Validation of the French version of HHIE-S (Hearing Handicap Inventory for the Elderly - Screening) questionnaire in French over-60 year-olds.

INTRODUCTION: The HHIE-S (Hearing Handicap Inventory for the Elderly - Screening) is widely used for hearing-loss disorder in the elderly. The main objective of the present study was to validate a French version. The secondary objective was to determinate a cut-off score as indication for hearing rehabilitation. METHODS: We translated the HHIE-S into French, respecting the cross-cultural adaptation process for medical questionnaires. An observational study assessed the translation (10 questions, scored from 0 to 40) used for screening purposes in a prospective cohort, aged ≥60 years, with comparison to pure tone, speech-in-silence and speech-in-noise audiometry. Subjects were considered hearing-impaired if the pure-tone average at 500, 1,000, 2,000 and 4,000 Hz was >20 dB HL in one or both ears. RESULTS: We tested 294 subjects (mean age =67±6 years). Hearing loss prevalence was 34.7 %. Cronbach's alpha (test reliability) was high (0.84). Taking HHIE-S score >8/40 as cut-off defining hearing loss, sensitivity was 80.4%, specificity 85.4 %, positive predictive value 74.5 % and negative predictive value 89.1 %. Seventy-three subjects (24.8 %) had theoretic indications for hearing aids, optimally detected by HHIE-S score >16/40 (88,4 %). CONCLUSION: Our study validated the French version of the HHIE-S. This tool could be useful in screening for age-induced hearing loss in the elderly French population.

Musical Ear Syndrome: Prevalence and characteristics in cochlear implant bearers.

INTRODUCTION: Musical Ear Syndrome (MES) is an uncommon phenomenon described as the perception of auditory musical sensations not corresponding to any external stimulus. It seems to be more frequent in case of profound hearing loss. Our objective was to evaluate prevalence, characteristics and risk factors in a population of cochlear implant patients. METHODS: A retrospective study was conducted in cochlear implant patients, who were adult (>18 years) in 2020 and underwent cochlear implantation between 1993 and 2019. We analyzed the presence and characteristics of MES. RESULTS: 118 of the 358 patients (33%) perceived or had perceived auditory musical sensations: 71 (19.8%) before, 100 (28%) after, and 53 (14.8%) both before and after implantation. The musical auditory sensations were usually short and well-tolerated, resembling instrumental music, and occurring several times a day. Thirteen patients (11%) considered them intolerable. Fatigue was a triggering factor in 40 patients (33.9%). Personal and medical characteristics, type of implantation, make of implant, etiology and tinnitus did not emerge as risk factors. On the other hand, MES+ patients were significatively younger (56±17.4 years versus 61.9±17.9 years; P=0.0009). Despite the phenomenon, patients were satisfied with implant functioning and subjective auditory performance was not affected. CONCLUSION: Prevalence of Musical Ear Syndrome was high in cochlear implant patients, and especially in younger subjects. It is essential to improve knowledge of this phenomenon.

Delayed blockade of the kinin B1 receptor reduces renal inflammation and fibrosis in obstructive nephropathy.

Renal fibrosis is the common histological feature of advanced glomerular and tubulointerstitial disease leading to end-stage renal disease (ESRD). However, specific antifibrotic therapies to slow down the evolution to ESRD are still absent. Because persistent inflammation is a key event in the development of fibrosis, we hypothesized that the proinflammatory kinin B1 receptor (B1R) could be such a new target. Here we show that, in the unilateral ureteral obstruction model of renal fibrosis, the B1R is overexpressed and that delayed treatment with an orally active nonpeptide B1R antagonist blocks macrophage infiltration, leading to a reversal of the level of renal fibrosis. In vivo bone marrow transplantation studies as well as in vitro studies on renal cells show that part of this antifibrotic mechanism of B1R blockade involves a direct effect on resident renal cells by inhibiting chemokine CCL2 and CCL7 expression. These findings suggest that blocking the B1R is a promising antifibrotic therapy.

