Is a Stroke Different Whether You are Right-handed or Left-handed?


Few people know that a stroke affecting the right side of the brain is dramatically different than a stroke affecting the left side of the brain. And even fewer people realize that a stroke will affect you differently if you are left handed vs. if you are right handed. There is a real reason that some people are often described as right brained or left brained!

Your Handedness

Your dominant hand is the hand that you prefer for tasks that require coordination, particularly handwriting, although most people also have a hand preference in sports such as tennis, baseball, ​and football.

Some people also notice that one foot is dominant (it is on the same side of the body as the dominant hand.)

About 10% of the population is born left-handed. Usually, parents can tell if a child is left-handed by around the age of 14-18 months, although some babies demonstrate hand preference even earlier. Historically, a variety of myths from just about every culture have deemed left-handedness as evil or inferior to right-handedness.

However, with the advancement of medical science, it is currently well-recognized in most parts of the world that neither left-handedness nor right-handedness is inferior or superior to the other. Believe it or not- this revelation is less than 70 years old!

The Language Center of Your Brain

People who are right-handed are right-handed because their language center is located in the left side of the brain while people who are left-handed generally have their language centers in the right side of the brain.

The side of your brain that holds your language function is called your dominant hemisphere.

There are a few regions in the brain that work together to control language function. The best understood are the Broca’s area and the Wernicke’s area, both located on the dominant side of the brain. The Broca’s area allows us to produce fluent speech while the Wernicke’s area allows us to understand the meaning of the language that we speak and hear.

Stroke and Your Right-handedness or Left-handedness

Neurologists will always ask you if you are right-handed or left-handed. The reason for this is that a stroke or any problem that affects the brain manifests differently depending on whether you are right-handed or left-handed.

You may have already guessed that your language function is one of the reasons that your neurologist is concerned about whether you are left-handed or right-handed. A stroke of the dominant parietal lobe or the dominant temporal lobe can cause a condition called aphasia, which is a serious disturbance of speech and communication.

But another important brain function is controlled by either the right side of your brain or the left side of your brain depending on your handedness. This is a much more subtle function called visual spatial perception.

Visual spatial perception is your awareness of the position of both sides of your environment in relation to your body. Visual spatial perception is controlled by a region in your brain that sits opposite and approximately symmetrical to the language regions in your brain.

Your non-dominant hemisphere controls your visual spatial perception.

A stroke involving the sensory portion of the cerebral cortex can cause a condition called hemiagnosia, which is a diminished awareness of one side of your body or a deficit in the perception of one side of your surroundings, described as hemispatial neglect. If you have a stroke in the sensory portion of your non-dominant cerebral cortex, which is on the same side as your dominant hand, this serious handicap can result.

When a right-handed person experiences a stroke on the right side of the brain, hemiagnosia results. Similarly, when a left-handed person experiences a large stroke in the left hemisphere, awareness of the environment may be impaired. This kind of stroke is frustrating for the stroke survivors, and even more baffling and overwhelming for the family.

Left-handedness and Weakness After a Stroke

The motor portion of one side of your brain controls the movements of the opposite side of your body. If you are left-handed, a stroke in the right cortical or subcortical motor region of the brain can cause weakness of your dominant left arm and leg. This would be a more significant problem for you than a stroke on the left side of your brain, which would weaken your right, less-coordinated, non-dominant side. You can more easily adapt to weakness on the non-dominant side of your body because most of the time your dominant side can take over.


Your whole brain works together as a highly sophisticated machine. The functions of language and spatial perception are each highly concentrated to one side of the brain and these two functions lie opposite each other. Swallowing problems are more common in large cortical strokes that affect the non-dominant side of the brain,

Interestingly, your left- or right-hand dominance reflects the organization of your brain. Your hand preference also provides a clue to your medical team about which side of your brain is affected by a stroke.


Martin Samuels and David Feske, Office Practice of Neurology,  2nd Edition, Churchill Livingston, 2003

Walter G. Bradley DM FRCP, Robert B. Daroff MD, Gerald M Fenichel MD, Joseph Jankovic MD, Neurology in Clinical Practice, 4th Edition, Butterworth-Heinemann, 2003

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