A large portion of his written work dealt with diseases of the spinal cord and neuropathological issues. He trained a number of prominent neurologists and neuropathologists, including Arnold Pick, Hermann Oppenheim, Karl Fürstner, Carl Moeli and Karl Wernicke. His son, Alexander Karl Otto Westphal (1863–1941) was also a psychiatrist, and is associated with the Westphal-Piltz syndrome (neurotonic pupillary reaction). Westphal, in addition to his multiple contributions to neurology and neuroanatomy, has been credited with introducing rational and non-censorious treatment to psychiatric hospitalization in Germany.