Surface electromyography as a tool to assess the responses of car passengers to lateral accelerations: Part I. Extraction of relevant muscular activities from noisy recordings.

The aim of this paper is to develop a method to extract relevant activities from surface electromyography (SEMG) recordings under difficult experimental conditions with a poor signal to noise ratio. High amplitude artifacts, the QRS complex, low frequency noise and white noise significantly alter EMG characteristics. The CEM algorithm proved to be useful for segmentation of SEMG signals into high amplitude artifacts (HAA), phasic activity (PA) and background postural activity (BA) classes. This segmentation was performed on signal energy, with classes belonging to a chi(2) distribution. Ninety-five percent of HAA events and 96.25% of BA events were detected, and the remaining noise was then identified using AR modeling, a classification based upon the position of the coordinates of the pole of highest module. This method eliminated 91.5% of noise and misclassified only 3.3% of EMG events when applied to SEMG recorded on passengers subjected to lateral accelerations.

Surface electromyography as a tool to assess the responses of car passengers to lateral accelerations. Part II: Objective comparison of vehicles.

The purpose of this study was to objectively assess the response of car passengers to lateral accelerations. Surface EMG signals were collected bilaterally from the cervical erector spinae (CES), latissimus dorsi (LD), erector spinae (ES), external oblique (EO), and vastus lateralis (VL) muscles of 10 subjects. Lateral acceleration was also recorded. Three chassis-seat configurations AA, BA and BB were tested, with the first letter denoting the chassis and the second the seat. SEMG signals were often contaminated by noise, and were, therefore, denoised using the methods explained in part I. Reciprocal phasic activity was observed for all muscles except for the EO, and the reaction of passengers to lateral accelerations was interpreted as a bust torsion. The RMS of EMG segments was used as an indication of muscle activity. Muscle activation of VL and ES were significantly affected by the configuration tested (p<0.05), with greater activation levels observed for the chassis A than for the chassis B. Such a finding implies that greater roll requires greater muscle activity, thus resulting in less comfortable vehicles. Therefore, SEMG can be used to provide an objective measure of discomfort in passengers subjected to lateral accelerations in a car seat.

Platelet-derived chemokines in atherosclerosis.

In atherosclerosis, activated platelets have been recently recognised not only to participate in thrombotic events but also to play an essential role in the development of atherosclerotic lesions. Upon their activation, platelets release several pro-inflammatory mediators including chemokines. Chemokines are key molecules in inflammation as they are able to recruit leukocytes, modulate their activation/differentiation and control their proliferation/apoptosis. In this review we will discuss recent findings regarding the specific roles of chemokines released by platelets on leukocytes and their effects on atherosclerosis.

Validation of balance-quality assessment using a modified bathroom scale.

The balance quality tester (BQT), based on a standard electronic bathroom scale has been developed in order to assess balance quality. The BQT includes automatic detection of the person to be tested by means of an infrared detector and bluetooth communication capability for remote assessment when linked to a long-distance communication device such as a mobile phone. The BQT was compared to a standard force plate for validity and agreement. The two most widely reported parameters in balance literature, the area of the centre of pressure (COP) displacement and the velocity of the COP displacement, were compared for 12 subjects, each of whom was tested on ten occasions on each of the 2 days. No significant differences were observed between the BQT and the force plate for either of the two parameters. In addition a high level of agreement was observed between both devices. The BQT is a valid device for remote assessment of balance quality, and could provide a useful tool for long-term monitoring of people with balance problems, particularly during home monitoring.

Is body balance more perturbed by respiration in seating than in standing posture?

The perturbing influence of respiration on balance was studied in sitting and standing subjects. The pneumograms and displacements of the centre of pressure of 10 normal subjects were recorded during quiet breathing, deep breathing and apnoea. The usual stabilometric parameters were measured, and a power spectrum density and time-locked averaging were used. The sway path was longer in seated subjects than in standing ones, suggesting that instantaneous compensatory phenomena are less efficient. The respiratory component of the sway path was larger in seated (0.16) than in standing subjects (0.09). It is concluded that respiration is a significant input for postural control, and that sitting entails less instantaneous steadiness. The concept of respiratory synergy is discussed.

