Recognition of acoustic signals when perception is subject to interference from noise has already been extensively studied. In this study the influence of hearing protectors (HP) (plugs, muffs) and hearing loss on signal recognition is examined. Different spectrums and levels of the noise are also included. The test results are ...

Mutagenesis of the POU-domain gene Brn4/Pou3f4 causes defects in the cochlear duct, semicircular canal, temporal bone and stapes footplate. The footplate defect suggested a middle-ear conductive component to the hearing loss associated with this mutation. This was examined by measuring velocity transfer functions at the umbo of wild type and ...

OBJECTIVES: The aim of the study was to assess the influence of short-term impulse noise on the size and dynamics of temporary threshold shift, which precedes permanent threshold shift, i.e. noise-induced hearing loss. It was hoped to use the findings for preventive activities. MATERIALS AND METHODS: The study included 80 ...

For signal detection and identification, the auditory system needs to integrate sound over time. It is frequently assumed that the quantity ultimately integrated is sound intensity and that the integrator is located centrally. However, we have recently shown that absolute thresholds are much better specified as the temporal integral of ...

Members of a Dutch DFNA13/COL11A2 family were evaluated with pure tone audiometry, stapedial reflexes, otoacoustic emissions, loudness scaling, difference limen for frequency, gap detection, and speech perception in quiet and noise. The tone audiometry showed a predominant loss for the low and middle frequencies, with only a few otoacoustic emissions ...

This review discusses hearing performance in primates and selective pressures that may influence it. The hearing sensitivity and sound-localization abilities of primates, as indicated by behavioral tests, are reviewed and compared to hearing and sound localization among mammals in general. Primates fit the mammalian pattern with small species hearing higher ...

The auditory region contains numerous structures that have proven useful for phylogenetic classification at various taxonomic levels. However, little work has been done in primates relating differences in morphology to variations in hearing performance. This study documents anatomical and physiological distinctions within primates and begins to address the functional and ...

BACKGROUND: Future fighter aircraft will include three-dimensional sound signals as part of the human-machine interface. The reduction in cerebral vascular flow associated with maneuvering acceleration (+Gz) may affect a pilot's ability to perceive and interpret such aural cues. We hypothesized that vascular deprivation along the cochlea produced by +Gz would ...

BACKGROUND: The effects of radio frequency (RF) and microwave radiation on humans have been the subject of continuous investigation. Clinical investigations related to occupational RF/microwave exposure have been reported by investigators (1). Since one of the major groups occupationally exposed to RF and microwave radiation includes those working in radio ...

The effect of onset asynchrony on discrimination of spectral shape was evaluated for hearing-impaired and normal-hearing listeners. Stimuli were the sum of four tones equally spaced on a logarithmic frequency scale. The standard stimulus had tones of equal amplitude, and the signal stimulus had two adjacent components increased in level, ...

The presence of cochlear-based compression at low frequencies was investigated by measuring phase effects in harmonic maskers. In normal-hearing listeners, the amount of masking produced depends strongly on the phase relationships between the individual masker components. This effect is thought to be determined primarily by properties of the cochlea, including ...

Mammals exposed to loud aerial sounds exhibit temporary threshold shifts (TTS) that are linearly related to increases of sound pressure above baseline hearing levels. It was unknown if this relationship held true for aquatic ectotherms such as fishes. To test this linear threshold shift hypothesis (LINTS) in fishes, we examined ...

Learning curves and behavioural audiograms of subterranean, socially living coruros (Spalacopus cyanus) were obtained using a positive reinforcement conditioning procedure. The individually varying audiograms revealed best hearing at frequencies between 1.25 and 1.6 kHz, which corresponds with the common pattern established in subterranean rodents studied so far. However, the broad ...

Hearing thresholds measured with high-frequency resolution show a quasiperiodic change in level called threshold fine structure (or microstructure). The effect of this fine structure on loudness perception over a range of stimulus levels was investigated in 12 subjects. Three different approaches were used. Individual hearing thresholds and equal loudness contours ...

Spectral enhancement is now being used in many hearing aids in an attempt to compensate for broadened cochlear filtering. However, spectral enhancement may be counteracted by multiband-compression algorithms designed to compensate for the reduced dynamic range of the impaired cochlea. An alternative scheme for spectral enhancement, contrast-enhancing frequency shaping (CEFS), ...

The purpose of this study was to compare threshold-matched ears with and without suspected cochlear dead regions in terms of the speech perception benefit from high-frequency amplification. The Threshold Equalizing Noise Test (TEN) was used to assess the presence of dead regions. Speech perception was measured while participants were wearing ...

OBJECTIVE: To determine the accuracy of questions in identifying subjects occupationally exposed to high noise level and those with hearing loss using noise dosimeter and pure-tone air conduction audiometry as the gold standards. DESIGN: A cross-sectional study involving 259 noise-exposed workers selected randomly from two factories in Eastern Saudi Arabia. ...

