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As the body centric communication technology develops in monitoring real-time healthcare, fitness, sports, and military, significant attention arises in regarding possible health risks. The aim of ...

Conventional integer-order lumped element models cannot fully describe the memory-dependent viscoelastic behaviour of bio-tissues. We propose a tunable and more predictive lumped element modelling ...

This paper examines the complex and evolving relationship between science and the military in the development of listening technologies by British, French and German combatants during the First World War to combat increasingly effective ballistics and artillery on the Western Front. Land-based combat changed from the visual to the aural with an increasing selection of audio-based surveillance technologies being made available, notably sound-ranging, in part to combat the physical limitations of the human ear in the battlefield space. The article concludes by analyzing how post-war physics responded to these developments in sound-based battlefield technologies.

Male Zebra Finches (Taeniopygia guttata) sing a unique, stereotyped song that they learn from a tutor during development. A set of interconnected areas of the brain work together so that the birds can perceive, learn and produce song. In this review, we introduce the major components of the song system and describe evidence for how each might contribute to these three aspects of song. In particular, we highlight studies that have measured patterns of gene expression in the song system. These experiments clarify the structural organisation, and reveal functional activities, of the neural system underlying vocal communication. The utility of gene expression studies has been greatly enhanced with the release of the Zebra Finch genome. Investigation of gene expression in the song system will therefore continue to be a powerful way to connect the workings of this neural circuit with the behaviour of song. Zebra Finches sing a soft song that sounds squeaky and cheerful to the human ear and, perhaps, more mechanical than musical. (Richard Zann, ‘The Zebra Finch’, 1996)

Nowadays the viability of ear-based biometric identification and the uniqueness of ears is beyond question, but reliable technical solutions as the basis for a successful commercial application hav...

Sonification is the process of translating any type of data into sound. In paleontology, it is possible to render various aspects of fossil shapes, such as cephalopod suture patterns or brachiopod commissure lines, as a series of musical tones that can be recognized easily by the human ear. Paleontological applications of sonification might enable auditory perception of morphologic patterns in fossils that may or may not be visually apparent. Some simple classroom demonstrations can help students understand the potential of using sound to identify different types of fossils with their eyes closed (i.e., using their ears alone).

The Antarctic fur seal (Arctocephalus gazella) and the Subantarctic fur seal (A. tropicalis) hybridize on a relatively small scale at Marion Island. To date the description of calls published for A. tropicalis and A. gazella are fragmented and not easily compared. We compare the vocal signalling of males and females of the two species of fur seals to aid understanding of the factors involved in hybridization. Five call types were compared: barking, guttural challenges and territorial calls emitted by adult males; the pup attraction call used by adult females and the response: female attraction call emitted by pups. The calls emitted by males of the two species have certain similarities but are separated by multivariate analyses. By contrast, the calls of females and pups of the two species are more similar and do not cluster separately. Since many of the differences in male calls are audible to the human ear, female seals can presumably also hear these differences and we suggest that interbreeding of the two fur seal taxa is not caused by similarity in male vocal communication. Following this preliminary study, further behavioural studies are required for a fuller understanding of hybridization in these animals.

The contributions to the generation of excitatory junction potentials (EJPs) during neurotransmission in a smooth muscle organ have been investigated. The effects of nerve stimulation intensity on ETPs with complex time courses have been explored in the guinea pig vas deferens. It is shown that complex EJPs are resolvable into intermediate rapid and slow components, produced by the activity of separately recruitable innervating axons. The effects of the putative gap junctional uncoupling agent heptanol on EJPs have also been studied. Heptanol abolished the EJP reversibly. However, brief stimulus-locked depolarizations continued to occur intermittently at the same latency as the EJP even while the EJP was completely suppressed. These depolarizations had properties very similar to those of SEJPs, and reflect the fundamental quantal depolarizations underlying the EJP. They are termed quantal EJPs (QEJPs). Our results show that there are two principal contributions to the generation of the EJP, namely (i) QEJPs produced by the activity of individual varicosities; (ii) the intermediate components produced by the recruitment of axons and simultaneous activation of several varicosities. These events sum together to generate the EJP of the vas deferens.

Temporomandibular joint vibration analysis (JVA) is the electronic recording of TMJ sounds, or, more accurately, vibrations occurring in the joint. Utilizing vibration transducers called accelerometers, a characteristic wave pattern is created for the various types of internal joint vibrations (conditions). Whereas the human ear cannot hear many of the frequencies that occur in the TMJ's, the accelerometers record all frequencies with equal efficiency. Once a vibration has been recorded, then it can be compared to other types of vibrations. This may make it possible to categorize the various types of internal conditions, and then, to monitor the joint status throughout treatment. Sample patients are shown with the initial and then progress joint vibration analyses. This electronic device may help answer the questions of whether orthodontic treatment helps, harms, or has any affect on the internal health of the TMJ. It may also be used to monitor different types of orthodontic treatment to help determine whether one type is more beneficial to the TMJ or not.

For 13 normal-hearing test persons, the acoustic impedance about 6 mm inside the ear canal entrance has been measured in the frequency range 90-20,000 Hz by using standing wave measuring tubes connected to the ear canal via small ear adaptor tubes. The results show good reproducibility but large individual differences.

Click-evoked otoacoustic emissions (CEOAE) were recorded in 28 subjects with mild to moderate flat or steeply sloping cochlear hearing loss. We used the same equipment and recording technique as previously employed in the testing of newborns. A rescaling and subtraction procedure was implemented in an attempt to eliminate the tail of the stimulus artifact. However, in some cases the method also seems to eliminate a true response. In ears with flat losses and with identified CEOAE, no one had a hearing loss exceeding 40 dB HL in the mid-frequency region (0.5, 1 and 2 kHz). Conversely, in ears with flat losses and without CEOAE, no one had a hearing loss less than 30 dB HL in this frequency region. In ears with sloping hearing losses the thresholds at 1 and 2 kHz were most important for the generation of the CEOAE and a significant correlation between the emission amplitude at 70aud (approximately dB p.e. SPL) and the threshold at 1 kHz was found.

Antagonist effects of suramin at the P2x-receptor in the rabbit ear artery were associated with agonist curve depression and a steep Schild plot. Kinetic analysis revealed a problem of slow equilibration and established conditions under which suramin fulfilled all criteria for simple competition.

Long-term studies of rabbit blood pressure require a reliable method for repeated blood pressure measurements. Ideally, this method would be simple, noninvasive, and accurate over the range of anticipated blood pressures. To facilitate our own studies of rabbit carotid artery graft patency, we have developed a technique for the indirect measurement of systolic blood pressure in the rabbit that utilizes a photoplethysmograph sensor placed distal to an inflatable air bladder positioned over the central ear artery. We have compared measurements obtained with this method to direct measurements of aortic pressure and found a linear correlation.

The effect of bleeding (20% of total blood volume) and of hypervolaemic haemodilution with dextran infusion (20% of total blood volume) on traumatic vasospasm was studied in the central ear arteries of 10 rabbits. The blood pressure dropped significantly after bleeding and the packed cell volume was significantly lower after dextran infusion. Neither treatment had any effect on the duration, intensity or severity of the vasospasm. The results suggest that moderate changes in blood volume do not influence traumatic vasospasm.

α,β-methyleneADP, the ectonucleotidase inhibitor, produced a potentiation and kinetic stabilization of ATP induced contractions of the rabbit ear artery. However, studies with stable and unstable agonists indicated that this effect was not due to inhibition of purine metabolism.

The P2x-receptor mediating contraction of the rabbit ear artery is characterised by the following agonist potency order: D-αβmethyleneATP < L-βγmethyleneATP < D-βγmethyleneATP ≥ 2-MeSATP < ATP.