Surface electromyogram power spectrum in human quadriceps muscle during incremental exercise.

Spectral electromyographic (EMG) changes in human quadriceps muscles were studied to reinvestigate discrepant results concerning mean power frequency (MPF) changes during dynamic exercise. An incremental test consisting of a quasi-linear increase in mechanical power on a bicycle ergometer (for 20-100% of maximal aerobic power) was performed by forty subjects. During this test, surface EMGs from the quadriceps muscles showed that EMG total power (PEMG) increased with a curvilinear pattern for every subject, whereas MPF kinetics varied from one subject to another. PEMG changes had the same shape, which would lead to disappointing results in terms of discrimination between subjects. The ability of normalized MPF kinetics to define significant clusters of subjects was tested using a principal component analysis. This analysis led to the projection of all experiments onto a plane and revealed a relevant grouping of MPF profiles. Differences in MPF kinetics between clusters are interpreted in terms of various possibilities of balance between physiological events leading to an increase or a decrease in MPF.

Surface electromyogram during voluntary contraction: processing tools and relation to physiological events.

Surface electromyography (SEMG) has been used extensively in the last years in a variety of applications, including muscle function assessment, pathology identification, ergonomics, pattern analysis, or population characterization. Advanced processing methods, especially in the spectral domain, provide the research worker with more and more precise and user-friendly tools for signal characterization, analysis, and classification. The use of such sophisticated tools requires many assumptions on signal characteristics, and the wide variety of computing options related to each processing method makes it difficult to compare the results of different works when these options are omitted in the reports or improperly applied. This work first aims at taking stock of the various processing methods which have emerged in the last years around surface electromyography: signal acquisition, random feature extraction, time and spectral parameter determination, statistical tests application. The main methods are briefly explained and discussed, then variations between apparently equivalent methods are pointed out, necessary hypotheses are underlined, and the use of such methods in SEMG processing is shown with respect to the more recent works. A second section shows how authors deal with parameters extracted from SEMG in order to relate them to physiological modifications (force, fiber type, fiber environment).

Uterine EMG analysis: a dynamic approach for change detection and classification.

Toward the goal of detecting preterm birth by characterizing events in the uterine electromyogram (EMG), we propose a method of detection and classification of events in this signal. Uterine EMG is considered as a nonstationary signal and our approach consists of assuming piecewise stationarity and using a dynamic change detector with no a priori knowledge of the parameters of the hypotheses on the process state to be detected. The detection approach is based on the dynamic cumulative sum (DCS) of the local generalized likelihood ratios associated with a multiscale decomposition using wavelet transform. This combination of DCS and multiscale decomposition was shown to be very efficient for detection of both frequency and energy changes. An unsupervised classification based on the comparison between variance-covariance matrices computed from selected scales of the decomposition was implemented after detection. Finally a class labeling based on neural networks was developed. This algorithm of detection-classification-labeling gives satisfactory results on uterine EMG: in most cases more than 80% of the events are correctly detected and classified whatever the term of gestation.

A model of EMG generation.

Simulation models are unavoidable in experimental research when the point is to develop new processing algorithms to be applied on real signals in order to extract specific parameter values. Such algorithms have generally to be optimized by comparing true parameter values to those deduced from the algorithm. Only a simulation model can allow the user to access and control the actual process parameter values. This constraint is especially true when dealing with biomedical signals like surface electromyogram (SEMG). This work is an attempt to produce an efficient SEMG simulation model as a help for assessing algorithms related to SEMG features description. It takes into account the most important parameters which could influence these characteristics. This model includes all transformations from intracellular potential to surface recordings as well as a fast implementation of the extracellular potential computation. In addition, this model allows multiple graphically-programmable electrode-set configurations and SEMG simulation in both voluntary and elicited contractions.

