Observation of the Velocity of Body Sway Ménière's Disease

Abstract

Vestibulo-spinal reflexes in Ménière's disease were analyzed using gravigrams and velocitygrams.Studies of vestibular disturbance have so far been centered around nystagmus. With the development of the gravicorder, however, a new approach to the testing of vestibulospinal reflexes began to be tried, which is based on the analysis of the center of gravity.A characteristic of gravigrams is that they are positional graphs and provide no information about time-course changes in the velocity with which the center of gravity moves. To clarify time-course changes in the velocity of the sway of the center of gravity while recording its movement, we processed data of the change in the time-course velocity, a component of dynamic control system, with a computer and obtained velocity-grams.On gravigrams, body movements differing in frequency are represented by the same area change as long as their amplitudes are the same. These same body movements, however, produce completely different velocitygrams, which are constructed on the basis of differentials of the above recordings.Eleven patients with Ménière's disease were then tested during a non-attack period with their eyes open and closed. It became clear from the above test that, even among patients who exhibited the same pattern of area change on gravigrams, velocitygrams were different from each other. This means that the velocity is controlled by a different recovery conditions.That the velocitygrams of patients in a non-attack period varied greatly suggests that each patient responded differently to treatment.The above findings indicate that the velocity of body sway, which is a parameter of the dynamic control functions, plays an important role in the clinical diagnosis of equilibrium disturbance.