As the third leading cause of death in the U.S., stroke is a fairly common occurrence. Therefore, it is beneficial to know the symptoms of stroke and how a stroke can affect different body functions.
A stroke on the left side of the brain will affect the right side of the body, while a stroke on the right side of the brain will affect the left side of the body. Brain functions are not perfectly symmetrical, though. This is why a stroke on the left versus right side of the brain might have different effects.
Reviewing the many structures and functions of the brain can help better understand the differences between a right or left side stroke.
Brain Structures and Functions Overview
- About the brain
- Symptoms - left side stroke
- Symptoms - right side stroke
- Symptoms - cerebellum/brainstem stroke
The brain has many different roles:
- Responsible for activities such as movement, memory, sensing, language, learning, and emotions
- Regulates survival functions like metabolism
- Takes up only 2% of body space, but it consumes 20% of the body’s energy!
The brain is a small organ with an average weight of three pounds. Yet, it’s an incredibly complex one: made up of 100 billion neurons and 1,000 trillion synapses.
The brain is divided into 3 main areas:
The cerebrum is the biggest part of the brain. The brain is made up of 2 hemispheres, the left hemisphere, and the right hemisphere. Each hemisphere is responsible for controlling different functions in our bodies.
For example, the left hemisphere is responsible for: logic, language skills, oral function, sequencing, linear thinking, mathematics, critical thinking, and judgment/reasoning. The right hemisphere is responsible for: imagination, art, nonverbal cues, visualization, rhythm, and intuition.
The saying that people are creative "right-brained" thinkers or analytical "left-brained" thinkers is a simplified way to explain the fact that some proceeses and functions reside more in one half of the brain than the other.
Physically, the left side of the brain controls the right side of the body and the right side of the brain controls the left side of the body. For example, if the left side of the body is affected, then the stroke likely happened in the right hemisphere. What if the right side of the body is affected? You guessed it, the left hemisphere of the brain was affected by the stroke. This is called a contralateral relationship.
The cerebellum is located in the back of the cerebrum. Even though it is smaller than the cerebrum, it actually contains more nerve cells. The cerebellum is involved in controlling muscle tones, from contracting to relaxing. The cerebellum also coordinates voluntary body movements to ensure the smooth performance of activities like balancing, walking, and reaching.
The brainstem is located in the middle of the brain, connecting the brain and spinal cord. Since the brainstem plays a major role in sustaining life functions, damage to the brainstem can be fatal. Its roles include:
- Life-sustaining functions such as breathing, consciousness, and temperature control
- Transmitting movement and sensory signals from the brain to the spinal cord for passage throughout the nervous system
Five Symptoms of Left and Right Side Strokes
Every stroke is different and will affect people differently based on its severity. However, if someone has a left side stroke it can cause the following five symptoms:
Weakness or paralysis to the right side of the body
Weakness is caused by damage to the brain and not damage to the limb itself.
Aphasia (speaking, language problems)
Since the left side of the brain controls language many people who have suffered from a left-sided stroke may have difficulties speaking or understanding language, this is called aphasia.
The left side of the brain controls critical thinking, judgment, reasoning, and sequencing, therefore, having a stroke on the left side of the brain can cause someone to have varying levels of cognitive impairments.
The left side of the brain controls all oral functions which include chewing and swallowing. After a left-sided stroke one may have trouble chewing and swallowing. One may be put on a feeding tube until they are able to relearn how to swallow or chew.
After having a stroke on the left side of the brain it is common for someone to suffer from visual impairments in the right eye. It is common for someone to lose half of their visual field in their right eye which is called hemianopia. One may also present with neglect to the right side of the body which is called visuospatial neglect.
All of the above-noted symptoms of a left-sided stroke are caused by damage in the brain. In order to retrain the brain after a left-sided stroke, it is important to strengthen the neural pathways that control all of these behaviors and movements by doing repetitive exercises. The more repetitive exercises and movements one does, the stronger the pathways in the brain will become. This is called neuroplasticity.
The right side of the brain controls the ability to pay attention, recognize things you see, hear or touch, and be aware of your own body. Below are some common symptoms that right side stroke includes.
Weakness or paralysis to the left side of the body
Weakness is caused by damage to the brain affecting nerve signal transmission to the rest of the body, not damage to the limb itself.
The ability to recognize objects, faces, voices or places can change after a brain injury. Individuals may need help interpreting an object with non-visual cues to make up for their inability to tell what something is with their eyes. In most cases, the body's ability to recognize things increases over time. However, some people will not fully recover from agnosia.
The ability to recall names of everyday objects may be affected. Despite knowing the purpose or shape of the object, the person will feel like the target word is on the "tip of their tongue" but not be able to remember it. This skill can get better over time, but for some, anomia will be a lasting communication problem.
Focusing attention on a conversation or paying attention to multiple things at once may be impacted by stroke. There are ways that individuals can use external reminders and aids to make up for attention deficits.
Perseveration (the repetition of a particular response)
Someone may have difficulty maintaining conversation or sequencing movement correctly. They may repeat a word or action or not be able to control the speed of their response. During a conversation, they might get stuck on a sentence or idea. During a task, they might continue to perform a part of the action and not move onto the next step. In these cases, treatment is needed with help to control behavior so that the patient can understand how to move through the entire task again.
1) Symptoms of a cerebellum stroke
Although strokes are less common in the cerebellum area, the effects can be severe.
Common effects of strokes in the cerebellum include:
- Inability to walk and problems with coordination and balance (ataxia)
2) Symptoms of a brainstem stroke
The brainstem is located at the base of the brain right above the spinal cord. Many of the body’s vital “life-support” functions are controlled by the brainstem. It also helps to control the main nerves involved with eye movement, chewing, and swallowing and maintains the homeostasis.
Examples of functions on brainstem:
- Breathing and heart functions
- Body temperature control
- Balance and coordination
- Chewing, swallowing, and speaking
A stroke in the brainstem can be fatal. Some individuals who survive brainstem strokes are left with Locked-In Syndrome, a rare condition in they cannot make voluntary movements other than with their eyes.
The human nervous system has neuroplasticity. While damaged brain cells will not survive, neurons in intact brain areas continue to expand and change even after the acute incident (from 6 months and beyond).
These neurons can take over the information and roles that the damaged area was responsible for, and the body changes accordingly. Neuroplasticity regenerates the brain's nerves and improves body functions through sensory and motor stimuli from the outside. This is why ongoing rehabilitation is beneficial after a stroke.
One way to continue to make progress in strengthening your neural pathways is using Neofect Smart Glove or Smart Board. These products can help the brain's ability to rewire itself and to increase the range of motion and strength in the upper extremities. The best part is that they do this with fun and engaging games! To learn more about the Neofect Smart Rehab Solutions, please call us at 888-623-8947 or email us at firstname.lastname@example.org.
- National Stroke Association - http://www.stroke.org/
- Johns Hopkins Medicine - https://www.hopkinsmedicine.org/health/conditions-and-diseases/stroke/effects-of-stroke