The just-noticeable difference in speech-to-noise ratio.

Just-noticeable differences (JNDs) have been measured for various features of sounds, but despite its importance to communication, there is no benchmark for what is a just-noticeable-and possibly meaningful-difference in speech-to-noise ratio (SNR). SNR plays a crucial role in speech communication for normal-hearing and hearing-impaired listeners. Difficulty hearing speech in background noise-a poor SNR-often leads to dissatisfaction with hearing-assistance devices.

Age-group differences in speech identification despite matched audiometrically normal hearing: contributions from auditory temporal processing and cognition.

Hearing loss with increasing age adversely affects the ability to understand speech, an effect that results partly from reduced audibility. The aims of this study were to establish whether aging reduces speech intelligibility for listeners with normal audiograms, and, if so, to assess the relative contributions of auditory temporal and cognitive processing. Twenty-one older normal-hearing (ONH; 60-79 years) participants with bilateral audiometric thresholds ≤ 20 dB HL at 0.

The neural substrate for binaural masking level differences in the auditory cortex.

The binaural masking level difference (BMLD) is a phenomenon whereby a signal that is identical at each ear (S0), masked by a noise that is identical at each ear (N0), can be made 12-15 dB more detectable by inverting the waveform of either the tone or noise at one ear (Sπ, Nπ). Single-cell responses to BMLD stimuli were measured in the primary auditory cortex of urethane-anesthetized guinea pigs. Firing rate was measured as a function of signal level of a 500 Hz pure tone masked by low-passed white noise.

A function for binaural integration in auditory grouping and segregation in the inferior colliculus.

Responses of neurons to binaural, harmonic complex stimuli in urethane-anesthetized guinea pig inferior colliculus (IC) are reported. To assess the binaural integration of harmonicity cues for sound segregation and grouping, responses were measured to harmonic complexes with different fundamental frequencies presented to each ear. Simultaneously gated harmonic stimuli with fundamental frequencies of 125 Hz and 145 Hz were presented to the left and right ears, respectively, and recordings made from 96 neurons with characteristic frequencies >2 kHz in the central nucleus of the IC.

Association of dietary factors with presence and severity of tinnitus in a middle-aged UK population.

Objective: The impact of dietary factors on tinnitus has received limited research attention, despite being a considerable concern among people with tinnitus and clinicians. The objective was to examine the link between dietary factors and presence and severity of tinnitus.

Design: This study used the UK Biobank resource, a large cross-sectional study of adults aged 40-69.

An overview of the major phenomena of the localization of sound sources by normal-hearing, hearing-impaired, and aided listeners.

Localizing a sound source requires the auditory system to determine its direction and its distance. In general, hearing-impaired listeners do less well in experiments measuring localization performance than normal-hearing listeners, and hearing aids often exacerbate matters. This article summarizes the major experimental effects in direction (and its underlying cues of interaural time differences and interaural level differences) and distance for normal-hearing, hearing-impaired, and aided listeners.

Decision criterion dynamics in animals performing an auditory detection task.

Classical signal detection theory attributes bias in perceptual decisions to a threshold criterion, against which sensory excitation is compared. The optimal criterion setting depends on the signal level, which may vary over time, and about which the subject is naïve. Consequently, the subject must optimise its threshold by responding appropriately to feedback.

Auditory brainstem and middle latency responses recorded at fast rates with randomized stimulation.

Randomized stimulation and averaging (RSA) allows auditory evoked potentials (AEPs) to be recorded at high stimulation rates. This method does not perform deconvolution and must therefore deal with interference derived from overlapping transient evoked responses. This paper analyzes the effects of this interference on auditory brainstem responses (ABRs) and middle latency responses (MLRs) recorded at rates of up to 300 and 125 Hz, respectively, with randomized stimulation sequences of a jitter both greater and shorter than the dominant period of the ABR/MLR components.

The application of electro- and magneto-encephalography in tinnitus research - methods and interpretations.

