Muscular atrophy, post-polio (PPMA): Late muscle wasting that occurs as part of the post-polio syndrome (PPS), a constellation of symptoms and signs that appear belatedly, from 20 to 40 years, after the initial polio infection and at least 10 years after what was once thought to be the "recovery" from polio. The typical features of PPS include unaccustomed weakness, muscle fatigue (and sometimes "central" fatigue), pain, breathing and/or swallowing difficulties, sleep disorders, muscle twitching (fasciculations) and gastrointestinal problems. The muscle problems in PPS can occur in previously-affected muscles or in muscles that were previously thought not to be muscles that were not affected at onset of the polio. The onset of PPS is usually gradual, over a period of years, but sometimes abrupt, with major loss of function suffered over several months or a couple of years. This process seems often to start after a physical or emotional trauma, an illness or accident.