Sound Hearing Research Articles

Prospective, randomized controlled assessment of the short‐ and long‐term efficacy of a hearing conservation education program in Canadian elementary school children

To assess the efficacy of a hearing conservation program in changing acoustic risk-taking and hearing conservation behaviors in elementary school children. Prospective, randomized, mixed design controlled study. Participants were grade-six students from 16 Vancouver School Board schools. Differences between the intervention and control group responses on a behavioral questionnaire were measured at baseline, and then at 2 weeks and 6 months after administration of a hearing conservation program (Sound Sense™). The intervention resulted in significant interactions for improved earplug use at dances (P = .019), rock concerts (P = .001), with percussion musical instruments (P = .002), and electric guitars (P = .028) at 2 weeks postintervention relative to baseline. Improvements in children's earplug use at dances (P = .041), rock concerts (P = .0024), and with power lawn mowers (P = .043) at 6 months postintervention relative to baseline were also observed. Behavior in the intervention group compared to control group improved in earplug use with any "other noises" at 2 weeks (P = .001), and 6 months (P = .022) relative to baseline. There was a tendency in the intervention group to reduce the duration of use of personal music devices at 2 weeks and 6 months after the hearing conservation program, which was nonsignificant. The Sound Sense™ hearing conservation program improved earplug use practices in elementary school children in the short and long term. The development, implementation and evaluation of a community-based health promotion project around hearing loss can serve as a tremendous opportunity for students to develop their knowledge and skills in health advocacy.

Intraoperative adjustments to optimize active middle ear implant performance

Conclusion: After initial contact of the active middle ear implant (AMEI) on the incus, significant increases in device performance can be achieved intraoperatively without affecting residual hearing by additional static loading of the incus with 62 μm (quarter turn) to 125 μm (half turn) increments via an adjustment screw. Objectives: To assess the performance gains of driving the incus with an AMEI under increasing static loads in cadaveric temporal bones. Methods: Incus drive efficacy was assessed using laser Doppler velocimetry measurements of stapes velocities over a frequency range of 0.25 to 8 kHz. Results were compared to stapes velocities following acoustic stimulation via insert earphone. Maximum equivalent ear canal sound pressure level (LEmax) and residual hearing loss after initial loading of the AMEI (first contact) were compared in each temporal bone. Additional increases in incus load were induced by turning an adjustment screw in quarter turn steps, corresponding to 62 μm increments per step. LEmaxand residual hearing loss were reassessed after each step. For each temporal bone, experiments were repeated for three different AMEIs. Results: On average across bones, incus stimulation upon initial contact produced an LEmaxof 125, 127, and 121 dB SPL and residual hearing losses of –2, –1, and –1 dB with respect to unloaded, unaided conditions for the three AMEIs, respectively. Across bones and transducers, increasing static transducer load by incrementing the AMEI up to 125 μm significantly improved performance without affecting residual hearing loss. Loading beyond 125 μm (half turn) did not improve performance but significantly increased residual hearing loss.

Teens at Risk: “We’re on the Edge of an Epidemic”

Teens at Risk: “We’re on the Edge of an Epidemic”

Sound transmission and directional hearing in field crickets: neurophysiological studies outdoors

Many studies provide detailed behavioural and neurophysiological information on the ability of crickets to localize a sound source under ideal acoustic conditions, but very little is known about how they perform in real habitats. We investigated directional hearing of crickets in the field using a neurophysiological approach, by recording the activity of the two prominent, bilaterally homologous AN1 neurons simultaneously in a cricket's habitat. The discharge and latency differences of the pair of neurons in response to conspecific chirps presented at different distances and directions were taken as a measure of directional information. The maximum hearing distance differed between individuals and weather conditions from 1 to 15 m (mean 9.2 m). Although the AN1 activity generally decreased with increasing distance, large fluctuations in the magnitude of responses occurred with distance, indicating that the intensity gradient over distance is often irregular. The directional information provided in the discharge differences of the two neurons also varied with distance. Again, there was no simple directional gradient on the transmission channel; rather, with decreasing distance to the source there were receiver locations providing suprathreshold responses, but no directional information. The consequences for the ability of field crickets to communicate acoustically close to the ground are discussed.

