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Phantom sound

A Cafarelli, A Verbeni, A Poliziani, P Dario, A Menciassi, L Ricotti
: Materials with tailored acoustic properties are of great interest for both the development of tissue-mimicking phantoms for ultrasound tests and smart scaffolds for ultrasound mediated tissue engineering and regenerative medicine. In this study, we assessed the acoustic properties (speed of sound, acoustic impedance and attenuation coefficient) of three different materials (agarose, polyacrylamide and polydimethylsiloxane) at different concentrations or cross-linking levels and doped with different concentrations of barium titanate ceramic nanoparticles...
November 21, 2016: Acta Biomaterialia
Simon Henin, Dovid Fein, Eric Smouha, Lucas C Parra
BACKGROUND: Tinnitus correlates with elevated hearing thresholds and reduced cochlear compression. We hypothesized that reduced peripheral input leads to elevated neuronal gain resulting in the perception of a phantom sound. OBJECTIVE: The purpose of this pilot study was to test whether compensating for this peripheral deficit could reduce the tinnitus percept acutely using customized auditory stimulation. To further enhance the effects of auditory stimulation, this intervention was paired with high-definition transcranial direct current stimulation (HD-tDCS)...
2016: PloS One
Bisma Rizvi, Eric Da Silva, Luba Slatkovska, Angela M Cheung, Jahan Tavakkoli, Ana Pejović-Milić
PURPOSE: Bone quantity, as determined by the current gold standard, dual energy X-ray absorptiometry (DXA), through measured areal bone mineral density (aBMD), is subject to positive biases if bone strontium levels are high. This is of particular concern for populations administered strontium-based compounds for the treatment of osteoporosis. This study investigated the dependence of bone mineral density (BMD) determinations, and associated ultrasound-determined indices, obtained by quantitative ultrasound (QUS), on bone strontium content using a new generation of trabecular bone-mimicking phantoms...
November 2016: Medical Physics
Taynara Q Santos, André V Alvarenga, Débora P Oliveira, Rodrigo P B Costa-Felix
The speed of sound and attenuation are important properties for characterizing reference materials such as biological phantoms used in ultrasound applications. There are many publications on the manufacture of ultrasonic phantoms and the characterization of their properties. However, few studies have applied the principles of metrology, such as the expression of the uncertainty of measurement. The objective of this study is to validate a method for characterizing the speed of sound and the attenuation coefficient of tissue-mimicking material (TMM) based on the expression of the measurement of uncertainty...
October 15, 2016: Ultrasound in Medicine & Biology
Krysta J Trevis, Neil M McLachlan, Sarah J Wilson
The cognitive mechanisms underpinning chronic tinnitus (CT; phantom auditory perceptions) are underexplored but may reflect a failure to switch attention away from a tinnitus sound. Here, we investigated a range of components that influence the ability to switch attention, including cognitive control, inhibition, working memory and mood, on the presence and severity of CT. Our participants with tinnitus showed significant impairments in cognitive control and inhibition as well as lower levels of emotional well-being, compared to healthy-hearing participants...
2016: Frontiers in Psychology
Iman Ghodratitoostani, Yossi Zana, Alexandre C B Delbem, Siamak S Sani, Hamed Ekhtiari, Tanit G Sanchez
Subjective tinnitus is the conscious (attended) awareness perception of sound in the absence of an external source and can be classified as an auditory phantom perception. Earlier literature establishes three distinct states of conscious perception as unattended, attended, and attended awareness conscious perception. The current tinnitus development models depend on the role of external events congruently paired with the causal physical events that precipitate the phantom perception. We propose a novel Neurofunctional Tinnitus Model to indicate that the conscious (attended) awareness perception of phantom sound is essential in activating the cognitive-emotional value...
2016: Frontiers in Neuroscience
James J Finneran, Jason Mulsow, Brian Branstetter, Patrick Moore, Dorian S Houser
The potential for bottlenose dolphins to actively focus their biosonar transmissions was examined by measuring emitted clicks in four dolphins using horizontal, planar hydrophone arrays. Two hydrophone configurations were used: a rectangular array with hydrophones 0.2 to 2 m from the dolphins and a polar array with hydrophones 0.5 to 5 m from the dolphins. The biosonar task was a target change detection utilizing physical targets at ranges from 1.3 to 6.3 m with all subjects and "phantom" targets at simulated ranges from 2...
