The percipient observations of Constantin von Economo on encephalitis lethargica and sleep disruption and their lasting impact on contemporary sleep research.

The study, and the preceding companion article, reviews the pioneering contributions of Constantin von Economo (1876-1931) to Neuroscience in a modern context. The neurological studies of von Economo include the discovery of a new nosological entity, encephalitis lethargica, with which his name is forever linked ('von Economo disease'). Based on a percipient analysis of pathoanatomical material from patients with encephalitis lethargica who manifested with either insomnia or somnolence, von Economo deduced the existence of distinct centres in the brain for the regulation of sleep and wakefulness. He presented a synthesis of his ideas in a series of lectures in New York in 1929 and at the First International Neurological Congress held in Berne in 1931. Constantin von Economo was nominated three times for the Nobel Prize in Physiology or Medicine for the discovery of encephalitis lethargica. As those studies have exerted and continue to exert the highest impact among von Economo's publications, the present article examines the spectrum of his observations on encephalitis lethargica and the cerebral control of sleep, documented in 63 published works--including post-humous translations into French and English of original German texts; complete bibliographic information is given. His remaining 76 works of an annotated total of 139 scientific publications deal with brain structure, evolution and intelligence, as well as general works on nervous and mental pathology and form the focus of the preceding article.