Open Ear Research Articles

Evaluation of extended-wear earplug technology as a transparent hearing-protection device

One of the greatest challenges in hearing conservation is providing adequate protection for those listeners who spend most of their time in quiet environments, but are occasionally exposed to high levels of noise that occur at unpredictable times. A classic example of this problem occurs for dismounted soldiers, who rely heavily on their natural hearing acuity to detect threats and opportunities on the battlefield but always face the risk of becoming engaged in a dangerously noisy firefight with little or no warning. One emerging technology that might have application in this domain is the extended-wear hearing aid, which is capable of remaining deep in the ear canal for weeks or months before being removed. Preliminary results suggest that the extended wear earplug can provide protection from blast or continuous noise that is comparable to a conventional earplug or muff, and that it can provide detection and localization performance comparable to that achieved with the open ear. Its form factor also makes it more likely to be compatible with headsets, radios, and personal protective equipment than traditional earplug or earmuff devices. The potential benefits and limitations of the extended-wear earplug as a hearing protector will be discussed. [Work supported by MRMC Grant W81XWH-14-1-0254; The opinions and assertions presented are the private views of the authors and are not to be construed as official or as necessarily reflecting the views of the Department of Defense.]

Direct Cost Comparison of Totally Endoscopic versus Open Ear Surgery

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Effects of low speed wind on the recognition/identification and pass-through communication tasks of auditory situation awareness afforded by military hearing protection/enhancement devices and tactical communication and protective systems

Objective: To investigate the effect of controlled low-speed wind-noise on the auditory situation awareness performance afforded by military hearing protection/enhancement devices (HPED) and tactical communication and protective systems (TCAPS). Design: Recognition/identification and pass-through communications tasks were separately conducted under three wind conditions (0, 5, and 10 mph). Subjects wore two in-ear-type TCAPS, one earmuff-type TCAPS, a Combat Arms Earplug in its ‘open’ or pass-through setting, and an EB-15LE™ electronic earplug. Devices with electronic gain systems were tested under two gain settings: ‘unity’ and ‘max’. Testing without any device (open ear) was conducted as a control. Study sample: Ten subjects were recruited from the student population at Virginia Tech. Audiometric requirements were 25 dBHL or better at 500, 1000, 2000, 4000, and 8000 Hz in both ears. Results: Performance on the interaction of communication task-by-device was significantly different only in 0 mph wind speed. The between-device performance differences varied with azimuthal speaker locations. Conclusions: It is evident from this study that stable (non-gusting) wind speeds up to 10 mph did not significantly degrade recognition/identification task performance and pass-through communication performance of the group of HPEDs and TCAPS tested. However, the various devices performed differently as the test sound signal speaker location was varied and it appears that physical as well as electronic features may have contributed to this directional result.

Variations in voice level and fundamental frequency with changing background noise level and talker-to-listener distance while wearing hearing protectors: A pilot study

Objective: Speech production in noise with varying talker-to-listener distance has been well studied for the open ear condition. However, occluding the ear canal can affect the auditory feedback and cause deviations from the models presented for the open-ear condition. Communication is a main concern for people wearing hearing protection devices (HPD). Although practical, radio communication is cumbersome, as it does not distinguish designated receivers. A smarter radio communication protocol must be developed to alleviate this problem. Thus, it is necessary to model speech production in noise while wearing HPDs. Such a model opens the door to radio communication systems that distinguish receivers and offer more efficient communication between persons wearing HPDs. Design: This paper presents the results of a pilot study aimed to investigate the effects of occluding the ear on changes in voice level and fundamental frequency in noise and with varying talker-to-listener distance. Study sample: Twelve participants with a mean age of 28 participated in this study. Results: Compared to existing data, results show a trend similar to the open ear condition with the exception of the occluded quiet condition. Conclusions: This implies that a model can be developed to better understand speech production for the occluded ear.

Surgical and Technical Modalities for Hearing Restoration in Ear Malformations.

