An open access dataset for developing automated detectors of Antarctic baleen whale sounds and performance evaluation of two commonly used detectors.

Since 2001, hundreds of thousands of hours of underwater acoustic recordings have been made throughout the Southern Ocean south of 60° S. Detailed analysis of the occurrence of marine mammal sounds in these circumpolar recordings could provide novel insights into their ecology, but manual inspection of the entirety of all recordings would be prohibitively time consuming and expensive. Automated signal processing methods have now developed to the point that they can be applied to these data in a cost-effective manner. However training and evaluating the efficacy of these automated signal processing methods still requires a representative annotated library of sounds to identify the true presence and absence of different sound types. This work presents such a library of annotated recordings for the purpose of training and evaluating automated detectors of Antarctic blue and fin whale calls. Creation of the library has focused on the annotation of a representative sample of recordings to ensure that automated algorithms can be developed and tested across a broad range of instruments, locations, environmental conditions, and years. To demonstrate the utility of the library, we characterise the performance of two automated detection algorithms that have been commonly used to detect stereotyped calls of blue and fin whales. The availability of this library will facilitate development of improved detectors for the acoustic presence of Southern Ocean blue and fin whales. It can also be expanded upon to facilitate standardization of subsequent analysis of spatiotemporal trends in call-density of these circumpolar species.

The Current State and Future Possibilities of Mobile Phone "Voice Analyser" Applications, in Relation to Otorhinolaryngology.

BACKGROUND: A large proportion of the population suffers from voice disorders. The use of mobile phone technology in healthcare is increasing, and this includes applications that can analyze voice. OBJECTIVE: This study aimed to review the potential for voice analyzer applications to aid the management of voice disorders. METHODS: A literature search was conducted yielding eight studies which were further analyzed. RESULTS: Seven out of the eight studies concluded that smartphone assessments were comparable to current techniques. Nevertheless there remained some common issues with using applications such as; voice parameters used; voice pathology tested; smartphone software consistency and microphone specifications. CONCLUSIONS: It is clear that further developments are required before a mobile application can be used widely in voice analysis. However, promising results have been obtained thus far, and the benefits of mobile technology in this field, particularly in voice rehabilitation, warrant further research into its widespread implementation.

The Relationship Between Vertical Ground Reaction Force, Loading Rate, and Sound Characteristics During a Single-Leg Landing.

CONTEXT: Landing kinetic outcomes are associated with injury risk and may be persistently altered after anterior cruciate ligament injury or reconstruction. However, it is challenging to assess kinetics clinically. The relationship between sound characteristics and kinetics during a limited number of functional tasks has been supported as a potential clinical alternative. OBJECTIVE: To assess the relationship between kinetics and sound characteristics during a single-leg landing task. DESIGN: Observational Setting: Laboratory. PARTICIPANTS: There was total of 26 healthy participants (15 males/11 females, age = 24.8 [3.6] y, height = 176.0 [9.1] cm, mass = 74.9 [14.4] kg, Tegner Activity Scale = 6.1 [1.1]). INTERVENTION: Participants completed single-leg landings onto a force plate while audio characteristics were recorded. MAIN OUTCOME MEASURES: Peak vertical ground reaction force, linear loading rate, instantaneous loading rate, peak sound magnitude, sound frequency were measured. Means and SDs were calculated for each participant's individual limbs. Spearman rho correlations were used to assess the relationships between audio characteristics and kinetic outcomes. RESULTS: Peak sound magnitude was positively correlated with normalized peak vertical ground reaction force (ρ = .486, P = .001); linear loading rate (ρ = .491, P = .001); and instantaneous loading rate (ρ = .298, P = .03). Sound frequency was negatively correlated with instantaneous loading rate (ρ = -.444, P = .001). CONCLUSIONS: Peak sound magnitude may be more helpful in providing feedback about an individual's normalized vertical ground reaction force and linear loading rate, and sound frequency may be more helpful in providing feedback about instantaneous loading rate. Further refinement in sound measurement techniques may be required before these findings can be applied in a clinical population.

SEREEGA: Simulating event-related EEG activity.

