Nerve Tests to Determine if One Had Polio

Question: I am 79 years old and was diagnosed with post-polio syndrome a few years ago. I was originally diagnosed with polio when I was nine years old. On a follow-up visit to Rancho Los Amigos in Downey, California, the doctor I saw (different from the one I had previously seen) told me he wasn’t certain that I had ever had polio and suggested it could have been something else (GBS, SMA or West Nile Virus). He is scheduling a nerve test that he says can determine whether or not it was polio. Is this common and will the test show definite results? Since my diagnosis of PPS I have been much more careful with what I am doing so as not to “wear out” the muscles I have left. If it turns out to be something else, I may be able to resume more of my previous activities.

Marny Eulberg, MD: It sounds like the physician you recently saw may have had different specialty training than the previous physician and thus approached your problems from a different way of thinking. It is quite reasonable to ask the question, “Do I think this person had polio or could it be something else?” That does become important when the alternate diagnosis carries with it treatment that is different from that of post-polio syndrome, especially if that treatment could be curative. It is true that prior polio infection has a unique pattern on EMG (likely the “nerve test” the doctor was referring to). I think it is improbable that your current treatment will have caused any significant adverse outcomes on your health, and would, at least in part, have been part of the treatment plan for any of the three other neuromuscular conditions you mentioned.

The results of the EMG, whether it confirms polio or not, might identify more clearly which nerves were affected and hence which muscle(s) were impacted and also identify muscles that you might be able to safely exercise more than you have.

I cannot state that the test will show definite results—if the pattern is clearly consistent with polio, then that makes PPS more likely. But if it doesn’t show the classic pattern of prior polio, then other diagnoses will be considered.

Reply from Frederick Maynard, MD: I agree with Dr. Eulberg that it is always appropriate to question a diagnosis of PPS, especially if the evidence is not typical or characteristic. Electrodiagnostic Studies (both electromyography and nerve conduction studies) can be very helpful in establishing a diagnosis of PPS, but they are unfortunately not definitive. What they can do is establish that any neuromuscular abnormality that you have is compatible with previous nerve death from a polio infection. After almost 70 years, it can be impossible to be certain that some changes are from previous polio. It can establish that changes are from some other conditions, which if they are treatable, certainly makes it worth doing.

Having said the above, I would also ask how reliable was your childhood diagnosis of polio at age nine? Information to consider in answering this includes the following: How severe was your weakness from the original polio and how long did it last? Which parts of the body were involved? Were you hospitalized and for how long? How much physical therapy did you receive afterward, and what improvements did you make? Was a spinal tap done?

Depending on the answers to these questions, one can say your acute polio and later course were typical and likely certain, or that your diagnosis can and should be open to questioning. The reason this detailed review is worth doing is because one can have had polio and then develop another superimposed and concurrent condition. This is particularly common among older polio survivors, who often develop a peripheral neuropathy that leads to new weakness and may be treatable. The nerve conduction studies are likely to clarify this issue; and if you have any sensory losses in your feet, this would certainly be important to establish.

Lastly, I would also echo Dr. Eulberg’s comment that recommendations for managing your new symptoms (we presume to be new and/or increased muscle weakness—but you did not describe specifically for us) based on a diagnosis of PPS would not be likely to have harmed you. They may well be the same regardless of what is the “true” diagnosis for your current concerns.

Given the long existing excellent reputation and long experience of work with polio patients at Rancho Los Amigos Medical Center, I think you should be reassured that their advice will be appropriate and helpful. The tests are not risky and hopefully will either be reassuring or revelatory of helpful new information.

Hopefully, this lengthy response will be helpful to you; and I might suggest you review some of the pertinent information in PHI’s Handbook on the Late Effects of Poliomyelitis for Physicians and Survivors to assist your understanding and confidence in the testing and recommendations that are forthcoming for you.

Post-Polio Health (Vol. 40, No. 3, Summer 2024)