The Romberg sign and early instruments for measuring postural sway.

In the first half of the 19th century, European physicians-including Marshall Hall, Moritz Romberg, and Bernardus Brach-described loss of postural control in darkness of patients with severely compromised proprioception. Romberg and Brach emphasized the relationship between this sign and tabes dorsalis. Later, other neurologists evaluated the phenomenon, which is now known as Romberg's sign, in a broader range of neurologic disorders using a variety of simple but increasingly precise and sensitive clinical tests. In the late 19th century, neurologists also developed instruments to measure and record postural sway in patients with neurologic disease. Principal contributors included Philadelphia neurologist Silas Weir Mitchell and his trainees Morris Lewis and Guy Hinsdale. The efforts of these neurologists anticipated later physiologic studies and ultimately the development of computerized dynamic platform posturography.