Some methods and parameters of body sway quantification and their neurological applications.
Methods and parameters are described to quantify body sway as measured by a force-transducing platform. Analogue data representing the coordinates of the body's center of force (COF) are fed into a digital computer. Th following parameters are then calculated and tested for their diagnostic significance: sway path (SP), mean amplitude of sway (MA), mean sway frequency (MF), their lateral and sagittal components, and the quotients sagittal/lateral of these as well as the sway area (SA) circumscribed by the COF. Quotients of eyes open/eyes closed for all these parameters determine the visual stabilization of posture. Sway position and sway direction histograms allow for a more detailed analysis of MA and SP. Despite considerable inter- and intraindividual variance of these parameters (in 28 normals), some of them seem of clinical significance not only for documentation and follow-up studies but also for differential diagnosis. In patients with cerebellar lesions (n = 12), SP and MA were up to 10 times larger with a marked antero-posterior instability, MF being above normal. Patients with labyrinthine lesions (n = 10) showed significant instability only with eyes closed, MF being slightly below normal.
D002524:Cerebellar Ataxia / Q000503:physiopathology; D003201:Computers; D006801:Humans; D007759:Labyrinth Diseases / Q000503:physiopathology; D009068:Movement; D011187:Posture; D014785:Vision, Ocular / Q000502:physiology