Hemiazygous Coil Placement for High‐Defibrillation Thresholds in a Patient with a Right‐Sided Implantable Cardioverter Defibrillator

A 41‐year‐old man underwent implantation of a right‐sided implantable cardioverter defibrillator after removal of an infected left‐sided system. Defibrillation threshold (DFT) testing on the right‐sided system failed to convert ventricular fibrillation at maximum device output (35 J) compared with a DFT of less than 15 J on the previous left‐sided system. A single‐coil lead was selectively placed into the hemiazygous vein, which courses leftward of the spine in a posterior‐anterior projection, resulting in an improved shocking vector and reduction in DFTs to less than 25 J. (PACE 2012; 35:e10–e12)     

Relationships among objective measures and speech perception in adult users of the HiResolution Bionic Ear

Abstract

The purpose of this study was to describe speech recognition performance for subjects using electrically evoked stapedial reflex thresholds (eSRT) based on programs with the HiResolution Bionic Ear system. A secondary goal was to evaluate the relationship of the electrically evoked compound action potentials (eCAP) as measured with neural response imaging (NRI) relative to the subjects' most comfortable stimulation levels (M levels). M levels, eSRT and eCAP thresholds were measured in 19 postlinguistically deafened adults using either a CII or HiRes 90K cochlear implant. The results showed that eSRTs could be measured easily in a majority of subjects, whereas eCAPS were measured in all subjects. There were close agreements between eSRTs and M levels in the subjects' behaviorally based programs. In contrast, the correspondence between M levels and eCAP thresholds was not as strong. New programs were created with M levels based on the eSRTs for 11 subjects. Programs created using eSRTs as a guide for setting levels yielded better speech recognition than programs using conventional behavioural measures of M levels. These data indicate that individuals can obtain strong benefits from cochlear implants using programs with stimulation levels based on objective measures. Copyright © 2008 John Wiley & Sons, Ltd.     

Compensated active noise cancellation earphone for audiometric screening tests in noisy environments

Abstract

Objective: This study investigated hearing screening tests by using a custom-designed compensated hybrid active noise cancellation (ANC) earphone and compared it with TDH39 and Audiocups audiometric earphones under conditions of quiet, 45?dB HL masking narrowband, wideband speech-shaped, and white noise.

Design: The hearing screening tests were conducted to characterise the shifts of screening results under noisy conditions, and real-ear attenuations at thresholds were assessed to quantify real-ear noise reduction performance.

Study sample: Twenty-four normal-hearing adults, aged 20–25?years, participated in this study.

Results: The ANC earphone exhibited significantly lower/better mean screening results than those of the TDH39 earphone at 250 and 500?Hz and those of the Audiocups earphone at 250?Hz under conditions of narrowband, speech-shaped, and white noise. Compared with the TDH39 earphone at 250 and 500?Hz, applying a hybrid ANC earphone reduced the shifts in screening results by 14.2 and 12.3?dB, respectively, under the narrowband noise condition.

Conclusion: This study demonstrated that the compensated hybrid ANC earphone provided lower shifts of screening results than the TDH39 and Audiocups earphones and that it was capable of screening at 250 and 500?Hz from 20?dB HL under 45?dB HL masking narrowband and wideband noise.     

Eye Colour and Susceptibility to Noise-Induced Permanent Threshold Shift

257 3rd-year apprentices were given ear, nose and throat examination, electroacoustic impedance tests and audiometry. Their eye colour was also recorded. Average hearing levels of otologically normal left ears were poorer at 4 kHz (p <0.05) for apprentices with eye colours indicating no melanin pigmentation of the iris than for apprentices with melanin iris pigmentation.

257 apprentis de 3e année, après avoir été examinés au point de vue ORL, ont subi une épreuve d'impédancemétrie et d'audiometrie. La couleur de leurs yeux a été notée.

La moyenne des niveaux du seuil d'audition des oreilles gauches otologiquement normales était plus élévee à 4 kHz (p<0,05) chez les apprentis sans pigmentation mélanique de l'iris que chez ceux ayant une pigmentation mélanique de l'iris.     

