scholarly journals Processing of simple and complex acoustic signals in a tonotopically organized ear

2014 ◽  
Vol 281 (1796) ◽  
pp. 20141872 ◽  
Author(s):  
Jennifer Hummel ◽  
Konstantin Wolf ◽  
Manfred Kössl ◽  
Manuela Nowotny
Keyword(s):  
High Frequency ◽  
Pure Tone ◽  
Neuronal Response ◽  
Mechanical Vibration ◽  
Laser Doppler Vibrometer ◽  
Low Frequency ◽  
Sensory Cells ◽  
Complex Signals ◽  
Communication Signals ◽  
Hearing Organ

Processing of complex signals in the hearing organ remains poorly understood. This paper aims to contribute to this topic by presenting investigations on the mechanical and neuronal response of the hearing organ of the tropical bushcricket species Mecopoda elongata to simple pure tone signals as well as to the conspecific song as a complex acoustic signal. The high-frequency hearing organ of bushcrickets, the crista acustica (CA), is tonotopically tuned to frequencies between about 4 and 70 kHz. Laser Doppler vibrometer measurements revealed a strong and dominant low-frequency-induced motion of the CA when stimulated with either pure tone or complex stimuli. Consequently, the high-frequency distal area of the CA is more strongly deflected by low-frequency-induced waves than by high-frequency-induced waves. This low-frequency dominance will have strong effects on the processing of complex signals. Therefore, we additionally studied the neuronal response of the CA to native and frequency-manipulated chirps. Again, we found a dominant influence of low-frequency components within the conspecific song, indicating that the mechanical vibration pattern highly determines the neuronal response of the sensory cells. Thus, we conclude that the encoding of communication signals is modulated by ear mechanics.

Air Conduction Thresholds and Secretory Otitis Media: A Conventional and Extra-High Frequency Audiometric Comparison

1989 ◽  
Vol 98 (10) ◽  
pp. 767-771 ◽  
Author(s):  
Iain W. S. Mair ◽  
Oddbjørn Fjermedal ◽  
Einar Laukli
Keyword(s):  
Otitis Media ◽  
Middle Ear ◽  
High Frequency ◽  
Pure Tone ◽  
Low Frequency ◽  
Secretory Otitis Media ◽  
Middle Ear Fluid ◽  
Ventilation Tubes ◽  
Air Conduction

A comparison has been made of air conduction threshold changes up to 1 year after myringotomy, aspiration of middle ear fluid, and insertion of ventilation tubes in ten patients with bilateral and 12 with unilateral secretory otitis media (SOM). Pure tone air conduction thresholds have been analyzed in three frequency groups: Low frequency (LF; 0.25, 0.5, and 1 kHz), high frequency (HF; 2,4, and 8 kHz), and extra-high frequency (EHF; 10, 12, 14, and 16 kHz). In the LF and HF ranges, significant improvement came during the first 24 hours after intubation, while in the EHF range, threshold lowering occurred gradually over the following 2 months. Possible explanations for these findings are discussed.

scholarly journals Comparison of Pure-Tone Average Methods for Estimation of Hearing Loss Caused by Environmental Exposure to Lead and Cadmium: Does the Pure-Tone Average Method Which Uses Low-Frequency Ranges Underestimate the Actual Hearing Loss Caused by Environmental Lead and Cadmium Exposure?

2018 ◽  
Vol 23 (5) ◽  
pp. 259-269 ◽  
Author(s):  
Da-An Huh ◽  
Yun-Hee Choi ◽  
Myung Sun Ji ◽  
Kyong Whan Moon ◽  
Seok J. Yoon ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Environmental Exposure ◽  
High Frequency ◽  
Pure Tone ◽  
Low Frequency ◽  
Cadmium Exposure ◽  
Metal Exposure ◽  
Frequency Method ◽  
Pure Tone Average ◽  
Lead And Cadmium

Previous studies have reported that exposure to lead and cadmium can damage the inner ear receptor, which perceives high-frequency sounds. However, few studies have used the pure-tone average (PTA), including high-frequency ranges, for the estimation of hearing loss caused by lead and cadmium exposure. We estimated hearing loss using the PTA test, in low-frequency, speech frequency, and high-frequency ranges and compared the differences in the results using 3 PTA calculation methods. We analyzed the data of 2,387 participants, between the ages of 19 and 85 years, that were obtained from the Korea National Health and Nutrition Examination Survey (KNHANES) of 2010–2012. A dose-response relationship between hearing loss and heavy metal exposure was observed in the high-frequency method after adjustment for confounding factors. When using the high-frequency PTA, it was found that doubling of the levels of lead and cadmium in the blood was associated with a 1.88- (95% CI 1.11–3.17) and 1.89-fold (95% CI 1.02–3.50) increase in the OR for hearing loss. In the case of the low-frequency and speech frequency PTA, however, there were no significant relationships between hearing loss and the concentrations of lead and cadmium in the blood. The outcomes of the present study suggest that the estimation of hearing loss caused by environmental exposure to lead and cadmium is affected by the frequencies used in the PTA calculation.

