Evaluating Parkinson’s Disease in Voice and Handwriting Using the Same Methodology

Abstract

Parkinson’s disease is manifested as well in handwriting as in voice. Different procedures have been used in previous research to estimate the dysfunctions of the illness in voice and handwriting. This paper proposes one parameter to evaluate the influence of the illness on both voice and handwriting as the symptoms affecting these two behaviors have a common origin. Specifically, the parameter proposed is based on the Kinematic Theory of rapid human movements. It allows to quantify the deficits caused by Parkinson’s disease in handwriting and voice. The velocity profile obtained to characterize voice between the first and second formant is computed by a spatio-temporal approximation. In handwriting, the velocity profile is obtained from the sampled positions of the pen on a digitizer tablet. Once the velocity profile is derived, it is transformed to fit into the lognormal model in which similarities between voice and handwriting have been found for the performance of these tasks by Parkinson’s patients. The experiments with different databases of voice and handwriting recorded from different patients in different labs display positive results pointing out a common parameter that is affected by the two types of communication modalities.