Systematic information processing style and perseverative worry

This review examines the theoretical rationale for conceiving of systematic information processing as a proximal mechanism for perseverative worry. Systematic processing is characterised by detailed, analytical thought about issue-relevant information, and in this way, is similar to the persistent, detailed processing of information that typifies perseverative worry. We review the key features and determinants of systematic processing, and examine the application of systematic processing to perseverative worry. We argue that systematic processing is a mechanism involved in perseverative worry because (1) systematic processing is more likely to be deployed when individuals feel that they have not reached a satisfactory level of confidence in their judgement and this is similar to the worrier's striving to feel adequately prepared, to have considered every possible negative outcome/detect all potential danger, and to be sure that they will successfully cope with perceived future problems; (2) systematic processing and worry are influenced by similar psychological cognitive states and appraisals; and (3) the functional neuroanatomy underlying systematic processing is located in the same brain regions that are activated during worrying. This proposed mechanism is derived from core psychological processes and offers a number of clinical implications, including the identification of psychological states and appraisals that may benefit from therapeutic interventions for worry-based problems.     

Reference hearing threshold levels for chirp signals delivered by an ER-3A insert earphone

Abstract

Objective: To establish reference hearing threshold levels for chirps and frequency-specific chirps. Design: Hearing thresholds were determined monaurally for broad-band chirps and octave-band chirps using the Etymotic Research, ER-3A insert earphone. The chirps were presented using two repetition rates, 20 and 90 stimuli/s, and with alternating polarity in blocks of one second duration. The test procedure and test conditions were in accordance with the recommendations given in . The ascending method () was applied using a step size of 5 dB. The chirps were played back from a Tucker Davies Technologies System II, and a Matlab program controlled the test setup. The results are specified in dB peak-to-peak equivalent threshold sound pressure levels (dB peETSPL). Study sample: The test group consisted of 25 otologically-normal young adults (age 18–25 years). Results: The results are in good agreement with the results from another investigation of hearing thresholds using the same chirp stimuli, and the values for the octave-band chirps are in line with the standardized reference values for corresponding tone bursts (). Conclusions: The results of the present investigation are relevant for the international standard on short duration signals, .     

Diagnostic Significance of the Electrocochleogram in Clinical Audiometry

In order to understand fully the diagnostic significance of electorcochleography (E. Co. G.) in clinical audiology, the present study was designed to cover 3 problems concerning (1) objective threshold audiometry by E. Co. G., (2) objective bone-conduction audiometry by E. Co. G., and (3) objective differential audiometry of sensory-neural hearing loss by E. Co. G.

The compound action potential (AP) of the cochlear nerve was used as an indicator for this purpose. It was recorded simultaneously from both ears of the same subject with a promontory electrode or a meatal skin electrode by means of an average response computer.

Acoustic signals such as clicks or 3 different tone-pips with center frequencies of 2 000, 4 000, and 8 000 Hz, were given to the subject by both air-conduction and bone-conduction.

Five different electric indices were determined from the AP measurements as measures of neurophysiological activity of the cochlea, i. e., (1) the threshold of the AP, (2) the input-output function of N₁, (3) the increments of the N₁ amplitude, (4) the intensity-latency relation of N₁, and (5) the wave form of the AP. These results lead to the following conclusions

(1) The promontory-recorded AP thresholds were in an excellent agreement statistically not only with the subjective thresholds for the same stimuli but also with the clinical hearing thresholds shown on the audiogram.

(2) The promontory-recorded AP provided significantly more precise and reliable data on E. Co. G. as compared with the meatal skin surface-recorded AP. The difference between the AP thresholds and the subjective thresholds, on the average, was + 0.2 dB, subjective more sensitive, for the promontory recording, and + 17.8 dB, subjective more sensitive, for the meatal skin surface recording. But the choice of electrodes must be according to what is required of the E. Co. G.

(3) The bone-conduction AP measurements could be carried out with the promontory electrode. There was a relatively good agreement between the bone-conduction AP thresholds and the bone-conduction subjective thresholds, but the agreement was worse than that for the air-conduction AP measurements.

