1. Date of download: 5/28/2016 Copyright © 2016 American Medical Association. All rights reserved. From: Nineteenth-Century Contributions to the Mechanical Recording of Postural Sway Arch Neurol. 2001;58(7):1147-1150. doi:10.1001/archneur.58.7.1147 Philadelphia (Pa) neurologist Silas Weir Mitchell's sway meter for measuring postural sway. It consisted of a pair of graduated rulers oriented perpendicular to each other and fixed on a stand. Figure Legend:

2. Date of download: 5/28/2016 Copyright © 2016 American Medical Association. All rights reserved. From: Nineteenth-Century Contributions to the Mechanical Recording of Postural Sway Arch Neurol. 2001;58(7):1147-1150. doi:10.1001/archneur.58.7.1147 Silas Weir Mitchell examining a patient at the Philadelphia (Pa) Orthopedic Hospital and Infirmary for Nervous Diseases around 1890, surrounded by assistants, house staff, and nurses. In the background (on the right next to a cabinet and behind both the patient and an observer) is Mitchell's sway meter. In his right hand, Mitchell is holding a reflex hammer invented by his assistant, John Madison Taylor, around 1888, the first hammer developed specifically for eliciting muscle stretch reflexes. Sitting (from the left) are George E. de Schweinitz, Taylor (recording Mitchell's observations), and the patient; standing (from the left) are an unknown man, Fred Packard, Charles W. Burr, Isaac Pearson Willits, Superintendent Jane Dalziel, Mitchell, Mason W. Zimmerman, a psychologist, and a nurse. Photograph courtesy of the College of Physicians of Philadelphia. Figure Legend:

3. Date of download: 5/28/2016 Copyright © 2016 American Medical Association. All rights reserved. From: Nineteenth-Century Contributions to the Mechanical Recording of Postural Sway Arch Neurol. 2001;58(7):1147-1150. doi:10.1001/archneur.58.7.1147 This photograph from the Infirmary for Nervous Diseases in Philadelphia, Pa (circa 1888-1889), depicts from left to right J. M. Cattell (seated), Guy Hinsdale (seated), Isaac Pearson Willits, John K. Mitchell, George E. de Schweinitz, C. Dalziel, William Osler (seated), Mrs Green, Joseph Otto, and Superintendent Jane Dalziel (seated). Photograph courtesy of Oxford University Press, New York, NY. Figure Legend:

4. Date of download: 5/28/2016 Copyright © 2016 American Medical Association. All rights reserved. From: Nineteenth-Century Contributions to the Mechanical Recording of Postural Sway Arch Neurol. 2001;58(7):1147-1150. doi:10.1001/archneur.58.7.1147 Ataxiagraph used by New York neurologist Charles Loomis Dana for graphically recording postural sway in the late 19th century. Figure Legend:

5. Date of download: 5/28/2016 Copyright © 2016 American Medical Association. All rights reserved. From: Nineteenth-Century Contributions to the Mechanical Recording of Postural Sway Arch Neurol. 2001;58(7):1147-1150. doi:10.1001/archneur.58.7.1147 Postural sway of a healthy person (top) and a patient with tabes dorsalis (bottom), both of which were recorded by Guy Hinsdale using a graphic recording apparatus. To make the recording, smoked paper was placed on a piece of cardboard that was in turn attached to the patient's head. The subject then stood under an index, which was free to move up and down in a fixed vertical line. Figure Legend:

6. Date of download: 5/28/2016 Copyright © 2016 American Medical Association. All rights reserved. From: Nineteenth-Century Contributions to the Mechanical Recording of Postural Sway Arch Neurol. 2001;58(7):1147-1150. doi:10.1001/archneur.58.7.1147 Postural sway of patient obtained by Hinsdale and Edward Tyson Reichert at the Philadelphia (Pa) Orthopedic Hospital and Infirmary for Nervous Diseases and published in 1887. Time in 5-second intervals is indicated by the top line, anteroposterior movement by the second line, lateral movement by the third line, and respirations by the bottom line. Figure Legend: