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Fulltext Experimental Analysis of Heat-Affected Zone (HAZ) in Laser Cutting of Sugar Palm Fiber Reinforced Unsaturated Polyester Composites

Masoud F, Sapuan SM, Ariffin MKAM, Nukman Y, Bayraktar E

Polymers (Basel), 2021 Feb 26;13(5).
PMID: 33652612 DOI: 10.3390/polym13050706

In this paper, the influence of processing input parameters on the heat-affected zone (HAZ) of three different material thicknesses of sugar palm fiber reinforced unsaturated polyester (SPF-UPE) composites cut with a CO2 laser was investigated. Laser power, traverse speed, and gas pressure were selected as the most influential input parameters on the HAZ to optimize the HAZ response with fixing all of the other input parameters. Taguchi's method was used to determine the levels of parameters that give the best response to the HAZ. The significance of input parameters was also determined by calculating the max-min variance of the average of the signal-to-noise ratio (S/N) ratio for each parameter. Analysis of variation (ANOVA) was used to determine each input parameter's contribution to the influence on HAZ depth. The general results show that the minimum levels of laser power and the highest levels of traverse speed and gas pressure gave the optimum response to the HAZ. Gas pressure had the most significant effect on the HAZ, with contribution decreases as the material thickness increased, followed by the traverse speed with contribution increases with the increase in material thickness. Laser power came third, with a minimal contribution to the effect on the HAZ, and it did not show a clear relationship with the change in material thickness. By applying the optimum parameters, the desired HAZ depth could be obtained at relatively low values.

Matched MeSH terms: Signal-To-Noise Ratio
Fulltext Noise exposure and hearing threshold profile among Zumba fitness regulars in Kuantan, Pahang, Malaysia

Ailin Razali, M. S. Othman, M. S. Rahman, N. F.I. Misaridin

IIUM Medical Journal Malaysia, 2020;19(2):67-73.
MyJurnal

Recreational noise exposure has become a major threat to the hearing system, and this
includes exposure to loud noise during group exercises such as Zumba Fitness, where loud music plays an
important role. This study aimed to assess the noise exposure and hearing threshold profile among Zumba
Fitness regulars in Kuantan, Malaysia. MATERIALS AND METHODS: Noise exposure and hearing profile
threshold were measured during Zumba Fitness sessions at a fitness studio in Kuantan, Malaysia from 24th
June 2014 to 12th August 2014. Noise exposure was measured using a noise dosimeter for one hour of Zumba
Fitness session with a total of nine sessions run by three different instructors while sound level pressure was
taken using a sound level meter during ambient, peak session and during cooling down. Thirty participants
answered questionnaires and underwent pure tone diagnostic audiometry test at a local clinic for hearing
threshold documentation. RESULTS: Some areas of the hall posed higher risks of causing noise-induced
hearing loss especially near the amplifiers. There were periods when the hearing level exceeded 115 dBA.
Early abnormal pattern could be observed in the hearing profiles of some of the participants to suggest
preliminary hearing problems. CONCLUSION: Zumba Fitness regulars have a risk of developing noise-induced
hearing loss and preventive steps should be properly addressed as NIHL is permanent and irreversible.

Matched MeSH terms: Noise
Fulltext Effectiveness of a Novel Index System in Preventing Early Hearing Loss among Furniture Industry Skills Training Students in Malaysia

Abdul Rahim KA, Jewaratnam J, Che Hassan CR, Hamid MD

Int J Environ Res Public Health, 2020 10 31;17(21).
PMID: 33142732 DOI: 10.3390/ijerph17218032

Occupational noise-induced hearing loss (ONIHL) is the most reported occupational disease in Malaysia. ONIHL is aggravated by the presence of early hearing loss amongst the youth prior to entering a real working environment. At technical and vocational education training (TVET) institutions, students may develop early ONIHL because training workshops are designed imitating the industrial working environment to produce skilled workers. The exceeding noise level at workshops and recent risk of non-occupational noise can cause early ONIHL among these students. Therefore, ONIHL must be addressed at the early stage of producing skilled workers. Octa hearing conservation index (OHCI) system is developed as a management and monitoring tool for hearing conservation program (HCP) in TVET institutions. Six existing and two new HCP components were used to build the index system. A pilot test on the effectiveness of the OHCI system was conducted in a selected TVET institution for six months. The post-HCP shows a 52.6% improvement compared to the pre-HCP. The implementation of HCP has shown improved awareness on the hazards of loud noise exposure and active use of hearing protection devices among participants. The OHCI system has a great potential as a tool to improve HCP implementation in TVET institutions, and eventually, industry.

Matched MeSH terms: Hearing Loss, Noise-Induced
Fulltext T1 and T2 Characteristics of Agarose Gel Phantom with different Gadolinium Oxide Concentration as Relaxation Modifier

Azhar, N. A. A., Tee, H. S., Yee, Y. Y., Awang, M. N. A., Abdul Manan, H., Yusoff, A. N.

Physics and Technology in Medicine, 2020;1(1):27-37.
MyJurnal

Many studies have been carried out to produce magnetic resonance imaging (MRI) phantoms as alternative to water phantom. Among the important properties of a phantom are the T1 and T2 relaxation times. The objective of this study is to investigate the T1 and T2 characteristics of the agarose gel phantoms with different relaxation modifier (gadolinium (III) oxide, Gd2O3) concentrations or [Gd2O3]. Six agarose gel phantoms were prepared with different [Gd2O3]. The T1 (fixed echo time (TE) and different repetition time (TR)) and T2 (fixed TR and different TE) measurements on all phantoms were conducted using the 3-T MRI system via spin echo (SE) and turbo spin echo (TSE) sequences, respectively. The signal-to-noise ratio (SNR) of all phantoms was calculated using Image-J software by implementing the region of interest (ROI) analysis. The SNR against TR and SNR against TE curves were fitted to the exponential equations for saturation, T1 and T2 determination. For every phantom, T1 curve demonstrated that the SNR increased exponentially with increasing TR, while T2 curves showed that the SNR decreased exponentially with increasing TE. Gd2O3 was found to successfully act as the relaxation modifier for the T1 but not the T2 curves. The T1 curve started to show saturated SNR (SNRo) and increasing SNRo for TR > 1000 ms and [Gd2O3] = 0.005 g/ml or higher. These behaviours are explained based on the dipole-dipole interaction that increases in phantoms with higher [Gd2O3], thus shortening the T1 relaxation. However, a systematic change in the T2 parameters with increasing [Gd2O3] was not observed. While Gd2O3 has significant effects on T1 relaxation parameters, the T2 relaxation parameters were minimally affected. With a shorter T1, the Gd2O3 added agarose gel can potentially be used as test phantom in fast imaging sequence, e.g. gradient echo pulse sequences.

Matched MeSH terms: Signal-To-Noise Ratio
Fulltext Effects of Reduced Gadolinium-Based Contrast Agents (GBCA) Volumes on MRI Image Quality: An Experimental Phantom Study

Ismail, N., Bashah, F. A. A., Zakaria, F.

Physics and Technology in Medicine, 2020;1(2):32-39.
MyJurnal

Many recent studies focused on the patient’s safety from the administration of gadolinium-based contrast agents (GBCAs), their concentration, the dose of administration and their effects on the image quality. The present study was aimed at evaluating the effects of reduced GBCAs (gadobutrol and gadoterate meglumine) volume on the image quality by using phantoms. Eight (8) human brain mimicking phantom made of nickel chloride (NiCl2) doped agarose gel were added with 0.00500 ml (100% volume), 0.00350 ml (75% volume), 0.00250 ml (50% volume) and 0.00125 ml (25% volume) of gadobutrol, 0.0100 ml (100% volume), 0.0075 ml (75% volume), 0.0050 ml (50% volume) and 0.0025 ml (25% volume) of gadoterate meglumine. The phantoms were scanned using a 1.5-T and a 3 T-MRI system. Signal-to-noise ratio (SNR) and the contrast agents enhancement were evaluated quantitatively and qualitatively. The 50% volume of gadobutrol and gadoterate meglumine at 3 T showed greater enhancement when compared with 50% and 100% volumes of gadobutrol and gadoterate meglumine at 1.5 T. It can be concluded that the volume of gadobutrol and gadoterate meglumine contrast agents can be reduced when using a higher field system

Matched MeSH terms: Signal-To-Noise Ratio
Speckle Noise Diffusion in Knee Articular Cartilage Ultrasound Images

Shoaib MA, Hossain MB, Hum YC, Chuah JH, Mohd Salim MI, Lai KW

Curr Med Imaging, 2020;16(6):739-751.
PMID: 32723246 DOI: 10.2174/1573405615666190903143330

BACKGROUND: Ultrasound (US) imaging can be a convenient and reliable substitute for magnetic resonance imaging in the investigation or screening of articular cartilage injury. However, US images suffer from two main impediments, i.e., low contrast ratio and presence of speckle noise.
AIMS: A variation of anisotropic diffusion is proposed that can reduce speckle noise without compromising the image quality of the edges and other important details.
METHODS: For this technique, four gradient thresholds were adopted instead of one. A new diffusivity function that preserves the edge of the resultant image is also proposed. To automatically terminate the iterative procedures, the Mean Absolute Error as its stopping criterion was implemented.
RESULTS: Numerical results obtained by simulations unanimously indicate that the proposed method outperforms conventional speckle reduction techniques. Nevertheless, this preliminary study has been conducted based on a small number of asymptomatic subjects.
CONCLUSION: Future work must investigate the feasibility of this method in a large cohort and its clinical validity through testing subjects with a symptomatic cartilage injury.

Matched MeSH terms: Signal-To-Noise Ratio
Fulltext Comparison of Low-Pass Filters for SPECT Imaging

Sayed IS, Ismail SS

Int J Biomed Imaging, 2020;2020:9239753.
PMID: 32308670 DOI: 10.1155/2020/9239753

In single photon emission computed tomography (SPECT) imaging, the choice of a suitable filter and its parameters for noise reduction purposes is a big challenge. Adverse effects on image quality arise if an improper filter is selected. Filtered back projection (FBP) is the most popular technique for image reconstruction in SPECT. With this technique, different types of reconstruction filters are used, such as the Butterworth and the Hamming. In this study, the effects on the quality of reconstructed images of the Butterworth filter were compared with the ones of the Hamming filter. A Philips ADAC forte gamma camera was used. A low-energy, high-resolution collimator was installed on the gamma camera. SPECT data were acquired by scanning a phantom with an insert composed of hot and cold regions. A Technetium-99m radioactive solution was homogenously mixed into the phantom. Furthermore, a symmetrical energy window (20%) centered at 140 keV was adjusted. Images were reconstructed by the FBP method. Various cutoff frequency values, namely, 0.35, 0.40, 0.45, and 0.50 cycles/cm, were selected for both filters, whereas for the Butterworth filter, the order was set at 7. Images of hot and cold regions were analyzed in terms of detectability, contrast, and signal-to-noise ratio (SNR). The findings of our study indicate that the Butterworth filter was able to expose more hot and cold regions in reconstructed images. In addition, higher contrast values were recorded, as compared to the Hamming filter. However, with the Butterworth filter, the decrease in SNR for both types of regions with the increase in cutoff frequency as compared to the Hamming filter was obtained. Overall, the Butterworth filter under investigation provided superior results than the Hamming filter. Effects of both filters on the quality of hot and cold region images varied with the change in cutoff frequency.

Matched MeSH terms: Signal-To-Noise Ratio
Fulltext Respiratory Motion Correction for Compressively Sampled Free Breathing Cardiac MRI Using Smoothl1-Norm Approximation

Bilal M, Shah JA, Qureshi IM, Kadir K

Int J Biomed Imaging, 2018;2018:7803067.
PMID: 29610569 DOI: 10.1155/2018/7803067

Transformed domain sparsity of Magnetic Resonance Imaging (MRI) has recently been used to reduce the acquisition time in conjunction with compressed sensing (CS) theory. Respiratory motion during MR scan results in strong blurring and ghosting artifacts in recovered MR images. To improve the quality of the recovered images, motion needs to be estimated and corrected. In this article, a two-step approach is proposed for the recovery of cardiac MR images in the presence of free breathing motion. In the first step, compressively sampled MR images are recovered by solving an optimization problem using gradient descent algorithm. TheL1-norm based regularizer, used in optimization problem, is approximated by a hyperbolic tangent function. In the second step, a block matching algorithm, known as Adaptive Rood Pattern Search (ARPS), is exploited to estimate and correct respiratory motion among the recovered images. The framework is tested for free breathing simulated andin vivo2D cardiac cine MRI data. Simulation results show improved structural similarity index (SSIM), peak signal-to-noise ratio (PSNR), and mean square error (MSE) with different acceleration factors for the proposed method. Experimental results also provide a comparison betweenk-tFOCUSS with MEMC and the proposed method.

Matched MeSH terms: Signal-To-Noise Ratio
Effect of noise and pesticide exposures among foggers in Selangor health district offices

Anita, AR., Noor Hassim, I.

Journal of Occupational Safety and Health, 2013;10(1):27-37.
MyJurnal

Fogging activity has become one of the important methods in tackling dengue outbreaks nowadays. Despite this, it is an occupation that has known hazards namely noise and pesticides which can affect the body organs. Based on this knowledge, a cross sectional study was conducted to determine the association between hearing impairment and serum cholinesterase level among foggers from five randomly selected Health District Offices in Selangor. A total of 200 workers comprising of 100 workers exposed to fogging activity and another 100 workers not exposed were randomly selected for this study. Data was obtained through self administered questionnaire, audiometric testing and serum cholinesterase level measurement. The overall prevalence of hearing impairment was 16% with foggers having significant higher prevalence (24%) compared to the non foggers (8%) (χ2=9.52, p=0.002). Measurement of serum cholinesterase showed that exposed workers had lower level compared to the non exposed group. Similarly, those who have hearing impairment had also lower serum cholinesterase level although it was not statistically different. Among all studied factors, age and duration of exposure to fogging activities were statistically different with hearing impairment (p

Matched MeSH terms: Noise
Fulltext Steady state visual evoked potential based BCI as control method for exoskeleton: a review

Norhafizan Ahmad, Raja Ariffin Raja Ghazilla, Muhammad Zikril Hakim Md Azizi

Malaysian Journal of Public Health Medicine, 2016;16(10):0-0.
MyJurnal

Brain Computer Interfaces (BCI) provide a vast possibility in enabling the brain to communicate directly with the computer, hence providing an alternative in controlling the machines without much effort. In fields of rehabilitations robotics, the applications of an exoskeletons in assisting a spinal cord injured (SCI) patients were growing. Steady state visually evoked potentials (SSVEP) based BCIs that utilizes the human visual reactions to the constant flickered stimulus quickly showed its potentials among the BCIs used in rehabilitations devices because of its advantages such as a higher immunity to noises and artefacts and also its robustness compared to other BCIs. Rehabilitation exoskeletons demands an approach that are more user friendly and the aspects of control scheme and mechanical parts that are more focused on assisting the patients in rehabilitations and providing a SCI patients an alternatives to explore their surroundings in a more intuitive ways. This paper highlights the current development trends in SSVEP based BCIs for rehabilitation exoskeletons and proposed the potential research scopes in the future that can improve the effectiveness, and its potential applications in rehabilitations.

