Upper limb prosthetics: assessment of success by trajectory analysis

Authors:

Burov Gennady Nikolayevich, PhD in Technical sciences, head of scientific direction, Albrecht Federal Scientific Centre of Rehabilitation of the Disabled, 50 Bestuzhevskaya Street, 195067 St. Petersburg, Russian Federation, tel.: +7-921-791-12-90, e-mail: zxzy@yandex.ru

Bolshakov Vladimir Alexandrovich, head of design department, Albrecht Federal Scientific Centre of Rehabilitation of the Disabled, 50 Bestuzhevskaya Street, 195067 St. Petersburg, Russian Federation, tel.: +7-921-757-87-16, e-mail: pko09_903@mail.ru

Drobakha Alena Sergeevna, junior research associate, Albrecht Federal Scientific Centre of Rehabilitation of the Disabled, 50 Bestuzhevskaya Street, 195067 St. Petersburg, Russian Federation, e-mail: drobaha-alena@mail.ru

Annotation:

Introduction. Trajectory analysis belongs to the category of complex, but obligatory stages of assessing the effectiveness of the rehabilitation biotechnical system ‘disabled person – hand prosthesis – environment’. The created measuring complex is a modern hardware tool for an objective assessment of the effectiveness of upper limb prosthetics by the method of kinematic analysis. In contrast to the known assessment methods, actions performed with a hand prosthesis can be regulated by representing the environment in the form of a two-dimensional trajectory. In this case, it is possible to continuously monitor the parameters of a given work operation and all deviations from the prescribed value of the measured values. The result of prosthetics is assessed by means of a certain quantitative indicator characterizing the ability of a prosthetic disabled person to perform a set of tests, the success of actions and the time spent on completing a specific test task.

Aim. Development of a technique and device for assessing the success of upper limb prosthetics by the method of trajectory analysis.

Materials and methods. In the developed methodology, an attempt was made to simultaneously use two principles of assessment — the principle of successful achievement of the result and the principle of comparison. Objectification of the assessment of the rehabilitation effect can be achieved taking into account the specificity of the motor activity of disabled people using prostheses of the upper extremities. All motor acts performed by a disabled person were divided into two main groups: manipulation of a free object and movement with a bound object along a rigid trajectory. To assess the effectiveness of prosthetics for different patients, they performed the same motor (work or control) operation. The effectiveness of the use of a technical device – a hand prosthesis – can be determined by the quantitative characteristics of the body movements of a disabled person, which can be recorded using potentiometric sensors, and with appropriate processing of electrical signals (differentiation in time) to assess the characteristics of the speed of body movements in the process of performing motor acts with the hands.

Results. The device for monitoring the execution of the test reference motor act is a tablet with the ability to adjust its position in terms of inclination angle and height. The reference trajectory should be displayed on the tablet field. A coordinate device mechanism must be fixed on the tablet, the end link of which must have a handle for gripping it with an artificial brush. The end link of the mechanism must be able to move freely in the field of the tablet when the handle is gripped by an artificial brush when exposed to the prosthetic limb. Data processing from coordinate sensors, analog-to-digital converter with recalculation and analysis of actual measurements by software makes it possible to form an indicator of the effectiveness of using a hand prosthesis based on trajectory research data.

Discussion. It is known that the main characteristics of the technical means that execute the operator’s commands are the speed and accuracy of performing a given movement. In the case when we are dealing with a biotechnical system as a whole and trying to characterize its effectiveness, it is necessary to take into account not only the features of the technical means, but also the operator himself. These factors include the level of amputation, the degree of mobility of the natural joints of the hand, the operator’s response time, and the time taken to complete the task.

Conclusion. In the course of the study, the data obtained allowed us to draw the following conclusions:
– trajectory analysis belongs to the category of complex, but obligatory stages of assessing the effectiveness of the rehabilitation biotechnical system ‘disabled person – hand prosthesis – environment’;
– the created measuring complex is a modern hardware tool for an objective assessment of the effectiveness of upper limb prosthetics by the method of kinematic analysis;
– the results of the study carried out with the help of the measuring complex can be used in the further formation of indicators for the integral assessment of the effectiveness of the rehabilitation biotechnical system;
– as the next stage in assessing the effectiveness of a rehabilitation biotechnical system, it can be recommended to analyze the energy consumption of the muscular system when using an upper limb prosthesis.

List of cited literature:

1. Neve Wilfred Korpernahetechnische Hilfen zur Rehabilitation Korperbehinderter. Berlin: VEB Verlagund Gesundheit; 1978. 175 s.

2. Burov GN. Sovremennoye sostoyaniye problemy upravleniya protezami verkhnikh konechnostey i dostigayemyy effekt protezirovaniya. [The current state of the problem of managing prostheses of the upper extremities and the achieved effect of prosthetics]. Vestnik gil’dii protezistov-ortopedov [Bulletin of the guild of prosthetics-orthopedists]. 2002;4(10):37-43. (In Russian).

3. Bakulev VI, Burov GN. K voprosu sozdaniya aktivnykh mekhanicheskikh protezov dlya invalidov s korotkimi kul’tyami verkhnikh konechnostey [On the issue of creating active mechanical prostheses for disabled people with short stumps of the upper extremities]. Vestnik gil’dii protezistov-ortopedov [Bulletin of the guild of prosthetists-orthopedists]. 2004;2(16):13-9. (In Russian).

4. Nader Max. Otto Bock. Prosthetic compendium. Upper Extremity Prostheses. Berlin: Schiele und Schon; 1990. 95 s.

5. Protezy verkhnikh konechnostey [Upper limb prostheses]. Katalog [Catalog] 2001-2002. Moskva: RKK «Energiya» [Moscow: RSC Energia]; 2002. 21 p. (In Russian).

6. Burov GN, Bol’shakov VA. Protez predplech’ya [Forearm prosthesis]. Patent [Patent] RF No. 2541816 dated 16.04.2015. (In Russian).

7. Burov GN, Bol’shakov VA. Protez predplech’ya [Forearm prosthesis]. Patent [Patent] RF № 2615278 dated 04.04.2017. (In Russian).