腦幹聽性反應檢查併用溫差試驗對診斷內聽道型聽神經瘤的實用性

Usefulness of Auditory Brainstem Response Test Combined with Caloric Test for Detection of Intracanalicular Acoustic Neuromas

許權振(Chuan-Jen Hsu) ； 林凱南(Kai-Nan Lin)

《中華民國耳鼻喉科醫學雜誌》 35卷2期 (2000/03) Pp. 113-118

https://doi.org/10.6286/2000.35.2.113

摘要

背景：聽神經瘤是常見的耳蝸後病變，早期診斷和早期手術有利於聽力和顏面神經功能的保留。分析局限於內聽道的小聽神經瘤的臨床特徵和聽力平衡功能檢查結果，並提出篩檢聽神經瘤的方法是本研究的目的。
方法：研究對象是13例經磁振造影（MRI）或手術診斷的局限於內聽道的聽神經瘤病例。分析討論內聽道小聽神經瘤的臨床症狀、溫差試驗、純音聽力圖、聽反射檢查和腦幹聽性反應檢查結果。
結果：13例以磁振造影診斷的內聽道型聽神經瘤病例，gadolinium顯影劑攝影均顯影，其中7例並經手術摘除證實為聽神經瘤。病人平均年齡43.8歲，男8例，女5例，左側聽神經瘤8例，右側聽神經瘤5例。臨床症狀以耳鳴最多（92%），其次是聽力損失（85%）和頭暈（61%）。純音聽力圖顯示高頻聽力損失較常見，2k、4k、8k Hz兩耳閾值相差10dB以上的病例分別佔77%，85%，77%。內聽道型聽神經瘤的腦幹聽性反應異常率100%（10/10），溫差試驗反應低下率90%（9/10），聽反射閾值異常率58%（7/12），聽反射衰退率10%（1/10）。腦幹聽性反應異常以兩耳第V波潛時差延長（IDL5）最常見。從臨床症狀出現到確定診斷的時間小於1年的病例有69%（9/13）。
結論：內聽道型聽神經瘤即使病變小於1cm，腦幹聽性反應異常率和溫差反應低下率均仍非常高，考慮目前磁振造影的高檢查費用和不普及性，對臨床症狀懷疑聽神經瘤的病人，我們認為在磁振造影檢查前先併用腦幹聽性反應和溫差試驗來篩檢是較實用和合理的。

關鍵字

內聽道型聽神經瘤 ； 腦幹聽性反應 ； 聽反射 ； 溫差試驗

並列摘要

BACKGROUND:Acoustic neuroma is a common retrocochlear lesion. Early diagnosis and early excision may offer the best chance for long-term preservation of hearing and facial function. The purpose of this study was to evaluate the validity of various cochleovestibular tets and propose a screening method for detecting acoustic neuromas including small intracanalicular ones.
METHODS:We reviewed the medical records of 13 patients with intracanalicular acous-tic neuromas which had been proved by gadolinium-magnetic resonance imaging or surgi-cal pathology. Cochleovestibular tests included pure tone audiogram, acoustic reflex, auditory brainstem response test and caloric test. We analyzed the clinical manifest-tations and characteristic audiovestibular findings of these cases.
RESULTS:The average age at diagnosis of intracanalicular acoustic neuroma was 43.8 years. There were 8 men and 5 women. The clinical manifestations included tinnitus（92%）, hearing loss(85%)and dizziness(61%). More than 70% of cases showed asymmetric hearing thresholds of 2k, 4k and 8k Hz. One hundred percent(10/10)of the ABR tests, 90%(9/10)of the caloric tesrs, and 58%(7/11)of the acoustic reflex tests were abnor-mal. Only 10% of the cases showed a decay of acoustic reflex. The most common finding of abnormal ABR was prolonged interaural absolute latency difference of wave V. Nine cases(69%)were diagnosed within one year after symptoms occurred.
CONCLUSIONS:Intracanalicular acoustic neuromas showed a high rate of asymmetric high tone hearing loss, and very high abnormal ABR and caloric test rates. Limited avail-ability and perceived high cost have prevented clinicians from using MRI as a first line investigation. The results suggested that ABR combined with the caloric test is an effi-cient end economical screening method in suspected cases of intracanalicular acoustic neuroma before MRI examination.

並列關鍵字

intracanalicular acoustic neuroma ； auditory brainstem response ； acoustic reflex ； caloric test