Auditory Evoked Potentials and Audiological Foliow-Up of Subjects Developing Noise-Induced Permanent Threshold Shift

Three examinations, including cochlear microphonics (CM) to 99/s 1 -kHz tones and auditory brainstem evoked potentials (ABEP) to 10/s and 55/s clicks, as well as psychoacoustical tests, were performed on 31 normally hearing subjects, exposed to occupational noise for over a year. The results showed prolongation of the absolute latency of peaks I, III and V, without significant changes in interpeak latency differences (IPLD) or CM latency. The site affected by increasing stimulus rate, giving rise to increased IPLD, appears to be central rather than cochlear. The efficacy of increased stimulus rate in detecting noise-induced auditory changes was higher than that achieved applying the 10/s click rate.

Nous avons precédé à trois examens consecutifs sur 31 sujets audiométriquement normaux mais exposés au bruit depuis plus d'un an. Chaque examen comprend l'enregistrement du potentiel microphonique cochléaire (CM) et des reponses du tronc cerebral (ABEP) évoquées par des clics aux cadences de stimulation de 10/s et de 55/s. De měme, des tests psychoacoustiques ont été faits. Les résultats ont montré une prolongation des latences absolues des pics I, III et Vsans changement significatif dans les différences de latences inter-pics (IPLD) ou dans le CM. L'influence d'une augmentation de la cadence de stimulation paraiˇt d'origine centrale plutôt que cochléaire. On a observé que la cadence rapide était plus efficace pour détecter les changements auditifs causés par le bruit.     

Intra and intersubject variability in auditory steady-state response amplitude with high modulation rates to 1000 Hz amplitude modulated and tone pip stimuli

Abstract

Objective: This study set out to provide further information on how high modulation/stimulus rates affect the auditory steady-state response (ASSR) amplitude for a 1000-Hz tone, and how this effect varies between individuals. Both sinusoidal amplitude modulated tones and tone pip stimuli were investigated. Design: Modulation/stimulus rates were 70, 80, and 90 Hz and the peak to peak stimulus levels were matched for the two different types of stimuli, at 90.5 dBSPLppe. Study sample: The study was carried out on fourteen normally-hearing adults (9 males and 5 females) Results: Overall the ASSR amplitude to the two types of stimuli was similar. In general there was an increasing response amplitude between rates of 70 and 90 Hz; The relationship between the amplitude of the response and the modulation /stimulus rate varied considerably between subjects. Conclusions: Optimum stimulus rates based on group data may not give the best rate in a significant proportion of subjects. Currently tone pip ABR is the primary method used in assessing hearing in babies. Finding a way of avoiding suboptimal stimulus rates for ‘80-Hz’ ASSR in babies will improve the likelihood of ASSR being seen as an alternative.     

Prevalence of complementary and alternative medicine (CAM) use by menopausal women: A systematic review of surveys

Large proportions of women have turned to complementary and alternative medicine (CAM) for relief from their menopausal symptoms. This highlights the need for more rigorous research into CAM. This article is aimed at critically reviewing surveys that examine the prevalence of CAM use by menopausal women worldwide. Eleven databases were searched for peer-reviewed surveys published in any language between 01 January 2000 and 27 October 2012. The bibliographies of the retrieved articles and relevant book chapters were also hand searched. Twenty-six surveys were identified, and they included a total of 32,465 menopausal women. The majority of these surveys were of poor methodological quality. Based on 6 surveys, 32.9% of women stated they were current/regular CAM users. Based on 9 surveys, 50.5% of women reported that they used CAM specifically for their menopausal symptoms. The average 12-month prevalence of CAM use was 47.7% (range: 33.1–56.2). Fifty-five percent of women did not disclose their use of CAM to their healthcare professional. The majority of women sought information about CAM from the media. The most popular CAM modality was herbal medicine, followed by soy/phytoestrogens, evening primrose oil, relaxation and yoga. There are a large number of predominantly low-quality surveys monitoring the prevalence of CAM use among menopausal women worldwide. The available evidence suggests that the prevalence of CAM use is high.     