In recent years, there has been a significant increase in the use of electroencephalography (EEG) and magnetoencephalography (MEG) to investigate changes in oscillatory brain activity associated with tinnitus with many conflicting results. Current view of the underlying mechanism of tinnitus is that it results from changes in brain activity in various structures of the brain as a consequence of sensory deprivation. This in turn gives rise to increased spontaneous activity and/or synchrony in the auditory centers but also involves modulation from non-auditory processes from structures of the limbic and paralimbic system.

Changes in the response properties of inferior colliculus neurons relating to tinnitus.

Tinnitus is often identified in animal models by using the gap prepulse inhibition of acoustic startle. Impaired gap detection following acoustic over-exposure (AOE) is thought to be caused by tinnitus "filling in" the gap, thus, reducing its salience. This presumably involves altered perception, and could conceivably be caused by changes at the level of the neocortex, i.

Positive pressure therapy for Meniere's syndrome/disease with a Meniett device: a systematic review of randomised controlled trials.

Background: Incidence rates of Meniere's syndrome/disease vary considerably from 157 per 100 000 in the United Kingdom to 15 per 100 000 in the United States. A wide range of treatments are used for the treatment of the condition with no consensus on the most effective intervention.

Objectives: To assess the effectiveness of the Meniett device in reducing the frequency and severity of vertigo in Meniere's syndrome/disease.

Searching for a talking face: the effect of degrading the auditory signal.

Previous research (e.g., McGurk & MacDonald, 1976) suggests that faces and voices are bound automatically, but recent evidence suggests that attention is involved in a task of searching for a talking face (Alsius & Soto-Faraco, 2011).

Relation between speech-in-noise threshold, hearing loss and cognition from 40-69 years of age.

Background: Healthy hearing depends on sensitive ears and adequate brain processing. Essential aspects of both hearing and cognition decline with advancing age, but it is largely unknown how one influences the other. The current standard measure of hearing, the pure-tone audiogram is not very cognitively demanding and does not predict well the most important yet challenging use of hearing, listening to speech in noisy environments.

The moving minimum audible angle is smaller during self motion than during source motion.

our heads rotate in three axes and move in three dimensions, constantly varying the spectral and binaural cues at the ear drums. In spite of this motion, static sound sources in the world are typically perceived as stable objects. This argues that the auditory system-in a manner not unlike the vestibulo-ocular reflex-works to compensate for self motion and stabilize our sensory representation of the world.

Gameplay as a source of intrinsic motivation in a randomized controlled trial of auditory training for tinnitus.

Background: Previous studies of frequency discrimination training (FDT) for tinnitus used repetitive task-based training programmes relying on extrinsic factors to motivate participation. Studies reported limited improvement in tinnitus symptoms.

Purpose: To evaluate FDT exploiting intrinsic motivations by integrating training with computer-gameplay.

Comparison of the benefits of cochlear implantation versus contra-lateral routing of signal hearing aids in adult patients with single-sided deafness: study protocol for a prospective within-subject longitudinal trial.

Background: Individuals with a unilateral severe-to-profound hearing loss, or single-sided deafness, report difficulty with listening in many everyday situations despite having access to well-preserved acoustic hearing in one ear. The standard of care for single-sided deafness available on the UK National Health Service is a contra-lateral routing of signals hearing aid which transfers sounds from the impaired ear to the non-impaired ear. This hearing aid has been found to improve speech understanding in noise when the signal-to-noise ratio is more favourable at the impaired ear than the non-impaired ear.

The effect of hearing aid microphone mode on performance in an auditory orienting task.

Objectives: Although directional microphones on a hearing aid provide a signal-to-noise ratio benefit in a noisy background, the amount of benefit is dependent on how close the signal of interest is to the front of the user. It is assumed that when the signal of interest is off-axis, users can reorient themselves to the signal to make use of the directional microphones to improve signal-to-noise ratio. The present study tested this assumption by measuring the head-orienting behavior of bilaterally fit hearing-impaired individuals with their microphones set to omnidirectional and directional modes.

