Simplified frequency selectivity measure as a potential candidate for hearing screening: changes with masker level and test-retest reliability of self-administered testing.

Objectives: This two-part pilot study investigated the feasibility of using a frequency selectivity measure (T) to develop a novel hearing screening test for cooperative adults. Study 1 determined the optimal masker level, while Study 2 assessed the reliability of a self-administered T test prototype performed at the selected masker level.

Design And Study Sample: Study 1 (normal hearing,  = 20) examined masker-level effects on T using a manual threshold determination method from an earlier study.

The equivalent threshold sound pressure levels and test-retest threshold variability of a consumer-grade insert earphone fitted with stock, foam, and otoacoustic emission probe ear tips.

Objective: Consumer-grade insert earphones (IEs) can be utilised for audiometry, but their calibration values and threshold reliability may differ from the audiometric IE. This study measured the equivalent threshold sound pressure levels (ETSPLs), and the test-retest threshold variation when a consumer IE (Sennheiser CX100) was fitted with: (1) silicone stock ear tips that came along with the earphone, (2) replacement foam ear tips (KZ acoustics) and (3) silicone otoacoustic emission (OAE) probe ear tips.

Design And Study Sample: Study 1 determined ETSPL values in 25 normal-hearing subjects aged 18-25 years at seven test frequencies (500-8000 Hz).

Simplified cochlear frequency selectivity assessment in normal-hearing and hearing-impaired listeners.

Objective: The ear's spectral resolution or frequency selectivity (FS) is a fundamental aspect of hearing but is not routinely measured in clinical practice. This study evaluated a simplified FS testing procedure for clinical use by replacing the time-consuming two-interval forced choice (2IFC) method with method of limits (MOL) carried out using a custom-made software and consumer-grade equipment.

Design And Study Sample: Study 1 compared the FS measure obtained with MOL and 2IFC procedure at two centre frequencies (CFs) (1 and 4 kHz) in 21 normal-hearing listeners.

Simplified cochlear frequency selectivity measure for sensorineural hearing loss screening: comparison with digit triplet test (DTT) and shortened speech, spatial and qualities of hearing scale (SSQ) questionnaire.

Purpose: Pure-tone audiometry (PTA) is the gold standard for screening and diagnosis of hearing loss but is not always accessible. This study evaluated a simplified cochlear frequency selectivity (FS) measure as an alternative option to screen for early frequency-specific sensorineural hearing loss (SNHL).

Methods: FS measures at 1 and 4 kHz center frequencies were obtained using a custom-made software in normal-hearing (NH), slight SNHL and mild-to-moderate SNHL subjects.

Calibration and initial validation of a low-cost computer-based screening audiometer coupled to consumer insert phone-earmuff combination for boothless audiometry.

Objective: To undertake calibration and preliminary validation of a custom-designed computer-based screening audiometer connected to consumer insert phone-earmuff combination for adult pure tone audiometry.

Design: Part 1 involved electroacoustic measurement and biological calibration of a laptop-earphone pair used for the computer-based audiometry (CBA). Part 2 compared CBA thresholds obtained without a sound booth with those measured using the gold-standard clinical audiometry.

Contralateral proximal interference.

A contralateral "cue" tone presented in continuous broadband noise both lowers the threshold of a signal tone by guiding attention to it and raises its threshold by interference. Here, signal tones were fixed in duration (40 ms, 52 ms with ramps), frequency (1500 Hz), timing, and level, so attention did not need guidance. Interference by contralateral cues was studied in relation to cue-signal proximity, cue-signal temporal overlap, and cue-signal order (cue after: backward interference, BI; or cue first: forward interference, FI).

Auditory attentional filter in the absence of masking noise.

Signals containing attended frequencies are facilitated while those with unexpected frequencies are suppressed by an auditory filtering process. The neurocognitive mechanism underlying the auditory attentional filter is, however, poorly understood. The olivocochlear bundle (OCB), a brainstem neural circuit that is part of the efferent system, has been suggested to be partly responsible for the filtering via its noise-dependent antimasking effect.

Hearing Risk among Young Personal Listening Device Users: Effects at High-Frequency and Extended High-Frequency Audiogram Thresholds.

Objective: The usage of personal listening devices (PLDs) is associated with risks of hearing loss. The aim of this study is to evaluate the effects of music exposure from these devices on high-frequency hearing thresholds of PLD users.

Materials And Methods: A total of 282 young adults were questioned regarding their listening habits and symptoms associated with PLD listening.

Integrating an open-source course management system (Moodle) into the teaching of a first-year medical physiology course: a case study.

Educators in medical schools around the world are presently experimenting with innovative ways of using web-based learning to supplement the existing teaching and learning process. We have recently used a popular open-source course management system (CMS) called the modular object-oriented dynamic learning environment (Moodle) to construct an online site (DPhysiol) to facilitate our face-to-face teaching of physiology to a group of first-year students in the Bachelor of Medicine and Bachelor of Surgery program. The integration of the Moodle site into our teaching was assessed using online log activity, student examination marks, and feedback from students.

Efferent pathways modulate hyperactivity in inferior colliculus.

Animal models have demonstrated that mild hearing loss caused by acoustic trauma results in spontaneous hyperactivity in the central auditory pathways. This hyperactivity has been hypothesized to be involved in the generation of tinnitus, a phantom auditory sensation. We have recently shown that such hyperactivity, recorded in the inferior colliculus, is still dependent on cochlear neural output for some time after recovery (up to 6 weeks).

Unmasking effects of olivocochlear efferent activation on responses of inferior colliculus neurons.

Behavioural studies suggest a role for the medial olivocochlear (MOC) system in improving detection and discrimination of signals in noise. Physiological studies in the cochlea support this notion, showing unmasking, an improvement of the dynamic range of primary auditory afferents in response to tones in noise after MOC system activation. However, little is known about unmasking effects in higher centres.

Effects of medial olivocochlear efferent stimulation on the activity of neurons in the auditory midbrain.

Medial olivocochlear (MOC) efferents are known to suppress spontaneous activity and sound-evoked responses of primary afferents by their actions on outer hair cells in the cochlea. This study investigated the effects of MOC activation on the responses of single neurons in the central nucleus of the inferior colliculus (CNIC) of anaesthetized guinea pigs. Extracellular responses of CNIC neurons to contralateral tones were recorded with and without MOC stimulation in normal animals and in animals acutely treated with gentamicin to eliminate peripheral effects of MOC activation.