Hearing aids re-habilitation in aged people

Presbyacusis is defined as the cumulative effects of aging on hearing ability. Each of them commonly feature different impairments, e.g on: sound hearing (mostly for high frequencies), speech understanding (mostly in noise), delayed speech processing by NCS and sound source localization. Its fuzzy and unclear simptomatology frequently leads to a delayed detection. In addition, the affected subjects rarely contact a specialist in order to sharply deal with such occurrences. Furthermore, whenever the presbyacusis is detected, only a small amount of patients will use hearing aids. To date, in US only the 20% of people supposed to need a hearing support, wear hearing aids and the 25-40% of those patients either leave or use them unevenly. Aims of this report are: - to examine the reasons leading people affected by presbyacusis to rarely wear hearing aids - to verify the possible technical hitches on fitting hearing-aids to aged patients (prosthetic grading), in order to provide them with correct rehabilitation pathways to an adequate sound and speech perception. The last part of this work concerns the rehabilitation issues for subjects affected by a multi-sensorineural impairment (e.g deaf-blindness).

Sounds of shallow water fishes pitch within the quiet window of the habitat ambient noise

The habitat ambient noise may exert an important selective pressure on frequencies used in acoustic communication by animals. A previous study demonstrated the presence of a match between the low-frequency quiet region of the stream ambient noise (termed 'quiet window') and the main frequencies used for sound production and hearing by two stream gobies (Padogobius bonelli, Gobius nigricans). The present study examines the spectral features of ambient noise in very shallow freshwater, brackish and marine habitats and correlates them to the range of dominant frequencies of sounds used by nine species of Mediterranean gobies reproducing in these environments. Ambient noise spectra of these habitats featured a low-frequency quiet window centered at 100 Hz (stream, sandy/rocky sea shore), or at 200 Hz (spring, brackish lagoon). The analysis of the ambient noise/sound spectrum relationships showed the sound frequencies matched the frequency band of the quiet window in the ambient noise typical of their own habitat. Analogous ambient noise/sound frequency relationships were observed in other shallow-water teleosts living in similar underwater environments. Conclusions may be relevant to the understanding of evolution of fish acoustic communication and hearing.

In-situ calibrated sound signals and hearing sensitivity.

The acoustic input impedance of the ear provides data on the acoustico-mechanical function of the ear and can be used diagnostically to assess outer and middle ear function. Sound signals delivered to the ear (canal) can be quantified in-situ if the complex reflectance of the ear has been determined. Hearing sensitivity can be expressed in terms of the forward-going sound pressure wave, or after correcting for acoustic delay, the fraction of the forward-going sound pressure wave transmitted to the middle ear. The latter is an estimate of the signal the cochlea receives. Data will be presented examining the virtues of expressing hearing sensitivity in terms of an in-situ calibrated sound signal.

High sound attenuating hearing protection device

A hearing protection device insertable into an earcanal is provided, the device generally including a stem portion, a sound attenuating portion affixed to and extending at least partially over the stem portion, and a volume of space disposed between and delimited by the sound attenuating portion and the stem portion, where at least a part of the sound attenuating portion is collapsible into the volume of space during insertion of the hearing protection device into the earcanal.

Free-space human interface for interactive music, full-body musical instrument, and immersive media controller

Method and apparatus entraining interactive media players into a sustained experience of 'Kinesthetic Spatial Sync' defined as a perceived simultaneity and spatial superposition between a non-tactile, full body input control process and immersive multisensory feedback. Asynchronous player input actions and clock-synchronous media feedback events exhibit a seamless synesthesia or multisensory events fused into an integral event perception, this being between musical sound (hearing), visual responses (sight), and body kinesthetic (radial extension, angular position, height, speed, timing and precision). This non-tactile interface process and multisensory feedback “look and feel” is embodied as an optimal ergonomic human interface for interactive music and as a six-degrees-of-freedom full-body-interactive immersive media controller 1. The invention provides for a wide scope of fully reconfigurable transfer functions between kinesthetic input features and media responses ( Creative Zone Behaviors) managed by means of MIDI protocol and/or display interface commands.

