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. Unlike previous methods that utilize accelerometers affixed to the hand, 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 quantitate differences in normal tremor and provides discriminating results in patients with neurologic disorders.