台灣地區早已處於高齡化社會型態，且居家照護中跌倒為主要健康問題之一。因為姿勢控制是維持日常生活功能獨立性的重要能力，並且平衡能力會隨著年齡遞減，所以老年人許多跌倒的原因都與平衡能力相關。研究指出即使靜態站立情況下老年人重心移動量仍會隨年齡增加，透過測力板量測並計算壓力中心(center of pressure)指標為常見的平衡狀態評估方法之一，因其設計上具有簡易操作及客觀性等優點。
本文目的是透過地面反作力(ground reaction forces)之相互運作關係，發展新的特徵變數以進行姿勢穩定度的評估。特徵變數著重於地面反作用力分量間的關聯度，有別於壓力中心指標只能藉由合力提供單一方向訊息。實驗以靜態站立進行量測，並透過年齡(18-24與65-73歲)及感官(開眼及閉眼)兩個實驗分組進行特徵變數之效能驗證。經由實驗結果顯示，新特徵變數於開眼(EO)、閉眼(EC)、年輕(YG)與年老(ED)四個項目P值最低皆能小於10-6，且AUC值於上述四個項目各為0.95、0.92、0.73、0.72。藉此可知，新特徵變數比傳統壓力中心指標更具有平衡狀態鑑別能力，其反應於不同年齡、感官條件之下皆表現出較佳的區隔效能。此外，新特徵變數尚具有另一優點，僅透過垂直方向分力即能進行分析，能夠有效將傳統三軸量測簡化為單軸，進而有效降低測力板製造成本。

Since Taiwan has entered into an aging society, falls among older people becomes a public health issue for home healthcare. Postural control is an essential ability for us to move independently and safely. The ability to maintain balance decreases with age, therefore most of the falls among older people relate to balance ability. Increased postural sway in older adults has been reported even during quiet standing. This could be derived from the motion of center of pressure (COP) by force plate measures, which have simple designs and are easy to use.
The goal of this work is to assess the stability of postural balance using a new set of features based on ground reaction forces (GRFs). The focus of the proposed approach is on the correlations between the vertical GRF components measured by force plates. The effectiveness of the proposed features is demonstrated by comparing their differences between two age groups (18-24 and 65-73 years) and two sensory conditions (eyes-open and eyes-closed) in quiet standing. The results showed that the p-values for the four conditions are less than 10-6 and the AUC value are 0.95, 0.92, 0.71 and 0.72. The experimental results show that the features are more sensitive to age and sensory condition variations than conventional center of pressure based features. An additional advantage of the proposed approach is that it reduces the force sensing dimension from three to one. As a result, the cost of the force plate can be substantially reduced.

論文審定書 i
誌謝 ii
摘要 iii
Abstract iv
目錄 v
圖目錄 vii
表目錄 viii
第一章 緒論 1
1.1引言 1
1.2文獻回顧 2
1.3測力板簡介 4
1.4研究動機與目的 5
第二章 研究方法 7
2.1實驗對象 7
2.2實驗流程 8
2.3實驗量測 10
第三章 靜止站立穩定性特徵變數之建構 11
3.1傳統特徵變數之壓力中心(COP) 11
3.2 靜態站立的反鐘擺模式(inverted pendulum model) 13
3.3 質量中心之垂直方向投影(COMα)的計算方法 14
3.3.1 固定截止頻率法 15
3.3.2 雙重積分法(double integration method) 17
3.3.3 最佳截止頻率法 18
3.4 發展新靜止站立穩定性之特徵變數 19
3.4.1 以垂直方向分力發展特徵變數 20
3.4.2 Mean correlation(Mc) 20
3.4.3 Correlation combination(Cc) 21
3.4.4 Zero crossing number(ZCN) 23
3.4.5 Entropy(EN) 23
3.4.6 以三軸分力發展特徵變數 24
3.4.7 新特徵變數Index B與Index F 24
3.4.8 以COMα發展特徵變數 25
3.4.9 時間響應關聯度(time response correlation, TRC) 26
第四章 實驗結果與分析 27
4.1實驗分析項目規劃 27
4.2特徵變數統計分析結果 28
4.2.1 以垂直方向特徵變數進行分析 29
4.2.2 以三軸特徵變數進行分析 32
4.3分類效能指標 34
4.4子集合組合法 35
4.5特徵變數分類效能 36
4.6不同子集合組合時特徵變數分類效能 43
4.7新特徵變數與COP指標之關聯度 48
第五章 結論與未來展望 50
參考文獻 52
附錄Ⅰ 所有特徵變數之12次實驗平均結果 62

1. Burt, C. W., & Fingerhut, L. A. (1998). Injury visits to hospital emergency departments: United States, 1992-95 (Vol. 131). Department of Health and Hu Ol and Prevention Nati.