Malformations of the external and middle ear often go along with an aesthetic and functional handicap. Independent of additional aesthetic procedures, a successful functional hearing restoration leads to a tremendous gain in quality of life for affected patients. The introduction of implantable hearing systems (bone conduction and middle ear devices) offers new therapeutic options in this field. We focus on functional rehabilitation of patients with malformations, either by surgical reconstruction or the use of different implantable hearing devices, depending on the disease itself and the severity of malformation as well as hearing impairment. Patients with an open ear canal and minor malformations are good candidates for surgical hearing restoration of middle ear structures with passive titanium or autologous implants. In cases with complete fibrous or bony atresia of the ear canal, the most promising functional outcome and gain in quality of life can be expected with an active middle ear implant or a bone conduction device combined with a surgical aesthetic rehabilitation in a single or multi-step procedure. Although the surgical procedure for bone conduction devices is straightforward and safe, more sophisticated operations for active middle ear implants (e.g., Vibrant Soundbridge, MED-EL, Innsbruck, Austria) provide an improved speech discrimination in noise and the ability of sound localization compared with bone conduction devices where the stimulation reaches both cochleae.

Enlightened Understanding, Empowerment and Leadership - Three Ways to Enhance Multiculturalism: Comment on Will Kymlicka’s article: “Solidarity in Diverse Societies”

© ( y c In my comment on Will Kymlicka’s (2015), very stimulating essay, I would like to argue that his basic scheme is sound, but incomplete and that his proposal for the progressive forces falls short in several respects. To begin with, Will Kymlicka stresses, in my view correctly, that the welfare state is built on national solidarity. The idea of the ‘people’s home’ (folkshemmet) of the Swedish Social Democrats, to which he refers in his text, serves as a perfect illustration of this point. Even the ‘universalistic’ Nordic welfare state intends to be universalistic within the boundaries of the national political community only. The welfare state is, as Kymlicka underlines, generally tied to an image of social membership, not to universal humanitarianism. In this respect it is important to keep in mind, as Kymlicka also argues, that the national community is conceived in egalitarian terms: the two fundamental principles of the nation – popular sovereignty and equality of all members of the national community – are at the same time the two core principles of democracy (Greenfeld, 1992: 10). The idea of democracy was, in Greenfeld’s nice formulation, contained in the idea of the nation like the butterfly in the chrysalis. (Kymlicka, 2015). Accordingly, Kymlicka (2015), suggests that appeals to national solidarity constitute a resource for progressives. One might add that appeals to national solidarity fall on particularly open ears among the poor, who identify more with the nation than the rich, because they have less to be proud of in their immediate social group compared to the rich and because they are more similar to the average member of their nation (Shayo, 2009: 162). However, national solidarity is an ambiguous resource for progressives – not only, as Kymlicka argues, because of its tendency to exclude groups not perceived as belonging to the nation, but also for yet another reason: as Shayo (2009) shows, people with a strong national identity are less supportive of redistribution in general, and, at the macro-level, the most nationalistic countries are known for being those with the least redistributive welfare states (and vice versa). The Swedes may again serve as an illustrative example. They are comparatively (compared to the Anglo-Saxon settler states, in particular) little nationalistic – class identities were relatively strong compared to national identities in Sweden – and, accordingly, Sweden did

La imagen de Barbación en las "Res Gestae" de Amiano Marcelino1

Este artículo analiza uno de los personajes secundarios más relevantes de las Res Gestae (RG) de Amiano Marcelino, el magister peditum Barbación. El historiador presenta a Barbación como un ser infame: colaborador en la muerte de Galo, cobarde, arrogante y desleal con Juliano durante la campaña militar del 357, delator de falsedades ante Constancio, merecedor de una muerte indigna. Sin embargo, un estudio de conjunto de los pasajes de Res Gestae, tomando como apoyo metodológico las técnicas de argumentación aplicadas al retrato y el concepto de ‘argumentación implícita’ de Sabbah 1978 y los métodos de caracterización de personajes de Pauw 1977, corrige esta visión comúnmente aceptada y demuestra la parcialidad del historiador. Así mismo se pone de manifiesto que el personaje, como otros actantes secundarios en las RG, es una réplica del carácter de Constancio II.

Systematic Evaluation of the Relationship between Physical and Psychoacoustical Measurements of Hearing Protectors’ Attenuation

The most commonly used methods to measure hearing protectors attenuation can be divided into two categories: psychoacoustical (subjective) and physical (objective) methods. In order to better understand the relationship between these methods, this article presents various factors relating attenuation values obtained with these methods through a series of tests. Experiments on human subjects were carried out where the subjects were instrumented on both ears with miniature microphones outside and underneath the protector. The subjects were then asked to go through a series of hearing threshold measurements (psychoacoustical method) followed by microphone sound recordings using high-level diffuse field broadband noises (physical method). The proposed test protocol allowed obtaining various factors relating the test methods as well as attenuation values and ratings for different protection conditions (open ear, earmuffs, earplugs, and dual protection). Results are presented for three models of passive earmuffs, three models of earplugs and all their combinations as dual hearing protectors. The validity and the relative importance of various terms used to correct the physical attenuation values when comparing with psychoacoustical attenuation values are examined.

