Development of a quantitative test for hand tremor measurement. Study of factors influencing the response in a control population.

The frequency spectrum of hand tremor amplitude was investigated in a group of 15 control subjects under four different conditions (rest position, wrist loading with 2 kg, pointer directed to a target, and wrist loading with 2 kg, pointer directed to a target, and wrist loading plus pointer). The series of four tremor recordings was repeated on three different days. The hand tremor pattern was recorded using an accelerometer connected to a tape recorder through a precision sound level meter. The tremor signals were subsequently analyzed with a real time spectrum analyzer. Different parameters (peak frequencies, acceleration amplitudes, moments, displacements, and velocities) have been determined and their variability has been characterized. The method described for hand tremor recording is suitable for field application.