Abstract
The righting reflex is essential for the maintenance of equilibrium, functioning to maitain the head and trunk in a state of balance with regard to gravity. Since patients suffering from vestibular disorders almost always complain of dizziness during such everyday movements as rising and walking, the righting reflex should be evaluated within the context of the above dynamic state. A new method of acceleration registrography was designed to enable the testing of this reflex in subjects standing on a moving platform.
Subjects stood blindfolded on the tilt platform, which was arranged to slope automatically to the right and left. The subjects were requested to maintain their heads in a vertical position and return the board to the horizontal position with a handheld electrical switch. During this time the tilt angle of the support platform and side to side acceleration of the head were measured simultaneously.
Participating in the study were 49 normal controls and 80 patients with peripheral vestibular disorders.
“Average amplitude of head sway”, one of the indicators measured, proved to be significantly larger in cases of peripheral vestibular disorders than in the controls. “Average head position” also deviated significantly from normal in patients with peripheral vestibular disorders, with 46 % showing difficulty in returning their heads to the vertical position ; of these, 79 % experienced such difficulty when the platform tilted in the direction of the diseased ear.
Currently used righting reflex and deviation tests, such as Romberg's test, Mann's test, and the stepping test were less successful in detecting such a high incidence on the diseased side. The test we devised thus appears to be more sensitive for measuring the labyrinthine righting reflex function and to represent more accurately the disequilibrium and/or dizziness experienced in everyday life.
