教師為職業用聲者中最常發生嗓音異常的族群之一。高度的用聲需求伴隨各種風險因子(例如:室內聲學條件欠佳、恢復時間不足),可能造成嗓音疲勞,衍生各種嗓音問題。過去對於嗓音疲勞之探討,依研究方式可分為:在實驗室情境以嗓音負荷作業誘發嗓音疲勞,或在真實工作情境中,探討職業用聲者於長時間用聲後的嗓音變化。本文除了回顧在實驗室情境下誘發嗓音疲勞,所造成的嗓音功能變化及恢復等相關文獻,亦以教師為例,回顧其在真實工作情境下的嗓音疲勞情形。整體而言,用聲者在長時間用聲後,常出現平均說話基頻、自覺發聲費力程度及喉部不適程度增加等症狀,嗓音恢復時間則從數分鐘至24小時不等。
Teachers are one of the most common professional voice users who probably have voice disorders. Heavy vocal demands in combination with other risk factors (e.g., poor room acoustics, insufficient recovery time) may cause vocal fatigue, and eventually lead to many kinds of voice problems. Past studies on vocal fatigue include voice changes of vocal fatigue induced by vocal loading tasks (i.e., experimentally induced), and of professional voice users after prolonged voice use in real-life situations. In addition to reviewing literatures on changes of vocal function and vocal recovery under vocal fatigue in laboratory setting, this article reviews vocal fatigue of teachers in natural settings. In general, average speaking fundamental frequency, self-perception of phonation effort, and laryngeal discomfort increased after prolonged voice use, and it may take several minutes to 24 hours for vocal recovery.