Gabrielle R. Merchant

COMPARISON OF EAR-CANAL REFLECTANCE AND UMBO VELOCITY IN PATIENTS WITH CONDUCTIVE HEARING LOSS: A PRELIMINARY STUDY

Objective: The goal of the present study was to investigate the clinical utility of measurements of ear-canal reflectance (ECR) in a population of patients with conductive hearing loss in the presence of an intact, healthy tympanic membrane and an aerated middle ear. We also sought to compare the diagnostic accuracy of umbo velocity (VU) measurements and measurements of ECR in the same group of patients. Design: This prospective study comprised 31 adult patients with conductive hearing loss, of which 14 had surgically confirmed stapes fixation due to otosclerosis, 6 had surgically confirmed ossicular discontinuity, and 11 had computed tomography and vestibular evoked myogenic potential confirmed superior semicircular canal dehiscence (SCD). Measurements on all 31 ears included pure-tone audiometry for 0.25 to 8 kHz, ECR for 0.2 to 6 kHz using the Mimosa Acoustics HearID system, and VU for 0.3 to 6 kHz using the HLV-1000 laser Doppler vibrometer (Polytec Inc, Waldbronn, Germany). We analyzed power reflectance |ECR|2 as well as the absorbance level = 10 × log10(1 − |ECR|2). All measurements were made before any surgical intervention. The VU and ECR data were plotted against normative data obtained in a companion study of 58 strictly defined normal ears (Rosowski et al., 2011). Results: Small increases in |ECR|2 at low-to-mid frequencies (400–1000 Hz) were observed in cases with stapes fixation, while narrowband decreases were seen for both SCD and ossicular discontinuity. The SCD and ossicular discontinuity differed in that the SCD had smaller decreases at mid-frequency (∼1000 Hz), whereas ossicular discontinuity had larger decreases at lower frequencies (500–800 Hz). SCD tended to have less air-bone gap at high frequencies (1–4 kHz) compared with stapes fixation and ossicular discontinuity. The |ECR|2 measurements, in conjunction with audiometry, could successfully separate 28 of the 31 cases into the three pathologies. By comparison, VU measurements, in conjunction with audiometry, could successfully separate various pathologies in 29 of 31 cases. Conclusions: The combination of |ECR|2 with audiometry showed clinical utility in the differential diagnosis of conductive hearing loss in the presence of an intact tympanic membrane and an aerated middle ear and seems to be of similar sensitivity and specificity to measurements of VU plus audiometry. Additional research is needed to expand upon these promising preliminary results.

Ear-canal reflectance, umbo velocity, and tympanometry in normal-hearing adults.

Objective: This study compares measurements of ear-canal reflectance (ECR) to other objective measurements of middle ear function including audiometry, umbo velocity (VU), and tympanometry in a population of strictly defined normal-hearing ears. Design: Data were prospectively gathered from 58 ears of 29 normal-hearing subjects, 16 females and 13 males, aged 22 to 64 yr. Subjects met all of the following criteria to be considered as having normal hearing: (1) no history of significant middle ear disease; (2) no history of otologic surgery; (3) normal tympanic membrane on otoscopy; (4) pure-tone audiometric thresholds of 20 dB HL or better for 0.25 to 8 kHz; (5) air-bone gaps no greater than 15 dB at 0.25 kHz and 10 dB for 0.5 to 4 kHz; (6) normal, type-A peaked tympanograms; and (7) all subjects had two “normal” ears (as defined by these criteria). Measurements included pure-tone audiometry for 0.25 to 8 kHz, standard 226 Hz tympanometry, ECR for 0.2 to 6 kHz at 60 dB SPL using the Mimosa Acoustics HearID system, and umbo velocity (VU) for 0.3 to 6 kHz at 70 to 90 dB SPL using the HLV-1000 laser Doppler vibrometer (Polytec Inc). Results: Mean power reflectance (|ECR|2) was near 1.0 at 0.2 to 0.3 kHz, decreased to a broad minimum of 0.3 to 0.4 between 1 and 4 kHz, and then sharply increased to almost 0.8 by 6 kHz. The mean pressure reflectance phase angle (∠ECR) plotted on a linear frequency scale showed a group delay of approximately 0.1 msec for 0.2 to 6 kHz. Small significant differences were observed in |ECR|2 at the lowest frequencies between right and left ears and between males and females at 4 kHz. |ECR|2 decreased with age but reached significance only at 1 kHz. Our ECR measurements were generally similar to previous published reports. Highly significant negative correlations were found between |ECR|2 and VU for frequencies below 1 kHz. Significant correlations were also found between the tympanometrically determined peak total compliance and |ECR|2 and VU at frequencies below 1 kHz. The results suggest that middle ear compliance contributes significantly to the measured power reflectance and umbo velocity at frequencies below 1 kHz but not at higher frequencies. Conclusions: This study has established a database of objective measurements of middle ear function (ECR, umbo velocity, tympanometry) in a population of strictly defined normal-hearing ears. These data will promote our understanding of normal middle ear function and will serve as a control for comparison to similar measurements made in pathological ears.