The current status of audiologic rehabilitation for profound unilateral sensorineural hearing loss

Audiologic rehabilitation of individuals with profound unilateral sensorineural hearing loss (USNHL) has traditionally been limited to the use of air-conduction contralateral routing of sound (CROS) hearing aids. Treatment for these individuals has expanded with new applications of the bone-anchored hearing aid (BAHA), transcranial hearing aid (t-CROS), and the cochlear implant. In this article, the authors review the literature that addresses these various treatment options. Contemporary review Historical information is available that describes the limited efficacy of air-conduction CROS hearing aids in lifting hearing handicap associated with USNHL. Current investigations on providing cross hearing are generally focused on use of the BAHA. Little is known at present whether new developments in hearing aid technology can improve on conventional air-conduction CROS or t-CROS approaches. Interestingly, the cochlear implant seems to be a viable option for individuals with USNHL and tinnitus who also have intact auditory nerve pathways. There is indication in the literature that BAHA provides greater relief of hearing handicap associated with USNHL than CROS hearing aids; however, both have been found to provide limited patient satisfaction and seemingly fall short of restoring true sound localization. Adequate trials have not been performed comparing BAHA with the best CROS hearing aid technology. Transcranial hearing aids and cochlear implants are experimental methods to treat USNHL and hold promise, although there remains a lack of studies available to fully support this.

Pilot study on the effectiveness of the conventional CROS, the transcranial CROS and the BAHA transcranial CROS in adults with unilateral inner ear deafness

The objective of the present pilot study is to evaluate the effectiveness of three conventional contralateral routing of sound (CROS) hearing aids in adults with unilateral inner ear deafness. The study included tertiary referral center. Ten patients with unilateral inner ear deafness and normal hearing in the contralateral ear were selected to evaluate three different methods of amplification: the CROS hearing aid, the completely in the canal hearing aid and the bone-anchored hearing aid CROS (BAHA). Each of the three hearing aids was tried in a random order for a period of 8 weeks. Audiometric performance, including speech-in-noise, directional hearing and subjective benefit were measured after each trial period, using the APHAB, SSQ and single-sided deafness questionnaire. Sound localization performance was essentially at chance level in all four conditions. Mixed results were seen on the other patient outcome measures that alternated in favor of one of the three CROS devices. After the trial, three patients chose to be fitted with the BAHA CROS and one with the conventional CROS. In conclusion, most of the patients experienced some degree of benefit with each of the three hearing aids. Preference for one of the three hearing aids was independent of the order in which they were tried. It would be worthwhile to formulate selection criteria; still, we recommend that all patients with unilateral inner ear deafness should be offered a trial with at least the BAHA CROS.

Sound production and hearing in coral reef butterflyfishes.

Butterflyfishes (family Chaetodontidae) exhibit a diversity of close affiliative social behaviors. All 87 species of Chaetodon have a laterophysic connection and extensions of the anterior horns of the swim bladder near the otic capsule, which are proposed to impart sound pressure sensitivity to the normally mechanosensitive lateral line and acceleration‐sensitive inner ear. Video kinematic analyses reveal that the motor action patterns used to produce pulsed sounds vary among species. The sound production mechanisms in Chaetodon and Forcipiger do not appear to be conserved, thus sound production may have evolved independently within the family. Species with long swim bladder horns have lower AEP hearing thresholds than those without, and deflation of the horns and bladder decreases hearing sensitivity in the former group. When the laterophysic connection and swim bladder horns are physically disrupted in wild fish, movement within their territories decreases and fish pairs swim closer together. Thus, the low intensity sounds produced by butterflyfishes may favor close social behaviors that increase communication efficiency among individuals on a noisy coral reef. We are currently investigating how hydrodynamic flow fields produced during social interactions may be used for intraspecific communication during these natural behaviors.