Acoustic Radiation Effects On Bone Conduction Threshold Measurement

AbstractAcoustic radiation is the sound energy escape from a bone vibrator that may be detected by air conduction mechanisms. The presence of acoustic radiation may result in an unreal bone conduction threshold, promoting an unreal air/bone gap in the high frequencies. Aimaim to analyze the acoustic radiation effect on the extension of air/bone gap at 2,000, 3,000 and 4,000 Hz. Materials and Methodour clinical and experimental study had a sample of 101 individuals, who matched inclusion criteria: to have an air/bone gap higher than 10 dB in the frequencies of 2,000; 3,000 and 4,000 Hz. All of them had their bone conduction threshold measured in two conditions: open ear canal and closed ear canal. Resultswe found that major differences between the two conditions evaluated occurred at the 4,000 Hz; data analysis showed significant difference in the extension for the air/bone gap; analysis of the number of cases of mixed hearing loss that changed to sensorineural was significant too. ConclusionThese studies concluded that when the MAE is occluded, the acoustic radiation phenomenon is controlled or avoided, enabling bone measures at the frequencies of 3,000 and 4,000Hz to be more accurate.

Noise exposure criteria for continuous noise: A case for reducing the 8 hour open ear exposure level

Personnel working in hazardous noise environments can be protected from noise induced hearing loss (NIHL) or other hearing related disabilities when their exposures are limited. Limiting noise exposures can be accomplished by engineering controls, administrative controls, and/or with the use of personal protective equipment. Damage risk criteria (DRC) were developed as a guide to limit personnel noise exposure in order to reduce the risk of NIHL. With the exception of the US Occupational Safety and Health Administration (OSHA), the US and many European countries accepted the DRC of 85 dB for 8 hours with a 3 dB per doubling exchange rate. Recent studies of the auditory response to noise dose, conducted at the Air Force Research Laboratory, found that A-weighted open ear exposures may be more hazardous (i.e., have a higher effective noise dose) than equal A-weighted level protected ear exposures. A potential conclusion of these studies is that hearing protectors are more effective than previously thought and reducing the open ear exposure criteria may be needed in order to minimize NIHL. This presentation will describe the pros and cons of reducing the 85 dBA DRC.

Bone-Conduction Hearing Aids

Bone-Conduction Hearing Aids

Effects of user training with electronically-modulated sound transmission hearing protectors and the open ear on horizontal localization ability

Objective: To determine if training with electronically-modulated hearing protection (EMHP) and the open ear results in auditory learning on a horizontal localization task. Design: Baseline localization testing was conducted in three listening conditions (open-ear, in-the-ear (ITE) EMHP, and over-the-ear (OTE) EMHP). Participants then wore either an ITE or OTE EMHP for 12, almost daily, one-hour training sessions. After training was complete, participants again underwent localization testing in all three listening conditions. A computer with a custom software and hardware interface presented localization sounds and collected participant responses. Study sample: Twelve participants were recruited from the student population at Virginia Tech. Audiometric requirements were 35 dBHL at 500, 1000, and 2000 Hz bilaterally, and 55 dBHL at 4000 Hz in at least one ear. Results: Pre-training localization performance with an ITE or OTE EMHP was worse than open-ear performance. After training with any given listening condition, including open-ear, performance in that listening condition improved, in part from a practice effect. However, post-training localization performance showed near equal performance between the open-ear and training EMHP. Auditory learning occurred for the training EMHP, but not for the non-training EMHP; that is, there was no significant training crossover effect between the ITE and the OTE devices. Conclusion: It is evident from this study that auditory learning (improved horizontal localization performance) occurred with the EMHP for which training was performed. However, performance improvements found with the training EMHP were not realized in the non-training EMHP. Furthermore, localization performance in the open-ear condition also benefitted from training on the task.

Cartilage conduction efficiently generates airborne sound in the ear canal.

