Left-Sided Strokes: What to Expect

The left side of the brain is considered the dominant hemisphere

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A stroke occurs when a lack of blood supply or bleeding causes damage to a region in the brain. Strokes in different parts of the brain cause different symptoms. A left-sided stroke is a stroke that damages the left side of the brain. This type of stroke typically causes language and speech problems, as well as physical symptoms that affect the right side of the body.

This article will discuss the types of strokes, signs, effects, treatment, and prevention.

Possible Effects of a Left-Sided Stroke - Illustration by Daniel Fishel

Verywell / Daniel Fishel

Types of Strokes

Most of the time, strokes are caused by insufficient blood supply to a region of the brain. Ischemia is a lack of blood supply due to blockage or narrowing of a blood vessel. 

Sometimes, a stroke can occur due to a hemorrhage (bleeding) often caused by a leaking blood vessel.

Ischemic

An ischemic stroke causes damage to a region of the brain that is supplied by the blood vessel that is obstructed (blocked).

This type of stroke can occur due to atherosclerotic disease within the blood vessels of the brain (hardening and narrowing due to a buildup of cholesterol plaques). Changes in blood vessels leading to narrowing and ischemic stroke may also be caused by high blood pressure, diabetes, and smoking.

Ischemic strokes may also occur due to a blood clot traveling to the brain from the heart or the carotid artery.

Hemorrhagic 

A hemorrhagic stroke can occur due to a ruptured brain aneurysm (a bulging area in the wall of an artery), a damaged blood vessel that leaks, or damage that occurred during an ischemic stroke

A hemorrhagic stroke can cause tissue death (infarction) in the area of the brain that is supplied by the bleeding blood vessel. Additionally, the accumulation of blood can cause further damage in nearby areas.

Brain damage from a hemorrhagic stroke can lead to seizures (uncontrolled electrical disturbances in the brain) due to irritation from the bleeding. In some people, seizures can persist even after the blood is completely reabsorbed. This most commonly occurs when the blood affects an area of the brain that controls motor function.

Signs of a Stroke 

There are several signs of a left-sided stroke. They include:

  • Weakness in the face, arm, and/or leg on the right side of the body
  • Decreased sensation on the right side of the body 
  • Effortful or slurred speech 
  • Speaking fluently but with incorrect or nonword content
  • Difficulty understanding language
  • Changes in visual perception
  • Severe and sudden head pain 
  • Sudden dizziness or loss of balance 
  • Confusion 
  • Left-sided sensory and motor symptoms if the stroke involves areas known as the cerebellum and brain stem

Get immediate medical attention if you or someone else experiences any of these symptoms. A stroke is a medical emergency that can worsen quickly, causing disability or death. The long-term effects can be minimized if treatment is started promptly. 

Effects 

The lasting effects of a left-sided stroke range from mild to severe, depending on the size of the stroke and the timing of treatment. 

Hemiplegia and Hemiparesis on the Right Side

Hemiplegia and hemiparesis can occur on the right side of the body after a left-sided stroke, which are:

  • Hemiplegia is complete paralysis, and it can affect the right side of the face, arm, and/or leg after a left-sided stroke.
  • Hemiparesis is partial weakness with some residual strength. 

Immediately after a left-sided stroke, right-body hemiplegia or hemiparesis will be apparent. After months or longer, the weak areas of the body can become gradually stronger and more coordinated. Individuals with moderate-to-severe weakness are more likely to experience spasticity, with stiffness and tightness of the muscles. 

Decreased Sensation on the Right Side 

Diminished sensation on the right side of the body can occur after a stroke involving the left sensory cortex or the left internal capsule. Diminished sensation can involve the face, arm, and/or leg, and sometimes the torso. 

Sensory impairment can indirectly affect your ability to control your body because you rely on sensory feedback to coordinate your movements. 

In addition to decreased sensation, sometimes paresthesias can occur in the same areas that have diminished sensation. Paresthesias involve numbness, tingling, burning, or a sense of pins and needles. They can occur when the specific area of the body is touched or without a trigger. 

Aphasia 

Left-sided strokes are known to cause aphasia, which is a language deficit. There are several types of aphasia, and they occur when one or more of the speech areas of the brain are damaged. 

Wernicke’s aphasia, also called fluent aphasia, causes difficulty understanding language. A person who has this type of aphasia can speak fluently, but the words do not make sense. Wernicke’s aphasia can occur when there is damage to the language area near the left sensory cortex of the brain.  

