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Development of a Balance Assessment Method in Dynamic Tasks (LOS) Using a Sway Control Model in Parkinson's Disease

Jasimi Zindashti, Niromand | 2022

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 54951 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Behzadipour, Saeed; Mohebbi, Abolfazl
  7. Abstract:
  8. Parkinson's disease impairs the patients' balance with the degeneration of the neurons related to their postural control. There are many rehabilitation methods to preclude the disease or weaken its effects. To assess the influence of these methods and their outcome, there are two main evaluation methods, including clinical (qualitative and dependent on the presence of a therapist) and quantitative, such as posturography. Using control models is one of the quantitative methods researchers have been used for more than three decades. Considering this and what have been done in the literature, the purpose of this research is to develop a balance assessment method in dynamic tasks, such as the limit of stability, using sway control models in Parkinson's disease. To do so, first, a 2-D control model has been developed (in anterior-posterior and medio-lateral directions) considering human body as a single inverted pendulum around ankle joint, and control parameters were identified for three groups, PD patients before and after a twelve-session therapy and healthy subjects, in static tests. Statistical results indicate that AP direction is probably more impaired in Parkinson's disease. Second, adding some new parts to the previous model, suitable for static tests, a control model being appropriate for studying postural control in the limit of stability task was developed, and control parameters as well as some of the important measures of LoS task were identified. Statistical results reveal that PD patients have significantly (P-value < 0.05) greater reaction time and the whole time of the task in all directions. Kp, proportional gain in controller, was the only control parameter identified, and it was significantly smaller in healthy subjects than PD patients in all directions; fear of falling and muscle co-contraction in patients can be the main reasons for this difference. Also, the size of anticipatory postural adjustments (APA) was significantly smaller in PD patients than healthy subjects, although there was no significant difference between these two groups in terms of APA duration. This difference can be explained considering the weak prediction in PD patients. Finally, correlations between identified or calculated parameters and clinical scores were found, and there were strong correlations for most of the related parameters and clinical tests in most directions. These acceptable correlations can partly confirm the developed model, identification method, and the usefulness of the proposed parameters in capturing the difference between patients
  9. Keywords:
  10. Balance ; Parkinson Disease ; Pressure Center ; Stability Limit ; Patient Equilibrium ; Balance Rehabilitation

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