Automated screening for high-frequency hearing loss.

Objective: Hearing loss at high frequencies produces perceptual difficulties and is often an early sign of a more general hearing loss. This study reports the development and validation of two new speech-based hearing screening tests in English that focus on detecting hearing loss at frequencies above 2000 Hz.

Design: The Internet-delivered, speech-in noise tests used closed target-word sets of digit triplets or consonant-vowel-consonant (CVC) words presented against a speech-shaped noise masker.

Late, not early mismatch responses to changes in frequency are reduced or deviant in children with dyslexia: an event-related potential study.

Background: Developmental disorders of oral and written language have been linked to deficits in the processing of auditory information. However, findings have been inconsistent, both for behavioural and electrophysiological measures.

Methods: In this study, we examined event-related potentials (ERPs) in 20 6- to 14-year-old children with developmental dyslexia and 20 age-matched controls, divided into younger (6-11 years, n = 10) and older (11-14 years, n = 10) age bands.

Effects of age and hearing loss on stream segregation based on interaural time differences.

The effect of interaural time differences (ITDs) on obligatory stream segregation for successive tone bursts was investigated for older listeners with normal hearing (ONH) and hearing loss (OHL), by measuring the threshold for detecting a rhythmic irregularity in an otherwise isochronous sequence of interleaved "A" and "B" tones. The A and B tones had equal but opposite ITDs from 0 to 0.5 ms.

Envelope enhancement increases cortical sensitivity to interaural envelope delays with acoustic and electric hearing.

Evidence from human psychophysical and animal electrophysiological studies suggests that sensitivity to interaural time delay (ITD) in the modulating envelope of a high-frequency carrier can be enhanced using half-wave rectified stimuli. Recent evidence has shown potential benefits of equivalent electrical stimuli to deaf individuals with bilateral cochlear implants (CIs). In the current study we assessed the effects of envelope shape on ITD sensitivity in the primary auditory cortex of normal-hearing ferrets, and profoundly-deaf animals with bilateral CIs.

The perception of apparent auditory source width in hearing-impaired adults.

In a previous study [Whitmer, Seeber and Akeroyd, J. Acoust. Soc.

Variations in the slope of the psychometric functions for speech intelligibility: a systematic survey.

Although many studies have looked at the effects of different listening conditions on the intelligibility of speech, their analyses have often concentrated on changes to a single value on the psychometric function, namely, the threshold. Far less commonly has the slope of the psychometric function, that is, the rate at which intelligibility changes with level, been considered. The slope of the function is crucial because it is the slope, rather than the threshold, that determines the improvement in intelligibility caused by any given improvement in signal-to-noise ratio by, for instance, a hearing aid.

Perception and coding of high-frequency spectral notches: potential implications for sound localization.

The interaction of sound waves with the human pinna introduces high-frequency notches (5-10 kHz) in the stimulus spectrum that are thought to be useful for vertical sound localization. A common view is that these notches are encoded as rate profiles in the auditory nerve (AN). Here, we review previously published psychoacoustical evidence in humans and computer-model simulations of inner hair cell responses to noises with and without high-frequency spectral notches that dispute this view.

Parcellation of Human and Monkey Core Auditory Cortex with fMRI Pattern Classification and Objective Detection of Tonotopic Gradient Reversals.

Auditory cortex (AC) contains several primary-like, or "core," fields, which receive thalamic input and project to non-primary "belt" fields. In humans, the organization and layout of core and belt auditory fields are still poorly understood, and most auditory neuroimaging studies rely on macroanatomical criteria, rather than functional localization of distinct fields. A myeloarchitectonic method has been suggested recently for distinguishing between core and belt fields in humans (Dick F, Tierney AT, Lutti A, Josephs O, Sereno MI, Weiskopf N.