On the topic of EMG’s identifying where polio affected the body
Question: I got the electrodiagnostic results of my "good" right hand. The doctor said there was evidence of prior, “old” anterior horn cell disease. Does this mean that Polio affected my right arm as well?
Answer: Statistically, the poliovirus affected all of the motor neurons that activate your muscles, even the muscles that seemingly were unaffected. For a limb to be weakened by the poliovirus, let alone paralysed, it had to lose more than 60% of its motor neurons. EMG’s can detect “old” polio damage and the death of motor neurons, which is what the physician meant by “evidence of prior, old anterior horn cell disease.”
But a negative/normal EMG doesn’t mean you didn't have polio. Motor neurons could have been damaged, causing paralysis, and then recovered, allowing recovery of muscle strength and leaving no EMG evidence of damaged motor neurons. The rapid recovery of damaged motor neurons created the “polio miracles,” where a child was admitted to a hospital with paralysis and walked out a month later.
See “‘Normal’ EMG’s in Polio Survivors with a History of Paralytic Polio” https:// www.papolionetwork.org/uploads/9/9/7/0/99704804/ how_to_interpret_emgs_of_polio_survivors.pdf Also, a negative EMG doesn’t mean you don't have PPS. Of the many published studies of polio survivors not one found that a clinical EMG could identify newly weakened muscles versus muscles whose strength hadn't changed in decades. BOTTOM LINE: AN EMG CANNOT DIAGNOSE PPS Yes, EMG and nerve conduction studies can be helpful to rule out diagnoses other than PPS, e.g., carpal tunnel syndrome, ALS, (Amyotrophic lateral sclerosis) CIDP (Chronic Inflammatory Demyelinating Polyneuropathy) and even pinched nerves. But if you're going to have an EMG see a rehab doctor, not a neurologist, since physical medicine doc’s EMG training has been found to be far superior to that of neurologists. See “Why Rehabilitative Physicians are best able to do EMG’s.” https://www.papolionetwork.org/uploads/9/9/7/0/99704804/ bruno_bytes__january_2019_.pdf