SBIR-STTR Award

Otoreflectance (OR) is a new class of hearing test instruments utilizing acoustic signals presented and recorded in the ear canal. OR instruments address limitations in existing screening and diagnostic instruments in such areas as: (1) detecting otitis media, (2) predicting conductive hearing loss, (3) augmenting the newborn hearing screening protocol to test for middle-ear dysfunction, and (4) the general assessment of middle-ear functioning at frequencies important for speech perception. OR provides calibrated measurements over a frequency range from approximately 0.25 to 8 kHz of such transfer functions as reflectance and admittance, and the power absorbed by the ear canal and middle ear. Energy reflectance and absorbed power are OR functions that are relatively insensitive to the position of the probe in the ear canal. This property may allow clinical interpretation of these functions at moderate and high frequencies at which the tympanometric admittance, which is sensitive to probe position, becomes difficult to interpret. One proposed class of OR instruments can be used with probes similar to otoacoustic emission probes to screen middle-ear functioning in several seconds at ambient pressure in the ear canal. Such rapidly performed measurements at ambient pressure may provide a test of middle-ear dysfunction in newborn hearing screening programs, and a test to screen for conductive hearing loss in children at risk for otitis media with effusion. Another proposed class of OR instruments, for which a static pressure pump will be added to the probe system, will be used to measured reflectance, admittance and absorbed power as functions of both frequency and static pressure in the ear canal. Such OR tympanometry instruments may have general audiological and screening utility for diagnosing middle-ear pathology due to the fact that the energy reflectance tympanogram has more orderly patterns at moderate and high frequencies than multifrequency tympanometers based only on admittance. A third proposed class of OR instruments may provide a sensitive test of the acoustic reflex threshold by measuring the wideband shift in OR responses elicited by a contralateral or ipsilateral activator sound. A protocol to measure supra-threshold reflex decay may provide additional wideband information that is unavailable in clinical reflex testing

Otoreflectance (OR) is a new class of hearing-test instruments utilizing acoustic signals presented and recorded in the ear canal. OR instruments address the following limitations in existing instruments to screen and diagnose middle-ear function: (1) detection of otitis media, (2) prediction of conductive hearing loss, (3) detection of middle-ear dysfunction in infants receiving a newborn hearing screening exam or follow-up audiologic assessment, and (4) general use to assess middle-ear function at frequencies in the bandwidth of speech. An OR test provides measurements over a wideband range (approximately 0.25 to 8 kHz) of such transfer functions as reflectance and admittance, and power absorbed by the ear canal and middle ear. Energy reflectance and absorbed power are OR functions that are relatively insensitive to probe position in the ear canal, and thus are well suited to interpreting middle-ear function at higher frequencies. One type of OR instrument can be used with probes similar to otoacoustic emission probes to screen middle-ear function in several seconds at ambient ear-canal pressure. Phase I of this project established the feasibility of measuring such OR responses in normal-hearing adults and children, as well as in children with surgically confirmed middle-ear fluid. Phase I also implemented a wideband OR test to assess the function of the middle-ear muscle reflex, and compared reflex thresholds in infants and adults with thresholds measured using conventional instruments. In Phase II, a wideband OR tympanometry instrument will be implemented, adding a pump to vary ear-canal static pressure, and OR tympanometry norms will be measured in adults. The test performance of ambient-pressure OR and conventional 226-Hz tympanometry will be compared in young children to detect middle-ear fluid and to predict a conductive hearing loss associated with otitis media with effusion. OR tympanometry will form part of a new objective and efficient wideband test to measure middle-ear muscle reflex thresholds, which will be compared to thresholds in adults and infants measured using a conventional test. The test performance of the ability of OR tympanometry, ambient-pressure OR, and conventional 1000-Hz tympanometry to detect middle-ear dysfunction will be compared in infants also receiving a standard newborn hearing screening exam. Outcomes from Phase II will evaluate whether OR is more accurate than conventional tests to screen and diagnose middle-ear dysfunction in clinical applications of important societal concern.

Thesaurus Terms:
biomedical equipment development, clinical biomedical equipment, diagnosis design /evaluation, ear disorder diagnosis, middle ear, middle ear disorder conductive hearing loss, hearing test, otitis media, tympanum bioengineering /biomedical engineering, clinical research, human subject, patient oriented research