What Is Hemiparesis and What Causes It?

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Hemiparesis is partial  weakness on one side of the body. Hemiparesis can affect either the left or right side of the body. The weakness may involve the arms, hands, legs, face or a combination. Almost 80 percent of stroke survivors experience hemiparesis, making it one of the most common effects of a stroke.

People who have hemiparesis are still able to move the affected side of the body, but with limited strength.

One side of the body may become completely weak, and this condition this is called hemiplegia.

Causes 

In addition to stroke, hemiparesis can be caused by a number of other medical conditions. The most common causes of hemiparesis are the following:

  • Stroke
  • Multiple sclerosis
  • Traumatic injury- may affect the brain, spine or nerves
  • Congenital medical conditions- medical conditions such as cerebral palsy that are present from birth may cause weakness of one side of the body
  • Spine disease
  • A tumor of the brain or spine
  • Infection of the brain, spine or meninges
  • Psychological  and psychiatric conditions can cause temporary weakness
  • Post ictal paralysis- temporary weakness after a seizure
  • Inflammatory and autoimmune conditions

Symptoms 

The most obvious symptom of hemiparesis is the partial paralysis of one side of the body. Symptoms correspond to the side of the brain or spine that has been damaged. An injury to the left side of the brain typically results in weakness on the right side of the body.

An injury to the right side of the brain typically results in weakness on the left side of the body.

Depending on the type of spine injury and the level of injury within the spine, hemiparesis may involve the same side of the body as the spine injury, or may involve the opposite side.

Some symptoms of hemiparesis include the following:

  • Inability to maintain balance
  • Difficulty walking
  • Inability to grasp objects
  • Decreased precision in movement
  • Muscle fatigue
  • Lack of coordination
  • Leaning to one side while standing, walking or sitting
  • Loss of bowel or bladder control

Diagnosis 

If you complain of any of the symptoms of hemiparesis, your doctor will do a physical examination. It can be difficult to determine whether your symptoms are the result of weakness, pain or another cause. The physical examination includes a test of your reflexes, your sensation and your strength, and your doctor will 'rate' your strength on a scale of 1-5. This rating can also help when the same doctor or other doctors assess your strength at a later time, as it can be used as a comparison.

The rating scale for muscle strength is as follows:

0/5 No movement

1/5 Mild muscle twitching

2/5 Movements from side to side, but cannot lift the arm or leg up against gravity

3/5 Can move up against gravity, but not against any force, such as mild pushing by the examiner

4/5 Can move against force, such as pushing by the examiner, but not with normal expected strength

5/5 Can move against force with expected strength

Diagnosis of the cause of hemiparesis can also be confirmed with imaging studies, which may include the following:

  • Brain or Spine CT scan
  • Brain or Spine MRI

Treatment 

Treatment of hemiparesis is first directed towards targeted treatment of the cause, whether the cause is a stroke, a brain tumor or an infection etc.

The goal of long term treatment of hemiparesis is to build strengthened motor skills and coordination and to improve your ability to manage  everyday activities.

Recovery 

Physical and occupational therapy are important in the recovery of hemiparesis. Therapy may include the use of electrical stimulation to the brain, imagery, the use of assistive devices such as a cane, walker or wheelchair. Fortunately, hemiparesis is not a progressive condition unless there is evidence of an aggressive, growing brain tumor.

Modifications to the home may need to be made to accommodate and help increase mobility. Some of the modifications may include:

  • Grab bars
  • Ramps
  • Raised toilet seats
  • A bench in the tub
  • Non-slip adhesive strips in the bathtub
  • Electric toothbrushes
  • Electric razors

A Word From Verywell

Hemiparesis is a common manifestation of neurological disease. Most often affecting the arm, leg or both, hemiparesis makes it difficult to maintain a normal level of independent daily activities, and it is one of the leading causes of disability. Stroke is the most common cause of hemiparesis, and that is why stroke prevention is an important part of healthy living that everyone should know about.

Sources:

Rehabilitation of Motor Function after Stroke: A Multiple Systematic Review Focused on Techniques to Stimulate Upper Extremity Recovery, Hatem SM, Saussez G, Della Faille M, Prist V, Zhang X, Dispa D, Bleyenheuft Y, Front Hum Neurosci. 2016 Sep 13;10:442

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