Mondnath Chockboondee.. Identification of Cochlear Retrocochlear pathology in sensorineural hearing loss patients by the use of acouctic reflex thresholds. Master's Degree(Communication Disorders). Mahidol University. Mahidol University Library and Knowledge Center. : Mahidol University, 2015.
Identification of Cochlear Retrocochlear pathology in sensorineural hearing loss patients by the use of acouctic reflex thresholds
Abstract:
hair cells in the cochlea and/or the neurons of the auditory part of cranial nerve VIII. The hearing loss treatment depends on the site of the lesion. Therefore, SNHL patients have to be diagnosed using special tests that identify the sites of the lesion. These tests determine whether the lesions are in the cochlea, or the retrocochlea. The audiological diagnostic evaluations are very important for treatment. They consist of subjective and objective evaluations. Subjective evaluations require patients cooperation. These tests can have some limitations, including a patients cooperation level, but also less sensitivity and specificity in identifying sites of lesion. Objective evaluations, or physiological tests are an instrument designed to measure unobserved constructs. A widely used objective evaluation nowadays is the auditory brainstem response (ABR). The test does not require patients cooperation. Several reports confirmed the sensitivity of ABR for diagnosing retrocochlear hearing loss to be as high as 98%, with a specificity of 90%. The results of ABR can give more sensitivity and specificity in identifying sites of lesion, but the test takes longer and is more expensive. The acoustic reflex measurement is another objective test. It can be used to diagnose the site of the lesion in hearing loss patients by comparing the acoustic reflex thresholds with pure tone air conduction thresholds, which is called sensation level. If the sensation level is lower than 60 dB, it means there is recruitment, which is a characteristic of cochlear hearing loss. Having a reflex threshold level elevated to greater than the 90th percentile cutoff level is considered indicative of retrocochlear hearing loss. The purpose of this research was to study the diagnostic accuracy on the sensitivity and specificity of the acoustic reflex test (ART) in identifying sites of lesions compared to the results of auditory brainstem response measurement (ABR). This was a retrospective study with data collection from clinical charts of sensorineural hearing loss patients who were referred by otorhinolaryngologists for ABR measurement from 2009 to 2013. The subjects consisted of 346 ears, from 232 patients (102 males, 130 females). The overall sensitivity of ART in identifying the site of lesion was 90.9% and specificity was 57.3%. However, the highest sensitivity and specificity of ART in identifying the site of lesion was 100% and 80.6% respectively in moderate SNHL (41-55 dBHL). The group of low frequency loss demonstrated highest sensitivity in identifying sites of lesion at 100% and the specificity was 75.8%.
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