Broca’s aphasia is a type of language deficit in which a person may have full or mildly impaired language comprehension, with difficulty forming words and sentences. This type of aphasia occurs when there is damage to the language area near the left motor cortex of the brain. 

Language Centers

Aphasia occurs when the language areas of the brain are damaged. Language is usually located on the left hemisphere of the brain. For nearly all people who are right-handed, the language functions are located on the left side of the brain. Some people who are left-handed have the language centers on the right side of the brain.

Apraxia of Speech

Speech apraxia is difficulty with the brain's control of the motor movements of speech. Unlike dysphagia, which is not specific to damage on one side of the brain and affects speech and swallowing, speech apraxia is a type of language impairment.

Apraxia of speech can begin during childhood due to developmental conditions, or it can occur as a result of damage to the left insular cortex, an area deep in the left hemisphere of the brain.

Cognitive Impairments

After a stroke affecting the left hemisphere of the brain, a person can develop difficulty thinking and making decisions. These cognitive deficits, often described as executive dysfunction, can occur due to damage of the left frontal lobe, left temporal lobe, or left parietal lobe. Generally, a larger stroke is expected to cause more severe cognitive impairments.

Homonymous Hemianopia

After a left-sided stroke involving the temporal lobe, parietal lobe or occipital cortex at the back of the brain, a person can have vision defects on the right side. Homonymous hemianopia from a left-sided stroke is vision loss on the right visual field of both eyes. It can affect the upper or lower field of vision or both. 

Treatment

A stroke should be treated immediately after symptoms begin. Calling for emergency transport to the hospital is important to get rapid and proper medical attention on arrival.

Treatment may include blood thinners, blood pressure control, and fluid management. Sometimes an interventional procedure may be needed to remove a blood clot or to relieve pressure within the skull. Advanced imaging in the emergency department may be required to help decide the risks and benefits of any potential intervention.

After your condition is stabilized, treatment focuses on recovery and rehabilitation. Physical and occupational therapy can help improve your motor control and get you as independent and physically able as possible.

After a stroke, patients who qualify for and complete a course of intensive/acute rehabilitation may have better outcomes and lower mortality (rates of death) than those who do not get this care.

Additionally, speech therapy is often needed for the management of aphasia, cognitive difficulties, and limitations with safe swallowing. All neurological rehabilitation takes time but can substantially help a person improve their ability to communicate with others and function independently.  

Prevention 

Stroke prevention is a comprehensive strategy that involves reducing the risk of cerebrovascular disease. Prevention involves medication, diet, and lifestyle approaches. 

Stroke prevention includes:

  • Smoking cessation 
  • Cholesterol and triglyceride control 
  • Blood pressure control 
  • Blood sugar control 
  • Management of heart disease, including abnormal heart rhythms such as atrial fibrillation 

After a stroke, these issues need to be cared for long term. 

Summary 

A left-sided stroke affects the left side of the brain and the right side of the body. This type of stroke can also cause cognitive and language problems, which can include either difficulty with comprehension, speech, or both.

A stroke is a medical emergency, and immediate treatment can help prevent disability or death. Recovery after a left-sided stroke involves physical rehabilitation, as well as speech and language therapy. 

A Word From Verywell

A left-sided stroke can be life-altering. It can cause weakness and communication problems that interfere with your ability to live your life the way you did before the stroke. These potential effects have a major impact on stroke survivors and their loved ones.

After a stroke, reach out for support to get the help you need to recover. It can take time and hard work, but it is important to be patient and maintain connections. Friends and family can help greatly by learning the effects of a left-sided stroke and modifying expectations, especially with communication.

Frequently Asked Questions

  • How common are left-sided strokes?

    Left-sided strokes occur about as frequently as right-sided strokes. According to the Centers for Disease Control and Prevention (CDC), every year, more than 795,000 people in the United States have a stroke.

  • Which side of the brain is worse to have a stroke on?

    The effects of a stroke on either side of the brain can range from mild to disabling. After a left-sided stroke, language can be a significant problem, and after a right-sided stroke, neglect of the left side of the body can be a significant problem.

  • How long does it take to recover from a left-sided stroke?

    It depends on how severe the stroke was and the amount of damage done. It can take months or longer to improve after a stroke. A person may recover almost completely or can have substantial permanent handicaps after a stroke. 

6 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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