Validity of Hearing Thresholds Obtained from the Rising Portion of the Audiogram in Sensorineural Hearing Loss

1984 ◽  
Vol 27 (2) ◽  
pp. 206-211 ◽  
Author(s):  
Larry E. Humes ◽  
Anne Marie Tharpe ◽  
Gene W. Bratt
Keyword(s):  
Hearing Loss ◽  
Sensorineural Hearing Loss ◽  
Recent Work ◽  
High Frequency ◽  
Pure Tone ◽  
Low Frequency ◽  
Sensorineural Hearing ◽  
Test Frequency ◽  
Hearing Thresholds

Two experiments were performed for this study. The purpose of both experiments was to examine the validity of pure-tone hearing thresholds obtained near the rising portion of a sensorineural hearing loss. Recent work by other investigators has suggested that thresholds obtained near the rising portion of the audiogram may not correspond to the severity of damage at the cochlear place associated with the test frequency. In the first experiment this issue was addressed in 11 subjects having low frequency sensorineural hearing loss, whereas 12 subjects (19 ears) having notch-shaped high-frequency sensorineural hearing losses were examined in the second experiment. The results indicated that thresholds obtained from the rising portion of the audiometric configuration were, in most instances, determined by sensitivity at the test frequency. An exception to this generalization involved low-frequency sensorineural hearing loss with a slope for the rising portion of the audiogram exceeding -25 dB/octave. In these cases the severity of the loss may be underestimated for test frequencies immediately adjacent to the rising portion of the audiogram.

scholarly journals Prospective Study of Dietary Patterns and Hearing Threshold Elevation

2019 ◽  
Vol 189 (3) ◽  
pp. 204-214
Author(s):  
Sharon G Curhan ◽  
Christopher Halpin ◽  
Molin Wang ◽  
Roland D Eavey ◽  
Gary C Curhan
Keyword(s):  
Hearing Loss ◽  
Prospective Study ◽  
Dietary Patterns ◽  
High Frequency ◽  
Pure Tone ◽  
Low Frequency ◽  
Threshold Elevation ◽  
Diet Adherence ◽  
Hearing Thresholds ◽  
Frequency Threshold

Abstract We conducted a prospective study of dietary patterns and longitudinal change in audiometric hearing thresholds among 3,135 women (mean age = 59 years) in the Nurses’ Health Study II (2012–2018). Diet adherence scores for the Dietary Approaches to Stop Hypertension (DASH) and Alternate Mediterranean (AMED) diets and the Alternate Healthy Eating Index 2010 (AHEI-2010) were calculated using validated food-frequency questionnaires. Baseline and 3-year follow-up hearing sensitivities were assessed by pure-tone audiometry at 19 US sites. We used multivariable-adjusted logistic regression models to examine independent associations between diet adherence scores and risk of ≥5 dB elevation in the pure-tone average (PTA) of low-frequency (LPTA0.5,1,2 kHz), mid-frequency (MPTA3,4 kHz), and high-frequency (HPTA6,8 kHz) hearing thresholds. Higher adherence scores were associated with lower risk of hearing loss. Compared with the lowest quintile of DASH score, the multivariable-adjusted odds ratios for mid-frequency and high-frequency threshold elevation in the highest quintile were 0.71 (95% confidence interval (CI): 0.55, 0.92; P for trend = 0.003) and 0.75 (95% CI: 0.59, 0.96; P for trend = 0.02); for AMED and AHEI scores, for mid-frequency threshold elevation, they were 0.77 (95% CI: 0.60, 0.99; P for trend = 0.02) and 0.72 (95% CI: 0.57, 0.92; P for trend = 0.002). Nonsignificant inverse associations were observed for high-frequency threshold elevation. There were no significant associations between adherence scores and low-frequency threshold elevation. Our findings indicate that eating a healthy diet might reduce the risk of acquired hearing loss.