Matched MeSH terms: Noise
Prevalence and associated factors of hearing impairment in aviation and manufacturing industry in Selangor

Ahmad Syazrin Muhamad

Journal of Occupational Safety and Health, 2011;8(2):35-44.
MyJurnal

Sound is one of the source of energy generated by vibration and is carried through the air in a form of pressure waves (Frederick, 1975). This pressure waves consist of pulsation or vibration of molecules of an elastic medium such as gas, liquid and even solid (Gerber, 1974). Due to its nature, sound can be irritating when it is excessive. The excessive amount of sound is called noise. Exposure to noise is common to the workers working at the industry. This can lead to hearing loss. Hearing loss is one of the most common health problems in the industrialized world. Working activities have been related to noise exposure due to increase use of machine that generates sounds. Many workers throughout the world experience hazardous noise exposure which is ≥ 85 decibels (dB) (Seter, 1998). Based on the previous study in the European region, most of the employers had difficulties to compensate workers diagnosed with hearing loss or hearing impairment cause by the working nature. (Rachiotis et al., 2006). According to European Survey on Working Conditions, about 7% of the workers considered that their work affects their health in the form of hearing disorders. Occupational risk factors for hearing loss include occupational noise, whole body vibration, work-related diseases and exposure to chemical. In this report, we specified in the noise exposure level of the workers.

Matched MeSH terms: Noise, Occupational
Fulltext The Acquisition, Analyses and Interpretation of fMRI Data: A Study on Functional Specialisation in Primary Auditory Cortices

Yusuf, A.N., Abdul Hamid, K., Mohamad, M., Abd hamid, A.I.

Medicine & Health, 2008;3(2):300-317.
MyJurnal

In this study, functional magnetic resonance imaging (fMRI) is used to investigate func-tional specialisation in human auditory cortices during listening. A silent fMRI paradigm was used to reduce the scanner sound artefacts on functional images. The subject was instructed to pay attention to the white noise stimulus binaurally given at an inten-sity level of 70 dB higher than the hearing level for normal people. Functional speciali-sation was studied using the Matlab-based Statistical Parametric Mapping (SPM5) software by means of fixed effects (FFX), random effects (RFX) and conjunction analyses. Individual analyses on all subjects indicated asymmetrical bilateral activation of the left and right hemispheres in Brodmann areas (BA) 22, 41 and 42, involving the primary and secondary auditory cortices. The percentage of signal change is larger in the BA22, 41 and 42 on the right as compared to the ones on the left (p>0.05). The average number of activated voxels in all the respective Brodmann areas are higher in the right hemisphere than in the left (p>0.05). FFX results showed that the point of maximum intensity was in the right BA41 whereby 599±1 activated voxels were ob-served in the right temporal lobe as compared to 485±1 in the left temporal lobe. The RFX results were consistent with that of FFX. The analysis of conjunction which fol-lowed, showed that the right BA41 and left BA22 as the common activated areas in all subjects. The results confirmed the specialisation of the right auditory cortices in pro-cessing non verbal stimuli.

Matched MeSH terms: Noise
Fulltext Environmental and occupational health impact of bauxite mining in Malaysia: a review

Lee, K.Y., Ho, L.Y., Tan, K.H., Tham, Y.Y., Ling, S.P., Qureshi, A.M., et al.

International Medical Journal Malaysia, 2017;16(2):137-150.
MyJurnal

In the perspective of recent bauxite mining in Malaysia, this review aims to identify the potential
environmental and health impacts on miners and surrounding communities. The environmental issues of
bauxite mining include, air, water and soil pollution due to bauxite dust; leaching of bauxite into water
sources resulting in reduced soil fertility as well as affecting agricultural food products and aquatic life.
Bauxite occupational exposure affects the health of miners, and has negative consequences on the health of
surrounding communities, such as increased respiratory symptoms, contamination of drinking water, other
potential health risks from ingestion of bauxite and heavy metals, including noise-induced hearing loss and
mental stress. This review discusses the processes of bauxite mining, its constituents and residual trace
elements, and their impact on the environment and health of exposed workers and communities. It also
explores the Malaysian legal requirements and standards of occupational exposure to bauxite.

