Modeling of the steady-state disturbance term in isometric force using components of the power spectrum.

The analysis of isometric force may provide early detection of certain types of neuropathology such as Parkinson's disease. Our long term goal is to determine if there are detectable differences between model parameters of healthy and unhealthy individuals. The participants in this study were twenty four healthy adults ages 18 through 24, both male and female. The experiments involved the participants exerting isometric force over a range from 5% to 65% of maximal voluntary contraction. The analysis involved the steady-state portion of the recorded time series. Five components of the power spectral density were extracted and used as features to classify the participants into two categories: (1) high strength; (2) low strength based upon the values of the five extracted spectral components. Even though the participants were all healthy and young the features exhibited enough differences to successfully classify 80% of the subjects into the proper category. This finding suggests that the 5-component model should be capable of discriminating between healthy individuals and those who are in an early stage of neurodegenerative disease.