(4) An air-bone gap was determined objectively from the input-output and intensity-latency relations of the bone-conduction AP compared to those of the air-conduction AP. The promontory-recorded AP measurements by bone-conduction should be very helpful in estimating objectively the degree of an air-bone gap.

(5) There were some interesting correlations between the changes in the electric indices of the AP measurements and the patterns of subtractive loss. Some patterns of subtractive loss seemed to be specified by various combinations of the threshold elevation of the AP, the 'H curve' type of input-output relation, the reduction in the maximum amplitude of N₁, and the distortion of the AP wave form.

(6) A distinctive pattern of the distorted AP wave form appeared in Ménière's disease. The depression and recovery of the AP was closely correlated with the course of audiological and vestibular symptoms of this disease.

(7) On the basis of observations on the AP measurements for sensorineural hearing loss, 3 conceptual populations of sensory units are hypothesized, i.e., (a) the more sensitive population of sensory units capable of discharging well-synchronized impulses with lower thresholds, (b) the less sensitive population of sensory units capable of discharging well-synchronized impulses with higher thresholds, and (c) the more sensitive population of sensory units capable of discharging less well-synchronized or dispersed impulses with lower thresholds.

Finally, some serious problems confronting the routing clinical use of E. Co. G. are discussed, and the current status of E. Co. G. is described. It seems reasonable to speculate that E. Co. G., combined with electric response audiometry, will serve as the most practical method of objective differential audiometry as well as of objective threshold audiometry.     

Adaptive response to hydrogen peroxide in yeast: Induction,time course,and relationship to dose–response models

The assay for trp5 gene conversion and ilv1‐92 reversion in Saccharomyces cerevisiae strain D7 was used to characterize the induction of an adaptive response by hydrogen peroxide (H₂O₂). Effects of a small priming dose on the genotoxic effects of a larger challenge dose were measured in exponential cultures and in early stationary phase. An adaptive response, indicated by smaller convertant and revertant frequencies after the priming dose, occurred at lower priming and challenge doses in young, well‐aerated cultures. Closely spaced priming doses from 0.000975 to 2 mM, followed by a 1 mM challenge, showed that the induction of the adaptive response is biphasic. In exponential cultures it was maximal with a priming dose of 0.125–0.25 mM. Very small priming doses were insufficient to induce the adaptive response, whereas higher doses contributed to damage. A significant adaptive response was detected when the challenge dose was administered 10–20 min after the priming exposure. It was fully expressed within 45 min, and the yeast began to return to the nonadapted state after 4–6 hr. Because of the similarity of the biphasic induction to hormetic curves and the proposal that adaptive responses are a manifestation of hormesis, we evaluated whether the low doses of H₂O₂ that induce the adaptive response show a clear hormetic response without a subsequent challenge dose. Hormesis was not evident, but there was an apparent threshold for genotoxicity at or slightly below 0.125 mM. The results are discussed with respect to linear, threshold, and hormesis dose–response models. Environ. Mol. Mutagen. 54:384–396, 2013. © 2013 Wiley Periodicals, Inc.     

Modelling the risk of noise-induced hearing loss among military pilots

Noise is a significant risk factor in aviation, especially in military aviation. Even though our earlier studies have shown that the risk of noise-induced hearing loss (NIHL) among military pilots is small and the monitoring of their hearing is effective, we still need to develop methods of assessing the risk of NIHL more effectively at both the general and individual levels. In addition, many other risk factors are considered to contribute to the development of hearing impairment. The novel NoiseScan data management system enables assessment of the risk of developing hearing impairment on the basis of known risk factors. This study investigates the risk of hearing impairment among Finnish Air Force pilots using reasonably accurate noise exposure data and other risk factors for hearing impairment. This risk is also compared with that of industrial workers, whose risk followed the ISO 1999 prediction. Hearing among Finnish military pilots turned out to be better than predicted by the ISO 1999 model. The industrial workers had a larger number of risk factors than the pilots. Owing to the small number of risk factors, the hearing of pilots corresponds to approximately the 80th percentile, being 9-13 dB better than the 50th percentile obtained with the industrial population.