Headphones Research Articles

Hearing loss and congenital rubella in Atlantic Canada.

There were 41 children born between 1973-1976 in Atlantic Canada who were victims of a severe rubella epidemic. This paper investigates prevalent audiometric patterns, incidence of middle ear disease, evidence regarding progressivity of hearing loss and any relationship between presence of middle ear disease and progressivity. Both surgical and audiological records were utilized in a combined retrospective-prospective study. Results indicate a typically flat audiogram for our group, with possible errors in the analysis of high frequency data accounting for differences between our center and those audiograms reported by other centers. Most of our children have a type A (normal) tympanogram (72.9%), but three have a type As which may be indicative of possible middle ear malformations. Six children (11 ears) have demonstrated only type AD and/or type B tympanograms. These may represent ongoing disease, middle ear malformation, or both. A number of variables (i.e., poor reliability, maturational effects, sound field compared to ear phone results) have contributed to a general feeling that progressivity of the hearing loss of rubella children may be a common phenomenon. A careful examination of our data found progressivity clearly documented in three cases. There was no relationship between presence of middle ear pathology and progressivity.

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Orthodynamic headphone

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Headphone construction

Headphone construction

Klinische Sprachaudiometrie durch Registrierung von Erwartungs-Potentialen

The expectancy potential or CNV, found by Walter et al. 1964, was checked for clinical application. For good comparison mono-syllable words from standard speech audiometry were used: 50 different “living beings” and 50 “things” were delivered via ear phones at random order and a set of their DC electric responses averaged seperately (Fig. 1). A flash series following only “living beings” after about 2 s had to be finished by the patient pressing a key as fast as possible. A punishing noise was applied when the key had been pressed at the wrong time or not at all. This measure stabilizes the patient's attention, one of the important psychological factors influencing CNV-amplitudes. A ramp-shaped CNV develops only after successfull discrimination of a “living being” and is finished by the visually evoked response. Though varying extremely, amplitudes can be judged independent of sound intensity down to a steep break-off at a level where only about 50% are understood. This result was found in 20 cases of inner ear damage. Control of the threshold area of speech audiograms is one of the applications of expectancy potentials. Far above threshold subjective discrimination and CNV amplitude curves are not corresponding. A decrease in the speech audiogram was only found in few cases, may be due to lack of motivation at discomfort sound intensity. In cases of cerebral disturbances like suspected acoustic agnosia CNV could be a valuable diagnostical tool. But many of these patients are not able to cooperate properly. On the other hand, one CNV-measurement on a 57 year old patient with motoric aphasia proved his ability of word significance discrimination. Expectancy potentials, as the upmost stage of ERA, will probably be applicated only in a few problematic cases.

Cortical evozierte Potentiale mit Hilfe eines rotatorischen Stimulus ? erste Ergebnisse bei gesunden Probanden

A system for stimulation and averaging of vestibular cortical evoked responses was constructed with the aid of a microcomputer. White noise was given to the test persons by ear phones sitting blindfolded on a rotation chair. With 64 sweeps an angular velocity of 2.5, 5, 7.5 or 10 degrees/s2 was given to the chair each time for 1s. After l s the chair stopped and at this point the sampling of EEG (Cz-A1 or CZ-A2) was done for 500 ms.

Auditory hallucinations treated by radio headphones.

A young man with chronic auditory hallucinations was treated according to the principle that increasing external auditory stimulation decreases the likelihood of auditory hallucinations. Listening to a radio through stereo headphones in conditions of low auditory stimulation eliminated the patient's hallucinations.

Listening device for localizing underground water leakages

A listening device for pinpointing water leakages, which includes a manually operated rod having a handle at one end for manually positioning of the listening device. An acoustic pick-up apparatus is mounted on the other end of the rod, and it comprises a ceramic audio tone transducer which is operatively connected to an amplifier-receiver which has a level meter on which visual leak signals may be seen. The acoustic pick-up apparatus is also connected to a head phone set to allow hearing of the leaks. The transducer includes a brass diaphragm directly attached to a threaded stud for mounting in the rod.

Headphone construction

Headphone construction

Headphones for Library and Educational Use (Book Review)

Headphones for Library and Educational Use (Book Review)

Perspectives on the Development of Post-Concrete Poetry

Authors of concrete poetry have been proclaiming the death of their art form since the end of the sixties (see Stereo Headphones, 1970:1, 2 and 3), and if the disappearance of this term from the contemporary scene is any indication, then it certainly must be dead. This passing, lamented by some, applauded by others, is accompanied by a problem which might irritate literary historians in particular: the cannot clearly be identified. In fact, it was not even identifiable during its lifetime, having appeared in Proteus-like masks and disguises. Now that its death has been announced, one is still not quite sure in which of its masks this Proteus died and in which it may still live on. Since the seventies, in small literary and artistic journals, anthologies, private printings and other editions, an identifiable relative of the deceased has been appearing.' Great festivals of phonetic poetry and new music (e.g., in Amsterdam, Glasgow, Stockholm, Berlin) evidence that not only the visual, but also the acoustic domain of what is still called concrete poetry survives with full academic recognition. Concrete poetry as the actual production and presentation of works connected in one way or another to the concretist program is not dead (cf. Schmidt 1975b:393-433).2 It may be more precise to say that concrete poetry has exhausted its innovative potential (as the renunciation of concrete poetry by many of its former authors suggests). This potential for innovation was founded on such distinctive features of concrete poetry as:

Auditory evoked potentials in the West Indian manatee (Sirenia:Trichechus manatus)

Potentials evoked by clicks and tone pips were recorded by fine wires inserted extracranially in four West Indian manatees (Trichechus manatus) in air. Sounds were delivered via padded ear phones.

Sealed headphone

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Use of Stereo Headphones for Patient Relaxation During Cataract Surgery Under Local Anesthesia

SUMMARY The use of stereo headphones to provide relaxing background music to patients undergoing cataract surgery under local anesthesia is described. This technique helps to relieve patient anxiety, reduces the amount of sedative medication required, obscures disturbing operating room noise, and facilitates teaching as the surgeon's comments are not allowed to disturb the patient.

The cancellation method for an accurate determination of an air-bone gap.

For a reliable detection of the bone conduction threshold blocking of the contralateral ear can be necessary but then the noise will affect the threshold in the test ear. To resolve this problem the cancellation method is used. The equalization of air and bone conduction sound level in the inner ear is very accurate, the relation between the intensities has been proved to be linear and independent of noise at the contralateral ear. An application for calibration of the bone conduction vibrator to the head phone is discussed. The benefit of the method for measuring an air-bone gap in an accurate way in patients suffering bilaterally from a severe conductive hearing loss is shown.

Out-of-head localized sound reproduction system for headphone

In stereo sound reproduction circuitry for use with a stereo signal source and stereo headphones, the improvement of dip filter means disposed between the stereo signal source and the stereo headphones, the dip filter means having a dip in the transmission characteristic thereof, the dip being in substantially the same frequency position as a dip which occurs in the sound pressure frequency response characteristic at the ear canal entrance when a sound source is disposed in front of a listener.

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Clinical Application of Sustained Auditory Evoked Potentials

This chapter discusses clinical application of sustained auditory evoked potentials. Clinical applications of evoked potentials range from the investigation of the effects of psychoactive compounds in normals to the search for neurophysiologic alterations that might accompany psychopathology. The chapter presents the results of 3 separate clinical studies designed to investigate the central nervous system (CNS) alterations seen: (1) in normal aging, (2) in schizophrenia, and (3) after long-term excessive consumption of alcohol. In each study, a similar paradigm is employed, allowing comparison among the results of the 3 studies. In each study evoked potentials were obtained during the presentation of sustained auditory stimuli 500 msec in duration. The stimulus series consisted of 500 Hz tones delivered at 4 different intensities above sensation threshold. The inter-stimulus interval (ISI) is 1500 msec and the stimuli were presented in a pseudo-random sequence with intensity following every other with equal frequency. The subjects received the stimuli through stereo headphones while sitting in a sound-attenuating booth.

Waveform coding in the inferior colliculus of the cat: cross-correlation of single unit responses with pseudorandom Gaussian white noise

The linear filter characteristics (impulse response) of 96 afferent neurons have been determined by the process of cross-correlating neuron spike discharges with Gaussian white noise input. The results, representing the linear kernel of the Wiener—Volterra functional expansion for nonlinear systems, take the form of spike response-locked signal averages. Spike patterns of single units in three chronic awake cats were recorded during binaural stimulation with uncorrelated white noise presented through equalized insert ear phones. Penetrations of the inferior colliculus were confirmed histologically. Cross-correlation analysis of approximately 10 000 spikes was performed for each ear for each unit. Strong waveform periodicities in the contralateral linear kernels were found in a large majority of the cell population, while a smaller percentage also showed periodicities in the ipsilateral kernel, but of a different frequency. Linear kernels also provide quantitative information about unit latencies, phase locking, and “memory.” Good agreement is found between frequency coding revealed by noise stimulation and frequency response histograms which we obtained from conventional harmonic analysis.

Influence of radio and television sets on implanted cardiac pacemakers (author's transl)

Investigations done on implanted pacemakers with a low threshold against extraneous signals and in-vitro tests under suitable conditions both showed that pacemaker wearers may go near television and accessories such as ultrsound distant control or flexless infrared ear phones without any danger. Radio and television sets are fitted to an increasing degree with electronic sensor switches which initiate various functions after a slight touch. This satisfies present regulations of German Electrical Engineers concerning permitted contact currents. However, pacemaker patients can cause impulse defects by use of sensor switches provided the contact current is less than 25 muA. Sensor technique will in the future be introduced for everyday use on a large scale. Therefore, pacemaker patients should be alerted to the possibilities of an influence, and industry should be made to reduce contact currents in sensors to values below 20 muA.