以穩定狀態聽性誘發反應預測行為聽力閾值

The Estimation of Behavioral Hearing Thresholds Through Auditory Steady-State Evoked Potentials

三歲以前是嬰幼兒聽力和語言發展的關鍵期，若未能及時診斷出聽力障礙的嬰幼兒，並儘早給予治療和聽力語言復健，對於未來發展適應社會的能力有很大的障礙。而三歲以下嬰幼兒聽力評估，在臨床上靠聲場純音聽力檢查及腦幹聽性誘發反應，但兩者通常均無法測得在語言頻率範圍內各個主要頻率（500 Hz、1000 Hz、2000 Hz、4000 Hz）的準確或可靠的聽力閾值。本實驗是要驗證由穩定狀態聽性誘發反應閾值來預測各頻率之行為聽力閾值，以期應用於無法施行行為純音聽力檢查的嬰幼兒。自民國89年5月至8月間，選擇31人，共62耳，其純音聽力閾值分佈從正常至極重度，每人均有可信賴的行為純音聽力閾值圖。而穩定狀態聽性誘發反應閾值則由自然睡眠下的大小孩、成人與投予鎮靜藥物的小孩測得，使用儀器為SSEP聽力檢查儀，刺激音為調頻/調幅之純音。吾人取500 Hz、1000 Hz、4000 Hz 等四個頻率，比較穩定狀態聽性誘發反應閾值與行為純音聽力閾值之關係；同時在每個頻率下，就行為純音聽力閾值不同分成正常（≦20 dB）、輕度（21~40 dB）、中度（41~70 dB）、重度（71~90 dB）和極重度（>90 dB）等五組做比較。結果顯示各組均可觀察到穩定狀態聽性誘發反應閾值與行為純音聽力閾值，在 500 Hz-4000 Hz之間，每個頻率皆呈強烈的線性關係，且皮爾森積差相關係數也均大於0.95；同時也觀察到隨著聽力閾值的上升，兩者間的差異也愈小。在 500 Hz、1000 Hz、2000 Hz、4000 Hz 等四個頻率下，穩定狀態聽性誘發反應確實可以預測行為聽力閾值。

The main purpose is to examine the relationship between pure tone thresholds and auditory steady-state evoked potentials, so that behavioral hearing thresholds can be estimated via auditory steady-state evoked potentials. Thirty-one children and adults with vary hearing thresholds were selected on the basis of appropriate audiogram. According to the hearing level, these patients were divided into five groups as normal (≦20 dB), mild(21~40 dB), moderate(41~70 dB), severe (71-90 dB) and profound (>90 dB) hearing impairment groups. At octave frequencies 500~4000 Hz, pure tone thresholds were examined SSEP thresholds were examined from natural sleeping adults and sedated children. Then these pure tone thresholds and SSEP thresholds were compared. Between pure tone thresholds and SSEP thresholds, there was a strong linear correlation. With the increasing severity of hearing loss, the difference of pure tone thresholds and SSEP ones was decreased. The present results suggest that SSEP thresholds can predict behavioral hearing thresholds.