The isolated rabbit ear artery contains both dilation-mediating P2Y-receptors and constriction-mediating P2X-receptors. Suramin antagonizes the effects of ATP at either receptor.

Using signal averaging technique, stimulated acoustic emissions can be recorded from the human ear with a probe in the external ear canal. An acoustic click stimulus was used, produced by half a sinusoid of 2 kHz with the polarity corresponding to the rarefaction mode. A number of different techniques were developed in order to evaluate the latency and configuration of the emissions objectively. Recordings from a normal-hearing subject served as an example and a clear response could be traced down and below the psychoacoustic threshold. The threshold was elevated and the response pattern altered when a sensorineural hearing loss was induced by ingestion of acetylsalicylate. No response could be recorded from a deaf ear with an intact eardrum and a mobile ossicular chain.

Twenty young children, in whom evoked acoustic emissions were recorded at birth, were re-examined at the age of 4 years. None of the children showed evidence of sensorineural hearing impairment and it was possible to record a reproducible emission in all ears, which displayed normal otoscopy and tympanometry (n = 9). The new recordings were compared with those obtained at birth and the latency and the amplitude of the response both appeared unchanged. However, in some ears the frequency content of the dominant part of the emission was considerably lower at the age of four. The implication of this finding is briefly discussed in view of recent data on cochlear development, obtained from animal research.

The human ear is very resistant against noise-induced damage in the low frequency range. The aim of the present study was to investigate whether or not the stapedium reflex is of any importance for this resistance. Subjects with peripheral facial palsy (Bell's palsy) including unilateral stapedius muscle paralysis were exposed to several different levels of narrow band noise centered at 0.5 and 2.0 kHz. Temporary threshold shift (TTS) at 0.75 kHz was significantly higher in the affected than in the nonaffected ear after 0.5 kHz noise at and above 110 dB SPL. After the exposure with 2.0 kHz narrow band noise there was no difference in TTS at 3.0 kHz between the affected and nonaffected ear. It is concluded that the attenuation provided by the stapedius reflex reduces TTS after low frequency noise exposure. An implication is that the stapedius reflex also may have the function of protecting the ear from hearing damage caused by low frequency noise exposure.

Many techniques have been proposed for reconstruction of the posterior canal wall and/or obliteration of the mastoid bowl after radical mastoidectomy. The variety of materials that have been used, biological as well as foreign materials of different kinds, indicates that the ideal solution has yet to be found. Plaster of Paris, a biocompatible, degradable ceramic material prepared from CaSO4, may have an osteogenic property and become an alternative implant material for ear surgery. However, its possible ototoxicity has not been studied previously. Plaster was implanted in the tympanic cavity of guinea pigs. On investigation in the scanning electron microscope after 4.5 to 8 months, no toxic damage to the hair cell morphology was observed. Thus, from an ototoxic point of view, plaster of Paris would seem suitable for use as an implant material in ear surgery. Studies concerning the possible osteogenic property of plaster of Paris and its clinical application in human ear surgery are in progress.

Evoked acoustic emissions were recorded from both ears in a series of 100 consecutive normal newborns. We used the same stimulus, a 2-kHz click, and recording technique as previously described. Analysis of the data showed that evoked emissions could be identified in all ears, except one at 70 dBaud (i.e. approximately 30 dB nHL). No significant differences could be demonstrated between males and females or between left and right ears with regard to the latency of the emissions, the peak-to-peak amplitude, the main frequency component, or the waveform correlation between the two 70 dBaud recordings in each ear. However, a significant correlation between left and right ears was found for the amplitude and frequency of the emissions. Practical and methodological problems related to the recording were elucidated. The tail of the stimulus artifact sometimes interfered with the first part of the emissions even though the recordings were made in a time window delayed 5 ms relative to the stimulus onset. We tried to solve this artifact problem by different off-line techniques, but found no useful solution. We therefore continued to use only a cosine tapering of the first 2 ms of the time window. Three different ways of determining latencies were evaluated and we found that the 'envelope' technique was the most simple and reliable. Recording of evoked acoustic emissions is a quick and non-invasive method and provided that the presence of the emissions is related to normal cochlear function, it can be used as a screening test in newborns.(ABSTRACT TRUNCATED AT 250 WORDS)