Reproducibility of Echocardiograph‐Derived Multilevel Left Ventricular Apical Twist Mechanics

Left ventricular (LV) twist mechanics are routinely assessed via echocardiography in clinical and research trials investigating the function of obliquely oriented myocardial fibers. However, echocardiograph‐derived measures of LV twist may be compromised by nonstandardized acquisition of the apical image. This study examined the reproducibility of echocardiograph‐derived parameters of apical twist mechanics at multiple levels of the apical myocardium. Two sets of 2D LV parasternal short‐axis images were obtained in 30 healthy subjects (24 men; 19–57 year) via echocardiography. Images were acquired immediately distal to the papillary muscles (apical image 1), immediately above the point of LV cavity obliteration at end systole (apical image 3), and midway between apical image 1 and apical image 3 (apical image 2). Repeat scans were performed within 1 hour, and twist mechanics (rotation and rotation rate) were calculated via frame‐by‐frame tracking of natural acoustic echocardiographic markers (speckle tracking). The magnitude of apical rotation increased progressively toward the apex (apical image 1: 4.2 ± 2.1°, apical image 2: 7.2 ± 3.9°, apical image 3: 11.8 ± 4.6°). apical images 1, 2, and 3 each had moderate to good correlations between repeat scans (ICC: 0.531–0.856). When apical images 1, 2, and 3 were averaged, rotation was 7.7 ± 2.7° and between‐scan correlation was excellent (ICC: 0.910). Similar results were observed for systolic and diastolic rotation rates. Averaging multiple standardized apical images, tending progressively toward the apex, generated the most reproducible rotation indices and may be optimal for the assessment of LV twist mechanics across therapeutic, interventional, and research studies; however, care should be taken given the influence of acquisition level on the magnitude of apical rotation.     

Original Papers · Travaux originaux: Factors Affecting the Prevalence of Tinnitus

The prevalence of tinnitus was studied in a large population of noise-exposed workers. It was found that 6.6% had tinnitus which was more than momentary. Results of two other studies were compared. Factors possibly relating to the prevalence of tinnitus were studied. The single most important factor found to be related to tinnitus is hearing level. The higher the hearing level, the faster the rate of increase in the prevalence of tinnitus. Other factors such as sex, age, laterality, smoking and shooting do not seem to have a significant, direct relationship with tinnitus, but they are related to the prevalence of tinnitus indirectly through the influence they have on hearing loss.

La prévalence des acouphènes a été étudiée dans une large population de travailleurs exposés aux bruits industriels. On a relevé que 6,6% des travailleurs avaient des acouphènes plus que passagers. Les résultats de deux autres recherches ont été comparés à celle-ci. Les facteurs associés à la prévalence des acouphènes ont été étudiés et seul le degré de surdité a paru lié. Une surdité importante augmente la probabilité d'acouphènes chez les travailleurs. D'autres facteurs comme le sexe, l'aˇge, la latéralité, le fait de fumer ou de tirer ne semblent pas avoir de rapport direct ou significatif avec les acouphènes mais peuvent ětre liés à ceux-ci indirectement à travers leur influence sur la surdité.     

Continuous and online analysis of heart rate variability

Spectral analysis of heart rate variability provides a probe to assess the function of the sympathetic and parasympathetic nervous systems. Time-frequency analysis of heart rate variability is useful for investigating autonomic nervous function in patients with syncope or non-sustained ventricular tachycardia, or in anaesthesia, etc. In this paper, we developed an algorithm for continuous and online analysis of heart rate variability. The algorithm was simulated and evaluated in MATLAB, and implemented on the digital signal processor. The electrocardiogram signals from MIT/BIH arrhythmia database and one patient with syncope demonstrate the capability of the proposed method in the continuous and online analysis of heart rate variability.     

一种生物气溶胶旋风式分离采集装置的设计与验证

目的:设计一种生物气溶胶旋风式分离采集装置,为小粒径生物气溶胶分离采集和分析提供有效手段。方法:对经典旋风式分离采集装置结构参数进行优化,借助Fluent软件对筒体直径等关键结构参数对粒径分离效果的影响进行模拟仿真,确定生物气溶胶旋风式分离采集装置的最优结构参数,之后采用高纯铝材料制作生物气溶胶旋风式分离采集装置。采用TSI9310尘埃粒子计数器和六级安德森采样器对设计的生物气溶胶旋风式分离采集装置的粒径分离效果进行实验验证。结果:设计的生物气溶胶旋风式分离采集装置筒体直径为18 mm,该装置对于粒径小于3.3μm的生物气溶胶粒子基本无阻留,对于粒径大于3.3μm的粒子,分离阻留效率随粒径的增加逐渐增大。结论:生物气溶胶旋风式分离采集装置可以有效分离小粒径生物气溶胶粒子、阻留大粒径生物气溶胶粒子,达到粒径分离效果。