Matched MeSH terms: Hearing Loss, Noise-Induced
Fulltext Region of Interest-Based Tamper Detection and Lossless Recovery Watermarking Scheme (ROI-DR) on Ultrasound Medical Images

Khor HL, Liew SC, Zain JM

J Digit Imaging, 2017 Jun;30(3):328-349.
PMID: 28050716 DOI: 10.1007/s10278-016-9930-9

Tampering on medical image will lead to wrong diagnosis and treatment, which is life-threatening; therefore, digital watermarking on medical image was introduced to protect medical image from tampering. Medical images are divided into region of interest (ROI) and region of non-interest (RONI). ROI is an area that has a significant impact on diagnosis, whereas RONI has less or no significance in diagnosis. This paper has proposed ROI-based tamper detection and recovery watermarking scheme (ROI-DR) that embeds ROI bit information into RONI least significant bits, which will be extracted later for authentication and recovery process. The experiment result has shown that the ROI-DR has achieved a good result in imperceptibility with peak signal-to-noise ratio (PSNR) values approximately 48 dB, it is robust against various kinds of tampering, and the tampered ROI was able to recover to its original form. Lastly, a comparative table with the previous research (TALLOR and TALLOR-RS watermarking schemes) has been derived, where these three watermarking schemes were tested under the same testing conditions and environment. The experiment result has shown that ROI-DR has achieved speed-up factors of 22.55 and 26.65 in relative to TALLOR and TALLOR-RS watermarking schemes, respectively.

Matched MeSH terms: Signal-To-Noise Ratio
Rigid/flexible polyurethane foam composite boards with addition of functional fillers: acoustics evaluations

Huang C, Lou C, Chuang Y, Lin J, Liu C, Yu Z

Sains Malaysiana, 2015;44:1757-1763.

Following rapid technological and industrial development, factories have been equipped with a great deal of machines.
The blend of industrial and residential areas in turn resulted in many environmental problems. In particular, machine
operation causes noise pollution that easily causes physiological and psychological discomfort for the human body thus
makes noise abatement a crucial and urgent issue. In this study, vermiculite functional fillers were added to polyurethane
(PU) foam mixtures in order to form sound absorbent PU foams. The correlations between the contents of functional fillers
and the sound absorption of flexible and rigid PU foams were then examined. The optimal PU foams were combined with
PET/carbon fiber matrices in order to yield the electromagnetic shielding effectiveness. The sound absorption, noise
reduction coefficient (NRC), electromagnetic shielding effectiveness and resilience rate of the composite boards were
finally evaluated. The test results indicated that rigid PU foam composites can reach a sound absorption coefficient of
0.8 while the flexible PU foam composites have higher mechanical properties.

Matched MeSH terms: Noise
Vehicular traffic noise prediction and propagation modelling using neural networks and geospatial information system

Ahmed AA, Pradhan B

Environ Monit Assess, 2019 Feb 26;191(3):190.
PMID: 30809746 DOI: 10.1007/s10661-019-7333-3

This study proposes a neural network (NN) model to predict and simulate the propagation of vehicular traffic noise in a dense residential area at the New Klang Valley Expressway (NKVE) in Shah Alam, Malaysia. The proposed model comprises of two main simulation steps: that is, the prediction of vehicular traffic noise using NN and the simulation of the propagation of traffic noise emission using a mathematical model. First, the NN model was developed with the following selected noise predictors: the number of motorbikes, the sum of vehicles, car ratio, heavy vehicle ratio (e.g. truck, lorry and bus), highway density and a light detection and ranging (LiDAR)-derived digital surface model (DSM). Subsequently, NN and its hyperparameters were optimised by a systematic optimisation procedure based on a grid search approach. The noise propagation model was then developed in a geographic information system (GIS) using five variables, namely road geometry, barriers, distance, interaction of air particles and weather parameters. The noise measurement was conducted continuously at 15-min intervals and the data were analysed by taking the minimum, maximum and average values recorded during the day. The measurement was performed four times a day (i.e. morning, afternoon, evening, and midnight) over two days of the week (i.e. Sunday and Monday). An optimal radial basis function NN was used with 17 hidden layers. The learning rate and momentum values were 0.05 and 0.9, respectively. Finally, the accuracy of the proposed method achieved 78.4% with less than 4.02 dB (A) error in noise prediction. Overall, the proposed models were found to be promising tools for traffic noise assessment in dense urban areas.