Stimulated acoustic emissions were recorded in a consecutive series of 20 full-term and otherwise normal neonates with the equipment and method previously used in adults. One ear randomly chosen was tested in each baby, and otoscopy and tympanometry were normal in all ears. A 2 kHz click stimulus was presented with a repetition rate of 10/sec and the recordings were performed at three intensities, i.e. 70, 50 and -20 dBatt (dBatt approximately dB p.e. SPL). The 50 dB recording was repeated for check of reproducibility. A clear and reproducible response could be identified from all ears at 50 dBatt. However, as in the adults, the response pattern differed significantly from one ear to another, both regarding the number of 'echoes', their latencies, response amplitudes, and frequency content. The 'echo' group latencies and amplitudes were within the same range as in normal adults and the amplitude input-output curves exhibited a clear non-linearity. The relationship between latency and frequency was just as ambiguous as in the adults. Also, in the neonates, the cross correlation analysis proved to be an efficient method to indicate whether or not a true response was present. The results from this investigation are compared with those described in the literature from other audiological tests and it is concluded that the recording of the stimulated acoustic emissions could be applicable as a screening procedure in newborns.

The fetal development of both the vestibular and cochlear aqueducts will be followed in otological series beginning with tlie 4-month stage. Postnatal progress and mature structure will be traced from the newborn infant to the adult of 70 years (in dissections, serial sections and reconstructions prepared from the latter).These features will be emphasized: histology of the osseous wall and the contained connective tissue; source and course of blood vessels derived from labyrinthine periotic tissue internally and meningeal layers externally; normal range in adult anatomy. On these structural bases, the two channels will be compared, with special reference to their present and prospective role in otological surgery.

The functional influence of non-otosclerotic fixating lesions of the middle ear is investigated by reviewing two unusual cases and, experimentally, by creating such lesions in human temporal bones and observing the subsequent alteration in sound transmission. The effect of experimental fixation at each of five specific sites on the ossicular chain is discussed with respect to clinical observations.

(1957). Frequency Modulation and The Human Ear. Acta Oto-Laryngologica: Vol. 47, No. 5, pp. 421-430.

THERE HAVE been a number of investigaj tions in the past few years designed to investigate the effects of varying the speed of presentation of meaningful material upon listener compre hension. There have also been studies which have investigated the differences between the auditory, visual, or audiovisual modes of presentation. There have, however, been few studies which have investigated the interrelationships between the speed and the mode of presentation. Goldstein (2) presented connected meaningful material at several rates ranging from 100 to 322 words per minute (wpm) both auditorally and visually. He found an almost linear loss in comprehension as the speed was increased. He also found that for his subjects who ranged in age from 18 to 65 years the auditory presentation resulted in higher levels of comprehension than the visual presenta tion at the lower speeds but that as the speed was increased, comprehension by the visual mode of presentation gradually became equal to that of the auditory presentation. Goldstein varied the rate of presentation by training an expert speaker to deliver the ma terial at the various rates used in the study. This j material was recorded and minor adjustments in speed were made by varying the playback speed of the recordings. Although Goldstein claimed a high level of intelligibility of the auditory ma terial, there is a possibility that some loss of in telligibility resulted from the speaker's increased rate. Goldstein presented the visual material with motion picture equipment. The rate of presenta tion could be very accurately controlled so that it matched exactly the rate of the auditory pres entation. Goldstein's conclusion that there seemed to be no "optimum rate" at which the ma terial should be presented was based upon a rather straightforward interpretation of the linear rela tionship between the rate of presentation and comprehension. If some sort of efficiency index had been calculated, an optimum level might have been determined, but this cannot be computed from the data given. Fairbanks, Guttman, and Miron (4) did compute an efficiency index based upon the number of comprehension test items answered correctly per unit time. Their study, however, was concerned only with the auditory mode of presentation. The optimum rate for the auditory presentation was reported as about 280 wpm. This rate was twice as fast as the original recording and is considerably faster than every day speech. In a later study by Fairbanks, Gutt man and Miron (5) subjects were presented with the material twice instead of just once. The re sults clearly indicate that the double presenta tion at the rate of 282 wpm results in higher comprehension scores than a single presentation at the slower rate of 141 wpm (p

