Paralysis is loss of muscle function for one or more muscles. Paralysis can be accompanied by a loss of feeling (sensory loss) in the affected area if there is sensory damage as well as motor. About 1 in 50 people in the U.S. have been diagnosed with some form of paralysis, transient or permanent. The word comes from the Greek παράλυσις, "disabling of the nerves", itself from παρά (para), "beside, by" and λύσις (lysis), "losing" and that from λύω (luō), "to lose". A paralysis accompanied by involuntary tremors is usually called "palsy".