Does Thumb Arthritis Change How Your Brain Controls Your Hand?

If you have thumb pain or rhizarthrosis, you may already know how much it can slow you down. But did you know that your brain may also change the way it controls your hand? A study from 2017 looked at what happens in the brain when people with thumb arthritis try to move or just imagine moving their thumbs.

This research helps us understand three important things:

Your brain activity changes when thumb pain makes it hard to use your hand.
These changes happen even when you just move your hand, not when you imagine moving it.
Motor imagery, which means imagining movements without doing them, stays strong even when you have thumb arthritis.

Key Findings at a Glance

Patients with rhizarthrosis are slower at moving and imagining thumb movements compared to healthy people.
Brain scans showed less activity in the motor control areas of the brain when patients actually moved their thumbs.
Both the painful hand and the less painful hand showed these brain changes, though the painful hand was affected more.
When patients imagined moving their thumbs, their brain activity looked almost normal.
These findings suggest that imagining movements might help recovery after treatment.

What Is Rhizarthrosis and Why Does It Matter?

What is rhizarthrosis? Rhizarthrosis is the medical name for osteoarthritis of the thumb joint at the base of your thumb. This is also called the trapeziometacarpal joint or TMC joint. It is the joint that lets you move your thumb toward your other fingers.

This joint is special. It allows your thumb to rotate and touch the tips of your other fingers. This movement is called opposition. Without it, you cannot pinch, grasp, or hold objects well.

When you have rhizarthrosis, this joint becomes painful and stiff. Simple tasks like opening a jar or turning a key can become very hard or impossible. The pain can be so bad that you stop using your thumb as much.

You may be wondering why this matters. When you stop using your thumb because of pain, your brain may change the way it represents and controls that hand. This study looked at whether those brain changes actually happen.

What Did the Researchers Do?

According to this study, researchers worked with 35 patients who had rhizarthrosis. Most of these patients had the condition mainly in one hand. The researchers also studied 35 healthy people for comparison.

Everyone in the study did two types of tasks:

They actually moved their thumbs to touch each finger in order.
They imagined doing the same movement without actually moving their thumbs.

While the people did these tasks, the researchers measured their brain activity using a special brain scan called fMRI. This scan shows which parts of the brain are working during different tasks.

What is fMRI? fMRI stands for functional magnetic resonance imaging. It is a safe brain scan that shows which parts of your brain are active when you do something or think about something.

The researchers wanted to see if the brains of people with thumb arthritis worked differently than the brains of healthy people.

What Did They Find About Movement Speed?

Research shows that patients with rhizarthrosis were slower than healthy people in both tasks. They were slower when they actually moved their thumbs. They were also slower when they just imagined moving their thumbs.

Here is where it gets interesting. In healthy people, there is a strong connection between how fast they move and how fast they imagine moving. If you move slowly, you also imagine slowly. This connection was still there in patients with thumb arthritis, but it was weaker.

This tells us that even though the patients have pain and move more slowly, their brain still tries to keep movement and imagination linked together.

What Changes Happened in the Brain?

Let us look closer at what the brain scans showed. When patients with rhizarthrosis actually moved their thumbs, the scans showed less activity in two important brain areas:

The primary motor cortex, which is the part of your brain that sends signals to your muscles to move.
The dorsal premotor cortex, which is the part that plans and prepares movements.

These changes happened in both hands. But the hand with more pain and stiffness showed even less brain activity than the other hand.

This is important. It means that an injury or problem in your hand can change how your brain works, even if your brain itself is perfectly healthy.

But what about when patients imagined moving their thumbs? Interestingly, the brain scans looked almost normal during imagination tasks. There were no big differences between patients and healthy people.

What Is Motor Imagery and Why Is It Important?

What is motor imagery? Motor imagery means imagining a movement in your mind without actually doing it. It is like playing a movie in your head of your hand moving, but keeping your hand still.

According to this study, motor imagery stays strong in people with rhizarthrosis. Even though their actual movements are slower and their brain shows less activity during real movements, their ability to imagine movements is preserved.

This finding is different from what happens when someone loses a hand completely or cannot move it at all for a long time. In those cases, even imagining movement becomes difficult.

Why does this matter to you? Because motor imagery might be a useful tool for recovery. After you have treatment for your thumb arthritis, such as surgery, practicing motor imagery might help your brain reconnect with your hand. This could speed up your recovery and help you regain function faster.

What Does This Mean for You?

If you have thumb arthritis, this research tells you several hopeful things. First, the changes in your brain are not permanent damage. They happen because you are using your hand less due to pain.

Second, your ability to imagine movement stays strong. This is a good sign. It means that your brain still remembers how to control your thumb, even if pain is getting in the way right now.

Third, treatments that help reduce your pain and restore movement might also help your brain return to normal patterns of activity. And using motor imagery as part of your recovery plan might give you an extra boost.

About This Site

This website is here to help you understand thumb pain and rhizarthrosis. We take published scientific articles and break them down into simple language. Every article we share is based on real medical research, not opinions or guesses. We invite you to explore more content on this site to learn about your condition, treatment options, and the latest research. Knowledge can help you feel more confident and empowered as you work with your doctor.

Frequently Asked Questions

Does thumb arthritis really change my brain?

Yes, according to this study, thumb arthritis can reduce activity in the parts of your brain that control hand movement. This happens when you actually move your hand, but not when you imagine moving it. The good news is that these changes are likely temporary and related to pain and reduced use, not permanent brain damage.

Will my brain go back to normal after treatment?

The study suggests that because motor imagery is preserved, your brain still has the ability to control your thumb. This means that with proper treatment and rehabilitation, your brain activity may return to more normal patterns. Talk to your doctor about the best treatment plan for you.

What is motor imagery and how can it help me?

Motor imagery is the practice of imagining movements without actually doing them. This study found that people with thumb arthritis can still do motor imagery well. Because of this, practicing motor imagery might help your recovery after treatment by keeping your brain connected to your hand movements.

Does thumb arthritis affect both hands in my brain?

Research shows that even if one hand is more affected by arthritis, both hands may show some changes in brain activity. However, the hand with more pain and stiffness shows greater changes. This tells us that how much you use your hand affects how your brain represents it.

Conclusion

Living with thumb arthritis is challenging. The pain and difficulty using your hand can affect your daily life in many ways. Now we know that it can also affect how your brain controls your hand.

But this research also brings hope. Your brain is flexible. The changes that happen because of pain and reduced use are not set in stone. With the right treatment and possibly some motor imagery practice, you may be able to help your brain and your hand work together better again.

If you have thumb pain or rhizarthrosis, talk to your doctor about your symptoms and treatment options. Understanding what is happening in your brain as well as your hand can help you make informed choices about your care.

Important Disclaimer

This article is for educational purposes only. It is not medical advice. It does not replace the care and guidance of a qualified healthcare professional. If you have thumb pain, arthritis, or any medical condition, please consult with your doctor. Only a medical professional can diagnose your condition and recommend the right treatment for you.

Research Article

Study Citation:
Gandola, M.; Bruno, M.; Zapparoli, L.; Saetta, G.; Rolandi, E.; De Santis, A.; Banfi, G.; Zerbi, A.; Sansone, V.; Paulesu, E. (2017). Functional brain effects of hand disuse in patients with trapeziometacarpal joint osteoarthritis: executed and imagined movements. Experimental Brain Research.

Full Article:
https://doi.org/10.1007/s00221-017-5049-6