Chapter 6. Mechanisms of changes in dynamic complexity of involuntary oscillations of the human hand with movement disorders

Abstract

The sixth chapter examines the mechanisms of changes in the dynamic complexity of hand tremor with an increase in the degree of motor disorders. For this, multifractal and wavelet properties of involuntary oscillations that arise during the performance of certain motor tasks by a healthy person and a person with varying degrees of motor pathology are investigated. It was shown that clinical manifestations of pathological tremor correlate, firstly, with a significant increase in the global energy of the wavelet spectrum and, secondly, with a decrease in the width of the singularity spectrum. At the same time, an improvement in the functional state (a decrease in the amplitude of a pathological tremor) corresponds to a decrease in long-term correlations and an increase in the randomness of up-down patterns, which corresponds to a partial shift of the singularity spectrum into the range of values typical for a tremor of the hand of a healthy person. The mechanism for reducing the dynamic complexity of patterns of involuntary oscillations of the human hand with an increase in the degree of motor disorders is based on a decrease in the contribution of strong fluctuations, accompanied by the appearance of long-term correlations of sequential values of tremor. The considered features in changes in tremor patterns make it possible to quantify the degree of movement disorders and can be used to facilitate the differential diagnosis of the parkinsonian and essential tremor in complex clinical cases.