The speed of the slow component of ocular nystagmus induced by angular acceleration of the head: its experimental determination and application to the physical theory of the cupular mechanism

Abstract

Angular accelerations around the vertical axis, of known magnitude and duration, have been applied in a number of normal human subjects by means of a rotating chair of new design. Theoretical and experimental evidence is advanced in support of Graybiel's hypothesis that the oculo-gyral illusion is dependent upon vestibular eye nystagmus. A new technique is described for the quantitative evaluation of the oculo-gyral illusion occurring during the application of known angular accelerations. According to the theoretical and experimental data given, this technique makes it possible to obtain instantaneous measurements of the speed of the slow component of such vestibular eye nystagmus occurring at any point in the course of application of known angular accelerations and accordingly of the instantaneous magnitude of the corresponding cupular deflexion. By this means it has been possible to substantiate the general theory of the cupular mechanism outlined by Steinhausen and to re-evaluate and confirm the physical constants of the system assigned to it by Van Egmond and his co-workers.