| Background:As a special group in society,disabled people's quality of life has gained widely attention.Because some or all of the ability to move had been loss,the lack of physical aspects produces great difficulties for their life,learning and working.And then it leads to a variety of psychological,physical barriers.In additionally,the number of disabled patients with amputation caused by car accidents and other reasons shows an increasing trend recent year.There are about 4 million forearm amputation patients in our country.As one of the most flexible organs,the loss of hand function will not only seriously affect the quality of daily life of patients with forearm amputation but also lead to great psychological trauma.In order to make people with physical disabilities better integrate into society,installing prostheses is the most effective way to help them.Among prostheses,myoelectric prosthetic hands are more flexible in their control.The characteristics of ease of use and strong directness make myoelectric prosthetic hands become the most widely used in modern upper extremity prosthesis area.Since it is very important to improve the quality of life and promote the rehabilitation of the disabled,myoelectric prosthetic hand is also one of the hot topics in rehabilitation medicine engineering field.According to the type of its controllable action,myoelectric hand is divided into single degree of freedom myoelectric hand and multi-degree of freedom myoelectric hand.At present single degree of freedom practical myoelectric hand has high market share in china because it is easy to operate,and marked relatively low price.Studies have shown that the proportion of single-degree-of-freedom myoelectric hands used in forearm amputations is 89%.However,there are many problems in how to replace the prosthetic limb better,such as how to choose the amputation level and position,how to deal with the stump correctly,how to choose a suitable prosthesis,how to carry on the function exercise instruction after operation in order to prevent the occurrence of deformity,how to instruct the patient to use and maintain the prosthesis correctly,how to do a good psychological counseling for them and make them quickly return to society.Because of long-term myoelectric control prosthesis,early wearing forearm prosthesis patients may easy nerve fatigue coupled with external electric field interference.It can cause electromyoelectric hand output and feedback control information to repeat poor reproducibility,instability,resulting in the patient's brain motor area sent out control amputation end muscle group recruitment information error.At the same time,no optimization scheme has been established for the rehabilitation training of forearm amputation patients by analyzing the biomechanical differences of forearm true limb and myoelectric hand.Based on the insufficient grip speed control of prosthetic limb at present,some amputees prefer to use a rope to pull a prosthetic hand rather than a myoelectric hand.Thus,to make better use of the myoelectric hand and how to increase the practicability and flexibility of myoelectric prosthetic hand are urgent problems need to be solved.With the increasing clinical use of myoelectric hand in forearm amputation patients.It is necessary to formulate better rehabilitation training program for the patients with forearm amputation to give the the patients corresponding guidance.Objective:to enhance the amputee's confidence in life,recover body and mind,and to make them better integrate into society.To summarize the practical guidelines for the assembly and use of prosthetic limbs and to study the biomechanical differences between forearm prostheses and forearm true limbs.Through the selection and fitting of prosthesis and the correct use of the prosthesis,establish the corresponding guidance of the rehabilitation training program for the patients.Enables the patient to perform the prosthetic function effectively.Method:Selected object are patients in our hospital from January 2015 to January 2016:the age of treatment is less than 50 years old,severe trauma of forearm amputation operation,choose to wear myoelectric hand.At the same time the objects have been wearing myoelectric hand for no less than 1 month,basically familiar with the use of myoelectric hand,and their clinical data is complete.At the same time,they shuold be without severe diseases of organs or tissues,such as heart,lung,liver,kidney and malignant tumor,and without mental illness or mental retardation.Healthy volunteers with no history of antidepressant or sedative use were used as control group.Single degree of freedom myoelectric hand was selected as the experimental material in this study.After entering the group,the experimenter selected the myoelectric hand with the appropriate size of the wearer's mouth for the patients.And trained patients to fully understand the use of prosthetic assembly,such as pay attention to the hands of the matching action.Electronic pressure sensors in the process of the experiment are used to measure data.The electronic pressure sensor was applied to the electromyoelectric hand or the elbow of the hand,the wrist wall and the fingertip of the knuckles.When the two groups of subjects were carrying out the lifting experiment,the electromyoelectric hand in the prosthetic limb group was parallel to the ground when the hand was still pulling the heavy object.The bottom end is vertically connected with the nylon belt and the weight weight,increasing the weight in turn until the nylon belt slips;The electromyoelectric hand imitated the