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Physical Acoustics Lab


Our research is concerned with increasing our knowledge of the human middle ear and cochlea based upon acoustic response testing in the ear canal. Such tests are noninvasive and provide clinically relevant information.  One project developed wideband acoustic reflectance as a measure of middle-ear function in infants and adults, which are obtained at either ambient pressure in the ear canal or in the form of a wideband tympanogram.  A second project examines new forms of otoacoustic emissions (OAE), which may provide a clearer understanding of mechanical processes on the basilar membrane. Particular emphasis has been placed on stimulus-frequency OAEs and transient-evoked OAEs, which yield objective physiological data that correlates to behavioral tests of hearing.  A third project studies models of middle-ear mechanics. New screening and diagnostic tests of middle-ear and cochlear function are under evaluation that have clinical promise to improve functional assessments across the age range.  Our lab is also involved with research in the Center for Perception and Communication in Children (CPCC).


Douglas Keefe, Ph.D.(Physics), Senior Scientist
Dr. Keefe has an active program in hearing research, especially in rega​rds to auditory processing in the ear canal, middle ear and cochlea. He has expertise in acoustics, mechanics, signal processing and computer engine​ering, and has also published research on musical acoustics.​
​​​​​​Denis F. Fitzpatrick, Ph.D. (Biology), Research Computer Engineer III
​Dr. Fitzpatrick performs computer hardware and software maintenance, and computer programming tasks. He also performs maintenance and calibration of digital, microprocessor-based, and analog devices and equipment used in the clinical and research laboratories.
Summary of Research Program

For Clinicians and Scientists

A wideband (WB) test battery of aural acoustic tests may improve the screening and diagnosis of middle-ear and cochlear dysfunction. The battery addresses current limitations in newborn hearing screening (NHS) and diagnostic programs; it may help identify adult ototoxic hearing loss and diagnose middle-ear disease in patients receiving middle-ear surgery. Testing is performed over frequencies important for speech perception, and either at ambient pressure or using WB tympanometry. The WB acoustic reflex test measures an infant’s threshold to improve the accuracy of NHS programs. A click-evoked otoacoustic emission (OAE) test assesses cochlear function using an extended bandwidth relative to clinical tests. Research is underway to assess whether adding a WB test battery to the initial and follow-up NHS exams improves the accuracy of detecting sensorineural and conductive hearing loss. Middle-ear problems detected in the initial NHS exam may predict middle-ear dysfunction in the first year of life, including infants with cranial-facial anomalies and developmental delays. Extended-bandwidth OAE tests may help detect hearing loss in adult cystic-fibrosis patients receiving ototoxic medications. Research is in progress to evaluate the accuracy of WB tests in differential diagnoses of otoscleroris and ossicular discontinuity in adult surgery patients. More basic research concerns the non-invasive testing and modeling of middle-ear and cochlear mechanics in humans.


The laboratory research is concerned with devising better ways to assess how the middle ear and inner ear function, and to find new techniques for identifying hearing loss in infants, young children, and adults. One project may improve the detection of middle-ear fluid in the ears of young children, a condition which is associated with the pain and discomfort of earaches in young children. Another project has special relevance for improving newborn hearing screening programs to detect hearing loss, by testing whether the middle ears of infants tested just hours after birth in the birthing hospital function differently from the middle ears of infants only a few days later. Improved methods of detecting hearing loss and related conditions are essential to referring children and adults to health specialists for rehabilitative services.