The history of progressive muscular atrophy: syndrome or disease?

Since its first description more than a century ago, there has been much debate about the diagnostic entity progressive muscular atrophy (PMA). Initially, PMA included all forms of progressive amyotrophy. With the identification of several myogenic and neurogenic diseases and the recognition of amyotrophic lateral sclerosis (ALS), PMA was deemed to disappear as a nosologic entity at the end of the 19th century. In the last century, various other lower motor neuron syndromes were distinguished which may previously have been designated as cases of PMA. In contrast, several observations provided evidence that PMA can be linked both clinically and pathologically to ALS. Therefore, PMA should be considered as a syndromal subtype within a clinical spectrum of motor neuron diseases.