dynamic lifting of heavy matter by hand,and then the two groups of subjects were extracted from 49N?98N and 147N respectively.The weight of 49N and 147N was 1 kg = 9.8N?147N = 15kg/kg respectively.98N stands for 10kg weight,49N for 5kg weight,from natural vertical arm to stretch arm horizontal ground to do dynamic lifting heavy object.Calculation of exercise time.Under the guidance of the experimenter,the two groups of research subjects made grip force experiment on the holding columnar object,the diameter of the cylinder was 4 cm,8 cm and 10 cm hollow water pipe.The grip force of myoelectric hand or real hand was measured by fingertip pressure sensor.The subjects were required to apply force for 10 s according to the order of all grasping modes.At the same time,both the size of 0-60N)and the speed of 0.5-2.0HZ)should be taken into account.If there is no loosening of the water pipe,it is determined to hold the cylinder firmly.The subjects of the two groups in the thumb clamping pressure experiment under the guidance of the experimenter were 1 yuan coins,glass balls and pencils in order.The holding pressure of real hand or electromyoelectric finger and thumb was measured by fingertip pressure sensor.The experimental pressure values were recorded and repeated three times.Results:There were 17 males and 13 females in artificial limb group,aged 20-47 years old,the mean age(38.6 ± 7.2)years old,time from injury to operation is 1-8 h,the average(4.2 + 0.8)h.In control group,17 cases were male,13 were female,aged 22-47 years old,average age(38.4 + 7.0)years old,there is no statistically significant difference in age,gender and education level(P>0.05).It is comparable.The results of lifting test showed that the drop time of static lifting weight in prosthesis group was 126.73±20.21s,and the strength was 204.31 ±52.65N.In the control group,the drop time and strength of the static lifting weight were 120.35 ±19.87s and 172.02 ±34.76N respectively.There was no significant difference in dropping time between the two groups(P>0.05),but the static lifting weight in the prosthesis group was significantly higher than that in the control group(P<0.05).The test results of dynamic lifting weight under three forces of 147N,98N and 49N showed that the lifting time of each weight in the prosthetic group was 5.92±1.50s,7.49±1.48s,11.52±2.53s,respectively.It was significantly lower than that in the control group(the titration time was 4.05± 1.43s,6.05±1.31s,9.27±2.15s).The difference was statistically significant(P<0.05).The results of grip strength test showed that the grip strength of thumb in prosthesis group was 42.17±5.33N,50.60±5.62N,72.48±6.12N,respectively.The grip strength of the control group was57.42±4.48 N,64.60±5.87 N,89.25±7.89 N respectively.The grip strength of the prosthesis group was lower than that of the control group,and the difference was statistically significant(P<0.05).The results of thumb clamping experiment showed that the holding force of 1 yuan coin,glass ball and pencil were 12.74 ±4.18N,16.24 ±4.37N and 10.21 ±3.41N respectively.Compared with the control group,the holding force of 1 yuan coin,glass ball and pencil were 14.42 ±4.27 N,18.17 ±4.72 N,12.42 ±3.85 N respectively.The difference was statistically significant(P<0.05).Conclusion:Under the training of the experimenter,the patients in the prosthesis group can use myoelectric hand skillfully and complete the experiment item according to the request.There is no significant difference between the two groups in the drop time of the static lifting heavy object.The static lifting weight in the prosthesis group was significantly higher than that in the control group,and the lifting time of each weight in the dynamic lifting weight group was significantly lower than that in the control group.The results showed that the single degree-of-freedom myoelectric hand was superior to the forearm real limb in bearing weight.The reason may be that electromyoelectric hand belongs to a mechanical actuator.Furthermore,it is made of a high polyester compound with a strong strength and is slower than the forearm limb in the lifting time of a heavy object.It also reflects that the efficiency of information output of artificial limb controlled by tendon at amputation end is significantly lower than that of brain control nerve,muscle and bone.It is further proved that the motor nerve bundles can produce clear control information and signal-to-noise ratio(SNR)is better than that of artificial biomimetic signals.In this study,the grip strength of each diameter columnar in prosthetic limb group is smaller than that in the control group.The holding force of 1 yuan coin,glass ball and pencil in the prosthetic group was lower than that in the control group.The reason may be that the precision of the myoelectric hand was extracted and corrected when the amputation object was holding the column object and during the experiment.At the same time,the patient also took pre-judgment action to complete the operation of myoelectric hand,resulting in a lower force value than the real hand operation.Thus,the weight bearing capacity of the single-degree-of-freedom myoelectric hand is stronger than that of the forearm real limb while the precision of force at finger tip and flexibility is lower than that of real limb.Myoelectric hand is widely used in forearm amputation patients,but it still needs to give corresponding guidance in the process of use.The further development of multi-degree-of-freedom myoelectric hand is also a new hope for amputation rehabilitation. |
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