Output sound pressure levels of personal music systems and their effect on hearing

This study looked at output levels produced by new generation personal music systems (PMS), at the level of eardrum by placing the probe microphone in the ear canal. Further, the effect of these PMS on hearing was evaluated by comparing the distortion product otoacoustic emissions and high frequency pure tone thresholds (from 3 kHz to 12 kHz) of individuals who use PMS to that of age matched controls who did not use PMS. The relationship between output sound pressure levels and hearing measures was also evaluated. In Phase I output SPLs produced by the PMS were measured in three different conditions - a) at volume control setting that was preferred by the subjects in quiet b) at volume control setting that was preferred by the subject in presence of 65 dB SPL bus noise c) at maximum volume control settings of the instrument. In Phase II pure tone hearing thresholds and DPOAEs were measured. About 30% of individuals in a group of 70 young adults listened to music above the safety limits (80 dBA for 8 hours) prescribed by Ministry of Environment and Forests, India. Addition of bus noise did not increase the preferred volume control settings of the subjects significantly. There were no significant differences between the experimental and control groups for mean pure tone threshold and for mean DPOAE amplitude comparisons. However, a positive correlation between hearing thresholds and music levels and a negative correlation between DPOAE measures and music levels were found.

From Cochlear Cell Death Pathways To New Pharmacological Therapies

Ototoxic drugs, intense sound or age-related hearing loss recruit most of the apoptotic pathways, but also several additional enzymatic pathways which eventually result in cell death. Here, we discuss therapeutic strategies based on the inhibition of regulators or executors of apoptotic cell death pathways and on the use of antioxidants.

Use of head mounted microphone arrays for active control

There has been an effort recently to create head mounted or user worn microphone arrays. These arrays pose challenges in their design and characterization but can be used for a number of different purposes. Initially these arrays were intended for sound source localization and natural hearing restoration (where the hearing of a user whose ears are obstructed by an encapsulating helmet or headset is restored). Once in place, and assuming the user is wearing headphones, these arrays can be used for a number of different applications including voice isolation for communication, focused listening and noise cancellation. Specifically this paper investigates the use of these arrays for the active control of noise both at the user's ears and in the communications/voice signals sent from the user. A numerical study, using both data generated numerically and experimentally, demonstrates that large reductions in noise can be achieved using adaptive active control methods.

Noise-Induced Hearing Loss in School-Age Children: What Do We Know?

An increasing number of children are exposed to louder sounds at younger ages, which may increase their risk for developing earlier and more severe noise-induced hearing losses. Factors that may be mediators or confounders of this noise exposure-hearing loss relationship include noise intensity and type, noise exposure incidences and duration, and individual susceptibility. The status of descriptive epidemiology in this area and the public health effects of noise-induced hearing loss are summarized. Results are analyzed using Hill's epidemiologic causal criteria. Longitudinal epidemiologic research is needed that will measure children's sound exposures and hearing outcomes within the same study to determine the extent of the problem and to improve understanding of possible causal pathways. In addition, hearing conservation programs need to be implemented more widely, and the programs' outcomes in increasing both knowledge and preventive behaviors need to be demonstrated in diverse locations. Some public policy health issues concerning prevention of noise-induced hearing loss in children are discussed.

Dual position hearing protection device

The present invention is a dual position hearing protection device. In one position, the device provides substantial sound attenuation and hearing protection. In the second position, an opening in the device permits sounds to enter the ear of the user relatively unobstructed. In the preferred embodiment of this invention the position of the device is changed simply by compressing the exposed end of the earplug.

Sound production and spectral hearing sensitivity in the Hawaiian sergeant damselfish, Abudefduf abdominalis

Sounds provide important signals for inter- and intraspecific communication in fishes, but few studies examine fish acoustic behavior in the context of coevolution of sound production and hearing ability within a species. This study characterizes the acoustic behavior in a reproductive population of the Hawaiian sergeant fish, Abudefduf abdominalis, and compares acoustic features to hearing ability, measured by the auditory evoked potential (AEP) technique. Sergeant fish produce sounds at close distances to the intended receiver (<or=1-2 body lengths), with different pulse characteristics that are associated primarily with aggression, nest preparation and courtship-female-visit behaviors. Energy peaks of all sounds were between 90 and 380 Hz, whereas courtship-visit sounds had a pulse repetition rate of 125 Hz with harmonic intervals up to 1 kHz. AEP threshold, which is probably higher than the behavioral threshold, indicates best sensitivity at low frequencies (95-240 Hz), with the lowest threshold at 125 Hz (123-127 dB(rms) re: 1 microPa). Thus, sound production and hearing in A. abdominalis are closely matched in the frequency domain and are useful for courtship and mating at close distances. Measured hearing thresholds did not differ among males and females during spawning or non-spawning periods, which indicates a lack of sex differences and seasonal variation in hearing capabilities. These data provide the first evidence that Abudefduf uses true acoustic communication on a level similar to that of both more derived (e.g. Dascyllus, Chromis) and more basal (e.g. Stegastes) soniferous pomacentrids. This correlation between sound production and hearing ability is consistent with the sensory drive model of signal evolution in which the sender and receiver systems coevolve within the constraints of the environment to maximize information transfer of acoustic signals.