OBJECTIVE: To report on clinical experience using dichotic multiple-stimulus auditory steady-state responses (ASSRs) as an objective technique to estimate frequency-specific hearing thresholds in hearing-impaired infants. METHODS: A comparison was made between the click-evoked auditory brainstem response (ABR), auditory steady-state responses and behavioral hearing thresholds (BHTs). Both ears of 10 infants ...

The identification of nonsense syllables in quiet and in three types of background (babble, cafeteria and single female speaker) was measured using four hearing aid compression algorithms differing in attack and release time constants, and using linear amplification. The speech level was always 65 dB SPL. The compression algorithms, which ...

Human hearing differs from that of chimpanzees and most other anthropoids in maintaining a relatively high sensitivity from 2 kHz up to 4 kHz, a region that contains relevant acoustic information in spoken language. Knowledge of the auditory capacities in human fossil ancestors could greatly enhance the understanding of when ...

Buus and Florentine [J. Assoc. Res. Otolaryngol. 3, 120-139 (2002)] have proposed that loudness recruitment in cases of cochlear hearing loss is caused partly by an abnormally large loudness at absolute threshold. This has been called "softness imperception." To evaluate this idea, loudness-matching functions were obtained using tones at very ...

OBJECTIVE: The performance of an adaptive beam-former in a 2-microphone, behind-the-ear hearing aid for speech understanding in noisy environments was evaluated. Physical and perceptual evaluations were carried out. This was the first large-scale test of a wearable real-time implementation of this algorithm. The main perceptual research questions of this study ...

Auditory feedback influences the development of vocalizations in songbirds and parrots; however, little is known about the development of hearing in these birds. The auditory brainstem response was used to track the development of auditory sensitivity in budgerigars from hatch to 6 weeks of age. Responses were first obtained from ...

The major consequence of sensorineural hearing loss (SNHL) is communicative difficulty, especially with the addition of noise and/or reverberation. The purpose of this investigation was to compare two types of technologies that have been shown to improve the speech-perception performance of individuals with SNHL: directional microphones and frequency modulation (FM) ...

For normally hearing subjects, harmonic complex tones that give "peaky" waveforms on the basilar membrane (Schroeder-positive phase, sine phase or cosine phase) lead to less forward masking than complex tones that give less peaky waveforms (Schroeder-negative phase or random phase), but have the same power spectrum. This difference has been ...

Blue-throated hummingbirds produce elaborate songs extending into the ultrasonic frequency range, up to 30 kHz. Ultrasonic song elements include harmonics and extensions of audible notes, non-harmonic components of audible syllables, and sounds produced at frequencies above 20 kHz without corresponding hearing range sound. To determine whether ultrasonic song elements function ...

Otoacoustic emissions (OAE) and pure tone audiogram (PTA) were examined in 26 ears of 25 patients suffering from sudden hearing loss from the 1st day to up to 505 days following the drop of hearing to test the hypothesis whether the OAEs are capable of delivering predictive information about the ...

OBJECTIVE: Cochlear implants (CIs) attempt to mimic the tonotopicity of the normal ear by stimulating more basal regions of the cochlea in response to higher frequencies. However, there may be a mismatch between the normal place-frequency map and that implemented by a CI. MATERIAL AND METHODS: Aiming to measure this ...

Effective objective HF (high-frequency) testing methodology provides for the early detection of ototoxic hearing loss because it typically progresses from high to low frequencies. Such early detection is considered necessary to prevent hearing loss from progressing into the frequency range important for understanding speech. Objective tests must be reliable, sensitive ...

The effect of fast-acting compression on speech recognition in fully modulated (FUM) noise in listeners with normal and impaired hearing was investigated in two experiments We wanted to determine the relationships between the benefit from compression and some audiological factors. Furthermore, the sensitivity to changes in compression parameters was also ...

OBJECTIVE: To determine the effectiveness of auditory steady-state response (ASSR) as a measure of hearing sensitivity in young children suspect for significant hearing loss. DESIGN: Within-subject comparisons of click auditory brainstem response (ABR) thresholds and ASSR thresholds. SUBJECTS: The study population comprised 42 children suspect for hearing loss and subsequently ...

OBJECTIVES: In this paper we test the concept of combining electrical stimulation for high-frequency sound with acoustic hearing for low-frequency information in the same ear. In addition, we test whether residual hearing can be preserved when an electrode is placed up to 10 mm into the inner ear, and whether ...

OBJECTIVES: To describe the chronologic changes of hearing in patients with large vestibular aqueduct syndrome (LVAS) and identify the prognostic factors. STUDY DESIGN: A retrospective chart-review study. METHODS: Twelve consecutive patients with LVAS were recruited at Taipei Veterans General Hospital between July 1986 and July 2000. The records of serial ...