A pseudoperiodic model for myoelectric signal during dynamic exercise.

A theoretical model of dynamic surface myoelectric signal (SMES) suitable for periodic exercise has been developed. It has been shown that the spectral content of SMES in the very low-frequency band can be related to burst patterns of SMES. Burst patterns were compared during cycling exercises at different pedaling rates. A simple spectral parameter, defined in the very low-frequency band, was related to movement efficiency.

Variability of some SEMG parameter estimates with electrode location.

Muscular action potential conduction velocity (CV) and mean power frequency (MPF) are commonly used parameters to describe the surface electromyographic signal (SEMG). The discrepancies concerning the behavior and interpretation of these main parameters in the literature have motivated this work. Our objective was to evaluate within- and between-individual reproducibility, sensitivity and variation of CV and MPF depending on the electrode location with respect to various contraction modalities. The results present evidence for significant influence of electrode location on CV and MPF, not only in their initial values but also in their changes during fatiguing efforts. This influence appears to be subject-dependent. This variability seems to be essentially due to the relative displacements of myotendinous and neuromuscular junctions with respect to the electrode set. Moreover, this study shows that MPF can be seen as force-dependent under certain conditions and that the CV-MPF relationship is strongly influenced by methodological factors. In conclusion, it seems irrelevant to derive reliable SEMG parameter estimates without considering electrode location. There is a strong need for proper standardization based on anatomical and methological aspects before attempting any individual characterization. Finally, we suggest a procedure for assessment of measurement quality.

Evolution in impedance at the electrode-skin interface of two types of surface EMG electrodes during long-term recordings.

The evolution in impedance at the electrode-skin interface of Beckman and Red Dot electrodes was assessed during long-term recordings. Impedance was measured between each pair of electrodes, arranged in a bipolar configuration on tibialis anterior (n=13). A waveform constructed of sinusoids of known frequencies, evenly distributed on a log scale from 1-16,384 Hz, was applied through the electrodes, and the result recorded by a DAQ system. SEMG signals were recorded at 1000 Hz during isometric dorsiflexion contractions of 30 s, performed every 15 min for 2 h. Impedance data were acquired at 65,536 Hz immediately before and after SEMG recordings. Large individual differences in impedance levels were observed at low frequencies. At high frequencies, impedance values depended only on the electrode type. Impedance decreased steadily with time for Beckman electrodes (p < 0.05), but did not decrease significantly for Red Dot electrodes. The magnitude of the reduction over time varied widely between individuals, and was related to the initial impedance values. The impedance-bandwidth product remained constant for each electrode type (95% confidence intervals 146.2-148.2 and 126.1-127.8 for Beckman and Red Dot electrodes respectively). When skin impedance is electrically modelled with a simple network containing a resistor and a capacitor, the capacitance varies with the properties of the electrode used, whereas resistance is dependent on the subject. Furthermore, the EMG spectrum is unaffected by impedance provided skin preparation is sufficient to reduce the impedance below 55 komega.

Motor unit conduction velocity distribution estimation: assessment of two short-term processing methods.

Muscle fibre conduction velocity (MFCV) can be used as an index of the structural and/or functional modifications that can occur during fatigue or pathological processes. Current evaluation of MFCV from surface electromyography (SEMG) classically produces an average value. However, a single mean value is not sufficient when modifications affect only a small part of the conduction velocity distribution. In such a case, an estimation of the whole motor unit conduction velocity distribution (MUCV) would be advantageous. The aim of this study was the evaluation of the quality of two short-term methods based on cross-correlation (CC) and peak-to-peak (PP) estimation. A comprehensive simulation program was used to generate signals with known MUCV distributions. The Dmax statistic of Kolmogorov-Smirnov was used as an error criterion to quantify the estimation error and to optimise the MUCV distribution computation algorithms. The minimum error was observed for an analysing window of 10ms for PP and 15ms for CC. Dmax was significantly lower for PP (0.195+/-0.054) than for CC (0.343+/-0.073). Various simulations showed the strong effect of the variance of the true distribution on the features of the estimated ones. Clinical data measured on the abductor pollicis brevis were studied. MUCV was estimated on a healthy subject (3.63+/-0.87ms(-1)), a patient suffering from a myopathy (2.73+/-0.51ms(-1)) and one suffering from a neuropathy (4.38+/-0.23ms(-1)). The results demonstrate the overall superiority of a peak-to-peak approach.

