International survey of bimodal hearing and bilateral cochlear implant service provision for adults.

Objectives: As cochlear implant (CI) criteria widen, more candidates with usable residual hearing are being considered for a CI. Unlike children, adults mostly receive only one implant. The aim of this survey was to determine bimodal-hearing and bilateral CI service provision for adults around the world.

Sensory unpleasantness of very-high frequency sound and audible ultrasound.

Audible very-high frequency sound (VHFS) and ultrasound (US) have been rated more unpleasant than lower frequency sounds when presented to listeners at similar sensation levels (SLs). In this study, 17 participants rated the sensory unpleasantness of 14-, 16-, and 18-kHz tones and a 1-kHz reference tone. Tones were presented at equal subjective loudness levels for each individual, corresponding to levels of 10, 20, and 30 dB SL measured at 1 kHz.

Integrated bimodal fitting and binaural streaming technology outcomes for unilateral cochlear implant users.

Objective: Adults typically receive only one cochlear implant (CI) due to cost constraints, with a contralateral hearing aid recommended when there is aidable hearing. Standard hearing aids differ from a CI in terms of processing strategy and function as a separate entity, requiring the user to integrate the disparate signals. Integrated bimodal technology has recently been introduced to address this challenge.

Transient otoacoustic emissions and audiogram fine structure in the extended high-frequency region.

Objective: Previous studies at conventional audiometric frequencies found associations between the ripple depth seen in audiogram fine structure (AFS) and amplitudes of both transient evoked otoacoustic emissions (TEOAEs) and overall hearing threshold levels (HTLs). These associations are explained by the cochlear mechanical theory of multiple coherent reflections of the travelling wave apically by reflections sites on the basilar membrane and basally by the stapes.

Design: The aim was to investigate whether a similar relationship is seen in the extended high-frequency (EHF) range from 8-16 kHz.

Deductive development and validation of a questionnaire to assess sensitivity to very low and very high frequency sounds: SISUS-Q (Sensitivity to Infra-Sound and Ultra-Sound Questionnaire).

Objective: Auditory research and complaints about environmental noise indicate that there exists a significant, small subgroup within the population which is sensitive towards infra- and low-frequency or ultra- and high-frequency sounds (ILF/UHF). This paper reports on the development, factorization and validation of measures of sensitivity towards frequencies outside the common hearing range.

Design: A multinational, cross-sectional survey study was run.

COAST (Cisplatin ototoxicity attenuated by aspirin trial): A phase II double-blind, randomised controlled trial to establish if aspirin reduces cisplatin induced hearing-loss.

Background: Cisplatin is one of the most ototoxic chemotherapy drugs, resulting in a permanent and irreversible hearing loss in up to 50% of patients. Cisplatin and gentamicin are thought to damage hearing through a common mechanism, involving reactive oxygen species in the inner ear. Aspirin has been shown to minimise gentamicin-induced ototoxicity.

Efficient time-domain simulation of nonlinear, state-space, transmission-line models of the cochlea (L).

Nonlinear models of the cochlea are best implemented in the time domain, but their computational demands usually limit the duration of the simulations that can reasonably be performed. This letter presents a modified state space method and its application to an example nonlinear one-dimensional transmission-line cochlear model. The sparsity pattern of the individual matrices for this alternative formulation allows the use of significantly faster numerical algorithms.

Fit for the frontline? A focus group exploration of auditory tasks carried out by infantry and combat support personnel.

In order to preserve their operational effectiveness and ultimately their survival, military personnel must be able to detect important acoustic signals and maintain situational awareness. The possession of sufficient hearing ability to perform job-specific auditory tasks is defined as auditory fitness for duty (AFFD). Pure tone audiometry (PTA) is used to assess AFFD in the UK military; however, it is unclear whether PTA is able to accurately predict performance on job-specific auditory tasks.

Theoretical analysis of signal-to-noise ratios for transient evoked otoacoustic emission recordings.

Recordings of transient-evoked otoacoustic emissions (TEOAEs) suffer from two main sources of contamination: Random noise and the stimulus artifact. The stimulus artifact can be substantially reduced by using a derived non-linear recording paradigm. Three such paradigms are analyzed, called here the level derived non-linear (LDNL), the double-evoked (DE), and the rate derived non-linear (RDNL) paradigms.

A wave finite element analysis of the passive cochlea.

Current models of the cochlea can be characterized as being either based on the assumed propagation of a single slow wave, which provides good insight, or involve the solution of a numerical model, such as in the finite element method, which allows the incorporation of more detailed anatomical features. In this paper it is shown how the wave finite element method can be used to decompose the results of a finite element calculation in terms of wave components, which allows the insight of the wave approach to be brought to bear on more complicated numerical models. In order to illustrate the method, a simple box model is considered, of a passive, locally reacting, basilar membrane interacting via three-dimensional fluid coupling.

Effect of contralateral acoustic stimulation on cochlear tuning measured using stimulus frequency and distortion product OAEs.

Objective: To study whether a change in cochlear tuning, measured using OAEs, could be detected due to contralateral activation of the efferent system using broadband noise.

Design: Cochlear tuning measures based on SFOAE phase gradients and SFOAE-2TS 'Q' were used to test this hypothesis. SFOAE magnitude and phase gradient were measured using a pure-tone sweep from 1248 to 2496 Hz at 50 dB SPL.

Investigating the wave-fixed and place-fixed origins of the 2f(1)-f(2) distortion product otoacoustic emission within a micromechanical cochlear model.

