Researchers studied nerve damage (called polyneuropathy) in people with Parkinson’s disease and similar conditions. They looked at 183 patients total and found that between 37-47% of them had nerve damage affecting their ability to feel and move normally. Interestingly, the nerve damage wasn’t caused by the usual suspects like diabetes or vitamin deficiencies. The study suggests that doctors should regularly check for nerve damage in Parkinson’s patients, especially older men, because treating it could help people stay mobile and independent longer.

The Quick Take

  • What they studied: How often nerve damage happens in people with Parkinson’s disease and similar brain conditions, and what causes it
  • Who participated: 183 patients: 104 with Parkinson’s disease, 52 with progressive supranuclear palsy (a rare brain disorder), and 27 with multiple system atrophy (another rare brain disorder). Most were older adults, and more men than women participated
  • Key finding: Between 37-47% of all patients had nerve damage. Patients with nerve damage were older, more likely to be male, and had more difficulty with movement and daily activities compared to those without nerve damage
  • What it means for you: If you or a loved one has Parkinson’s disease, especially if you’re an older male, ask your doctor to check for nerve damage. Finding and treating it early might help you stay more active and independent. However, this is one study, so talk to your doctor about what it means for your specific situation

The Research Details

Doctors at a major hospital in Germany looked at all patients admitted with Parkinson’s disease or similar conditions over a certain time period. They checked each patient’s movement abilities, did special nerve tests (called electroneurography, which measures how well nerves send signals), and looked for common causes of nerve damage like diabetes or vitamin deficiencies. They also reviewed what medications each patient was taking and at what doses.

This type of study is called a ‘cross-sectional’ study because researchers looked at all the patients at one point in time, like taking a snapshot. They weren’t following people over months or years to see what happened next. Instead, they gathered all the information they needed from hospital records and patient visits.

Understanding how common nerve damage is in Parkinson’s patients helps doctors know to look for it. If doctors don’t check for nerve damage, they might miss a treatable problem that’s making patients less able to walk and move around. This study is important because it shows that nerve damage is very common in these patients, but the usual causes don’t explain why. This means doctors need to investigate further to find out what’s really causing the problem.

This study looked at real patients from a real hospital, which is good. However, the study only included patients who came to one hospital in Germany, so the results might not be exactly the same everywhere else. The researchers did careful nerve testing, which is reliable. One limitation is that they didn’t follow patients over time to see if the nerve damage got worse or better, so we don’t know the long-term effects. The study is also relatively small (183 patients), so larger studies would give us more confidence in the findings.

What the Results Show

The biggest finding was that nerve damage is very common in all three groups of patients studied. Between 37% and 47% of patients had some form of nerve damage, which is much higher than in the general population. This means that if you have Parkinson’s disease or a similar condition, there’s roughly a 1 in 2 to 1 in 3 chance you might have nerve damage too.

Patients who had nerve damage were typically older and more likely to be male. They also had more trouble with movement and daily activities compared to patients without nerve damage. Their scores on movement tests were noticeably worse, suggesting that the nerve damage was affecting their ability to function.

The type of nerve damage most commonly seen was a specific pattern where the longest nerves in the body (the ones going to the feet) were affected first. This is called ’length-dependent’ nerve damage, and it’s the most common type of nerve damage overall.

Surprisingly, the researchers found no connection between nerve damage and the medications used to treat Parkinson’s disease. This was unexpected because some medications can sometimes cause nerve damage as a side effect.

The study found that common causes of nerve damage—like diabetes, vitamin B12 deficiency, and heavy alcohol use—were not more common in patients with nerve damage than in those without it. This suggests that something else about having Parkinson’s disease itself might be causing the nerve damage, rather than these other well-known risk factors. This is an important clue for future research.

Previous research has suggested that nerve damage might happen in Parkinson’s patients, but this study provides clearer numbers. The 37-47% prevalence rate is higher than what some earlier studies suggested, which means nerve damage might be even more common than doctors previously thought. This study also adds new information about patients with the rarer conditions (PSP and MSA), which haven’t been studied as much before.

This study only looked at patients at one hospital in Germany, so the results might be different in other countries or populations. The study didn’t follow patients over time, so we don’t know if the nerve damage got worse, stayed the same, or improved. The study couldn’t prove that Parkinson’s disease causes the nerve damage—it only showed that they happen together. The researchers didn’t investigate all possible causes of nerve damage, so there might be other explanations they didn’t test for. Finally, the study is relatively small, so larger studies would help confirm these findings.

The Bottom Line

If you have Parkinson’s disease, especially if you’re over 60 or male, ask your doctor to check for nerve damage. This might include special nerve tests or blood work. If nerve damage is found, your doctor can work with you to manage it and potentially slow down any worsening. These recommendations are based on this one study, so discuss them with your healthcare team to see what’s right for your situation. (Confidence level: Moderate—this is good evidence, but more research is needed)

This research is most relevant for people with Parkinson’s disease, progressive supranuclear palsy, or multiple system atrophy. It’s especially important for older men with these conditions. Family members and caregivers should also pay attention because nerve damage can affect a person’s ability to walk and stay independent. Doctors who treat these patients should consider screening for nerve damage as part of regular care.

Nerve damage develops slowly over time, so you won’t notice changes overnight. If your doctor finds nerve damage and starts treatment, it might take weeks to months to see improvement in symptoms like numbness or weakness. The goal is usually to prevent it from getting worse rather than to completely reverse it, so patience and consistent follow-up with your doctor are important.

Want to Apply This Research?

  • If you have Parkinson’s disease, track your balance and walking ability weekly using a simple scale (1-10, where 1 is very difficult and 10 is easy). Also note any numbness, tingling, or weakness in your feet or hands. Share these notes with your doctor at appointments to help them monitor for nerve damage.
  • Work with your doctor or physical therapist to do balance and strength exercises 3-4 times per week. These exercises can help compensate for nerve damage and reduce fall risk. Use the app to set reminders for these exercises and track which ones you complete.
  • Set a monthly reminder to check in with yourself about any changes in numbness, tingling, or weakness. Every 3-6 months, ask your doctor if you need nerve testing (electroneurography) to monitor for new or worsening nerve damage. Use the app to log these appointments and test results so you have a clear picture of changes over time.

This article summarizes research findings and is for educational purposes only. It is not medical advice. Nerve damage is a serious condition that requires professional medical evaluation and treatment. If you have Parkinson’s disease or symptoms of nerve damage (such as numbness, tingling, or weakness in your hands or feet), please consult with your neurologist or healthcare provider. Do not start, stop, or change any medications based on this article. Your doctor can determine whether nerve testing is appropriate for your individual situation and recommend the best treatment plan for you.