He made early observations associated with syphilis to tabes dorsalis (nerve fiber and nerve cell degeneration). In his research of tabes dorsalis, he tried to find the link between this condition and syphilis. He also made contributions in his research of poliomyelitis, claudication intermittens, and progressive muscular atrophy. In 1878, he described myasthenia gravis, a condition sometimes referred to as the "Erb-Goldflam disease" (named along with neurologist Samuel Goldflam). Myasthenia gravis is a neuromuscular disorder that leads to fatigue and muscle weakness.