The Cybermouse: a simple method of describing the trajectory of the human mandible in three dimensions

A simple method of recording the three-dimensional movements of the mandible together with up to 10 channels of other physiological data is described. The system is based on a commercially available device, the Cybermouse (IPC, Freemont, CA, U.S.A.), consisting of a lightweight ultrasonic emitter which can be attached to the chin by means of an elasticated band, and a base unit which contains three ultrasonic detectors. A microprocessor in the base unit calculates the position of the emitter by analysing the differences in the times of arrival of signals from the emitter. Physiological data is acquired using the PICO-ADC11 (Pico Technology, Cambridge, U.K.) a 10-channel analogue-to-digital converter. As an example, an application where temporomandibular joint sounds and mandibular movement data were collected simultaneously is described. The Cybermouse is of sufficient accuracy for use in most situations, and its ease of use and relatively low cost outweights its few disadvantages when compared to more complex systems.