The prediction of hearing thresholds with dichotic multiple frequency steady state evoked potentials compared to an auditory brainstem response protocol

Abstract

Even though a test battery approach is necessary to assess auditory function on several levels for hearing assessment, the pure tone test is considered the most time efficient, accurate tool to profile hearing at barely audible levels as a function of frequency in the co-operative patient. There are, however, patients unable to co-operate under standard testing conditions, in which case, the pure tone test is rendered useless or incomplete. Subsequently, objective testing procedures such as evoked potentials are utilized to categorize hearing across the severity and configurations of hearing loss and are defined as testing procedures that require no voluntary response from the patient. The Auditory Brainstem Response test protocol (ABR) is generally accepted as the n lost commonly used evoked potential technique utilized in the categorization of hearing across a frequency spectrum when conventional testing is invalid. Recently a new evoked potential technique has been developed, the dichotic Multiple Frequency Auditory Steady State Evoked Potential (Mf ASSEP). For audiometric purposes, SSEP have some advantages over ABR. However, no comparison between the Mf ASSEP and other evoked potentials that are currently used with high frequency, such as the ABR, has been attempted (Sininger&Cone-Wesson, 2002). T he aim of the study was to determine the validity and accuracy of dichotic Mf /J SSEP for use in predicting hearing status in comparison to the Gold Standard of pure tone audiometry as well as the evoked potential standard of auditory brainstem response (click and tone burst at 500 Hz stimuli) in a group of normally hearing and a group of adolescents with hearing loss. Pure tone air conduction thresholds between 500- 4000 Hz were predicted with the Mf ASSEP technique and ABR. Furthermore, the duration of testing for each procedure was calculated. Results indicated that the Mf ASSEP could predict pure tone thresholds between f 00-4000 Hz irrespective of severity, or particular configuration of hearing loss c cross the frequency spectrum more accurately, and with more frequency specificity, \then compared to the ABR protocol. The procedure was also more time efficient and objective. The Mf ASSEP technique could not, however, provide additional diagnostic information of neural synchrony such as is possible with the Auditory Brainstem Response. It was, therefore, concluded that both procedures should be included in test batteries, specifically when used with difficult-to-test populations, as each provides unique information of particular importance to the audiologist attempting to predict hearing in difficult-to-test populations.