2. Piirtola, M., & Era, P. (2006). Force platform measurements as predictors of falls among older people-a review. Gerontology, 52(1), 1-16.
3. Kurz, I., Oddsson, L., & Melzer, I. (2013). Characteristics of balance control in older persons who fall with injury–A prospective study. Journal of Electromyography and Kinesiology, 23(4), 814-819.
4. Kelsey, J. L., Procter-Gray, E., Hannan, M. T., & Li, W. (2012). Heterogeneity of falls among older adults: implications for public health prevention. American journal of public health, 102(11), 2149-2156.
5. O'neill, T. W., Varlow, J., Silman, A. J., Reeve, J., Reid, D. M., Todd, C., & Woolf, A. D. (1994). Age and sex influences on fall characteristics. Annals of the rheumatic diseases, 53(11), 773-775.
6. Hektoen, L. F., Aas, E., & Lurås, H. (2009). Cost-effectiveness in fall prevention for older women. Scandinavian journal of public health, 37(6), 584-589.
7. Tinetti, M. E., Speechley, M., & Ginter, S. F. (1988). Risk factors for falls among elderly persons living in the community. New England journal of medicine, 319(26), 1701-1707.
8. Tinetti, M. E., Liu, W. L., & Claus, E. B. (1993). Predictors and prognosis of inability to get up after falls among elderly persons. Jama, 269(1), 65-70.
9. Lamb, S. E., Jørstad‐Stein, E. C., Hauer, K., & Becker, C. (2005). Development of a common outcome data set for fall injury prevention trials: the Prevention of Falls Network Europe consensus. Journal of the American Geriatrics Society, 53(9), 1618-1622.
10. Stevens, J. A., Corso, P. S., Finkelstein, E. A., & Miller, T. R. (2006). The costs of fatal and non-fatal falls among older adults. Injury prevention, 12(5), 290-295.
11. Langhorne, P., Coupar, F., & Pollock, A. (2009). Motor recovery after stroke: a systematic review. The Lancet Neurology, 8(8), 741-754.
12. Jørgensen, L., Engstad, T., & Jacobsen, B. K. (2002). Higher incidence of falls in long-term stroke survivors than in population controls depressive symptoms predict falls after stroke. Stroke, 33(2), 542-547.
13. Forster, A., & Young, J. (1995). Incidence and consequences offalls due to stroke: a systematic inquiry. BMJ, 311(6997), 83-86.
14. Horak, F. B. (1991). Assumptions underlying motor control for neurologic rehabilitation. In Contemporary management of motor control problems: Proceedings of the II STEP conference, (pp. 11-28). Alexandria, VA: Foundation for Physical Therapy.
15. Winter, D. A., Patla, A. E., & Frank, J. S. (1990). Assessment of balance control in humans. Med Prog Technol, 16(1-2), 31-51.
16. Winter, D. A. (1995). Human balance and posture control during standing and walking. Gait & posture, 3(4), 193-214.
17. A. Karlsson, A., & Persson, T. (1997). The ankle strategy for postural control—a comparison between a model-based and a marker-based method. Computer methods and programs in biomedicine, 52(3), 165-173.
18. Browne, J. E., & O'Hare, N. J. (2001). Review of the different methods for assessing standing balance. Physiotherapy, 87(9), 489-495.
19. Jančová, J. (2008). Measuring the balance control system–review. Acta Medica , 51(3), 129-137.
20. Rasku, J., Joutsijoki, H., Pyykkö, I., & Juhola, M. (2012). Prediction of a state of a subject on the basis of a stabilogram signal and video oculography test. Computer methods and programs in biomedicine, 108(2), 580-588.
21. Furlanetto, T. S., Candotti, C. T., Comerlato, T., & Loss, J. F. (2012). Validating a postural evaluation method developed using a Digital Image-based Postural Assessment (DIPA) software. Computer methods and programs in biomedicine, 108(1), 203-212.
22. Golriz, S., Hebert, J. J., Foreman, K. B., & Walker, B. F. (2012). The reliability of a portable clinical force plate used for the assessment of static postural control: repeated measures reliability study. Chiropractic & manual therapies, 20(1), 1-6.
23. Benda, B. J., Riley, P. O., & Krebs, D. E. (1994). Biomechanical relationship between center of gravity and center of pressure during standing. IEEE Transactions on Rehabilitation Engineering, 2(1), 3-10.
