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標題: | 有心血管危險因子之中老年人心肺適能與轉換任務行為表現及相關腦活化間的關係:功能性磁振造影研究 The Relationships of Cardiorespiratory Fitness with Task-switching Behavioral Performances and Associated Brain activation in Middle-aged and Older Adults with Cardiovascular Risks: An fMRI Study |
作者: | Yu-Wei Chiu 邱羽薇 |
指導教授: | 湯佩芳(Pei-Fang Tang) |
關鍵字: | 腦部活化,心肺適能,心血管危險因子,中老年人,轉換任務, brain activation,cardiorespiratory fitness,cardiovascular risks,middle-aged and older adults,task-switching, |
出版年 : | 2020 |
學位: | 碩士 |
摘要: | 背景與目的:文獻指出,心肺適能較高的健康老年人在認知轉換任務過程中,會出現較高的腦部活化與較好的轉換任務表現。然而在具有心血管危險因子的中老年人中,其心肺適能、轉換任務行為表現與腦部活化三者間的關係尚不明確。因此本研究旨在探討,在有心血管危險因子之中老年人中,其心肺適能與轉換任務行為表現及相關腦活化間的關係。 方法:本研究收錄68位認知正常、慣用右手之中老年人(台灣版蒙特利爾認知評估≥24分,年齡介於45~78歲,女性43位、男性25位)。受試者均有高血壓、血糖異常、血脂異常等此三種心血管危險因子中之至少一項因子。所有受試者接受症狀限制的心肺運動測試以及六分鐘行走測試,以測量其心肺適能相關參數,並依其心肺適能高低被分為較低心肺適能組和較高心肺適能組。受試者並接受神經心理學評估與修改版數值史楚普測試,以此測試下所有非轉換和轉換情境測驗下的正確率、反應時間、和此兩參數的轉換成本代表其轉換任務行為表現。研究者同時以功能性磁振造影取得受試者在執行修改版數值史楚普測試時大腦活化的資料,利用全體受試者轉換情境下腦部活化>非轉換情境下腦部活化之對比,設定voxel-wise FWE p< 0.005及> 83體素為閾值,擷取出8個位於額葉區域的功能性興趣腦區。使用淨相關分析,控制年齡和教育程度,探討全體受試者心肺適能與轉換任務行為表現及當下腦部活化間的關係,並針對較低及較高心肺適能組,分開探討其轉換任務行為表現和腦部活化之間的關係。 結果:根據受試者心肺運動測試表現是屬於同年齡和同性別體重標準化尖峰攝氧量推估百分比的後1/3還是前2/3,將受試者分為較低心肺適能組(女性15位,45.7~66.4 %;男性8位,67.0~78.9 %)與較高心肺適能組(女性28位,66.9~102.0 %;男性17位,79.3~126.1 %)。相關性分析部分,在全體受試者中發現,心肺適能越低者,轉換任務行為表現越差(r= 0.334, p= 0.007),且執行轉換任務時的左中額回的大腦活化強度越高(r= -0.259, p= 0.037)。分組看時,較低心肺適能組中,轉換情境下右側上額回、兩側中額回、和左側輔助運動區的活化強度越高者,與兩側中額回和左側輔助運動區的活化轉換成本越高者,其在轉換情境的正確率轉換成本越高、反應時間或反應時間轉換成本越長(r= 0.447~0.727, 所有p< 0.05)。而較高心肺適能組則為轉換情境下,左側中額回與輔助運動區的活化轉換成本越高者,其轉換情境的反應時間轉換成本越長(r= 0.313~0.383, 所有p< 0.05),但與正確率無關(所有p> 0.05)。 討論:本研究中的受試者整體心肺適能大多未達同年齡和同性別體重標準化尖峰攝氧量推估值,顯示有心血管危險因子者之心肺適能多數偏低。其中,整體而言,心肺適能越低者在執行非轉換與轉換任務時,左中額回活化越高,顯示腦活化較無效率。但較高心肺適能組在執行轉換任務時,出現無效率之腦活化主要在左側額葉;而較低心肺適能組則主要出現在雙側額葉。這表示在有心血管危險因子的中老年人中,較低心肺適能者會在較多額葉區出現無效的大腦活化。 結論: 本研究結果顯示,有心血管危險因子中老年人若能維持較高的心肺適能,則其認知任務表現較佳,無效的額葉腦活化區域也會較少。本研究結果支持較佳心肺適能對有心血管危險因子中老年人認知與腦活化效率之正面效益。 Background: Past research found that healthy elderly with higher cardiorespiratory fitness (CRF) showed higher brain activity during task-switching and better task-switching performance. However, the relationships among CRF, task-switching behavior and associated brain activity in middle-aged and older adults with cardiovascular risks (CVRs) remain unclear. Therefore, this study was aimed to investigate the relationships of CRF with task-switching behavioral performance and associated brain activation in middle-aged and older adults with CVRs. Methods: Sixty-eight cognitively normal right-handed adults (Montreal Cognitive Assessment score-Taiwanese version ≥ 24, age range= 45-78 years, 43 females) with CVRs of hypertension, impaired fasting glucose, or dyslipidemia, or any combination of these, participated in this study. All participants underwent a symptom-limited cardiopulmonary exercise test and the Six-minute Walk Test to measure their CRF. They also undertook neuropsychological assessments on task-switching and an fMRI experiment for brain activation during a modified numerical Stroop task. The accuracy rate (AR) and reaction time (RT) of all non-switch and switch trials and for switch cost (SC) on the Stroop