StatusThe thesis was presented on the 11 May, 2006
Approved by NCAA on the 29 June, 2006
Abstract– 0.37 Mb / in romanian
6.91 Mb /
The peculiarities of the functioning of a motor control system are studied at healthy volunteers and at patients with diseases of the central structures of motor control system. As a model of movement, we chose bimanual control by isometric effort supported by examinee under visual or tactile feedback.
The purpose of the present research is to find a dependence of parameters of registered efforts from functional state of structures of motor control system.
The study was performed on 90 normal volunteers, 50 patients with essential tremor and 150 patients with Parkinson's disease (aged from 15 to 70 years).
With the aid of tensotremorography, a voluntary effort was recorded and characteristics of involuntary and voluntary components of the hands' isometrically recorded efforts were studied.
The analysis of parameters of isometric effort allows to present a picture of integrated activity in structures of motor system and their changes under influence of a developing pathology, and under drug treatment adjusting a mediator activity in structures of a brain, or after therapeutic procedures exerting a correcting influence on pathologically changed functions of controlling at central nervous system.
The range of 0-2 Hz characterizes opportunities of voluntary control of effort and the changing of spectral density in this range corresponds to the transmission of signals in the circuits which are closed through exteroceptive (in our case visual or tactile feedback) inputs. The changes in 2-4 Hz range may be in agreement with program control with the using of the internal long latent regulatory loops in which there are a cyclic activity through the ascending spino-thalamo-cortical pathways. The activity corresponded to a segmental level is reflected in the range of 7-15 Hz. In healthy subjects the spectral power in range of 3-7 Hz is suppressed. The increase of spectral power in the "forbidden" range of 3-7 Hz, obviously, is characteristic for the impairments of the central mechanisms of automatic control of movements.
In comparison with the healthy examinees the spectral analysis reveals the increased activity of descending influences with dominance of separate peaks in a range of 4-7 Hz at tremor form of Parkinsonism or dysfunctions of structures of basal ganglia. Under action of medicinal therapy on a background of common decreasing of amplitude of all spectral components the activity forming an increased involuntary oscillations (visible tremor) of parts of a body, disappears. Supporting of the same long isometric efforts up to fatigue also is characterized by the increasing of activity in all an analyzed range of frequencies (0-20 Hz) at healthy examinees.
In addition to a diagnostic application and control of efficiency of medicinal therapy, in our opinion, the received data allow developing the ideas and the modeling representations about functional organization of motor system and about mechanisms of realization of a motor function in interaction with sensory systems of organism at norms and pathological state.