What is paralysis?

Paralysis is a loss of strength in and control over a muscle or group of muscles in a part of the body. Most of the time, this is not due to a problem with the muscles themselves. It is more likely due to a problem somewhere along the chain of nerve cells that runs from the body part to your brain and back again. These nerve cells deliver the signals for your muscles to move.

There are many types and degrees of paralysis. It can be partial, when you still have some control of your muscles, or complete, when you can’t move your muscles at all. It can be permanent, when muscle control never comes back, or temporary, when some or all muscle control returns. Paralysis can also be flaccid, when the muscles get flabby and shrink, or spastic, when the muscles are tight and hard and jerk around oddly (spasm).

Paralysis can occur in any part of the body and is either localized, when it affects only one part of the body, or generalized, when it affects a wider area of the body. Localized paralysis often affects areas such as the face, hands or vocal cords. Generalized paralysis is broken down based on how much of the body is paralyzed:

  • Monoplegia – affects one limb only, such as one arm or one leg
  • Diplegia -- affects the same area on both sides of the body, such as both arms or both sides of the face
  • Hemiplegia – affects one side of the body, such as the leg and arm of the same side of the body
  • Paraplegia – affects both legs and sometimes parts of the lower half of the body
  • Quadriplegia -- affects both arms and both legs and sometimes the entire area from the neck down. The function of the heart, lungs, and other organs might also be affected.

What causes paralysis?

Muscle movement is controlled by trigger signals relayed from the brain. When any part of the relay system – such as the brain, nerves or spinal cord – is damaged, the signals to move do not make it through to the muscles and paralysis results. There are many ways the relay system can be damaged.

A person can be born with paralysis due to a birth defect such as spina bifida, which occurs when the brain, spinal cord and/or the covering that protects them do not form the right way. In most cases, people get paralysis as the result of an accident or a medical condition that affects the way muscles and nerves function. The most common causes of paralysis include:

  • Stroke
  • Spinal cord injury
  • Multiple sclerosis

Some other causes include:

  • Head injury
  • Cerebral palsy
  • Guillain-Barre syndrome
  • Toxins/poisons

What are the symptoms of paralysis?

Symptoms of paralysis may vary based on the cause, but are often easy to spot. A person born paralyzed due to a birth defect or paralyzed suddenly due to a head or spinal cord injury will not be able to move and will have little or no feeling in the affected body parts. Someone who becomes paralyzed due to a medical condition might lose muscle control and feeling slowly. The person might feel tingling or numbing sensations, weakness or muscle cramps before losing control of his or her muscles.

How common is paralysis?

A study called the Paralysis Population Survey, which was started by the Christopher and Dana Reeve Foundation and conducted by the University of New Mexico’s Center for Development and Disability, found that nearly one in 50 Americans is living with some form of paralysis – about six million people.

How does the doctor diagnose paralysis?

Diagnosing paralysis is often easy to do because the main symptoms – loss of muscle control and loss of feeling in a body part – are obvious. Diagnosis is aided further if the paralysis occurs after an event such as a stroke or spinal cord injury. Sometimes, the doctor might want to learn more about the injury that’s causing your paralysis, the degree of the paralysis and/or the state of the nerves involved. To do that, the doctor might use one or more of these tests:

  • X-ray – This test uses small amounts of radiation to produce detailed images of the dense structures inside the body, such as the bones.
  • CT scan – CT uses computers to combine many X-ray images into cross-sectional views of the inside of the body.
  • MRI – MRI uses a large magnet, radio waves and a computer to create clear images of the body.
  • Myelography – This test uses a contrast dye that is injected into the spinal canal to make the nerves show up very clearly on an X-ray, CT scan, or MRI.
  • Electromyography (EMG) – This test is used to measure the electrical activity in the muscles and nerves.

How is paralysis treated?

Currently, there is no cure for paralysis. In certain cases, some or all muscle control and feeling returns on its own or after treatment. For example, this occurs in cases of Bell’s palsy, a temporary paralysis of the face. It might also occur to some extent with therapy after a stroke.

The goals of treatment are to address any problems that can occur along with the paralysis, to enable the paralyzed person to live as independently as possible and to provide the person with a high quality of life. Some of the treatments used for people with paralysis include:

  • Physical therapy – uses treatments such as heat, massage and exercise to stimulate nerves and muscles
  • Occupational therapy – concentrates on ways to perform activities of daily living
  • Mobility aids – including manual and electric wheelchairs and scooters
  • Supportive devices – such as braces, canes and walkers
  • Assistive technology – such as voice-activated computers, lighting systems and telephones
  • Adaptive equipment – such as special eating utensils and controls for driving your car

What other problems can occur with paralysis?

Because paralysis can happen to any muscle or group of muscles, many body functions can be affected. Some of the problems that can occur along with paralysis include:

  • Problems with blood flow, breathing and heart rate
  • Changes in the normal function of organs, glands and other tissues
  • Changes to muscles, joints and bones
  • Skin injuries and pressure sores
  • Blood clots in the legs
  • Loss of urine and bowel control
  • Sexual problems
  • Problems speaking or swallowing
  • Behavior changes

What is the outlook for people with paralysis?

Paralysis, especially sudden paralysis, leads to many emotions. For this reason, depression is common in people with paralysis. Help is available to cope with this difficult life transition. Having paralysis requires making major changes to your way of life. People with some types of paralysis, such as monoplegia, hemiplegia and paraplegia, can usually lead independent and active lives with the help of mobility aids and supportive and adaptive devices. While people with quadriplegia need lifelong care and support from others, they can still live happy and fulfilling lives.

When should I call my health care provider?

Call your health care provider if you experience any numbing or tingling feelings in your muscles, or if you suddenly cannot move a muscle or body part.

Also, call 9-1-1 right away if you have any of the signs of a stroke. A stroke is a medical emergency and effective treatments are available, but they must be started within a few hours after stroke symptoms begin. The American Stroke Association’s signs of a stroke include the sudden onset of:

  • Drooping face
  • Weakness in an arm
  • Speech problems
  • Numbness or weakness of a leg
  • Confusion and trouble understanding
  • Trouble seeing in one or both eyes
  • Trouble walking, dizziness, loss of balance or coordination
  • Headache with no known cause


This article was reviewed by Frederick Frost, MD. Dr. Frost is a Cleveland Clinic staff physician with board certification in physical medicine and rehabilitation and spinal cord injury medicine. He is the Chairman of Cleveland Clinic’s Department of Physical Medicine and Rehabilitation as well as the Executive Director of Cleveland Clinic Rehabilitation and Sports Therapy.

© Copyright 1995-2014 The Cleveland Clinic Foundation. All rights reserved.

This information is provided by the Cleveland Clinic and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition. This document was last reviewed on: 12/16/2013…#15345