Postural performance of vestibular loss patients under increased postural threat¹

Issue title: 8th Symposium on the Role of the Vestibular Organs in Space Exploration April 8–10, 2011, Houston, TX, USA

Guest editors: Charles M. Oman

Article type: Research Article

Authors: Young, Laurence R.^{a; *} | Bernard-Demanze, Laurence^b | Dumitrescu, Michel^b | Magnan, Jacques^c | Borel, Liliane^b | Lacour, Michel^b

Affiliations: [a] Man-Vehicle Laboratory, Massachusetts Institute of Technology, Cambridge, MA, USA | [b] CNRS/Aix-Marseille Université, UMR 6149 Neurosciences Intégratives et Adaptatives, Marseille, France | [c] Service ORL et Chirurgie Cervico-Faciale, Hôpital Nord, Marseille, France | Man Vehicle Laboratory, Massachusetts Institute of Technology, Cambridge, MA, USA

Correspondence: [*] Corresponding author: Laurence R. Young, Apollo Program Professor of Astronautics and Professor of Health Sciences and Technology, Massachusetts Institute of Technology, Room 37-219, 77 Massachusetts Avenue, Cambridge, MA 02139-4305, USA. Tel.: +1 617 253 7759; Fax: +1 617 258 8111; E-mail: [email protected]

Note: [1] This paper was presented at the Session: Sensorimotor Integration at the 8th Symposium on the Role of the Vestibular Organs in Space Exploration, April 8–10, 2011, Houston, TX, USA

Abstract: The effects of increasing postural task difficulty on balance control was investigated in 9 compensated vestibular loss patients whose results were compared to 11 healthy adults. Subjects were tested in static (stable support) and dynamic (sinusoidal translation of the support) conditions, both at floor level and at height (62 cm above the floor), and with and without vision, to create an additional postural threat. Wavelet analysis of the center of foot pressure displacement and motion analysis of the body segments were used to evaluate the postural performance. Evaluation questionnaires were used to examine the compensation level of the patients (DHI test), their general anxiety level (SAST), fear of height (subjective scale), and workload (NASA TLX test). (Vestibular loss patients rely more on vision and spend more energy maintaining balance than controls, but they use the same postural strategy as normals in both static and dynamic conditions.) Questionnaire data all showed differences in behavior and perceptions between the controls and the patients. However, at height and without vision, a whole body strategy leading to rigid posture replaces the head stabilization strategy found for standing at floor level. The effects of height on postural control can be attributable to an increase in postural threat and attention changes resulting from modifications in perception.

Keywords: Posture, vision, height, balance, vestibular loss patients

DOI: 10.3233/VES-2012-0449

Journal: Journal of Vestibular Research, vol. 22, no. 2-3, pp. 129-138, 2012