BACKGROUND: Electroencephalography (EEG) is a popular method to monitor brain activity, but it is difficult to evaluate EEG-based analysis methods because no ground-truth brain activity is available for comparison. Therefore, in order to test and evaluate such methods, researchers often use simulated EEG data instead of actual EEG recordings. Simulated data can be used, among other things, to assess or compare signal processing and machine learning algorithms, to model EEG variabilities, and to design source reconstruction methods. NEW METHOD: We present SEREEGA, Simulating Event-Related EEG Activity. SEREEGA is a free and open-source MATLAB-based toolbox dedicated to the generation of simulated epochs of EEG data. It is modular and extensible, at initial release supporting five different publicly available head models and capable of simulating multiple different types of signals mimicking brain activity. This paper presents the architecture and general workflow of this toolbox, as well as a simulated data set demonstrating some of its functions. The toolbox is available at https://github.com/lrkrol/SEREEGA. RESULTS: The simulated data allows established analysis pipelines and classification methods to be applied and is capable of producing realistic results. COMPARISON WITH EXISTING METHODS: Most simulated EEG is coded from scratch. The few open-source methods in existence focus on specific applications or signal types, such as connectivity. SEREEGA unifies the majority of past simulation methods reported in the literature into one toolbox. CONCLUSION: SEREEGA is a general-purpose toolbox to simulate ground-truth EEG data.

A comparison of the Avisoft (5.2) and Ultravox (2.0) recording systems: Implications for early-life communication and vocalization research.

Alterations in early-life communicative behaviors are a common feature of neurodevelopmental conditions, such as autism and epilepsy. One method of investigating communication in murine models is through analyzing ultrasonic vocalizations. These vocalizations are commonly recorded with either the Avisoft or the Ultravox recording programs. However, since no study has compared whether the systems are equally sensitive, the findings in one program may not be reproducible in the other. To directly compare the two programs, we elicited vocalizations from male and female 129SvEvTac and C57BL/6 mouse pups via the maternal isolation paradigm, recording vocalizations simultaneously with both systems. We held the detection parameters identical for each system and found that there was only a medium correlation between Avisoft and Ultravox overall. Further analysis indicated that Avisoft detected more total vocalizations, as well as more vocalizations at the set frequencies of 50, 60, and 70 kHz than Ultravox, p < .05. No statistically significant difference was present at 80 kHz. These findings demonstrate that different recording systems do not detect the same quantity of vocalizations as one another, even when detection parameters are congruent. Therefore, it may be useful to revisit previous negative results obtained with Ultravox and repeat the experiments using Avisoft. Ultimately, ultrasonic vocalizations are a valuable tool, capable of examining early-life phenotypes. However, a more thorough understanding of the relationships between recording systems is necessary to achieve a more comprehensive and reproducible assessment of vocalizing behaviors.

Spatial and temporal patterns of sound production in East Greenland narwhals.

Changes in climate are rapidly modifying the Arctic environment. As a result, human activities-and the sounds they produce-are predicted to increase in remote areas of Greenland, such as those inhabited by the narwhals (Monodon monoceros) of East Greenland. Meanwhile, nothing is known about these whales' acoustic behavior or their reactions to anthropogenic sounds. This lack of knowledge was addressed by instrumenting six narwhals in Scoresby Sound (Aug 2013-2016) with Acousonde™ acoustic tags and satellite tags. Continuous recordings over up to seven days were used to describe the acoustic behavior of the whales, in particular their use of three types of sounds serving two different purposes: echolocation clicks and buzzes, which serve feeding, and calls, presumably used for social communication. Logistic regression models were used to assess the effects of location in time and space on buzzing and calling rates. Buzzes were mostly produced at depths of 350-650 m and buzzing rates were higher in one particular fjord, likely a preferred feeding area. Calls generally occurred at shallower depths (<100 m), with more than half of these calls occurring near the surface (<7 m), where the whales also spent more than half of their time. A period of silence following release, present in all subjects, was attributed to the capture and tagging operations, emphasizing the importance of longer (multi-day) records. This study provides basic life-history information on a poorly known species-and therefore control data in ongoing or future sound-effect studies.

Low-cost synchronization of high-speed audio and video recordings in bio-acoustic experiments.

In this paper, we present a method for synchronizing high-speed audio and video recordings of bio-acoustic experiments. By embedding a random signal into the recorded video and audio data, robust synchronization of a diverse set of sensor streams can be performed without the need to keep detailed records. The synchronization can be performed using recording devices without dedicated synchronization inputs. We demonstrate the efficacy of the approach in two sets of experiments: behavioral experiments on different species of echolocating bats and the recordings of field crickets. We present the general operating principle of the synchronization method, discuss its synchronization strength and provide insights into how to construct such a device using off-the-shelf components.