Normative reflectance and transmittance measurements on healthy newborn and 1-month-old infants.

Objective: Ear-canal-based wideband reflectance (WBR) measurements may provide objective measures to assess and monitor middle-ear status in young babies. This work presents WBR measurements of power reflectance and transmittance on populations of healthy newborn babies (3 to 5 days) and healthy 1-mo-old babies (28 to 34 days). Thus, this work determines how power reflectance and transmittance vary between newborn and 1-mo-old babies and characterizes the range of these measures in normal populations. Design: Power reflectance and transmittance were calculated from pressure measurements made in the ear canals of seven newborn (12 ears) and eleven 1-mo-old (19 ears) babies. Permutation tests, t tests, and regression (random effects) models were used to test the effects of age (newborn versus 1 mo), gender, and ear side (right versus left). Results: The power reflectance and transmittance did not differ significantly for the age comparison (newborn versus 1 mo), although the results suggest a possible difference between newborn and 1-mo-old ears near 2000 Hz. There were no differences between the male and female ears. There are small but significant differences between left and right ears in three frequency bands encompassing 500 to 4000 Hz, where the predicted power reflectance mean for the left ear differs from the right ear by 0.02 to −0.07 depending on the frequency band. Conclusions: At most frequencies, power reflectance and transmittance are indistinguishable for newborn and 1-mo-old healthy babies, with limited or no differences between the two age groups and the males and females. There were small differences in some frequency bands for left and right ears. The measurements made here are similar to other published results in some frequency ranges but differ in other frequency ranges; differences among other studies from neonatal intensive care unit babies, healthy newborn babies, and healthy 1-mo-old babies are discussed.

Effects of middle-ear disorders on power reflectance measured in cadaveric ear canals.

Objective: Reflectance measured in the ear canal offers a noninvasive method to monitor the acoustic properties of the middle ear, and few systematic measurements exist on the effects of various middle-ear disorders on the reflectance. This work uses a human cadaver-ear preparation and a mathematical middle-ear model to both measure and predict how power reflectance R is affected by the middle-ear disorders of static middle-ear pressures, middle-ear fluid, fixed stapes, disarticulated incudostapedial joint, and tympanic-membrane perforations. Design: R was calculated from ear-canal pressure measurements made on human-cadaver ears in the normal condition and five states: (1) positive and negative pressure in the middle-ear cavity, (2) fluid-filled middle ear, (3) stapes fixed with dental cement, (4) incudostapedial joint disarticulated, and (5) tympanic-membrane perforations. The middle-ear model of Kringlebotn (1988) was modified to represent the middle-ear disorders. Model predictions are compared with measurements. Results: For a given disorder, the general trends of the measurements and model were similar. The changes from normal in R, induced by the simulated disorder, generally depend on frequency and the extent of the disorder (except for the disarticulation). Systematic changes in middle-ear static pressure (up to 6300 daPa) resulted in systematic increases in R. These affects were most pronounced for frequencies up to 1000 to 2000 Hz. Above about 2000 Hz there were some asymmetries in behavior between negative and positive pressures. Results with fluid in the middle-ear air space were highly dependent on the percentage of the air space that was filled. Changes in R were minimal when a smaller fraction of the air space was filled with fluid, and as the air space was filled with more saline, R increased at most frequencies. Fixation of the stapes generally resulted in a relatively small low-frequency increase in R. Disarticulation of the incus with the stapes led to a consistent low-frequency decrease in R with a distinctive minimum below 1000 Hz. Perforations of the tympanic membrane resulted in a decrease in R for frequencies up to about 2000 Hz; at these lower frequencies, smaller perforations led to larger changes from normal when compared with larger perforations. Conclusions: These preliminary measurements help assess the utility of power reflectance as a diagnostic tool for middle-ear disorders. In particular, the measurements document (1) the frequency ranges for which the changes are largest and (2) the extent of the changes from normal for a spectrum of middle-ear disorders.

