Understanding Hemiparesis: Weakness on One Side of the Body

Hemiparesis involves weakness on one side of the body. It is a secondary effect of injury to the central nervous system. Because of this, treatment involves engaging the central nervous system’s natural ability to rewire and heal itself. This guide will explain how that works, along with the causes and treatments available for hemiparesis.

Table of contents

• Causes
• Treatment
• Therapies
• Timeline

Causes of Hemiparesis

Hemiparesis is most commonly caused by a stroke. When a stroke occurs, the supply of blood in the brain becomes disrupted, which causes brain cells to die.

When a stroke affects the areas of the brain responsible for movement, it can cause issues with motor control such as hemiparesis or hemiplegia. Hemiparesis involves weakness on one side of the body while hemiplegia involves paralysis on one side of the body.

Each hemisphere of the brain controls movement on the opposite side of the body. Therefore, hemiparesis typically affects the side of the body opposite to the side of the stroke.

For example, a left hemisphere stroke may cause right-sided hemiparesis while a right hemisphere stroke may cause left-sided hemiparesis. However, some strokes or brain injuries can cause muscle weakness on the same side as the injury, which is called ipsilateral hemiparesis.

Hemiparesis is common in stroke survivors, with almost eight out of every ten survivors experiencing it. This is because movement is a brain-wide function. Not only does the motor cortex play a role in the ability to move, but other areas of the brain, such as the cerebellum, also contribute. As a result, there is an increased risk of a stroke or brain injury affecting an area of the brain that contributes to movement.

Stroke is not the only cause of hemiparesis. The condition can also be caused by cerebral palsy, brain injury, or other diseases that affect the nervous system or brain such as cancers or tumors. These causes are less common but still prevalent.

Treatment for Hemiparesis

Hemiparesis occurs as a secondary effect of damage to the brain or central nervous system. Fortunately, the central nervous system can heal itself through the phenomenon of neuroplasticity. This is how neural pathways are created, reorganized, and strengthened.

Neuroplasticity occurs based on demand: the tasks that you practice most frequently are the neural pathways that will be the strongest. This is why everyday tasks like tying your shoes eventually become “thoughtless.” Because you’ve practiced it a thousand times, the neural pathways for that skill are very strong.

When hemiparesis is involved, neuroplasticity helps the brain create and strengthen new pathways that control movement. The stronger these pathways become, the more strength and coordination the individual will have with their affected side.

Rehabilitative therapies, such as physical and occupational therapy, all focus on neuroplasticity and are crucial for helping survivors regain movement. This is important for regaining independence and the ability to accomplish daily activities.

Therapies Available for Hemiparesis

Therapy for hemiparesis falls under the category of neurorehabilitation, which aims to rehabilitate the nervous system.

It’s important to know that hemiparesis recovery is a long-game. Neuroplasticity does not occur overnight. It requires repetitive training (as you’re about to learn) and a consistent rehabilitation program to keep recovery going.

With that said, here are some effective, evidence-based therapies available for hemiparesis:

Massed Practice / Repetitive Practice

It’s well-known that neuroplasticity occurs based on frequency and consistency. The more we practice a task, the better we get at it. This is referred to as “massed practice,” and it’s an essential ingredient in hemiparesis recovery.

Repeating skilled movements with the weakened side is essential for engaging neuroplasticity and improving motor control. Massed practice is the foundation that all other therapies build upon.

Physical Therapy

During physical therapy, individuals are guided through specific exercises that help restore optimal functioning. A physical therapist understands how to prescribe exercises for individuals with hemiparesis that target their affected limbs with the right amount of challenge (not too easy, not too difficult).

Physical therapy exercises help retrain the affected limbs through repetitive practice. The more the individual exercises their affected side, the more neuroplasticity occurs in response.

Occupational Therapy

While physical therapy focuses on restoring optimal movement functions, occupational therapy focuses on helping individuals increase their independence with activities of daily living (such as dressing, bathing, and self-feeding). Occupational therapists help prescribe exercises that are functional and task-specific (such as lifting a cup and placing it back down) and suggest compensation techniques to help the individual navigate their new life (such as using cups with handles).

Compensation techniques help individuals with hemiparesis accomplish difficult tasks by using shortcuts. Although this does not help with motor recovery, compensation is often necessary to carry out essential daily tasks effectively. As long as the individual continues to exercise their affected side on a regular basis, they can continue to maximize their chances of motor recovery.

Home Exercise Programs

Depending on the frequency of your rehabilitation sessions, many therapists will suggest participating in a home exercise program to continue building upon the skills you’ve learned in therapy. It is essential to continue practicing outside of therapy sessions to optimize neuroplasticity and functional recovery.

Most insurance plans cover a limited amount of physical and occupational therapy for individuals with neurological injuries. Once insurance stops covering therapy, individuals may see their therapist just once per week, if at all. This is where home exercise programs become even more important, as they can help individuals continue to improve movement by practicing therapeutic exercises with massed practice at home.

