聽常成人在雙任務範式下之聆聽費力度評估與應用

聆聽費力度(Listening effort,LE)是近年聽覺認知的熱門話題，它常被用來測量聽者在複雜情境下的認知負荷程度，但測量方式尚未被統一標準化。目前可藉由問卷、行為及生理方式進行測量，其中行為測量中的雙任務範式(Dual-task paradigms) 則可方便於被用來測量聆聽費力度。本研究目的在比較聽力正常成人以單耳或雙耳聆聽，在安靜及噪音情境下聽辨日常語句的聆聽費力度和次任務的表現差異，及個體的主觀感受之相關外，同時建立聽力正常成人雙耳及單耳之聆聽費力度5%-95%百分位數範圍，可作為未來與聽力損失個案之比較參考。受試者為40名聽力正常及4名聽力損失之年輕成人，採用雙任務範式進行測試，主任務測驗材料為「台灣版噪音下漢語語句聽辨測驗」(MHINT)；次任務測驗材料為「視覺手動遊戲」(Flow free)。 受試者於下列三個情境（安靜、SNR 0 dB、SNR -5 dB）分別執行雙任務作業後，用雙任務效應(Dual-task effect, DTE%)公式計算其聆聽費力度。最後以「聆聽費力度自評表」(ACALES)評量主觀感受。統計方法為描述統計，二因子相依變異數分析及皮爾森(Pearson) 積差係數進行分析，並計算5%-95%百分位數範圍，與聽力損失組進行比對。研究結果為聽常受試者以單耳聆聽時，在安靜與噪音情境下的聆聽費力度及次任務表現皆達顯著差異，噪音情境的DTE%與主觀感受評分呈顯著相關；於雙耳聆聽時，則各情境間的聆聽費力度及次任務表現無顯著差異，且主觀感受也亦無顯著相關。四位聽力損失受試者時，僅有一位單側人工耳蝸使用者於複雜環境的語句聽辨正確率低於5%-95%百分位數(小於百分位數 5%)，其餘三位個案於複雜情境下的語句聽辨正確率皆落在聽常組5%-95%百分位數內(大於百分位數 5%)。本研究設計之雙任務範式提供一個可用模型檢測聽常成人與聽損成人之聆聽費力度，單耳聆聽且吵雜情境下之個體變異性高，未來需進一步研究釐清。

Listening effort (LE) is a popular research topic in auditory cognition in recent years, it measures the cognitive load of listeners in complex situations. This study explores the listening effort in dual-task paradigms for normal-hearing adults with monaural versus binaural hearing. Also, the correlation between listeners’ subjective rating of LE and sentence recognition was examined. We also build up the baseline of LE in young adults with normal hearing which used as a comparison basis to the small group with hearing in this study.40 subjects with normal-hearing (NH) and 4 cases with hearing loss were tested with dual-task paradigm. Test materials were derived from Mandarin Hearing in Noise Test (MHINT). Participants were seated in a sound-treated room under 3 conditions (quiet, SNR 0 dB, and SNR -5 dB) and repeated daily sentences they heard as well as play a visual game (Flow Free) simultaneously. In addition, LE were rated by listeners with the Adaptive Categorical Listening Effort Scaling (ACALES). Two-way ANOVA and Pearson Correlation Coefficient were analyzed and use 5%-95% percentile build up the baseline.No significant differences were found in LE and secondary task scores across three conditions when the NH subjects listen binaurally. However, significant differences were observed when they listened monaurally in noisy conditions (SNR 0 dB and SNR -5 dB ). Moreover, LE values were significantly correlated with subjective rating scores when they listen monaurally. Conversely, no significant correlation was observed when they listen binaurally. When subjects with hearing loss listened monaurally in complex conditions, 3 of them performed well within baseline, only one case performed below the lower limit (without the 5%-95% percentile). When they listened binaurally in complex conditions, they all performed well (within the 5%-95% percentile). This study indicates that dual-task paradigm provides a usable model to investigate listening effort in clinical setting. However, the reason of high variability when people listen monaurally at complex conditions need to be investigated in the future.