運用多尺度熵於不同刺激及老化影響下之穩定性研究

The Stability for Different Effect and Aging on Multiscale Entropy

楊澤浤(Tse-Hung Yang)

指導教授 ： 江行全

元智大學/工程學院/工業工程與管理學系/碩士(2008年)

https://doi.org/10.6838/YZU.2008.00173

摘要

老年人發生跌倒往往與平衡的穩定度有直接的相關，以往研究老年人跌倒問題大多為跌倒因子相關性的分析，且需要龐大樣本資料導致分析複雜且實際應用困難。因此本研究設計在不同靜止站立時間以及導入注意力影響下之壓力中心點(COP)實驗，主要利用其移動軌跡分析以及在物理學能量的概念下求取複雜度來顯示出青年與老年兩族群之差異。研究對象為安養院15位老年人(65歲以上)以及13位青年人(30歲以下)，經由測試所得之數據導入經驗模態分解方法(EMD)進行前處理，刪去低頻而留下能量較大之高頻訊號，進而利用多尺度熵(MSE)方法求取複雜度値，再利用參數最佳化找出最適參數進行分析。另外，本研究又利用晃動位移距離之不同觀點下來相互比較。研究結果發現受測者靜止站立時若轉移注意力對於站立穩定度會產生些微影響，而在增長站立時間下更能明顯觀察出青年人優於老年人有較高之複雜度値，以物理學能量觀點來看，青年人穩定度較老年人佳。另一方面，利用壓力中心點實驗移動軌跡數據分析結果為青年人在晃動位移距離遠低於老年人，代表老年人站立時晃動程度比青年人穩定性差且易有大幅度晃動現象產生。

關鍵字

壓力中心點(COP) ； 經驗模態分解方法(EMD) ； 多尺度熵(MSE)

並列摘要

Age-related deterioration of postural stability is one of the most important causes of falls among the elderly. Mostly the relevant research study the elderly fall problem to fall factor analysis in the past, needing huge sample to analyzing that cause the study difficulty and complicatedly. For this reason, we designed an experiment to determine changes in the center of pressure (COP) during different time periods of standing at rest and at attention. We analyzed raw data on time-series changes in COP sway and determined the differences in the complexity of postural dynamics between young individuals and the elderly. In order to study the effects of aging on the complexity of postural dynamics, we used parameter optimization to determine the optimum parameter and used the empirical mode decomposition (EMD) to detrend the signals and finally determine the complexity on the basis of multiscale entropy (MSE) from data on 15 healthy elderly (over 65 years of age) and 13 healthy young (under the age of 30 years) subjects. The results showed that the postural dynamics were less complex in the elderly than in the young subjects; this difference was more obvious with increase in the time of standing. This implies that postural stability in young individuals is better than that in the elderly. Further, analysis of the raw data revealed that the extent of COP sway was clearly larger in the elderly than in the young subjects. This indicates that the elderly are apt to sway more than young subjects while standing.

並列關鍵字

Center of pressure (COP) ； Empirical mode decomposition (EMD) ； Multiscale entropy (MSE)

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