Animal studies have demonstrated artemisinin brain stem toxicity with auditory centres being especially affected; there has, to date, been no evidence of such toxicity with oral artemisinins in humans. Subjects working at a construction site in Mozambique had audiometric assessments taken on joining and leaving the project. Subjects with uncomplicated ...

Based on insight obtained from a newly developed cochlea model, we argue that noise-driven limit cycles are the basic ingredient in the mammalian cochlea hearing process. For insect audition, we provide evidence in favor of the persistence of this principle. We emphasize the role of bifurcations for the emergence of ...

OBJECTIVE: The purposes of the study were: (1) To evaluate the intrasession test-retest reliability of pure-tone thresholds measured in the 0.5-16 kHz frequency range for a group of otologically healthy subjects using Sennheiser HDA 200 circumaural and Etymotic Research ER-2 insert earphones and (2) to compare the data with existing ...

Psychophysical estimates of cochlear function suggest that normal-hearing listeners exhibit a compressive basilar-membrane (BM) response. Listeners with moderate to severe sensorineural hearing loss may exhibit a linearized BM response along with reduced gain, suggesting the loss of an active cochlear mechanism. This study investigated how the BM response changes with ...

This review concentrates on the effects of low frequency noise (LFN) up to 100 Hz on selected physiological parameters, subjective complaints and performance. The results of laboratory experiments and field studies are discussed in relation to the thresholds of hearing, of vibrotactile sensation and of aural pain. The effects of ...

In this study, the performance of 48 listeners with normal hearing was compared to the performance of 46 listeners with documented hearing loss. Various conditions of directional and omnidirectional hearing aid use were studied. The results indicated that when the noise around a listener was stationary, a first- or second-order ...

This study examined the effects of cochlear hearing loss on the ability to discriminate increments in the duration of a stimulus under conditions where the frequency and/or amplitude of the stimulus change dynamically. Three stimulus types were used: pure tones, frequency-modulated tones, and narrow bands of noise. The carrier/center frequency ...

Fish-eating "resident"-type killer whales (Orcinus orca) that frequent the coastal waters off northeastern Vancouver Island, Canada have a strong preference for chinook salmon (Oncorhynchus tshawytscha). The whales in this region often forage along steep cliffs that extend into the water, echolocating their prey. Echolocation signals of resident killer whales were ...

BACKGROUND: When the ear is presented with two simultaneous pure tones, the cochlea produces intermodulation products called distortion product otoacoustic emissions (DP-OAEs). When cochlear function is affected by noise or ototoxic drugs, DP-OAEs decrease in amplitude or disappear. The aim of this study was to investigate whether DP-OAEs are a ...

High noise levels may have an adverse effect on the normal cochlea function and lead to significant hearing loss. Clinically, exposure to high intensity impulse noise produces a wide range of audiometric effects which may result in long term or even irreversible symptoms. Nevertheless, there is sometimes a spontaneous rebound ...

Laser Doppler vibrometry was used to measure the sound-induced tympanic membrane (TM) velocity, assessed near the umbo, in 56 normal hearing human subjects at nine sound frequencies. A second series of measurements was made in 47 subjects with sensorineural hearing loss (SNHL). Each set of measurements has features in common ...

The purpose of this study was to determine the effects of reverberation and noise on the precedence effect in listeners with hearing loss. Lag burst thresholds (LBTs) for 4-ms noise bursts were obtained for 2 groups of participants: impaired hearing and normal hearing. Data were collected in reverberant and anechoic ...

Hearing impairment is often associated with damage to the hair cells of the cochlea. An area of the cochlea with complete loss of function of inner hair cells is known as a 'dead region'. Dead regions can be identified by measuring detection thresholds for pure tones in quiet and in ...

Behavioral thresholds were measured from 31 adults with normal hearing for 500, 1000, 2000, and 4000 Hz brief tones presented using a B-71 bone oscillator. Three occlusion conditions were assessed: ears unoccluded, one ear occluded, and both ears occluded. Mean threshold force levels were 67, 54, 49, and 41 dB ...

This study examined the effects of mild-to-moderate sensorineural hearing loss on vowel perception abilities of young, hearing-impaired (YHI) adults. Stimuli were presented at a low conversational level with a flat frequency response (approximately 60 dB SPL), and in two gain conditions: (a) high level gain with a flat frequency response ...

The directional dependence of sound pressure transformation of head and pinna has been measured in the phyllostomid bat Phyllostomus discolor for the frontal hemisphere using a maximum length sequence method. The azimuthal position of the axis of highest pinna gain came closer to the midsagital plane with increasing frequency. The ...

In different insect taxa, ears can be found on virtually any part of the body. Comparative anatomy and similarities in the embryological development of ears in divergent taxa suggest that they have evolved multiple times from ubiquitous stretch or vibration receptors, but the homology of these structures has not yet ...