task were calculated for each participant. Whole group contrast of the BOLD magnitude at SC for all participants was performed using voxel-wise FWE p< 0.005 and the cluster size threshold of 83 continuous voxels to delineate 8 functional regions-of-interest (ROIs) regions in the frontal areas. Partial correlations, controlling for age and education, for investigating the relationships of CRF with task-switching behavioral performance and brain activation during task-switching, were applied for all participants. And two separate partial correlations, also controlling for age and education, were performed for investigating the relationships between task-switching performances and BOLD magnitude for the LF and the HF groups, respectively. Results: The participants were assigned to the lower fitness (LF) or higher fitness (HF) group according to their CRF percentages (lower 1/3 or higher 2/3) on age-and sex-specific predicted peak oxygen consumption (LF: 15 females, 45.7~66.4%, 8 males, 67.0~78.9%; HF: 28 females, 67.0~78.9%, 17 males, 79.3~126.1%). For all participants, the lower the CRF was, the poorer the task-switching behavioral performance was (r= 0.334, p= 0.007), and the higher the brain activation in the switch trials (r= -0.259, p= 0.037) was in the left middle frontal gyrus (MFG). In the LF group, greater BOLD magnitude in the right superior frontal gyrus, bilateral MFG, and left supplementary motor area (SMA) and greater BOLD cost in bilateral MFG and left SMA during the switch trials was correlated with greater SC of AR, longer RT, or longer RT cost (r= 0.447~0.727, all p< 0.05). Whereas in the HF group, during the switch trials, greater BOLD cost in the left MFG and SMA was associated with only longer SC of RT, but not with AR (r= 0.313~0.383, all p< 0.05). Discussion: The overall CRF of the participants in this study was lower than the predicted normalized peak oxygen consumption based on age and sex, suggesting that the majority of middle-aged and older adults with CVRs do have decreased CRF. In the whole group, when performing the non-switch and switching tasks, those with lower CRF presented greater left MFG activation, suggesting ineffective activation. Ineffective brain activation during task-switching was mainly found in the left frontal gyri for the HF group but was found in bilateral frontal gyri in the LF group. These results suggest that in middle-aged and older adults with CVRs, lower CRF level is associated with the presence of ineffective frontal activation in more frontal regions during task-switching. Conclusions: Results of this study indicate that middle-aged and older adults with CVRs with better CRF are able to have better task-switching behavioral performance and present less ineffective frontal activation during task-switching, compared to those with poorer CRF. These findings support the positive impact of better CRF on cognitive functions and brain activation in this population. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/69494 |
DOI: | 10.6342/NTU202003950 |
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顯示於系所單位: | 物理治療學系所 |
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