認知障礙老人之活動能力及認知能力表現對於跌倒及害怕跌倒之相對貢獻分析

Abstract

跌倒是影響老年人健康與獨立能力的重要議題，而認知障礙及失智症老年人之「跌倒」與「害怕跌倒」發生率為一般老人之二至三倍，比例更高，也更值得重視。跌倒及害怕跌倒有可能互為因果，亦可能各有獨立機制。活動能力與認知能力是影響跌倒與害怕跌倒的兩大重要因素，近期更有學者提出活動與認知能力的交互作用，也就是雙項任務評估方式可能可以更進一步了解兩種能力之相對貢獻性。本研究目的為評估社區認知障礙或失智老人之認知能力、活動能力及雙重任務表現，進而探討上述能力表現與跌倒及害怕跌倒之關聯性及相對貢獻度。 本研究之主要研究對象為居住於社區之認知障礙或失智老人。根據醫院病歷或日照中心資料做個案之初步篩檢，經個案本人及其有同意權人同意後進行收案。每位受試者皆完成基本資料收集(包括年齡、性別、跌倒史及巴氏量表分數等)並接受約30分鐘的測試評估，評估工具包括簡版圖像化跌倒關注程度量表(測量害怕跌倒程度)、簡易智能狀態測驗(測量認知能力)、聖路易大學心智狀態測驗(測量認知能力)、計時起走測試(測量活動能力)、計時起走及減三雙重任務測試(測量認知及活動能力之雙重影響)等共五項。完成評估後滿一個月時，評估人員以電話訪問並記錄受試者自初測至電訪期間之跌倒次數與跌倒經驗。本研究使用描述性統計分析並呈現兩組受試者之基本資料特性，並使用相關性分析(correlation analysis)及迴歸分析法(regression analysis)做後續資料處理，以了解各項評估結果與跌倒次數或害怕跌倒程度之相關性及相對貢獻程度。 本研究共納入57位個案，包含17位男性及40位女性，平均年齡為79.7歲。依照簡易智能狀態測驗標準分類，47.4%的個案為重度認知功能障礙。一個月期間的跌倒次數平均為0.14次，範圍由0至1次；參加研究前一年內的跌倒次數平均為1.09次，範圍由0至12次。運用迴歸分析法，設定自變項為年齡、性別、巴氏量表分數、計時起走及減三雙重任務測試(雙重任務成本值)、計時起走測試及認知能力測驗，以跌倒次數或害怕跌倒程度做為依變項進行分析。研究結果顯示若以個案跌倒次數為依變項，無論是回溯性(retrospective)還是前瞻性(prospective)分析，均顯示認知能力分數與跌倒次數呈現正相關(以簡易智能狀態測驗為自變項，回溯性r=0.165; 前瞻性r=0.234)，雙重任務成本值(dual task cost)與跌倒次數呈現負相關(回溯性r= -0.185; 前瞻性r= -0.061)，貢獻程度為認知能力(以簡易智能狀態測驗為自變項|Beta|=0.371)大於活動能力(|Beta|=0.283)，雙重任務表現(|Beta|=0.023)之貢獻度最小。若以個案害怕跌倒程度為依變項，則發現認知能力(以簡易智能狀態測驗為自變項r= -0.154)、活動能力(r= -0.373, p= 0.004)及雙重任務成本值(r= -0.088)與害怕跌倒程度均呈現負相關，貢獻程度為活動能力(|Beta|=0.289)大於認知能力(以簡易智能狀態測驗為自變項|Beta|=0.084)，雙重任務表現(|Beta|=0.06)之貢獻度最小。 統合上述論點，認知能力愈好的認知障礙或失智社區老人，跌倒機率反而愈高；而活動能力表現與個案之害怕跌倒程度有統計上之顯著相關。若將研究結果運用於臨床策略中，適當給予輕度至中度認知障礙老人及其主要照顧者跌倒防範之概念，同時增加個案之活動能力訓練以降低害怕跌倒程度或跌倒次數，或許可達到降低跌倒發生率之目的，而雙重任務表現與認知障礙或失智社區老人之跌倒次數有相關，但相對貢獻度較少，是否適合作為社區失智老人之重要跌倒預測評估測驗則尚須進一步探究。

With aging of the world population, “Falls” and “Fear of falling” become an important issue which may influence health and independence of the older adults. The incidence of falls and fear of falling are twice or more on cognitive impaired older adults. The relationship between falls and fear of falling on cognitive impaired older adults remains unclear. Mobility and cognition may be the main factors that influence falls and fear of falling, and the interaction between these two factors has been suggest recently. This study aims to find out the relative contribution of mobility and cognition to falls and fear of falling in. The participants in this study were cognitive impaired community-dwelling older adults recruited from National Taiwan University hospital and day care centers in Neihu and Songshan. The basic data (age, gender, fall history, Barthel index) of each subject were collected. The assessment tool including Iconographical Falls Efficacy Scale (Icon-FES, fear of falling), Timed ”Up & Go” test (TUG, mobility), Mini-Mental Status Examination (MMSE, cognition), Saint Louis University Mental Status Examination (SLUMS, cognition), Timed ”Up & Go” and Subtraction by Threes dual task (interaction between mobility and cognition). One month after the assessment, the assessor will recorded the number of falls by calling the subjects. The descriptive statistics analysis were used to describe the basic characteristics of the participants, the correlation and regression analysis were used to understand the relative contribution of those factors to falls and fear of falling. This study recruited 57 participants (17 male and 40 female), the average age was 79.7 years old. 47.4% severe cognitive impaired older adults were included in this study. The average number of falls before this assessment is 1.09 in one year, range from 0 to 12. The average number of falls after the assessment is 0.14 in 1 month, range from 0 to 1. For numbers of falls, the correlation analysis shows positive relationship with MMSE scores (retrospective/prospective r= 0.165/0.234), negative relationship with dual task cost (retrospective/prospective r= -0.185/-0.061). The order of important contributors for falls is cognition (|Beta|=0.371), mobility (|Beta|=0.283) and dual task performance (|Beta|=0.023). For fear of falling, the correlation analysis shows positive relationship with TUG seconds (r= 0.373, p=0.004), negative relationship with MMSE scores (r= -0.154), dual task cost (r= -0.088). The order of important contributors for fear of falling is mobility (|Beta|=0.289), cognition (|Beta|=0.084) and dual task performance (|Beta|=0.06). In conclusion, fall incidence may be higher in those who have better cognition status in cognitive impaired community-dwelling older adults, and the mobility may be an important factor for fear of falling due to significant high correlation. the dual task performance have low correlation and relative contribution to the number of falls, whether or not to use this kind of assessment for assessing clinical cognitive impaired older adults needs more research to find out. The result of this study can be a useful concept for designing clinical fall-prevention program.