A Study on the Fine Structure of the Lateral Line Organ of the Sea Eel

1973 ◽  
Vol 31 ◽  
pp. 648-649
Author(s):  
K. Hama
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Lateral Line ◽  
Low Frequency ◽  
Sensory Cells ◽  
Apical Surface ◽  
Voltage Electron ◽  
Sensory Epithelia ◽  
Low Frequency Vibration ◽  
Transmission Electron

The lateral line organs of the sea eel consist of canal and pit organs which are different in function. The former is a low frequency vibration detector whereas the latter functions as an ion receptor as well as a mechano receptor.The fine structure of the sensory epithelia of both organs were studied by means of ordinary transmission electron microscope, high voltage electron microscope and of surface scanning electron microscope.The sensory cells of the canal organ are polarized in front-caudal direction and those of the pit organ are polarized in dorso-ventral direction. The sensory epithelia of both organs have thinner surface coats compared to the surrounding ordinary epithelial cells, which have very thick fuzzy coatings on the apical surface.

Simulations of high-resolution images of amorphous silicon films

1986 ◽  
Vol 44 ◽  
pp. 544-545
Author(s):  
G. Y. Fan ◽  
J. M. Cowley
Keyword(s):  
Electron Microscope ◽  
High Frequency ◽  
Fourier Transformation ◽  
Amorphous Materials ◽  
Low Frequency ◽  
Chromatic Aberration ◽  
Structure Information ◽  
Frequency Components ◽  
High Resolution Images ◽  
Spatial Frequency Spectrum

It is well known that the structure information on the specimen is not always faithfully transferred through the electron microscope. Firstly, the spatial frequency spectrum is modulated by the transfer function (TF) at the focal plane. Secondly, the spectrum suffers high frequency cut-off by the aperture (or effectively damping terms such as chromatic aberration). While these do not have essential effect on imaging crystal periodicity as long as the low order Bragg spots are inside the aperture, although the contrast may be reversed, they may change the appearance of images of amorphous materials completely. Because the spectrum of amorphous materials is continuous, modulation of it emphasizes some components while weakening others. Especially the cut-off of high frequency components, which contribute to amorphous image just as strongly as low frequency components can have a fundamental effect. This can be illustrated through computer simulation. Imaging of a whitenoise object with an electron microscope without TF limitation gives Fig. 1a, which is obtained by Fourier transformation of a constant amplitude combined with random phases generated by computer.

SEM image sharpness analysis

1996 ◽  
Vol 54 ◽  
pp. 142-143
Author(s):  
M. T. Postek ◽  
A. E. Vladar
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Quantitative Information ◽  
Primary Electron ◽  
Image Sharpness ◽  
Critical Dimensions ◽  
Sem Image ◽  
Frequency Changes ◽  
Electron Microscopes ◽  
Scanning Electron

Fully automated or semi-automated scanning electron microscopes (SEM) are now commonly used in semiconductor production and other forms of manufacturing. The industry requires that an automated instrument must be routinely capable of 5 nm resolution (or better) at 1.0 kV accelerating voltage for the measurement of nominal 0.25-0.35 micrometer semiconductor critical dimensions. Testing and proving that the instrument is performing at this level on a day-by-day basis is an industry need and concern which has been the object of a study at NIST and the fundamentals and results are discussed in this paper.In scanning electron microscopy, two of the most important instrument parameters are the size and shape of the primary electron beam and any image taken in a scanning electron microscope is the result of the sample and electron probe interaction. The low frequency changes in the video signal, collected from the sample, contains information about the larger features and the high frequency changes carry information of finer details. The sharper the image, the larger the number of high frequency components making up that image. Fast Fourier Transform (FFT) analysis of an SEM image can be employed to provide qualitiative and ultimately quantitative information regarding the SEM image quality.