Power reflectance as a screening tool for the diagnosis of superior semicircular canal dehiscence.

Hypothesis Power reflectance (PR) measurements in ears with superior canal dehiscence (SCD) have a characteristic pattern, the detection of which can assist in diagnosis. Background The aim of this study was to determine whether PR coupled with a novel detection algorithm can perform well as a fast, noninvasive, and easy screening test for SCD. The screening test aimed to determine whether patients with various vestibular and/or auditory symptom(s) should be further considered for more expensive and invasive tests that better define the diagnosis of SCD (and other third-window lesions). Methods Power reflectance was measured in patients diagnosed with SCD by high-resolution computed tomography. The study included 40 ears from 32 patients with varying symptoms (e.g., with and without conductive hearing loss, vestibular symptoms, and abnormal auditory sensations). Results Power reflectance results were compared to previously published norms and showed that SCD is commonly associated with a PR notch near 1 kHz. An analysis algorithm was designed to detect such notches and to quantify their incidence in affected and normal ears. Various notch detection thresholds yielded sensitivities of 80% to 93%, specificities of 69% to 72%, negative predictive values of 84% to 93%, and a positive predictive value of 67%. Conclusion This study shows evidence that PR measurements together with the proposed notch-detecting algorithm can be used to quickly and effectively screen patients for third-window lesions such as SCD in the early stages of a diagnostic workup.

Aging and the effect of target-masker alignment

Similarity between target and competing speech messages plays a large role in how easy or difficult it is to understand messages of interest. Much research on informational masking has used highly aligned target and masking utterances that are very similar semantically and syntactically. However, listeners rarely encounter situations in real life where they must understand one sentence in the presence of another (or more than one) highly aligned, syntactically similar competing sentence(s). The purpose of the present study was to examine the effect of syntactic/semantic similarity of target and masking speech in different spatial conditions among younger, middle-aged, and older adults. The results of this experiment indicate that differences in speech recognition between older and younger participants were largest when the masker surrounded the target and was more similar to the target, especially at more adverse signal-to-noise ratios. Differences among listeners and the effect of similarity were much less robust, and all listeners were relatively resistant to masking, when maskers were located on one side of the target message. The present results suggest that previous studies using highly aligned stimuli may have overestimated age-related speech recognition problems.

The Audiometric and Mechanical Effects of Partial Ossicular Discontinuity.

