人體的各類生理系統藉由穩定的自然節律持續得運作著，就好比音樂透過反覆樂節帶領著音符向前。感壓反射在血壓中造成十秒一次的週期變化，以此維持著血壓穩定，這樣固定的節律被稱作梅爾波。本實驗將探討音樂是否能用來增強血液中0.1Hz的梅爾波，我們在音樂的編曲結構中加入與梅爾波週期相同、不斷反覆的樂句，試圖找出能帶動血壓節律的最大影響因子並強化梅爾波的能量，增進體內接受器對血壓變化的敏感度，使血壓變化恆定趨穩，進一步幫助控制血壓。感壓反射不佳除了對血壓調控有影響外，也會增加罹患心血管疾病的風險，故增進感壓反射的功能相當重要。 實驗一共分為三組：(1) 希伯來奴隸大合唱-驗證前人研究 (2) 音量週期變化音樂 (3) 旋率週期變化音樂。透過三組實驗來探討如何在音樂的編曲上加入反覆的元素最能調控生理上的週期波動。請受測者依序聆聽三組音樂，每段音樂間隔五分鐘安靜休息，並同時測量心電訊號(ECG)、光電容積描記(PPG)、非侵入性連續血壓訊號及胸廓起伏訊號。 訊號收錄後，使用Matlab軟體進行生理訊號分析：(1)以快速傅立葉轉換定量訊號在各頻率下的強度，如此便能比較不同組別間血壓週期在0.1Hz下的貢獻多寡 (2)小波轉換進行時頻分析，以得知各類生理訊號隨著音樂進行時動態的強度變化 (3)用同步性分析(coherence)計算不同段音樂中心率與血壓變化之間的關聯。最後使用學生T檢定進行統計分析，計算各組訊號在音樂與基準線的顯著水準，以此判定三組音樂對生理訊號的影響。 以目前12位健康年輕成年人的實驗中，發現僅有週期旋律之音樂相較於基準測量值，血壓在0.1±0.025之間的能量有顯著的提升(p-value < 0.05)，且血壓與心率間的同步性(coherence)亦有顯著的提升(p-value < 0.05)，顯示這類型的音樂極可能能幫助人們增進梅約波的強度，使壓感反應更加靈敏。 ;There are many physiological systems orchestrated together in maintaining the function of our body under various conditions and the interconnected interactions among different control mechanisms can be analogous to the basic riffs of music, a combination of music notes and rhythm. Baroreflex, a crucial physiological mechanism for blood pressure regulation, operates around 0.1 Hz and produces a prominent oscillatory wave of blood pressure signal known as Mayer’s wave. This study aims to discuss whether the baroreflex can be enhanced by listening to the music with different combinations of music notes and rhythm at 0.1 Hz and which combination can enhance the amplitude of the Mayer’s wave the most. In addition, we believed that the homeostatic control of blood pressure can be improved as a consequence of enhancing the baroreflex sensitivity. The recruited subjects will undergo three different sessions consecutively for this study and during each session, the subjects will listen to one of the three different combinations of musical arrangements: (1) the music with loop melody (2) the same music without loop melody (3) only loop melody without music. During session 1 and 2, their musical arrangement are the same, except for the loop melody (rhythm) and during session (3), there is only the loop melody without other music. Between each session, there are 5-minute resting period to wash out the possible effects of music. The electrocardiogram, photoplethysmography, non-invasive continuous blood pressure and chest inductance plethysmography signals will be simultaneously recorded during the study. The data will be processed by Matlab and the amplitudes of the Mayer’s wave can be quantified by calculating the power of the spectrum around 0.1 Hz using fast Fourier transform. In addition, the spectrogram will be constructed by wavelet transform for observing the dynamical changes of the oscillation of Mayer’s wave. Finally, the effects of different combinations of musical arrangements can be further analyzed by different biostatistics methods and hope the results can benefit those people with diminished baroreflex sensitivity such as patients with cardiovascular diseases.
