hemiplegia, it is fully disrupted and the arm and leg can’t move (6).
How Is Hemiparesis Diagnosed?
A physical and neurological exam can reveal signs of a stroke, such as changes in walking, speech problems and weakness (7). Imaging such as MRI and CT helps identify the area of injury and the blood vessel involved. Lab tests, such as cholesterol levels and markers of inflammation, are also commonly used.
How Is Hemiparesis Usually Treated?
In a sudden stroke, emergency treatment may be needed to break up or remove a blood clot, stabilize a blood vessel or relieve pressure on the brain. Medications to reduce clotting, lower blood pressure and lower cholesterol are commonly used to help prevent future strokes.
The movement, thinking and other neurological problems that follow a stroke are usually treated with physical, occupational and speech therapy (8). These therapies are very helpful. As recovery slows, many programs shift more toward teaching people ways to work around lost abilities. Our care focuses on continuing to look for ways to improve function in the systems that remain.
How the NeuroRescue Program Can Help
Our care is designed to work alongside your physician, neurologist and stroke rehabilitation team, never in place of them. Please don’t change or stop any medication, including blood thinners or blood pressure medication, without talking with your prescriber.
One important idea in stroke recovery is called diaschisis. Nerve cells need three main things to stay healthy: glucose, oxygen and activity. They need ongoing stimulation to keep making the proteins and other parts they need to stay healthy and work well. In a stroke, nerve cells supplied by the blocked or burst blood vessel lose their supply of glucose and oxygen, and many are lost unless blood flow is restored quickly.
No one can bring back nerve cells that have been lost. But the lost cells usually aren’t the only reason for the symptoms after a stroke.
That’s where diaschisis comes in. Each nerve cell receives signals from thousands of other nerve cells, and that input helps keep it active and healthy. When nerve cells are lost in a stroke, other nerve cells they connected to, even in areas with a normal blood supply, can lose that input. Those cells may become less active, lose endurance and tire easily, even though they still get plenty of glucose and oxygen (9).
These weakened but still-living nerve cells need the right amount of activity. Too little activity can leave them underused, while too much can overwhelm them. But if we can find another pathway that feeds into these cells, and activate it at a level they can handle, it may help rebuild function in the affected areas.
This idea guides our approach to stroke rehabilitation. We use detailed testing to look not only at which areas are damaged, but also at which systems are still working but weakened. We look for pathways we can use to support those weakened systems, and we adjust how much and how often we stimulate them so they’re challenged without being overwhelmed. Then we choose therapies based on what your nervous system needs, with the goal of helping you recover as much function as possible.
Electrical stimulation. Gentle electrical stimulation of the nerves through the skin, called repetitive peripheral sensory stimulation, can stimulate the brain through the nerves of the body. It has been studied for improving movement in people with hemiparesis after stroke (10).
Light therapy. Photobiomodulation uses low-level laser and LED light. It has been studied as a way to support nerve cell energy and function after a stroke and other blood vessel injuries (11, 12).
Transcranial magnetic stimulation. TMS uses magnetic pulses to stimulate specific areas of the brain. It has been studied for restoring movement and for chronic pain after a stroke (13, 14). TMS is generally safe and well tolerated. At our clinic, TMS is provided by our psychiatric mental health nurse practitioner, who will evaluate whether it may be appropriate for you.
Balance and vestibular therapy. Balance problems are very common after a stroke and raise the risk of falls, including head injuries. Reducing fall risk is a priority in our care. Vestibular therapy has been shown to help improve balance after a stroke (15).
Vision and eye movements. Vision is often affected after a stroke. People may have trouble mapping their surroundings and their body, keeping their eyes steady on a target, following moving objects or handling busy visual environments, and some lose part of their field of vision. We use visual exercises and rehabilitation tailored to your needs, an approach supported by research (16). Certain eye movement exercises have also been studied for supporting thinking and executive function (17), and one study found improvements in brain wave activity and symptom scores after stroke (18).
Constraint-induced movement therapy. Sometimes the best way to help a weak arm is to limit use of the stronger arm while doing intensive practice with the weaker one. This approach can help improve movement over time (19).
Mirror therapy. Mirror therapy uses a mirror image of your stronger limb to give your brain a different picture of the weaker limb during movement exercises (20). It has also been studied in a virtual reality environment (21), and we use our Virtualis system for this.
Spinal adjustments. Research suggests spinal adjustments may do more than move a joint. Studies using EEG, brain stimulation and brain imaging have found that adjustments can produce short-term changes in how the brain processes sensory and movement information, including in the prefrontal cortex and the areas that plan and control movement (22, 23, 24, 25). One study in people with chronic stroke found that a single adjustment session increased the brain’s drive to a weakened leg muscle compared with a control, though it didn’t measure whether strength or walking improved (26), and joint manipulation has also been studied for movement after stroke (27). Researchers are still working to understand how long these changes last and how they relate to symptoms, but they help explain why we look at how your whole nervous system is working, not just your spine. Chiropractic adjustments are used when appropriate and safe for you, along with physical exercise and soft tissue therapies.
Some programs include mild hyperbaric therapy as a structured recovery option between more demanding therapy sessions. 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. 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.
Our goal is to help you regain as much control, strength and confidence in your movement as possible, so you can do more of what matters to you.
Your Next Step
Living with weakness after a stroke or brain injury can be frustrating and exhausting, but recovery can continue long after the hospital. You don’t have to do it alone. To find out if the NeuroRescue Program is right for you, contact one of our patient care coordinators to schedule your Discovery Day.
