Post-Polio Patients Have Swallowing Abnormalities that Increase the Risk of Choking Wednesday, April 24, 1991 Many post-polio patients have swallowing abnormalities that increase the risk of choking but are unaware of their condition, according to a study directed by a scientist at the National Institute of Neurological Disorders and Stroke (NINDS) and published in the April 25 issue of the New England Journal of Medicine.* Fact Sheet