The 2f(1)-f(2) distortion product otoacoustic emission (DPOAE) arises within the cochlea due to the nonlinear interaction of two stimulus tones (f(1) and f(2)). It is thought to comprise contributions from a wave-fixed source and a place-fixed source. The generation and transmission of the 2f(1)-f(2) DPOAE is investigated here using quasilinear solutions to an elemental model of the human cochlea with nonlinear micromechanics.

Fluid coupling in a discrete model of cochlear mechanics.

A discrete model of cochlear mechanics is introduced that includes a full, three-dimensional, description of fluid coupling. This formulation allows the fluid coupling and basilar membrane dynamics to be analyzed separately and then coupled together with a simple piece of linear algebra. The fluid coupling is initially analyzed using a wavenumber formulation and is separated into one component due to one-dimensional fluid coupling and one comprising all the other contributions.

Spontaneous otoacoustic emissions measured using an open ear-canal recording technique.

Spontaneous otoacoustic emissions (SOAEs) and synchronized spontaneous otoacoustic emissions (SSOAEs) were recorded using both the standard closed-canal method of recording and a novel open-canal method which involved suspending the probe at the entrance to the ear canal with no occluding tip. In both conditions, a probe tube microphone was inserted down the ear canal to measure the acoustic pressure near the tympanic membrane. Open- and closed-canal recordings were obtained in twelve otologically normal ears, all of which exhibited SSOAEs, and 6 of which exhibited SOAEs.

The influence on predicted harmonic and distortion product generation of the position of the nonlinearity within cochlear micromechanical models.

Numerical techniques are used to explore the influence on the predicted basilar membrane (BM) response of the position of the nonlinearity within the micromechanical feedback loop of an active nonlinear cochlear model. This position is found to influence both the harmonic and distortion product spectra of the predicted BM response. The BM motion at the fundamental or primary frequencies is not significantly altered by the position of the nonlinearity, however, provided that the gain is appropriately adjusted.

Limit cycle oscillations in a nonlinear state space model of the human cochlea.

It is somewhat surprising that linear analysis can account for so many features of the cochlea when it is inherently nonlinear. For example, the commonly detected spacing between adjacent spontaneous otoacoustic emissions (SOAEs) is often explained by a linear theory of "coherent reflection" [Zweig and Shera (1995). J.

Comparing two proposed measures of cochlear mechanical filter bandwidth based on stimulus frequency otoacoustic emissions.

It has been hypothesized that the sharpness of the cochlear mechanical filter is related to two measures based on stimulus frequency otoacoustic emissions (SFOAEs). The first is the group delay of the SFOAE; the second is the bandwidth of the SFOAE two-tone suppression isoinput tuning characteristic. A corollary of this is that natural variability in cochlear mechanical bandwidth within a population would lead to a positive correlation between these two SFOAE-based measures of tuning within that population.

Statistics of instabilities in a state space model of the human cochlea.

A state space model of the human cochlea is used to test Zweig and Shera's [(1995) "The origin of periodicity in the spectrum of evoked otoacoustic emissions," J. Acoust. Soc.

The effect of stimulus rate and time-separation on Volterra slices of otoacoustic emissions.

Volterra slices (VSs) of otoacoustic emissions are temporal non-linear interaction components which can be measured using the maximum length sequence technique of stimulation. Previous studies have found, but not explained, non-monotonic variations in the amplitude of VSs when stimulus rate is increased. In this study, a simple phenomenological model is investigated which provided possible insights into the effect of rate on VS amplitudes.

A state space model for cochlear mechanics.

The stability of a linear model of the active cochlea is difficult to determine from its calculated frequency response alone. A state space model of the cochlea is presented, which includes a discretized set of general micromechanical elements coupled via the cochlear fluid. The stability of this time domain model can be easily determined in the linear case, and the same framework used to simulate the time domain response of nonlinear models.

Click-evoked otoacoustic emissions (CEOAEs) recorded from neonates under 13 hours old using conventional and maximum length sequence (MLS) stimulation.

Maximum length sequence (MLS) stimulation allows click evoked otoacoustic emissions (CEOAEs) to be averaged at very high stimulation rates. This enables a faster reduction of noise contamination of the response, and has been shown to improve the signal-to-noise ratio (SNR) of CEOAEs recorded from adult subjects. This study set out to investigate whether MLS averaging can enhance the SNR of CEOAEs recorded in newborns within the first day after birth, and so improve the pass rates for OAE screening in this period, when false alarm rates are very high.

A parametric model of the spectral periodicity of stimulus frequency otoacoustic emissions.

A model for estimating the spectral period of stimulus frequency otoacoustic emissions (SFOAEs) is presented. The model characterizes the frequency spectrum of an SFOAE in terms of four parameters which can be directly related to cochlear mechanical quantities featuring in the theory of SFOAE generation proposed by Zweig and Shera [J. Acoust.

The effect of suppression on the periodicity of stimulus frequency otoacoustic emissions: experimental data.

In a companion paper [Lineton and Lutman, J. Acoust. Soc.

Modeling the effect of suppression on the periodicity of stimulus frequency otoacoustic emissions.

The distributed roughness theory of the origins of spectral periodicity in stimulus frequency otoacoustic emissions (SFOAEs) predicts that the spectral period will be altered by suppression of the traveling wave (TW) [Zweig and Shera, J. Acoust. Soc.