Muscle Function Changes After Stroke
Feb 21, 2020
Stroke Lingo Part 3: Muscle Function Changes After Stroke

If you or your loved one has experienced a stroke, one of the first things your therapists will look into is your overall muscle tone. By taking a close look at what your muscles are able to do and what they struggle with, the therapists can put together a plan of action to help you with strengthening, improving coordination, and working toward your functional goals. In part 3 of our “Stroke Lingo” series, let’s talk about words that have to do with muscle tone dysfunction after a stroke.

Muscle Function Changes After Stroke

Muscle tone: the amount of tension a muscle has at rest. There is a delicate and complex balance at play with muscle tone, which allows muscles to be flexible enough to move through space, but firm enough to hold the body steady against the effects of gravity. “Normal” muscle tone is what helps you to maintain your posture, and it will generally relax while you are asleep to allow your body to get comfortable and rest. When a person has “normal” muscle tone, there is a continual partial amount of tension that allows muscles to react quickly and smoothly whenever they are needed to make joints move.

An example of how normal muscle tone may affect you while you participate in a functional task: when you are riding a bike, there is enough tone in your muscles to keep your body seated upright, and there is enough flexibility to allow smooth, coordinated movements of the legs and feet to cycle with the pedals.

bicycle

Hypertonicity: a high amount of muscle tone, and therefore increased tension and resistance when the muscle is passively stretched. If you are experiencing hypertonicity, your stroke may have damaged a part of your brain that controls the signal from your brain to your muscles. This signal is now firing on overdrive, causing tension and tightness. It’s as if the muscles just can’t relax. Sometimes this tension will force the affected arm to pull in and flex toward the body, making it difficult to move or straighten out. Hypertonicity limits a joint’s ability to move. It is usually somewhat (or very) difficult to try to stretch out the joints, and often another person has to help complete stretches on a daily basis to try to keep at least some flexibility. As you can imagine, this is totally exhausting, and makes function very difficult.

hypo
A hypertonic right arm might rest tightly against the body despite intent to relax the limb.

Hypertonicity may affect you after your stroke diagnosis, but it is not always clear exactly when. Some begin to experience it right away, while others notice their muscles becoming tighter and more difficult to move weeks or months down the road.

An example of how hypertonicity may affect you while you participate in a functional task: when you are trying to apply deodorant, you need someone else to help pull your arm away from your side because of the high amount of tension pulling your joints closer together and flexing your arm toward your body.

Spasticity: A particular type of hypertonicity, which causes muscles to stiffen as a reaction to being stretched quickly. Though many people use the word “spasticity” as a general term to describe anyone with noticeably stiff muscles following a stroke or brain injury, it actually more specifically refers to tightness that happens when a quick stretch is applied to the muscle. When you have spasticity, the tightness can worsen with quicker movements. Spastic muscles often also need a good amount of [slow] stretching before you engage in a particular task, so that they have time to lengthen and become flexible enough. Spasticity is affected by both the sensory and motor parts of the brain that control your movement. It is considered “overactivity of the stretch reflex.”

You may have hypertonicity in your muscles without actually having spasticity!

An example of how spasticity may affect you while you perform a functional task: when you try to quickly open up your fingers from a fisted position in order to place your hand around your coffee cup, your fingers react to being moved quickly and tense up even more, forming a tighter fist position.

Contracture: a type of joint deformity related to prolonged tightness that keeps the joint positioned a specific way for a long time. After an extended time working on overdrive from hypertonicity, the muscle tissues can become shortened and hardened. This makes it extremely difficult, if not impossible, to move the joints around anymore. If you are experiencing contracture, the joints that are affected are more or less “frozen” in place.

Hypotonicity- a low amount of muscle tone. This is often noted after stroke, when muscles become completely or partially paralyzed. The muscles may no longer feel like they have much or any resistance to being stretched and moved around. Though hypotonia doesn’t automatically mean “weak,” weakness and hypotonia can often go hand in hand.

spasticity
A hypotonic right arm might hang limply at one's side despite attempts to move or reposition the limb.

After a stroke, you may experience a range of levels of “tone”, and your tone may change along your journey. If you have had a stroke that impacts your muscles in one of the ways listed above, you may need the help of a therapist to guide you with best practices to manage the symptoms and work toward using your arm (and/or leg!) more functionally. There are many types of strategies to include various modalities, stretches, exercises, and functional task training that can all help with improved use of the limb and more protected joints. Check in with your therapist for suggestions tailored to your specific needs!

All content provided on this blog is for informational purposes only and is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. If you think you may have a medical emergency, call 911 or your doctor immediately. Reliance on any information provided by the NEOFECT website is solely at your own risk.

References:

American Stroke Association: www.stroke.org

Bhimani, R, and Anderson, L. Clinical understanding of spasticity: Implications for practice. Rehabilitation Research and Practice, 2014: 279175 doi: 10.1155/2014/279175

Stroke Foundation: www.strokefoundation.org.au

WRITTEN BY

  • Natalie Miller, OTR/L
    Natalie is an occupational therapist and health writer based out of Richmond, VA. Natalie recently pivoted into the pediatric setting after spending eleven years working in adult neurorehabilitation.
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