Matched MeSH terms: Noise, Transportation
Fulltext CT brain image advancement for ICH diagnosis

Shaik Amir NS, Kang LZ, Mukari SA, Sahathevan R, Chellappan K

Healthc Technol Lett, 2020 Feb;7(1):1-6.
PMID: 32190334 DOI: 10.1049/htl.2018.5003

A critical step in detection of primary intracerebral haemorrhage (ICH) is an accurate assessment of computed tomography (CT) brain images. The correct diagnosis relies on imaging modality and quality of acquired images. The authors present an enhancement algorithm which can improve the clarity of edges on CT images. About 40 samples of CT brain images with final diagnosis of primary ICH were obtained from the UKM Medical Centre in Digital Imaging and Communication in Medicine format. The images resized from 512 × 512 to 256 × 256 pixel resolution to reduce processing time. This Letter comprises of two main sections; the first is denoising using Wiener filter, non-local means and wavelet; the second section focuses on image enhancement using a modified unsharp masking (UM) algorithm to improve the visualisation of ICH. The combined approach of Wiener filter and modified UM algorithm outperforms other combinations with average values of mean square error, peak signal-to-noise ratio, variance and structural similarity index of 2.89, 31.72, 0.12 and 0.98, respectively. The reliability of proposed algorithm was evaluated by three blinded assessors which achieved a median score of 65%. This approach provides reliable validation for the proposed algorithm which has potential in improving image analysis.

Matched MeSH terms: Signal-To-Noise Ratio
So much for the city: Urban-rural song variation in a widespread Asiatic songbird

Hill SD, Aryal A, Pawley MDM, Ji W

Integr Zool, 2018 Mar;13(2):194-205.
PMID: 29078034 DOI: 10.1111/1749-4877.12284

Song plays a fundamental role in intraspecific communication in songbirds. The temporal and structural components of songs can vary in different habitats. These include urban habitats where anthropogenic sounds and alteration of habitat structure can significantly affect songbird vocal behavior. Urban-rural variations in song complexity, song length and syllable rate are not fully understood. In this study, using the oriental magpie-robin (Copsychus saularis) as a model, we investigated urban-rural variation in song complexity, song length, syllable rate, syllable length and inter-syllable interval. Comparing urban and rural songs from 7 countries across its natural Asiatic range (Bangladesh, India, Malaysia, Nepal, Singapore, Sri Lanka and Thailand), we found no significant differences in oriental magpie-robin song complexity. However, we found significant differences in temporal song variables between urban and rural sites. Longer songs and inter-syllable intervals in addition to slower syllable rates within urban sites contributed the most to this variance. This indicates that the urban environment may have driven production of longer and slower songs to maximize efficient transmission of important song information in urban habitats.

Matched MeSH terms: Noise
A critical review of hearing-aid single-microphone noise-reduction studies in adults and children

Chong FY, Jenstad LM

Disabil Rehabil Assist Technol, 2018 08;13(6):600-608.
PMID: 29072542 DOI: 10.1080/17483107.2017.1392619

