Time varying amplitude probability density function: application to the study of head rest comfort in a car

Evolution of the amplitude probability density function (APDF) of EMG signals from neck muscles were studied in order to make an objective diagnostic of the benefit of using a head rest in a car. This method is simple: several APDFs over a long period of time are computed and observed. Interesting results are obtained with 6 subjects (N=8), especially with evolutions of static and median load. The sign of the evolution appears to be discriminant. Obviously, the major drawback is the lack of explanation of results observed: as the classical APDF, this method is only an a posteriori approach.