To help individuals stay motivated at home, you can look for interactive, at-home therapy devices such as Flint Rehab’s FitMi. The FitMi turns regular rehab exercises into an engaging game. Individuals usually accomplish hundreds, if not thousands, of repetitions per exercise session, which helps incorporate massed practice at home.

Electrical Stimulation

During electrical stimulation therapy, electrical currents are applied to your muscles through pads on the skin. This helps stimulate movement on the weakened side. For example, if an individual struggles with hand or wrist movement, a therapist can apply electrical stimulation to the muscles in the forearm, which contract when stimulated and help flex and/or extend the wrist and fingers, depending on the placement.

While e-stim can be used alone, it leads to more improvement when combined with task-related training.

Constraint-Induced Movement Therapy

Constraint-Induced Movement Therapy (CIMT) is a popular treatment for hemiparesis. It involves restraining your unaffected side while exercising your affected side for several hours a day for 10-15 consecutive weekdays. Although CIMT is most commonly used for affected arms/hands, it is becoming a more utilized treatment for affected lower extremities as well. This therapy is aggressive in the volume of therapy required, which could explain why there’s an abundance of evidence supporting it for recovery of arm/hand function.

Mirror Therapy

Another evidence-based treatment for hemiparesis is mirror therapy. During this therapy, a mirror is placed over the hemiparetic arm or leg. Then, the individual practices rehab exercises with their stronger arm or leg while watching the moving image in the mirror. This mirror image “tricks” the brain into thinking both arms or legs are moving, which helps spark neuroplasticity.

Mental Practice

All of these treatments for hemiparesis involve active movement. Surprisingly, there’s another treatment available that requires no movement at all: mental practice. This involves mentally rehearsing specific activities to improve performance of those activities.

Although mental practice is a cognitive, not physical, treatment for hemiparesis, it helps activate neuroplasticity and trigger cortical changes.

Evidence shows that better results occur when mental practice is combined with other physically active therapies. For example, individuals with hemiparesis can spend time before physical therapy mentally rehearsing their exercises before actually performing them.

Botox

Spasticity involves tightness in the muscles after a neurological injury. It affects about 25% of stroke survivors. When muscle stiffness from spasticity prevents individuals from participating in rehabilitative therapies, treating the spasticity with medications like Botox or baclofen can help.

Botox is a “nerve block” that blocks the signals that cause the muscles to contract. This injectable treatment provides relief for about 3 months, after which individuals can receive repeat treatments. During this period of relaxed muscles, individuals can focus on accomplishing massed practice of rehabilitation exercises to help rewire the brain and address the root cause of hemiparesis.

Baclofen

Baclofen is a medication that helps relax spastic muscles. Just like Botox, results are temporary, but they offer a window of opportunity to pursue rehabilitation exercise. As with Botox, improvements made while under the medication’s effects can carryover even when the medication wears off due to neuroplasticity.

Orthotics

The use of orthotics may be recommended to stabilize, support, or stretch affected muscles. For example, an ankle-foot orthosis (AFO) may be used to support the muscles of the ankle if a survivor experiences foot drop, while a hand splint may be used to stretch the muscles of affected fingers. Ideally, orthotics should be used short-term with other rehabilitation exercises, as over time the affected movements should improve and the orthotic will no longer be needed.

As with all treatments for hemiparesis, a combination of therapies usually works best. Talk to your doctor and therapists to explore your options and decide which approaches are best for you.

How Long Does Hemiparesis Recovery Take?

Recovery from neurological injury is different for every person because every injury is different. Every person’s brain is wired differently, and every injury impacts different neural pathways.

Hemiparesis looks different in every individual. Each person’s brain is wired a bit differently, which makes recovery after every neurological injury unique.  As a result, it can be challenging to predict recovery outcomes and timing. However, there are some general patterns that can help you understand what to expect.

After a stroke or brain injury, the brain enters a phase of heightened neuroplasticity as it attempts to rapidly heal from the injury. When this state slows down, it results in a “plateau” that many survivors are familiar with.

This plateau often occurs at the 3-month mark. Individuals with hemiparesis can make incredible gains during this time, especially when frequently participating in inpatient and outpatient therapy sessions.

Beyond the 3 month mark, recovery becomes contingent upon your consistency with home therapy. When rehabilitation and home programs are ignored, survivors tend to remain at the same level of ability. But when rehabilitation is pursued, even after stopping for months or years, recovery can continue.

See our stroke recovery timeline to see videos from survivors at all stages of recovery who are improving because they are pursuing recovery at home.

Outlook

Hemiparesis occurs as a secondary effect of neurological injury. Fortunately, the central nervous system is able to heal and repair itself via neuroplasticity. This is how neural pathways are created, reorganized, and strengthened.

Through massed practice and other rehabilitative therapies, individuals with hemiparesis can improve movement on their weakened side. Diligence with home therapy is important because neuroplasticity requires repetition and consistency to occur.

We hope this guide has helped educate and motivate you on the road to recovery with hemiplegia.