PURPOSE: Single-microphone noise reduction (SMNR) is implemented in hearing aids to suppress background noise. The purpose of this article was to provide a critical review of peer-reviewed studies in adults and children with sensorineural hearing loss who were fitted with hearing aids incorporating SMNR.
METHOD: Articles published between 2000 and 2016 were searched in PUBMED and EBSCO databases.
RESULTS: Thirty-two articles were included in the final review. Most studies with adult participants showed that SMNR has no effect on speech intelligibility. Positive results were reported for acceptance of background noise, preference, and listening effort. Studies of school-aged children were consistent with the findings of adult studies. No study with infants or young children of under 5 years old was found. Recent studies on noise-reduction systems not yet available in wearable hearing aids have documented benefits of noise reduction on memory for speech processing for older adults.
CONCLUSIONS: This evidence supports the use of SMNR for adults and school-aged children when the aim is to improve listening comfort or reduce listening effort. Future research should test SMNR with infants and children who are younger than 5 years of age. Further development, testing, and clinical trials should be carried out on algorithms not yet available in wearable hearing aids. Testing higher cognitive level for speech processing and learning of novel sounds or words could show benefits of advanced signal processing features. These approaches should be expanded to other populations such as children and younger adults. Implications for rehabilitation The review provides a quick reference for students and clinicians regarding the efficacy and effectiveness of SMNR in wearable hearing aids. This information is useful during counseling session to build a realistic expectation among hearing aid users. Most studies in the adult population suggest that SMNR may provide some benefits to adult listeners in terms of listening comfort, acceptance of background noise, and release of cognitive load in a complex listening condition. However, it does not improve speech intelligibility. Studies that examined SMNR in the paediatric population suggest that SMNR may benefit older school-aged children, aged between 10 and 12 years old. The evidence supports the use of SMNR for adults and school-aged children when the aim is to improve listening comfort or reduce listening effort.

Matched MeSH terms: Noise
Fulltext Different bimodal neuromodulation settings reduce tinnitus symptoms in a large randomized trial

Conlon B, Hamilton C, Meade E, Leong SL, O Connor C, Langguth B, et al.

Sci Rep, 2022 Jun 30;12(1):10845.
PMID: 35773272 DOI: 10.1038/s41598-022-13875-x

More than 10% of the population suffers from tinnitus, which is a phantom auditory condition that is coded within the brain. A new neuromodulation approach to treat tinnitus has emerged that combines sound with electrical stimulation of somatosensory pathways, supported by multiple animal studies demonstrating that bimodal stimulation can elicit extensive neural plasticity within the auditory brain. More recently, in a large-scale clinical trial, bimodal neuromodulation combining sound and tongue stimulation drove significant reductions in tinnitus symptom severity during the first 6 weeks of treatment, followed by diminishing improvements during the second 6 weeks of treatment. The primary objective of the large-scale randomized and double-blinded study presented in this paper was to determine if background wideband noise as used in the previous clinical trial was necessary for bimodal treatment efficacy. An additional objective was to determine if adjusting the parameter settings after 6 weeks of treatment could overcome treatment habituation effects observed in the previous study. The primary endpoint at 6-weeks involved within-arm and between-arm comparisons for two treatment arms with different bimodal neuromodulation settings based on two widely used and validated outcome instruments, Tinnitus Handicap Inventory and Tinnitus Functional Index. Both treatment arms exhibited a statistically significant reduction in tinnitus symptoms during the first 6-weeks, which was further reduced significantly during the second 6-weeks by changing the parameter settings (Cohen's d effect size for full treatment period per arm and outcome measure ranged from - 0.7 to - 1.4). There were no significant differences between arms, in which tongue stimulation combined with only pure tones and without background wideband noise was sufficient to reduce tinnitus symptoms. These therapeutic effects were sustained up to 12 months after the treatment ended. The study included two additional exploratory arms, including one arm that presented only sound stimuli during the first 6 weeks of treatment and bimodal stimulation in the second 6 weeks of treatment. This arm revealed the criticality of combining tongue stimulation with sound for treatment efficacy. Overall, there were no treatment-related serious adverse events and a high compliance rate (83.8%) with 70.3% of participants indicating benefit. The discovery that adjusting stimulation parameters overcomes previously observed treatment habituation can be used to drive greater therapeutic effects and opens up new opportunities for optimizing stimuli and enhancing clinical outcomes for tinnitus patients with bimodal neuromodulation.

Matched MeSH terms: Noise

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