A noncontacting human tremor sensor and measurement system

A two-dimensional noncontacting displacement transducer has been developed for the primary purpose of measuring human hand tremor. No electrical or mechanical connections are required. The device consists of a square frame with each side representing a capacitor plate. A test subject´s hand inserted into the center of the frame forms the moving plate of two separate differential capacitor systems (horizontal and vertical axes) used in bridge configurations with 100-kHz excitation and appropriate signal conditioning. Sensitivity is 2 V/cm over a typical dynamic range. Clinical evaluations indicate that the device is sensitive enough to quantify differences in normal tremor and provides discriminating results in patients with neurologic disorders.