A new method for producing pressure variations in the pneumatic system of the human ear under control is described, i.e. the mastoid puncture technique. Several investigations are made; the volume displacement capacity of the normal ear drum, the role of the drum as a middle ear pressure regulator, vacuum effects on hearing and transudation, all these changes arc produced by intra-aural pressure variations under control. The accuracy of the previous methods for indirect determination of the middle tar pressure is analysed.

IntroductionIt has been known for a number of years that the response of the human ear is not limited to the range 20 Hz. to 20 KHz., as many books on Acoustics and Audiology suppose (1)(2). Both in this laboratory and elsewhere it has been shown that the limits of hearing extend at least from 2 Hz. to 200 KHz. (3)(4). It must be pointed out that these limits are not set by the hearing mechanism but rather by present day instrumentation. One of the major difficulties in producing a sensation in the ear at these extreme frequencies is in supplying the cochlea with sufficient energy. These difficulties have been amply demonstrated at the infrasonic end in the work on the threshold (4)(5). However, little consideration would appear to be currently given to the problem of stimulating the ear at ultrasonic frequencies; what little information there is in the literature suggests study of this region might be rewarding from both a clinical and from a functional view point.

During continuous tone stimulation a gradual decrease of the provoked impedance change in the normal human ear occurs. The reactivation from this reflex fatigability when superimposing a second tone is studied by means of an electroacoustic impedance bridge. The assumption that the reactivation implies a frequency difference between the two tones is not confirmed in our investigations.

An experimental set-up in which an automatic sound level recorder is employed has been used to obtain a graphic representation of the sound conduction in specimens of human temporal bones. The influence of application of various forces to the stapedius and tensor tympani muscles has been investigated with special respect to output to input ratio and the formation of harmonics.

A review is given of the intra-aural muscular reflexes elicited by air current stimulation of the external human ear. Air current stimulation is advantageous compared with acoustic stimulation, being independent of the hearing in the contralateral ear, provided the reflex path is intact. The diagnostic scope of impedance measurements is thus substantially increased.

Cochlear cell damage in the wake of broad-band noise stimulation has been found to be widespread throughout the length of the basilar membrane. This appears to be the case not only with experimental animals, but is also noted in post-mortem specimens of human ear tissues. The speculation is offered that pure-tone hearing tests do not fully depict the status of the cochlear end organ in that greater damage may exist than in apparent from the audiometric findings. It is suggested that signal-to-noise ratio test techniques provide informative supplementary evidence pertaining to the degree of cochlear destruction caused by noise exposure.Kokleaer celleskade efter stimulation med bredbandstoj er fundet spredt i hele basilarmem-branens langde – bade hos forsogsdyr og i sektionspraeparater af humane orer. Den teori fremsaettes, at det almindelige toneaudiogram ikke fuldt aftegner cochleas status, idet der kan eksistere storre skade end audiometrifundene lader formode. Formentlig vil en proveteknik med bestemmelse ...

SummaryThe human ear can detect cardiotocographically recorded transient accelerations of the fetal heart, and this may provide a simple practical method of antenatal screening.

(1860). LXXI. On the sensitiveness of the human ear to the pitch of musical notes. The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science: Vol. 20, Supplement, pp. 523-525.