SBIR-STTR Award

The purpose of the proposed project is to combine wideband acoustic immittance (WAI) and middle-ear muscle reflex (MEMR) testing using new approaches that improve sensitivity, increase test efficiency, and provide objectivity in interpretation. Acoustically elicited MEMRs have a long history of value in the clinical evaluation of hearing loss. While sensitive to and affected by middle-ear disorders linked to conductive hearing losses, MEMRs 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 response. MEMRs 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 infants. Measuring 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 stimuli. The broadband nature of WAI is a well-documented advantage in infant testing. Despite the fact that MEMR is a robust and sensitive measure, it is under utilized clinically, based on factors that include subjectivity in response determination, intrasubject variation, uncertainty about MEMR response presence, and lack of confidence among clinicians in interpreting responses. We propose development of an instrument that will provide a new and sensitive approach to objective measurement of MEMR using a WAI approach. Creating the hardware and software using this approach should reduce subjectivity in clinician interpretation and encourage increased clinical utilization and application in patients of all ages. The 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 pathways. A 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 MEMRs. The ipsilateral hardware and software that allowed the pilot study will be integrated into the new commercial system. The binaural system necessary for contralateral reflex measurement will be developed as a dual- channel Mimosa Acoustics system. Phase I human subject data collection will be completed on a small number of infants, adults with normal hearing, and adults with known hearing losses to demonstrate efficacy of the new system and method. The 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 application. This will involve further development of the dual-channel system to achieve additional new approaches to MEMR measurement, refinement of recording and analysis methods, and testing in larger clinical populations in the context of auditory screening and diagnostic applications.

Public Health Relevance Statement:
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 ages. The procedure focuses on a new measurement method (wideband acoustic immittance) that improves testing of infants, in particular, where higher frequency ranges need to be used. The new system and test methods should provide improved sensitivity, efficiency and objectivity in interpretation, which will support accurate clinical hearing screening in infants and diagnostic evaluation of persons of all ages with normal hearing and with hearing loss.

Project Terms:
Academic Medical Centers; Acoustic Stimulation; Acoustics; Adult; Affect; Age; Audiology; Auditory; base; behavioral response; Binaural; Brain Stem; Characteristics; Clinical; clinical practice; Collaborations; Collection; Computer software; Conductive hearing loss; Contralateral; Cranial Nerves; Data; Data Collection; design; Development; Device or Instrument Development; Devices; Diagnostic; Disease; Ear; ear muscle; electric impedance; Ensure; Environment; Evaluation; External auditory canal; Feedback; Frequencies; Goals; Hearing; hearing impairment; hearing screening; human subject; improved; Infant; instrument; Ipsilateral; Link; Measurement; Measures; Methods; middle ear; middle ear disorder; Mimosa; Nature; Nerve; Neural Pathways; Neurophysiology - biologic function; Newborn Infant; novel strategies; Pathway interactions; Patients; Pattern; Persons; Phase; Physiological; Pilot Projects; Population; postsynaptic; Procedures; prototype; Publishing; Recording of previous events; Reflex action; Research; research and development; research clinical testing; Research Personnel; response; screening; Signal Transduction; software development; Software Tools; sound; standard of care; Stimulus; Synapses; System; Technology; Testing; Time; tool; Translational Research; Uncertainty; Variant; Work

The objective of this project is to build and evaluate a middle-ear muscle reflex (MEMR) test system that is based on measurement of wideband acoustic immittance (WAI). This WAI-MEMR system will be accurate, scientifically and technically sound, stable, reliable, safe, and clinician friendly. Acoustically elicited MEMRs have a long history of value in the clinical evaluation of hearing loss. While sensitive to and affected by middle- ear disorders linked to conductive hearing losses, MEMRs also demonstrate particular sensitivity to synaptic and postsynaptic disorders related to the eighth nerve and auditory brainstem pathways through activation of neural pathways ipsilateral and contralateral to the physiologic middle-ear response. MEMRs are objective in providing information rapidly without requiring behavioral responses from the patient, and this objectivity facilitates their use in infants. Measuring 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 stimuli. The broadband nature of WAI is a well-documented advantage in infant testing. However, even though MEMR is a robust and sensitive measure, it is underutilized clinically on account of concerns that include subjectivity in response determination, intrasubject variation, uncertainty about MEMR response presence, and lack of confidence among clinicians in interpreting responses. The specific aims for this Phase II project are to (1) build a dual-probe WAI-MEMR system that is capable of ipsilateral, contralateral, and binaural stimulus paradigms and allows flexible and precise manipulation of test parameters; (2) develop automated processes for analyzing and quantifying WAI-MEMR responses to provide a method for objective test interpretation; (3) develop and test artifact rejection methods, a user-friendly probe, and calibration methods; (4) define stimulus and acquisition parameters further through human-subject testing of infants, children, and adults with normal hearing and with hearing loss; and (5) implement new paradigms and evaluate the new Phase II dual-channel system in adults and infants with normal hearing. The accomplishments completed during Phase I have resulted in a prototype dual-probe system that has been tested in adults with normal hearing and hearing loss with promising results. Work has begun toward automated analysis as well as defining frequency, amplitude, and threshold characteristics in infants and adults. The ongoing, productive collaboration between Dr. Jeng at Mimosa Acoustics and Dr. Hood at Vanderbilt University will continue throughout the Phase II project period for the development and evaluation of the WAI-MEMR approach. Creating hardware and software that uses this approach should reduce subjectivity in clinician interpretation and encourage increased clinical utilization and application in patients of all ages. In addition, the expanded capabilities that both WAI and a dual-probe system provide will foster advancement in understanding the characteristics of the MEMR in various populations and facilitate applications in clinical practices.

Public Health Relevance Statement:
NARRATIVE This project will develop a new, innovative middle-ear reflex test system that can be used clinically and in research. The new system uses a recently developed measurement method (wideband acoustic immittance) that is particularly valuable in infants where higher frequency ranges need to be used. The new system and test methods will provide improved efficiency and objectivity in interpretation, which will support accurate clinical hearing screening in infants and diagnostic evaluation of persons of all ages with normal hearing and with hearing loss.

Project Terms:
Academic Medical Centers; Acoustics; Address; Adult; Affect; Age; aged; Area; Audiology; Auditory; automated analysis; base; behavioral response; Binaural; Brain Stem; Calibration; Characteristics; Child; Clinical; clinical development; clinical practice; Clinical Protocols; Collaborations; Computer software; Conductive hearing loss; Contralateral; Data; design; Development; Devices; Diagnostic; Disease; Ear; ear muscle; electric impedance; Evaluation; External auditory canal; flexibility; Fostering; Frequencies; Growth; hearing impairment; hearing screening; human subject; improved; Infant; innovation; Ipsilateral; Lead; Link; Longevity; Manuals; Measurement; Measures; Methods; middle ear; middle ear disorder; Mimosa; Morphologic artifacts; Nature; Nerve; Neural Pathways; Neurophysiology - biologic function; Newborn Infant; normal hearing; novel strategies; Pathway interactions; patient response; Patients; Pattern; Persons; Phase; phase 1 study; Physiological; Population; postsynaptic; Process; prototype; Publishing; Recording of previous events; Reflex action; relating to nervous system; Research; research clinical testing; response; Secure; Sensory; sound; Source; standard of care; Stimulus; Synapses; System; Techniques; Testing; Time; tool; Uncertainty; Universities; user-friendly; Variant; Work