August 2016: Journal of the Acoustical Society of America
Donald M Caspary, Daniel A Llano
Tinnitus is defined as a phantom sound (ringing in the ears), and can significantly reduce the quality of life for those who suffer its effects. Ten to fifteen percent of the general adult population report symptoms of tinnitus with 1-2% reporting that tinnitus negatively impacts their quality of life. Noise exposure is the most common cause of tinnitus and the military environment presents many challenging high-noise situations. Military noise levels can be so intense that standard hearing protection is not adequate...
August 20, 2016: Hearing Research
Corinna Breusing, Arne Biastoch, Annika Drews, Anna Metaxas, Didier Jollivet, Robert C Vrijenhoek, Till Bayer, Frank Melzner, Lizbeth Sayavedra, Jillian M Petersen, Nicole Dubilier, Markus B Schilhabel, Philip Rosenstiel, Thorsten B H Reusch
Deep-sea hydrothermal vents are patchily distributed ecosystems inhabited by specialized animal populations that are textbook meta-populations. Many vent-associated species have free-swimming, dispersive larvae that can establish connections between remote populations. However, connectivity patterns among hydrothermal vents are still poorly understood because the deep sea is undersampled, the molecular tools used to date are of limited resolution, and larval dispersal is difficult to measure directly. A better knowledge of connectivity is urgently needed to develop sound environmental management plans for deep-sea mining...
September 12, 2016: Current Biology: CB
Christopher Montagne, Yi Zhou
Multisensory interactions involve coordination and sometimes competition between multiple senses. Vision usually dominates audition in spatial judgments when light and sound stimuli are presented from two different physical locations. This study investigated the influence of vision on the perceived location of a phantom sound source placed in a stereo sound field using a pair of loudspeakers emitting identical signals that were delayed or attenuated relative to each other. Results show that although a similar horizontal range (+/-45°) was reported for timing-modulated and level-modulated signals, listeners' localization performance showed greater variability for the timing signals...
July 2016: Journal of the Acoustical Society of America
Sara L Johnson, Christopher Dillon, Henrik Odéen, Dennis Parker, Douglas Christensen, Allison Payne
MR-guided high-intensity focussed ultrasound (MRgHIFU) non-invasive ablative surgeries have advanced into clinical trials for treating many pathologies and cancers. A remaining challenge of these surgeries is accurately planning and monitoring tissue heating in the face of patient-specific and dynamic acoustic properties of tissues. Currently, non-invasive measurements of acoustic properties have not been implemented in MRgHIFU treatment planning and monitoring procedures. This methods-driven study presents a technique using MR temperature imaging (MRTI) during low-temperature HIFU sonications to non-invasively estimate sample-specific acoustic absorption and speed of sound values in tissue-mimicking phantoms...
November 2016: International Journal of Hyperthermia
Richard Holy, Pavol Prazenica, Eva Stolarikova, Petr Dosel, Petra Fundova, Daniel Kovar, Jaromir Astl
Tinnitus is a phantom perception of sound in the absence of overt acoustic stimulation. The focus of our attention is a combined therapy of tinnitus. In this prospective study (2013-2014) we evaluated the data of normal-hearing patients with tinnitus treated with various treatment modalities. In Group 1 we evaluated the data of 84 patients/124 ears after six weeks of treatment with betahistine dihydrochloride (72 mg). In Group 2, we evaluated the data of 36 patients/ 55 ears unimproved from Group 1 who were then treated for six weeks with hyperbaric oxygen (HBO₂) therapy combined with gingko biloba extract (120 mg)...
May 2016: Undersea & Hyperbaric Medicine: Journal of the Undersea and Hyperbaric Medical Society, Inc
Krysta J Trevis, Neil M McLachlan, Sarah J Wilson
BACKGROUND: Maintenance of chronic tinnitus has been proposed to result from a vicious cycle of hypervigilance occurring when a phantom sound is associated with anxiety and limbic system overactivity. Depression, obsessive-compulsiveness, illness attitudes and coping strategies are known to impact tinnitus, but their relationship with the vicious cycle is unknown. As such, we aimed to identify psychological mediators of the vicious cycle. We also examined the relationship between coping strategies and any identified mediators to facilitate the translation of our research to treatment settings...
