Study On The New Method Of Stability Analysis During Paraplegic FES-Assisted Walking Based On RTG

Paraplegia is a severe disability of lower limbs from spinal cord injury (SCI).Moreover, its incidence has been climbing over the years. Clear evidence showed thatthe technique of functional electrical stimulation (FES) could take good effect inresuming paraplegic patient walking ability and might be applied broadly in clinics inthe future. FES is a methodology that uses bursts of short electrical pulses tostimulate leg muscle and generate walking. As various FES protocols or assistantequipments bring different walking effects, how to evaluate these walking effects hasbecome a hot problem in the guide of effective FES use in recent years. Especially onthe stability analysis of walking result, relevant research was so limited that it neededto be developed further and faster. This thesis presented a new method based on risk-trend-gram (RTG) to analyzethe stability of paraplegic FES-assisted walking, which took walker rolling index(WRI) as the stability evaluation indicator and, combining with its localization intime and space, formed the morphological curve in RTG to visually describe thestability conditions during paraplegic walking. The main component of the newmethod was a special-designed walker dynamometer system. Through a 12-channlesstrain gauge bridges network instrumented on walker frame and other circuits, thissystem could instantly obtain the data of handle reaction vector (HRV) applied bypatient to the walker during walking and, after calculation, transform into RTG todisplay. To avoid the additional influence on the real walking effect, an indirectmeasurement pattern was adapted in the new method with some particular techniques,including the finite element analysis of walker frame, theoretic deduction inmechanics, redundancy-optimization algorithm and strain gauge orientation, toguarantee the measure results as credible as possible. The experimental calibration and clinical trial results demonstrated the newmethod was reliable and practical. In this design, force accuracy was better than1.01%, non-linearity was less than 2.901%, and crosstalk was less than 3.188%.Application demos were given from recruited subjects undergoing FES-assistedwalking training in Paraplegic Rehabilitation Center of Queen Mary Hospital of HongKong University and Gait Lab of Duchess of Kent Children's Hospital. Pilot studyshowed that the new method possessed the potential clinical usefulness in evaluatingthe stability of paraplegic FES-assisted walking and might provide the foundation to IIIenact the relevant national rehabilitation criterions for effective FES usage. The originalities of this thesis were the followings: ① The new concept of RTG and the new method based RTG were introduced toanalyze the stability of paraplegic FES-assisted walking, which broke fresh ground intraditional walking effect evaluation research. ② The new stability indicator of WRI was proposed and defined according tothe relevant mechanics analysis of walker usage. ③ The new concept of self relative coordinates system was presented. And aparaplegic trunk simplified model was founded according to the correlative clinicalfacts to guide RTG fixing the position in self relative coordinates system. ④ For the first time the finite element analysis was applied into the theoreticloading test on standard walker frame. The test result provided the basis of straingauge placement in walker dynamometer system and even might give some newideas to the redesign of future walker frame. ⑤ For the first time an indirect measurement pattern of HRV was designed anddemonstrated systematically, which effectively resolved the problem of the directmeasurement pattern that might distort real walking effect and ensured the validity ofHRV data. ⑥ For the first time a walker dynamometer system was established upon HRVindirect measurement, the core part of which was a 12-channles strain gauge bridges...