Static and Dynamic Posturography in Patients With Vestibular and Cerebellar Lesions

Abstract

BODY SWAY is a normal phenomenon that occurs to some degree in everyone. Although sway can be estimated by several different methods, the most commonly used technique is to record displacement of the center of pressure on a force-measuring platform (posturography). Numerous studies in patients with a variety of neurologic disorders suggest that posturography might be a useful clinical tool for evaluating balance problems in patients.^1-8 Since sway tends to be small when subjects stand on a stable platform, moving platforms (dynamic posturography) have been developed in an attempt to increase test sensitivity. The platform can be either tilted or linearly displaced and sway can be measured immediately after the movement or during the movement. Furthermore, in an effort to dissect the different sensory contributions to the maintenance of balance, systems have been developed to selectively manipulate somatosensation and vision.⁹ With these devices, the angle of sway is fed back to a dynamic posture platform or to a movable visual surround so that movement about the ankle joint or movement of the visual surround is "sway referenced." Sway measured during sway-referencing conditions with eyes closed increases in patients with vestibular lesions because such patients are reliant on proprioceptive and visual input to compensate for the vestibular loss. Such an abnormality on posturography has been called a vestibular pattern, suggesting that it is specific for vestibular system disease.^2,9