Middle-ear reflex testing using WAI

PROJECT SUMMARYThe purpose of the proposed project is to combine wideband acoustic immittanceWAIand middle ear muscle reflexMEMRtesting using new approaches that improve sensitivityincrease test efficiencyand provide objectivity in interpretationAcoustically elicited MEMRs have a long history of value in the clinical evaluation of hearing lossWhile sensitive to and affected by middle ear disorders linked to conductive hearing lossesMEMRs demonstrate particular sensitivity to synaptic and post synaptic disorders related to the VIIIth nerve and auditory brainstem pathways through activation of neural pathways ipsilateral and contralateral to the physiologic middle ear responseMEMRs are objective in providing information in a brief period of time without requiring behavioral responses from the patient and this objectivity facilitates their use in infantsMeasuring MEMRs in the context of WAI provides clear advantages over current methods based on the ability to evaluate responses over a broader frequency range and to elicit responses to lower intensity stimuliThe broadband nature of WAI is a well documented advantage in infant testingDespite the fact that MEMR is a robust and sensitive measureit is under utilized clinicallybased on factors that include subjectivity in response determinationintrasubject variationuncertainty about MEMR response presenceand lack of confidence among clinicians in interpreting responsesWe propose development of an instrument that will provide a new and sensitive approach to objective measurement of MEMR using a WAI approachCreating the hardware and software using this approach should reduce subjectivity in clinician interpretation and encourage increased clinical utilization and application in patients of all agesThe specific aims of this project are to build a prototype instrument that is capable of measuring WAI based MEMR for both ipsilateral and contralateral reflex pathwaysA pilot study presented in this application shows clear differences between subjects with normal auditory function and responses obtained from a passive coupler and a patient known to lack MEMRsThe ipsilateral hardware and software that allowed the pilot study will be integrated into the new commercial systemThe binaural system necessary for contralateral reflex measurement will be developed as a dualchannel Mimosa Acoustics systemPhase I human subject data collection will be completed on a small number of infantsadults with normal hearingand adults with known hearing losses to demonstrate efficacy of the new system and methodThe results obtained in the Phase I project will inform development of software tools for analysis and display and will guide plans for the Phase II applicationThis will involve further development of the dual channel system to achieve additional new approaches to MEMR measurementrefinement of recording and analysis methodsand testing in larger clinical populations in the context of auditory screening and diagnostic applications This project will develop a new clinical test system to assess the middle ear reflex that is a valuable objective measure of hearing status in patients of all agesThe procedure focuses on a new measurement methodwideband acoustic immittancethat improves testing of infantsin particularwhere higher frequency ranges need to be usedThe new system and test methods should provide improved sensitivityefficiency and objectivity in interpretationwhich will support accurate clinical hearing screening in infants and diagnostic evaluation of persons of all ages with normal hearing and with hearing loss