24. Caron, O., Faure, B., & Brenière, Y. (1997). Estimating the centre of gravity of the body on the basis of the centre of pressure in standing posture. Journal of biomechanics, 30(11), 1169-1171.
25. Bergland, A., & Wyller, T. B. (2004). Risk factors for serious fall related injury in elderly women living at home. Injury Prevention, 10(5), 308-313.
26. Prieto, T. E., Myklebust, J. B., Hoffmann, R. G., Lovett, E. G., & Myklebust, B. M. (1996). Measures of postural steadiness: differences between healthy young and elderly adults. IEEE Transactions on Biomedical Engineering, 43(9), 956-966.
27. Moghadam, M., Ashayeri, H., Salavati, M., Sarafzadeh, J., Taghipoor, K. D., Saeedi, A., & Salehi, R. (2011). Reliability of center of pressure measures of postural stability in healthy older adults: effects of postural task difficulty and cognitive load. Gait & posture, 33(4), 651-655.
28. Swanenburg, J., de Bruin, E. D., Favero, K., Uebelhart, D., & Mulder, T. (2008). The reliability of postural balance measures in single and dual tasking in elderly fallers and non-fallers. BMC musculoskeletal disorders, 9(1), 162.
29. Moghadam, M., Ashayeri, H., Salavati, M., Sarafzadeh, J., Taghipoor, K. D., Saeedi, A., & Salehi, R. (2011). Reliability of center of pressure measures of postural stability in healthy older adults: effects of postural task difficulty and cognitive load. Gait & posture, 33(4), 651-655.
30. Rougier, P. R. (2008). What insights can be gained when analysing the resultant centre of pressure trajectory?. Neurophysiologie Clinique/Clinical Neurophysiology, 38(6), 363-373.
31. Vette, A. H., Masani, K., Sin, V., & Popovic, M. R. (2010). Posturographic measures in healthy young adults during quiet sitting in comparison with quiet standing. Medical engineering & physics, 32(1), 32-38.
32. Aslan, U. B., Cavlak, U., Yagci, N., & Akdag, B. (2008). Balance performance, aging and falling: a comparative study based on a Turkish sample. Archives of gerontology and geriatrics, 46(3), 283-292.
33. Potvin, A. R., Syndulko, K., Tourtellotte, W. W., Lemmon, J. A., & Potvin, J. H. (1980). Human neurologic function and the aging process. Journal of the american geriatrics society, 28(1), 1-9.
34. Gill, J., Allum, J. H. J., Carpenter, M. G., Held-Ziolkowska, M., Adkin, A. L., Honegger, F., & Pierchala, K. (2001). Trunk sway measures of postural stability during clinical balance tests effects of age. The Journals of Gerontology Series A: Biological Sciences and Medical Sciences, 56(7), M438-M447.
35. Sabatini, A. M. (2000). Analysis of postural sway using entropy measures of signal complexity. Medical and Biological Engineering and Computing, 38(6), 617-624.
36. B³aszczyk, J. W., & Klonowski, W. (2001). Postural stability and fractal dynamics. Acta Neurobiol. Exp, 61, 105-112.
37. Ladislao, L., & Fioretti, S. (2007). Nonlinear analysis of posturographic data. Medical & biological engineering & computing, 45(7), 679-688.
38. Lord, S. R. (2006). Visual risk factors for falls in older people. Age and ageing, 35(suppl 2), ii42-ii45.
39. Coleman, A. L., Cummings, S. R., Yu, F., Kodjebacheva, G., Ensrud, K. E., Gutierrez, P., ... & Mangione, C. M. (2007). Binocular Visual‐Field Loss Increases the Risk of Future Falls in Older White Women. Journal of the American Geriatrics Society, 55(3), 357-364.
40. Salonen, L., & Kivelä, S. L. (2012). Eye diseases and impaired vision as possible risk factors for recurrent falls in the aged: a systematic review. Current gerontology and geriatrics research, 2012.
41. Stelmach, G. E., & Worringham, C. J. (1985). Sensorimotor deficits related to postural stability. Implications for falling in the elderly. Clinics in geriatric medicine, 1(3), 679-694.
42. Riva, D., Mamo, C., Fanì, M., Saccavino, P., Rocca, F., Momenté, M., & Fratta, M. (2013). Single stance stability and proprioceptive control in older adults living at home: gender and age differences. Journal of aging research, 2013.
43. Bohannon, R. W., Larkin, P. A., Cook, A. C., Gear, J., & Singer, J. (1984). Decrease in timed balance test scores with aging. Physical Therapy, 64(7), 1067-1070.
