目的：臨床在實施動作訓練時，因患者本體感覺之缺損，常需輔以視覺追蹤或頭部轉動配合動作的學習，是否經由改變眼、前庭與心臟之間的神經反射，影響心臟迷走神經的興奮性？相關研究顯示眼外肌張力增加或頭部位置改變，兩者皆可能改變心臟迷走神經的興奮性。而股四頭肌等長收縮為臨床常用的運動處方，所以本研究的目的為評估股四頭肌等長收縮時，輔以視覺追蹤及頭部擺位對心跳、血壓及心臟自律神經調控的影響；以了解動作訓練時眼、前庭與心臟之間交互影響。方法：以11位健康男性為受試者，接受四次運動測試，以心電圖儀及非侵入性血壓計持續收集心跳及平均動脈壓的變化。以Acq knowledge III資料擷取系統，持續收集心電圖、血壓之變化，再將心電圖以HRV660.EXE軟體做心跳變異性分析。受試者採平躺髖關節彎曲60°姿勢，以10磅負荷做股四頭肌等長收縮持續10分鐘。四種測試為(一)頭擺正中，遮眼。(二)頭後仰30°，遮眼。(三)頭擺正中，眼球由外下向內上方向，以每分鐘30下的頻率轉動，重複5分鐘。(四)頭後仰30°，眼球由外下向內上方向，以每分鐘30下的頻率轉動，重複5分鐘。四種測試採平衡隨機順序。以二因子變異分析檢測頭部擺位及視覺追蹤對心跳、血壓及心跳變異是否有顯著影響，結果：運動中四組的心跳範圍為77.4±10.5至81.6±9.6 beats/min，血壓則為79.3±15.3至89.0±22.0 mmHg。恢復期四組的心跳範圍為72.9±9.1至81.6±9.6 beats/min，血壓85.9±17.7 mmHg。以單因子重複量數變異分析，顯示運動前、中、後的平均心跳、血壓並無顯著的變化(p＞0.05)。以二因子重複量數變異分析顯示只有視覺追蹤有較低之心跳次數及心跳變異之常化低頻達顯著差異(p＜0.05)。結論：視覺追蹤傳入的訊息，參與控制心臟血管反射的作用，而腦幹可整合眼球、前庭和本體感受器傳來的訊息，以維持正常心跳血壓。因此建議在實施動作訓練輔以視覺追蹤時，必須考慮視覺追蹤對患者心血管之負荷。
Purposes: Motor training programs usually combine with visual following and head positioning to provide more sensory inputs. However, previous studies reported that these neural afferents can modulate cardiac sympathetic activity. The purpose of this study was to evaluate interaction of visual following and vestibular afferents on cardiac autonomic activity during quadriceps isometric exercise. Methods: Heart rate (HR) and mean artery pressure (MAP) were continually measured through electrocardiography and indirect blood pressure monitor. Power spectrum was used to analyze the fluctuations of heart rate variability (HRV) in 11 healthy male subjects (mean age 22.0±1.5 yrs). Subjects were assessed in four experimental conditions in a randomized order. The four trails were (1) head in midline with eye closed (HMEC); (2) head in hyperextension 30° with eye closed (HEEC) to activate otoliths and neck muscle afferents; (3) head midline with visual following (HMEV); and (4)head hyperextension with visual following (HEVF). All the variables were tested with ANOVA. Results: There were significance influences of visual following on the HR and normalized low-frequency power (LFnu) of HRV in four trails but head position. Conclusion: Our data indicate that visual following results cardiac vagal activity change during exercise stage. The present study adds strength to the concept that the oculars afferents during visual following mediates the reduction in sympathetic activities.
