2014年8月11日 訊 /生物谷BIOON/ --近日研究表明，記憶力和注意力等認知能力不僅在中風後很重要，在中風前也非常重要。記憶和認知能力下降可能會增加65歲以上老人中風的風險。中風後認知功能比之前前快速下降了幾乎兩倍。中風和認知能力的下降增加了老年人死亡的風險，發表在美國心臟協會的《中風》雜誌上的研究顯示，先前的研究顯示心血管處於亞健康狀態會增加認知障礙的風險，比如說在記憶和學習等方面會存在問題。然而，與之相反的一面顯示，認知障礙可能會影響心血管健康，特別是中風，這在之前還沒有建立起這種認知。
「大多數臨床研究觀察中風後的認知損害事件，Kumar Rajan博士說，只有少數以大量人群研究為基礎的研究測量在中風和因各種原因導致死亡前長期的認知功能。」
研究人員分析了7217名65歲以上老人認知功能(61%為非裔美國人，59%為女性)。每三年對他們進行四個測試，評估參與者在中風前和中風後的認知能力，如短期和長期記憶力，注意力，意識和其他心智功能。
研究人員發現：那些中風前認知測試得分越低的測試者他們中風的機率就會高出61%；相比中風前中風後認知功能快速下降了幾乎兩倍；中風外加認知減退增加了死亡的風險；關於中風前認知功能下降增加中風的風險非洲裔美國人比歐裔美國高五倍。
「認知功能差引起老年中風；然而，快速的認知功能下降可能是由中風引起的，」Rajan表示，「低認知功能通常與神經系統障礙和腦功能障礙有關。神經系統的退化會導致一些健康問題，比如中風就是其中之一。」研究心理健康可以幫助防止未來的老年人中風，Rajan說。「從保健的角度來看，認知能力下降不僅是一種神經退化的標誌，也是老年中風的標誌，」他說。研究人員還發現低認知功能和死亡之間有某種較強的聯繫。在實驗之前得過中風的參與者在四個測試中得到比均分低的認知測試分數，這些人中78%的人在觀察期間死去。
「健康、積極的身體和認知活動可能有助於減緩認知功能衰退，」Rajan說。在美國，中風是導致殘疾的首要原因，在死因排名中處於第四。中風發生的原因是大腦的血液供應被切斷，大腦的短暫失血會導致嚴重的身體殘疾和精神障礙。（生物谷Bioon.com）
Association of Cognitive Functioning, Incident Stroke, and Mortality in Older Adults
Kumar B. Rajan, PhD, Neelum T. Aggarwal, MD, Robert S. Wilson, PhD, Susan A. Everson-Rose, PhD, MPH and Denis A. Evans, MD
Background and Purpose—Stroke increases the risk of dementia; however, bidirectional association of incident stroke and cognitive decline below dementia threshold is not well established. Also, both cognitive decline and stroke increase mortality risk. Methods—A longitudinal population-based cohort of 7217 older adults without a history of stroke from a biracial community was interviewed at 3-year intervals. Cognitive function was assessed using a standardized global cognitive score. Stroke was determined by linkage with Medicare claims, and mortality was ascertained via the National Death Index. We used a Cox model to assess the risk of incident stroke, a joint model with a piecewise linear mixed model with incident stroke as a change point for cognitive decline process, and a time-dependent relative risk regression model for mortality risk. Results—During follow-up, 1187 (16%) subjects had incident stroke. After adjusting for known confounders, lower baseline cognitive function was associated with a higher risk of incident stroke (hazard ratio, 1.61; 95% confidence interval, 1.46–1.77). Cognitive function declined by 0.064 U per year before incident stroke occurrence and 0.122 U per year after stroke, a nearly 1.9-fold increase in cognitive decline (95% confidence interval, 1.78–2.03). Both stroke (hazard ratio, 1.17; 95% confidence interval, 1.08–1.26) and cognitive decline (hazard ratio, 1.90; 95% confidence interval, 1.81–1.98) increased mortality risk. Conclusions—Baseline cognitive function was associated with incident stroke. Cognitive decline increased significantly after stroke relative to before stroke. Cognitive decline increased mortality risk independent of the risk attributable to stroke and should be followed as a marker for both stroke and mortality.