Inhibition of the c-Jun N-Terminal Kinase-Mediated Mitochondrial Cell Death Pathway Restores Auditory Function in Sound-Exposed Animals

We tested and characterized the therapeutic value of round window membrane-delivered (RWM) d-JNKI-1 peptide (Bonny et al., 2001) against sound trauma-induced hearing loss. Morphological characteristics of sound-damaged hair cell nuclei labeled by Hoechst staining show that apoptosis is the predominant mode of cell death after sound trauma. Analysis of the events occurring after sound trauma demonstrates that c-Jun N-terminal kinase (JNK)/stress-activated protein kinase activates a mitochondrial cell death pathway (i.e., activation of Bax, release of cytochrome c, activation of procaspases, and cleavage of fodrin). Fluorescein isothiocyanate (FITC)-conjugated d-JNKI-1 peptide applied onto an intact cochlear RWM diffuses through this membrane and penetrates cochlear tissues with the exception of the stria vascularis. A time sequence of fluorescence measurements demonstrates that FITC-labeled d-JNKI-1 remains in cochlear tissues for as long as 3 weeks. In addition to blocking JNK-mediated activation of a mitochondrial cell death pathway, RWM-delivered d-JNKI-1 prevents hair cell death and development of a permanent shift in hearing threshold that is caused by sound trauma in a dose-dependent manner (EC50 = 2.05 microM). The therapeutic window for protection of the cochlea from sound trauma with RWM delivery of d-JNKI-1 extended out to 12 h after sound exposure. These results show that the mitogen-activated protein kinase/JNK signaling pathway plays a crucial role in sound trauma-initiated hair cell death. Blocking this signaling pathway with RWM delivery of d-JNKI-1 may have significant therapeutic value as a therapeutic intervention to protect the human cochlea from the effects of sound trauma.

A history of fish bioacoustic studies

Interest in fish sound production and hearing dates back to the writings of Aristotle (384–322 BCE) and Pliny the Elder (23–79 CE), both of whom noted not only that fish make sounds, but also speculated that fish must be able to hear despite their not having apparent ears. The fact that fish could hear was first demonstrated with the work of G. H. Parker in 1903 and later by Karl von Frisch. Studies on sound production were sporadic in the early part of the 20th century and often based on anecdotes until technology derived from antisubmarine warfare became available after World War II. This equipment enabled investigators to listen to fish and correlate sounds with behavior. It was not until the early 1960s that intensive investigations started on fish hearing. This paper will review the history of the study of fish bioacoustics and discuss the contributions of a large number of investigators including those of Arthur Myrberg. Indeed, Art’s research stands as a landmark in the field, as well as a fine example of true scholarship. Furthermore, his charismatic presentations of his work were instrumental in stimulating the investigations of other scientists.Interest in fish sound production and hearing dates back to the writings of Aristotle (384–322 BCE) and Pliny the Elder (23–79 CE), both of whom noted not only that fish make sounds, but also speculated that fish must be able to hear despite their not having apparent ears. The fact that fish could hear was first demonstrated with the work of G. H. Parker in 1903 and later by Karl von Frisch. Studies on sound production were sporadic in the early part of the 20th century and often based on anecdotes until technology derived from antisubmarine warfare became available after World War II. This equipment enabled investigators to listen to fish and correlate sounds with behavior. It was not until the early 1960s that intensive investigations started on fish hearing. This paper will review the history of the study of fish bioacoustics and discuss the contributions of a large number of investigators including those of Arthur Myrberg. Indeed, Art’s research stands as a landmark in the field, as well as a fine exa...