An analytic evaluation of the upper break frequency of the human otolith organ

Abstract

Experimental data in the literature suggests that the upper break frequency of the human otolith organ is about 1.5 rad/sec. This paper presents an analytical technique to show that this value is approximately two orders of magnitude too small. The accepted lumped parameter model of the otolith organ is approximated to be independent of cupular stiffness for small time. Removal of the stiffness leads to a problem which, when subjected to a change in linear velocity, is analogous to Stokes' impulsive plate problem. The displacement of this"elasticity-independent" impulsive plate problem is compared with that predicted by the lumped parameter model when subjected to the same input. The solution of the former is approximated to be in the same exponential form as the latter, from which a value for the short time constant of the system is extracted. This value, the reciprocal of the upper break frequency, is approximately .0067 sec, giving a value for the upper break frequency of 150 rad/sec. This value is shown to be supported by several sources.