Objectives: Ossicular discontinuity may be complete, with no contact between the disconnected ends, or partial, where normal contact at an ossicular joint or along a continuous bony segment of an ossicle is replaced by soft tissue or simply by contact of opposing bones. Complete ossicular discontinuity typically results in an audiometric pattern of a large, flat conductive hearing loss. In contrast, in cases where otomicroscopy reveals a normal external ear canal and tympanic membrane, high-frequency conductive hearing loss has been proposed as an indicator of partial ossicular discontinuity. Nevertheless, the diagnostic utility of high-frequency conductive hearing loss has been limited due to gaps in previous research on the subject, and clinicians often assume that an audiogram showing high-frequency conductive hearing loss is flawed. This study aims to improve the diagnostic utility of high-frequency conductive hearing loss in cases of partial ossicular discontinuity by (1) making use of a control population against which to compare the audiometry of partial ossicular discontinuity patients and (2) examining the correlation between high-frequency conductive hearing loss and partial ossicular discontinuity under controlled experimental conditions on fresh cadaveric temporal bones. Furthermore, ear-canal measurements of umbo velocity and wideband acoustic immittance measurements were investigated to determine the usefulness regarding diagnosis of ossicular discontinuity. Design: The authors analyzed audiograms from 66 patients with either form of surgically confirmed ossicular discontinuity and no confounding pathologies. The authors also analyzed umbo velocity (n = 29) and power reflectance (n = 12) measurements from a subset of these patients. Finally, the authors performed experiments on six fresh temporal bone specimens to study the differing mechanical effects of complete and partial discontinuity. The mechanical effects of these lesions were assessed via laser Doppler measurements of stapes velocity. In a subset of the specimen (n = 4), wideband acoustic immittance measurements were also collected. Results: (1) Calculations comparing the air–bone gap (ABG) at high and low frequencies show that when high-frequency ABGs are larger than low-frequency ABGs, the surgeon usually reported soft-tissue bands at the point of discontinuity. However, in cases with larger low-frequency ABGs and flat ABGs across frequencies, some partial discontinuities as well as complete discontinuities were reported. (2) Analysis of umbo velocity and power reflectance (calculated from wideband acoustic immittance) in patients reveal no significant difference across frequencies between the two types of ossicular discontinuities. (3) Temporal bone experiments reveal that partial discontinuity results in a greater loss in stapes velocity at high frequencies when compared with low frequencies, whereas with complete discontinuity, large losses in stapes velocity occur at all frequencies. Conclusion: The clinical and experimental findings suggest that when encountering larger ABGs at high frequencies when compared with low frequencies, partial ossicular discontinuity should be considered in the differential diagnosis.

Additivity of masking at the cocktail party

Multi-talker listening environments, like crowded restaurants, are highly complex. In addition to the target talker, the auditory scene may consist of a combination of one or two interfering talkers close to a listener that would likely be relatively high in level (e.g., from people at the same or a nearby table) and numerous additional masking talkers at greater distances whose outputs reach the listener at lower levels. Our understanding of how these masking components combine is limited by the fact that most studies of multi-talker listening present all interfering talkers at the same level. The current study explored the extent to which error rates in a speech understanding task could be predicted from the error rates for two individual components of the masker, specifically from (a) two higher-level (closer) talkers and (b) four lower-level (more distant) talkers. The variables of angular location and level difference of the “closer” and “farther” talkers were explored. At least for an initial subset...

Comparison of Ear‐Canal Reflectance and Umbo Velocity in Patients with Conductive Hearing Loss

Patients who present at hearing clinics with a conductive hearing loss (CHL) in the presence of an intact, healthy tympanic membrane create a unique challenge for otologists. While patient counseling, treatment options, and outcome vary with differing middle‐ear pathologies, a non‐invasive diagnostic that can differentiate between these pathologies does not currently exist. We evaluated the clinical utility and diagnostic accuracy of two non‐invasive measures of middle‐ear mechanics: ear‐canal reflectance (ECR) and umbo velocity (VU).

How repetition influences speech understanding by younger, middle-aged and older adults

Abstract Objective: To examine benefit from immediate repetition of a masked speech message in younger, middle-aged and older adults. Design: Participants listened to sentences in conditions where only the target message was repeated, and when both the target message and its accompanying masker (noise or speech) were repeated. In a follow-up experiment, the effect of repetition was evaluated using a square-wave modulated noise masker to compare benefit when listeners were exposed to the same glimpses of the target message during first and second presentation versus when the glimpses differed. Study Sample: Younger, middle-aged and older adults (n = 16/group) for the main experiment; 15 younger adults for the follow-up experiment. Results: Repetition benefit was larger when the target but not the masker was repeated for all groups. This was especially true for older adults, suggesting that these individuals may be more negatively affected when a background message is repeated. Data obtained using noise maskers suggest that it is slightly more beneficial when listeners hear different (versus identical) portions of speech between initial presentation and repetition. Conclusions: Although subtle age-related differences were found in some conditions, results confirm that repetition is an effective repair strategy for listeners spanning the adult age range.