By attaching a transducer to the aural cartilage, a relatively loud sound is audible even with a negligibly small fixation force. Previous study has identified several pathways for sound transmission by means of cartilage conduction. This investigation focused on the relative contribution of direct vibration of the aural cartilage to sound transmission in an open and in an occluded ear. Thresholds with and without an earplug were compared for three experimental conditions: the transducer being placed on the tragus, pretragus, and mastoid. Eight volunteers with normal hearing participated. The thresholds increased with distance of the transducer from the ear canal (tragus, pretragus, mastoid, in that order). The differences were statistically significant for all conditions except for the occluded ear at 4 kHz. With the earplug inserted, the thresholds for the tragus condition were most sensitive below 2 kHz, indicating a significant contribution of direct vibration of the aural cartilage. Direct vibration of the aural cartilage can enhance sound transmission. At low frequencies, cartilage conduction can deliver sound efficiently across a blockage in the ear canal. Stray airborne sound radiating from the transducer dominates cartilage conduction in the open ear at high frequencies.

Investigations on the physical factors influencing the ear canal occlusion effect caused by hearing aids

The occlusion effect refers to the altered perception of one's own voice when the ear canal is fully or partially obstructed. While the loudness increase due to body conducted sounds requires an assessment by psychoacoustic methods, the ratio of sound pressure inside the ear canal with occluded versus open ear canal for the same internally generated signal can be measured physically. This paper aims at better understanding the occlusion effect from a physical viewpoint and at determining the influence of different physical factors on the own voice perception, introducing a simple and intuitively understandable model for this phenomenon. Based on this model, the dependency of the occlusion effect on (i) the geometries of the individual ear canal and the vent, (ii) the insertion depth of the occluding object and (iii) vocalization are discussed.

Warfighter auditory situation awareness: Effects of augmented hearing protection/enhancement devices and TCAPS for military ground combat applications

Objective: To determine the effects of current hearing protection/enhancement devices (HPEDs) and tactical communications and protection systems (TCAPS) on auditory detection and identification of three critical military signals associated with potential “threats.” Design: Utilizing a 6 × 3 within-subject experimental design, 24 normal-hearing Virginia Tech Reserve Officer Training Corps (ROTC) cadets and active duty soldiers participated. Study sample: Five HPEDS and TCAP devices plus the open ear were tested. On each trial, either wearing a device or with open ears, subjects walked along a 3000-foot line of discrete distance markers toward the auditory threat, which was not visible but still within line-of-sight over flat terrain, stopping to listen when instructed. On approach to the threat, the linear distance at first detection was measured, followed by a continued approach until positive identification occurred. Then the subject reversed direction, retreating away from the threat until detection was lost. Results: ANOVA and post hoc tests were applied to determine statistically-significant differences among HPEDs, TCAPS, and the open ear on the objective detection and identification distance measures. Conclusions: The results have serious implications for selection of HPDs, HPEDs, and TCAPS for applications where preservation of auditory situational awareness via the fundamental detection and identification tasks are essential.

The Vision Is Set, Now Help Chronicle the Change

The Vision and Change effort to explore and implement needed changes in undergraduate biology education has been ongoing since 2006. It is now time to take stock of changes that have occurred at the faculty and single-course levels, and to consider how to accomplish the larger-scale changes needed at departmental and institutional levels. This article is a continuation of our efforts to keep people informed about the next steps for Vision and Change, in particular ongoing activities that need community (your) input, and what resources are available to support the Vision stated in 2009: “the biology we teach should reflect the biology we do” (American Association for the Advancement of Science [AAAS], 2011 ).

English

One hundred and forty four finger millet landraces collected from different regions of Ethiopia and some introduced from Kenya, Eritrea, Zambia and Zimbabwe were planted with six improved varieties in randomized complete block design at Gute and Arsi Negele (Ethiopia) during 2011 to assess genetic diversity for qualitative traits with respect to geographic location and agro-ecologies. Erect type growth habit, open ear type, light green ear (glumes) color, enclosed grains by glumes, lower spikelet density and purple black seed color was predominant phenotypic classes for the traits recorded in the present study. At 75% similarity level, finger millet populations from Ethiopia and Eritrea were grouped together; Kenyan, Zambian and Zimbabwe’s landraces formed the second cluster. Agro-ecological proximity was manifested in clustering of landraces on the basis of altitude classes. The resemblance probably implies either similarities in climatic and other edaphic factors of those geographical locations and agro ecologies; selection by farmers were practiced for the same traits, or same primary seed source. Shannon diversity analysis indicated that variation was highest at the lowest level (among landraces), followed by within regions, among regions or countries, within altitudes, with the least similarities appear among altitudes. This implied that intensive collection and in situ genetic conservation should be given due attention at lower class than the subsequent classes.   Key words: Eleusine coracana, finger millet, qualitative traits, Shannon diversity index. &nbsp