44. Hasson, C. J., Caldwell, G. E., & van Emmerik, R. E. (2008). Changes in muscle and joint coordination in learning to direct forces. Human movement science, 27(4), 590-609.
45. Amiridis, I. G., Hatzitaki, V., & Arabatzi, F. (2003). Age-induced modifications of static postural control in humans. Neuroscience letters, 350(3), 137-140.
46. Horak, F. B., Nashner, L. M., & Diener, H. C. (1990). Postural strategies associated with somatosensory and vestibular loss. Experimental Brain Research, 82(1), 167-177.
47. Mergner, T. (2007). Modeling sensorimotor control of human upright stance. Progress in brain research, 165, 283-297.
48. Bove, M., Nardone, A., & Schieppati, M. (2003). Effects of leg muscle tendon vibration on group Ia and group II reflex responses to stance perturbation in humans. The Journal of physiology, 550(2), 617-630.
49. Bacsi, A. M., & Colebatch, J. G. (2005). Evidence for reflex and perceptual vestibular contributions to postural control. Experimental brain research, 160(1), 22-28.
50. Schmid, M., Nardone, A., De Nunzio, A. M., Schmid, M., & Schieppati, M. (2007). Equilibrium during static and dynamic tasks in blind subjects: no evidence of cross-modal plasticity. Brain, 130(8), 2097-2107.
51. Hess, J. A., & Woollacott, M. (2005). Effect of high-intensity strength-training on functional measures of balance ability in balance-impaired older adults. Journal of manipulative and physiological therapeutics, 28(8), 582-590.
52. McCollum, G., & Leen, T. K. (1989). Form and exploration of mechanical stability limits in erect stance. Journal of Motor Behavior, 21(3), 225-244.
53. Himann, J. E., Cunningham, D. A., Rechnitzer, P. A., & Paterson, D. H. (1988). Age-related changes in speed of walking. Medicine and science in sports and exercise, 20(2), 161-166.
54. Heinrich, S., Rapp, K., Rissmann, U., Becker, C., & König, H. H. (2010). Cost of falls in old age: a systematic review. Osteoporosis international, 21(6), 891-902.
55. Berg, K., Wood-Dauphinee, S., & Williams, J. I. (1995). The Balance Scale: reliability assessment with elderly residents and patients with an acute stroke. Scandinavian journal of rehabilitation medicine, 27(1), 27-36.
56. Renfro, M. O., & Fehrer, S. (2011). Multifactorial screening for fall risk in community-dwelling older adults in the primary care office: Development of the Fall Risk Assessment & Screening Tool. Journal of Geriatric Physical Therapy, 34(4), 174-183.
57. Powell, L. E., & Myers, A. M. (1995). The activities-specific balance confidence (ABC) scale. The Journals of Gerontology Series A: Biological Sciences and Medical Sciences, 50(1), M28-M34.
58. Dempster, W. T. (1958). Analysis of two-handed pulls using free body diagrams. Journal of Applied Physiology, 13(3), 469-480.
59. Hasan, S. S., Robin, D. W., Szurkus, D. C., Ashmead, D. H., Peterson, S. W., & Shiavi, R. G. (1996). Simultaneous measurement of body center of pressure and center of gravity during upright stance. Part I: Methods. Gait & posture, 4(1), 1-10.
60. Winter, D. A., Patla, A. E., Prince, F., Ishac, M., & Gielo-Perczak, K. (1998). Stiffness control of balance in quiet standing. Journal of neurophysiology, 80(3), 1211-1221.
61. Lafond, D., Duarte, M., & Prince, F. (2004). Comparison of three methods to estimate the center of mass during balance assessment. Journal of biomechanics, 37(9), 1421-1426.
62. Winter, D. A. (1995). ABC (anatomy, biomechanics and control) of balance during standing and walking. Waterloo Biomechanics.
63. Corriveau, H., Hébert, R., Raîche, M., & Prince, F. (2004). Evaluation of postural stability in the elderly with stroke. Archives of physical medicine and rehabilitation, 85(7), 1095-1101.
64. Corriveau, H., Hébert, R., Prince, F., & Raîche, M. (2001). Postural control in the elderly: an analysis of test-retest and interrater reliability of the COP-COM variable. Archives of physical medicine and rehabilitation, 82(1), 80-85.
65. Gage, W. H., Winter, D. A., Frank, J. S., & Adkin, A. L. (2004). Kinematic and kinetic validity of the inverted pendulum model in quiet standing. Gait & posture, 19(2), 124-132.