November 1, 2016: Journal of Affective Disorders
Nuria González-Salido, Luis Medina, Jorge Camacho
Automated ultrasound breast imaging would overcome most of the limitations that precludes conventional hand-held echography to be an effective screening method for breast cancer diagnosis. If a three dimensional (3D) ultrasound dataset is acquired without manual intervention of the technician, repeatability and patient follow-up could be improved. Furthermore, depending on the system configuration, resolution and contrast could be enhanced with regard to conventional echography, improving lesion detectability and evaluation...
September 2016: Ultrasonics
Julien G Ott, Alexandre Ba, Damien Racine, Anais Viry, François O Bochud, Francis R Verdun
PURPOSE: This study aims to assess CT image quality in a way that would meet specific requirements of clinical practice. Physics metrics like Fourier transform derived metrics were traditionally employed for that. However, assessment methods through a detection task have also developed quite extensively lately, and we chose here to rely on this modality for image quality assessment. Our goal was to develop a tool adapted for a fast and reliable CT image quality assessment in order to pave the way for new CT benchmarking techniques in a clinical context...
May 3, 2016: Zeitschrift Für Medizinische Physik
Isabela Miller de Carvalho, Lucas Lobianco De Matheo, José Francisco Silva Costa Júnior, Cecília de Melo Borba, Marco Antonio von Krüger, Antonio Fernando Catelli Infantosi, Wagner Coelho de Albuquerque Pereira
Ultrasonic phantoms are objects that mimic some features of biological tissues, allowing the study of their interactions with ultrasound (US). In the diagnostic-imaging field, breast phantoms are an important tool for testing performance and optimizing US systems, as well as for training medical professionals. This paper describes the design and manufacture of breast lesions by using polyvinyl chloride plastisol (PVCP) as the base material. Among the materials available for this study, PVCP was shown to be stable, durable, and easy to handle...
August 2016: Ultrasonics
Kenneth B Bader, Michael J Crowe, Jason L Raymond, Christy K Holland
Tissue-mimicking phantoms are employed for the assessment of shocked histotripsy pulses in vitro. These broadband shock waves are critical for tissue ablation and are influenced by the frequency-dependent attenuation of the medium. The density, sound speed and attenuation spectra (2-25 MHz) were measured for phantoms that mimic key histotripsy targets. The influence of non-linear propagation relative to the attenuation was described in terms of Gol'dberg number. An expression was derived to estimate the bandwidth of shocked histotripsy pulses for power law-dependent attenuation...
July 2016: Ultrasound in Medicine & Biology
Anusha Mohan, Dirk De Ridder, Sven Vanneste
Phantom sound perception is the perception of a sound in the absence of a corresponding external sound source. It is a common symptom for which no treatment exists. Gaining a better understanding of its pathophysiology by applying network science might help in identifying targets in the brain for neuromodulatory approaches to treat this elusive symptom. Brain networks are commonly organized as functional modules which have a densely connected core network coupled to a communally-organized peripheral network...
April 18, 2016: NeuroImage
Mohamad Issa, Silvia Bisconti, Ioulia Kovelman, Paul Kileny, Gregory J Basura
Tinnitus is the phantom perception of sound in the absence of an acoustic stimulus. To date, the purported neural correlates of tinnitus from animal models have not been adequately characterized with translational technology in the human brain. The aim of the present study was to measure changes in oxy-hemoglobin concentration from regions of interest (ROI; auditory cortex) and non-ROI (adjacent nonauditory cortices) during auditory stimulation and silence in participants with subjective tinnitus appreciated equally in both ears and in nontinnitus controls using functional near-infrared spectroscopy (fNIRS)...
2016: Neural Plasticity
Sven Vanneste, Margriet Faber, Berthold Langguth, Dirk De Ridder
Tinnitus is an auditory phantom percept with a tone, hissing or buzzing sound in the absence of an objective physical sound source. It has been shown that tinnitus can lead to emotional and cognitive impairment and people with tinnitus perform worse than a control group on different cognitive tasks. The hippocampus is known to play an important role in cognitive performance, and also in the pathophysiology of tinnitus. Hippocampal deficits have been described in animal models of tinnitus and in tinnitus patients a decrease in grey matter in the hippocampus has been demonstrated...
March 22, 2016: Brain Research
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