The return tilt test and labyrinthine disorders

Abstract

The tilt test, a form of Goniometry is based on the principle of maintenance of equilibrium while standing on a board which can be tilted to the point where the subject is unable to remain upright. The point at which the subject can no longer preserve his balance indicates the degree of equilibrium as related to the feedback system of righting reflexes. We wish to report our experiences with an electric-motor driven tilt board with an autoregulating switch, under feasible various angular velocities of tilting. As the return tilt test, the subject is required to stand on a board tilted to 15° either to the right or left. He is instructed to grip the board firmly with his bare feet, to push the switch and try to maintain his equilibrium while on the board, then to stop the tilt at the point where the body axis returns upright on the perfectly flat non-tilted board. The degree at the stopping point is then calculated as a parameter position : normal, bending to the right, left and backwards. Subjects are classified into 4 groups including controls. Patients with labyrinthine disorders such as Meniere's disease and/or sudden deafness show higher incidences of insufficient return. Patients with central lesions feel a loss of return to a normal equilibrium, and in those with whiplash injuries, the values vary to the extent where some subjects are unable to stand on the board during the return tilt. An accurate performance was always noted in the control subjects. Among the 4 groups, a return under the angular velocity of 1°/sec yielded the most accurate values. We are of the opinion that this test should be included in the routine clinical testing of patients with labyrinthine disorders.