66. Winter, D. A., Patla, A. E., Prince, F., Ishac, M., & Gielo-Perczak, K. (1998). Stiffness control of balance in quiet standing. Journal of neurophysiology, 80(3), 1211-1221.
67. Brenière, Y. (1996). Why we walk the way we do. Journal of motor behavior, 28(4), 291-2.
68. Winter, D. A., Prince, F., Frank, J. S., Powell, C., & Zabjek, K. F. (1996). Unified theory regarding A/P and M/L balance in quiet stance. Journal of neurophysiology, 75(6), 2334-2343.
69. Hahn, M. E., & Chou, L. S. (2004). Age-related reduction in sagittal plane center of mass motion during obstacle crossing. Journal of Biomechanics, 37(6), 837-844.
70. Wright, R. L., Peters, D. M., Robinson, P. D., Watt, T. N., & Hollands, M. A. (2015). Older adults who have previously fallen due to a trip walk differently than those who have fallen due to a slip. Gait & posture, 41(1), 164-169.
71. Mackey, D. C., & Robinovitch, S. N. (2005). Postural steadiness during quiet stance does not associate with ability to recover balance in older women. Clinical Biomechanics, 20(8), 776-783.
72. Maki, B. E., & McIlroy, W. E. (1996). Postural control in the older adult. Clinics in geriatric medicine, 12(4), 635-658.
73. Lugade, V., Lin, V., & Chou, L. S. (2011). Center of mass and base of support interaction during gait. Gait & posture, 33(3), 406-411.
74. Pickerill, M. L., & Harter, R. A. (2011). Validity and reliability of limits-of-stability testing: a comparison of 2 postural stability evaluation devices. Journal of athletic training, 46(6), 600-606.
75. King, D. L., & Zatsiorsky, V. M. (1997). Extracting gravity line displacement from stabilographic recordings. Gait & Posture, 6(1), 27-38.
76. B³aszczyk, J. W. (2008). Sway ratio a new measure for quantifying postural stability. Acta Neurobiol Exp, 68, 51-57.
77. Shimba, T. (1984). An estimation of center of gravity from force platform data. Journal of Biomechanics, 17(1), 53-60.
78. Duarte, M., Freitas, S. M. S. F., & Zatsiorsky, V. (2011). Control of equilibrium in humans—Sway over sway. Motor Control, Oxford University Press, Oxford, 219-242.
79. Egoyan, A., & Moistsrapishvili, K. (2013). Equilibrium and Stability of the Upright Human Body. General Science Journal.
80. Zatsiorsky, V. M., & King, D. L. (1998). An algorithm for determining gravity line location from posturographic recordings. Journal of Biomechanics, 31(2), 161-164.
81. Schepers, H. M., van Asseldonk, E. H., Buurke, J. H., & Veltink, P. H. (2009). Ambulatory estimation of center of mass displacement during walking. IEEE Transactions on Biomedical Engineering, 56(4), 1189-1195.
82. Zabjek, K. F., Coillard, C., Rivard, C. H., & Prince, F. (2008). Estimation of the centre of mass for the study of postural control in Idiopathic Scoliosis patients: a comparison of two techniques. European Spine Journal, 17(3), 355-360.
83. Zatsiorsky, V. M., & Duarte, M. (2000). Rambling and trembling in quiet standing. MOTOR CONTROL-CHAMPAIGN, 4(2), 185-200.
84. Downey Jr, T. J., Meyer, D. J., Price, R. K., & Spitznagel, E. L. (1999). Using the receiver operating characteristic to asses the performance of neural classifiers. In Neural Networks, 1999. IJCNN'99. IEEE International Joint Conference, 5, 3642-3646.
85. Fawcett, T. (2006). An introduction to ROC analysis. Pattern recognition letters, 27(8), 861-874.
86. Gunnarsson, R. K., & Lanke, J. (2002). The predictive value of microbiologic diagnostic tests if asymptomatic carriers are present. Statistics in medicine, 21(12), 1773-1785.
87. Swanenburg, J., de Bruin, E. D., Favero, K., Uebelhart, D., & Mulder, T. (2008). The reliability of postural balance measures in single and dual tasking in elderly fallers and non-fallers. BMC musculoskeletal disorders, 9(1), 162.
88. Moghadam, M., Ashayeri, H., Salavati, M., Sarafzadeh, J., Taghipoor, K. D., Saeedi, A., & Salehi, R. (2011). Reliability of center of pressure measures of postural stability in healthy older adults: effects of postural task difficulty and cognitive load. Gait & posture, 33(4), 651-655.