Principles of constructing active orthoses of upper extremity in flaccid paralyses
The purpose - to identify the cardinal principles of constructing active ortheses of a hand for self-service of invalids with different forms of flaccid paresis and paralyses. Material and methods. Based on the analysis of literature sources (276 neurological and 24 orthopedic) and determining the nature of neurological and biomechanical deficit of the upper limb function, we identified breaches of motor synergy during self-service test in 31 invalids with different forms and degrees of flaccid paresis and paralyses of the upper limb. The minimum group of operations and actions in vital activity was identified, which provides independent existence of an invalid. Accessibility of operations was researched on a stand-simulator of loads estimating the possibility (0; 1) and quality of their execution with scores 0 to 5. The parametric criteria of the action quality were: zonal reachability of the object (± Z), developed dinamometric effort of the hand (FN) and control cost (+ U) measured by the excess length of motion (+ AL). The execution time Ts was measured with a stopwatch. The efficiency of operations and actions was estimated with the standards of their structures and execution time. Electroactivity of the intact muscles was registered with a reference pattern: from the trapezium muscle to thenar and hypothenar of the hand. The structure? Amplitude and capacity of EMG were measured. Results. Active orthoses are divided into groups according to the preservation of the shoulder girdle, the forearm and the wrist muscles and the corresponding joints. Depending on the level of the lesion, either the hand grasping and holding and motor skills are disrupted, with a relatively preserved ability to manipulate the arm, or, conversely, the ability to manipulate the arm decreases with the preserved function of the hand grip. The reductions in the estimated parameters are very diverse for the disabled people. The electroactivity of the preserved muscles in paresis is destructive, but it is sufficient in capacity and can be used to control the active orthosis of the hand. Conclusions. The formulated seven principles make it possible to build an individual active orthosis of the upper limb for various types of flaccid paresis. The electroactivity of the preserved hand muscles is destructive, but sufficient in power and can be used to control the active orthosis. Using signals from other muscle groups is laborious and ineffective.