Factors Influencing Use of Hearing Protection by Trumpet Players

Although a great many brass players, and trumpet players in particular, successfully use high-fidelity earplugs, others report problems with their use. This article discusses factors that may discourage a brass player from using hearing protection: These include (a) a lack of acclimatization time; (b) a loss of "fortissimo blare" from the aural distortion generated by the 110- to 120-dB SPL produced at the open ear with fortissimo playing; (c) a shallow earmold seal, leading to a large occlusion effect; (d) a poor seal combined with incorrect acoustic mass in the sound channel; and (e) hearing loss where many harmonic overtones of even moderately loud playing may become inaudible with earplugs to a lifelong trumpet player with high-frequency hearing loss. The limitations imposed by each of these can usually be overcome with modifications of the hearing protection device (HPD) or with acclimatization time, allowing a lifetime of playing without the all-too-common "musicians' hearing loss" and/or tinnitus. A review of these factors helps to delineate some of the perceptual issues that musicians may have with any change in the spectrum of their instrument-whether it is related to attenuation or amplification.

A new team for Zoomorphology

In 2003, Thomas Bartolomaeus took over as chief editor of the journal Zoomorphology, and after 9 years of intensive input, he handed over the editorship of the journal to me. In the name of the entire Editorial Board, I thank him very much for leading the journal through this period. Being chief editor of a journal with such a tradition and with such a presence in the field of zoological morphology is a responsible and respectful task. Previous editors have done their best to establish the journal and respond to changes in the scientific community, for example by adjusting journal size, the title, the publishing language and so on. Zoomorphology has always put much emphasis on quality, both of text and of illustrations. This is essential for morphological publications and will continue to be an important topic. Under Thomas Bartolomaeus as an editor, the impact of the journal grew continuously. Zoomorphology is one of the two leading journals dedicated to this field of research. A rich choice of manuscripts is received, confirming a high quality of the published ones. I am looking back to a fascinating and impressive history of Zoomorphology, and I am honoured that trust is put into me to continue this important tradition. I am aware of the workload that an editorship of a journal like Zoomorphology creates. But I am curious and excited to take that task. This decision is made easy, because we have extended the team in the Editorial Board considerably. The term ‘‘dream team’’ is not far from being true. I am thankful for this team of experienced and enthusiastic colleagues. We cover a large area of expertise, in different animal taxa and in different techniques. Two past chief editors, Otto Kraus and Thomas Bartolomaeus, remain in the Editorial Board and share their experience with us. I am also very thankful to the publisher Springer in Heidelberg for a good and productive atmosphere in the publishing process. It is our aim to continue to publish high-quality papers in the area of morphology of multicellular animals. We offer our authors an open ear to their needs and try our best to keep the ‘‘throughput time’’ of manuscripts to a minimum. The coach of the recent German soccer champion said, looking back to the past season, that it was hard work, but no problem with a team like this. I am sure that I will be able to say something similar whenever looking back. But for now, I am looking forward to work with this new team for Zoomorphology!

Calibration aspects of binaural sound reproduction over insert earphones

Earphones are nowadays widely adopted for the reproduction of audio material in mobile multimedia and communication platforms, e.g. smartphones. Reproduction of high-quality spatial sound on such platforms can dramatically improve their applicability, and since two channels are always available in earphone-based reproduction, binaural reproduction can be applied directly. This paper is concerned with the theoretical and practical aspects relevant to the correct reproduction of binaural signals over insert earphones. To this purpose, a theoretical model originally developed to explain the acoustic transmission to and within the open ear canal is revisited [Mo/ller, Appl. Acoust., 36, 171-218 (1992)]. The model is modified accordingly in order to investigate the aspects of the transmission within the blocked ear canal that are significant to the calibration required to preserve the natural spatial cues that exist during normal hearing conditions, i.e. during an open-ear-canal situation. To evaluate the validity of the theoretical considerations outlined in this paper, measurements are conducted using an IEC711 occluded-ear simulator with a number of different types of insert earphones.