“Normal” EMGs in Paralytic Polio Survivors
Question: I have a friend who at age 79 is now developing weakness in the hips. She was around me when I got polio and her cousin was the carrier. The question is can she have a normal EMG and have had polio? The doctor told her that she could not have had polio because her nerves are fine.
Dr. Bruno’s Responses: Studies show that a substantial percentage of polio survivors with a clear history of muscle weakness or paralysis have normal in-office EMGs, meaning that there was no EMG evidence that they ever had had polio (see above). One study using regular EMG found that almost 25% of paralytic polio survivors' limbs had no evidence of motor neurons having been killed.
What’s more, using a special "macro" EMG found over-sprouted motor neurons in 85% of muscle that were thought to have had "no clinical polio." And research by David Bodian and Alan McComas showed that seemingly unaffected muscles had lost 40% of their motor neurons. So, a “normal” EMG is not evidence of the absence of poliovirus-damaged neurons.
For more information search "EMG", Non-Paralytic Polio and Poliovirus in the Index of the ENCYCLOPEDIA of POLIO & PPS. Everything is listed by subject.