Duchenne muscular dystrophy quantification: a multivariate analysis of surface EMG.

The paper describes a method of quantifying Duchenne muscular dystrophy which is examiner independent and uses surface electromyographic signals (EMG). A standardised protocol is proposed. Spectral parameters are first computed from digitised EMG, then a polynomial model is deduced from the evolution of each parameter. A discriminant analysis between healthy and DMD subjects leads to the determination of a discriminant plane and a level of sickness index.

Automatic identification of motor unit action potential trains from electromyographic signals using fuzzy techniques.

A technique is proposed that allows automatic decomposition of electromyographic (EMG) signals into their constituent motor unit action potential trains (MUAPTs). A specific iterative algorithm with a classification method using fuzzy-logic techniques was developed. The proposed classification method takes into account imprecise information, such as waveform instability and irregular firing patterns, that is often encountered in EMG signals. Classification features were determined by the combining of time position and waveform information. Statistical analysis of inter-pulse intervals and spike amplitude provided an accurate estimation of features used in the classification step. Algorithm performance was evaluated using simulated EMG signals composed of up to six different discharging motor units corrupted with white noise. The algorithm was then applied to real signals recorded by a high spatial resolution surface EMG device based on a Laplacian spatial filter. On six groups of 20 simulated signals, the decomposition algorithm performed with a maximum and an average mean error rate of 2.13% and 1.37%, respectively. On real surface EMG signals recorded at different force levels (from 10% to 40% of the maximum voluntary contraction), the algorithm correctly identified 21 MUAPTs, compared with the 29 MUAPTs identified by an experienced neurophysiologist. The efficiency of the decomposition on surface EMG signals makes this method very attractive for non-invasive investigation of physiological muscle properties. However, it can also be used to decompose intramuscularly recorded EMG signals.

MicroPACS: a PC-based small PACS implementation.

To make picture archiving and communication systems (PACS) a practical reality for small-scale structures, it appears necessary to build a network that integrates and optimises production management, analysis and storage of images, and to include the ability to communicate with other similar remote structures. To solve the various technical problems related to small-scale PACS implementation, MicroPACS, a local area network, was developed around PC-like microcomputers. Every necessary function is assessed and implemented, including a centralised data-base, a distributed image bank, different storage levels and a specific task for image exchanges. An additional protocol was also developed for remote consultation through ISDN. Standardisation of image encapsulation and a point-to-point link between remote sites ensure easy transfers between heterogeneous local networks or bases and integrity of local databases.

Uterine EMG spectral analysis and relationship to mechanical activity in pregnant monkeys.

The objective is to analyse internal and external recordings of uterine EMG in order to reveal common features and to assess the relationship between electrical activity and intra-uterine pressure modification. Three monkeys participated in the study, one as a reference and the others for data. EMGs are recorded simultaneously, internally by unipolar wire electrodes and externally by bipolar Ag/AgCl electrodes. Intra-uterine pressure is recorded as a mechanical index. Except for delay measurements, parameters are derived from spectral analysis and relationships between recordings are assessed by studying the coherence. Spectral analysis exhibits two basic activities in the analysed frequency band, and frequency limits are defined as relevant parameters for electrical activity description. Parameter values do not depend on the internal electrode location. Internal and external EMGs present a similar spectral shape, despite differences in electrode configuration and tissue filtering. It is deduced that external uterine EMG is a good image of the genuine uterine electrical activity. To some extent, it can be related to an average cellular electrical activity.