Hemiparesis refers to weakness in one leg, arm, or side of the face. Hemiplegia describes severe or complete unilateral loss of strength or paralysis. Both may result from a stroke and other conditions.

Hemiparesis and hemiplegia may have the same cause, but depending on the severity and location of brain and spinal damage, you may develop one or the other.

Hemiparesis can range from minor to severe weakness — as in loss of strength — resulting in:

  • difficulty standing
  • difficulty walking
  • lack of coordination
  • loss of balance
  • difficulty or inability to raise the affected arm or leg
  • drooping eyelid or corner of the mouth
  • unusual sensations in the affected side of the body
  • strain on the unaffected side of the body caused by overcompensation

Hemiplegia is more severe than hemiparesis. It involves a complete loss of strength or paralysis (inability to move) on one side of the body. It may affect your arm, face, or leg only, or all of them.

Although the paralysis may not be extensive (whole body), it could affect your ability to:

  • breath
  • swallow
  • speak
  • control your bladder
  • control your bowel
  • move one side of your body

Your brain and spinal cord control muscle movement. If either a region of your brain or spinal cord is damaged, they’re not able to direct this function.

Most cases of hemiparesis and hemiplegia are caused by strokes. Depending on the site and type of stroke, symptoms of hemiparesis or hemiplegia may be of various severity levels.

Read about other early signs and symptoms of a stroke.

Other causes of hemiparesis and hemiplegia may include:

Your spinal cord and brain have a left side and a right side. The halves are identical. Each half controls the movements on one side of the body.

An injury to one side of the spinal cord or brain may result in weakness or paralysis on the side of the body that half controls.

If you have multiple strokes on both sides of the brain, you may experience hemiparesis or hemiplegia on both sides of the body.

Read about how a stroke affects your body.

A doctor will most likely use a number of diagnostic procedures and imaging tests to diagnose hemiparesis and hemiplegia.

These might include:

Developing hemiparesis or hemiplegia after a stroke or brain injury may result in short- and long-term health complications, such as:

Treatments for either hemiparesis or hemiplegia focus on addressing the root cause. Recovery is possible, but you may need to follow a treatment plan for months. Improvement may be gradual.

To treat the weakness or paralysis, doctors may recommend:

  • Physical therapy (PT): In this targeted training, a physical therapist can stimulate your muscles to prevent muscle spasticity and atrophy while keeping joints flexible and loose.
  • Occupational therapy (OT): This therapy can help you develop skills to compensate for the difficulty moving one part of your body. You may learn methods and techniques for taking care of common and practical activities.
  • Mobility aids: Support, like wheelchairs and walkers, may be needed to allow you to do some of these activities on your own.
  • Adaptive equipment: Devices that facilitate driving, cleaning, eating, and other practical daily tasks can make life easier.
  • Assistive technology: Voice-activated devices such as telephones and computers can help with home and work productivity.
  • Alternative treatments: Other treatments may include dietary changes or acupuncture.

Hemiparesis is a mild or partial weakness on one side of the body. Hemiplegia is a severe or complete loss of strength or paralysis on one side of the body.

The difference between the two conditions primarily lies in severity. They can both be:

  • the result of the same causes, like a stroke
  • diagnosed the same way
  • treated similarly

Following diagnosis, a doctor can put together a treatment plan which may include physical and occupational therapies. Recovery is possible but may take weeks to months.