Real Ear Sound Pressure Levels Developed by Three Portable Stereo System Earphones

1992 ◽  
Vol 1 (4) ◽  
pp. 52-55 ◽  
Author(s):  
Gail L. MacLean ◽  
Andrew Stuart ◽  
Robert Stenstrom
Keyword(s):  
High Frequency ◽  
Sound Pressure ◽  
Low Frequency ◽  
Test System ◽  
Output Frequency ◽  
Frequency Effects ◽  
Adult Men ◽  
Frequency Responses ◽  
Significant Difference ◽  
Sound Pressure Levels

Differences in real ear sound pressure levels (SPLs) with three portable stereo system (PSS) earphones (supraaural [Sony Model MDR-44], semiaural [Sony Model MDR-A15L], and insert [Sony Model MDR-E225]) were investigated. Twelve adult men served as subjects. Frequency response, high frequency average (HFA) output, peak output, peak output frequency, and overall RMS output for each PSS earphone were obtained with a probe tube microphone system (Fonix 6500 Hearing Aid Test System). Results indicated a significant difference in mean RMS outputs with nonsignificant differences in mean HFA outputs, peak outputs, and peak output frequencies among PSS earphones. Differences in mean overall RMS outputs were attributed to differences in low-frequency effects that were observed among the frequency responses of the three PSS earphones. It is suggested that one cannot assume equivalent real ear SPLs, with equivalent inputs, among different styles of PSS earphones.

Evaluation of Special Hearing Aids for Deaf Children

1971 ◽  
Vol 36 (4) ◽  
pp. 527-537 ◽  
Author(s):  
Norman P. Erber
Keyword(s):  
Hearing Aids ◽  
High Frequency ◽  
Hearing Aid ◽  
Low Frequency ◽  
Acoustic Stimulation ◽  
Deaf Children ◽  
Frequency Range ◽  
Frequency Limit ◽  
Unpublished Studies ◽  
Published Research

Two types of special hearing aid have been developed recently to improve the reception of speech by profoundly deaf children. In a different way, each special system provides greater low-frequency acoustic stimulation to deaf ears than does a conventional hearing aid. One of the devices extends the low-frequency limit of amplification; the other shifts high-frequency energy to a lower frequency range. In general, previous evaluations of these special hearing aids have obtained inconsistent or inconclusive results. This paper reviews most of the published research on the use of special hearing aids by deaf children, summarizes several unpublished studies, and suggests a set of guidelines for future evaluations of special and conventional amplification systems.

Efeitos do Método Pilates sobre a variabilidade da frequência cardíaca, flexibilidade e variáveis antropométricas em indivíduos sedentários

2016 ◽  
Vol 17 (1) ◽  
pp. 66
Author(s):  
Maria Lina Silva Leite
Keyword(s):  
High Frequency ◽  
Low Frequency

O objetivo deste estudo foi avaliar os efeitos do Método Pilates sobre a variabilidade da frequência cardíaca, na flexibilidade e nas variáveis antropométricas em indivíduos sedentários. O presente estudo contou com 14 voluntárias do sexo feminino, na faixa etária entre 40 e 55 anos, que realizaram 20 sessões de exercícios do Método Pilates, duas vezes por semana, com duração de 45 minutos cada sessão, dividida em três fases: repouso, exercício e recuperação. As variáveis estudadas foram: os dados antropométricos, flexibilidade avaliada utilizando o teste de sentar-e-alcançar com o Banco de Wells, e intervalos R-R usando um cardiotacômetro. O processamento dos sinais da frequência cardíaca foi efetuado em ambiente MatLab 6.1®, utilizando a TWC. Os dados coletados foram submetidos ao teste de normalidade de Shapiro Wilk e foi utilizado o teste de Wilcoxon e Anova One Way (α = 0,05). Nos resultados, observou-se que não houve diferenças significativas entre os valores antropométricos e de frequência cardíaca, porém houve aumento da flexibilidade com o treinamento. Comparando a primeira e a vigésima sessão com relação aos parâmetros low frequency (LF), high frequency (HF), e relação LF/HF, não houve diferença na fase de repouso e foram constatadas diferenças significativas de LF (p = 0,04) e HF (p = 0,04) na fase de exercício e diferença significativa de LF/HF (p = 0,05) na fase de recuperação. Comparando os parâmetros nos períodos de repouso, exercícios e recuperação durante a primeira sessão e durante a vigésima sessão, não houve diferença significativa nos parâmetros LF, HF e LF/HF. Pode-se concluir que, em relação à flexibilidade, foi observada uma melhora significativa, enquanto a análise da frequência cardíaca caracterizou a intensidade do exercício de 50% da capacidade funcional das voluntárias. Em relação aos parâmetros LF, HF e LF/HF foram observados um aumento da variabilidade da frequência cardíaca, provavelmente produto da atividade do Método Pilates. A Transformada Wavelet (TWC) mostrou-se um Método adequado para as análises da variabilidade da frequência cardíaca.Palavras-chave: frequência cardíaca, Transformada Wavelet, Pilates.

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