Migratory behavior of eastern North Pacific gray whales tracked using a hydrophone array.

Eastern North Pacific gray whales make one of the longest annual migrations of any mammal, traveling from their summer feeding areas in the Bering and Chukchi Seas to their wintering areas in the lagoons of Baja California, Mexico. Although a significant body of knowledge on gray whale biology and behavior exists, little is known about their vocal behavior while migrating. In this study, we used a sparse hydrophone array deployed offshore of central California to investigate how gray whales behave and use sound while migrating. We detected, localized, and tracked whales for one full migration season, a first for gray whales. We verified and localized 10,644 gray whale M3 calls and grouped them into 280 tracks. Results confirm that gray whales are acoustically active while migrating and their swimming and acoustic behavior changes on daily and seasonal time scales. The seasonal timing of the calls verifies the gray whale migration timing determined using other methods such as counts conducted by visual observers. The total number of calls and the percentage of calls that were part of a track changed significantly over both seasonal and daily time scales. An average calling rate of 5.7 calls/whale/day was observed, which is significantly greater than previously reported migration calling rates. We measured a mean speed of 1.6 m/s and quantified heading, direction, and water depth where tracks were located. Mean speed and water depth remained constant between night and day, but these quantities had greater variation at night. Gray whales produce M3 calls with a root mean square source level of 156.9 dB re 1 µPa at 1 m. Quantities describing call characteristics were variable and dependent on site-specific propagation characteristics.

[Technical advancements in cochlear implants : State of the art]. / Technische Entwicklungen bei Cochleaimplantaten : Stand der Technik.

Twenty years ago, cochlear implants (CI) were indicated only in cases of profound hearing loss or complete deafness. While from today's perspective the technology was clumsy and provided patients with only limited speech comprehension in quiet scenarios, successive advances in CI technology and the consequent substantial hearing improvements over time have since then resulted in continuous relaxation of indication criteria toward residual hearing. While achievements in implant and processor electronics have been one key factor for the ever-improving hearing performance, development of electro-acoustic CI systems-together with atraumatic implantation concepts-has led to enormous improvements in patients with low-frequency residual hearing. Manufactures have designed special processors with integrated hearing aid components for this patient group, which are capable of conveying acoustic and electric stimulation. A further milestone in improvement of hearing in challenging listening environments was the adoption of signal enhancement algorithms and assistive listening devices from the hearing aid industry. This article gives an overview of the current state of the art in the abovementioned areas of CI technology.

Estimating the location of baleen whale calls using dual streamers to support mitigation procedures in seismic reflection surveys.

In order to mitigate against possible impacts of seismic surveys on baleen whales it is important to know as much as possible about the presence of whales within the vicinity of seismic operations. This study expands on previous work that analyzes single seismic streamer data to locate nearby calling baleen whales with a grid search method that utilizes the propagation angles and relative arrival times of received signals along the streamer. Three dimensional seismic reflection surveys use multiple towed hydrophone arrays for imaging the structure beneath the seafloor, providing an opportunity to significantly improve the uncertainty associated with streamer-generated call locations. All seismic surveys utilizing airguns conduct visual marine mammal monitoring surveys concurrent with the experiment, with powering-down of seismic source if a marine mammal is observed within the exposure zone. This study utilizes data from power-down periods of a seismic experiment conducted with two 8-km long seismic hydrophone arrays by the R/V Marcus G. Langseth near Alaska in summer 2011. Simulated and experiment data demonstrate that a single streamer can be utilized to resolve left-right ambiguity because the streamer is rarely perfectly straight in a field setting, but dual streamers provides significantly improved locations. Both methods represent a dramatic improvement over the existing Passive Acoustic Monitoring (PAM) system for detecting low frequency baleen whale calls, with ~60 calls detected utilizing the seismic streamers, zero of which were detected using the current R/V Langseth PAM system. Furthermore, this method has the potential to be utilized not only for improving mitigation processes, but also for studying baleen whale behavior within the vicinity of seismic operations.

A Deep Denoising Autoencoder Approach to Improving the Intelligibility of Vocoded Speech in Cochlear Implant Simulation.

OBJECTIVE: In a cochlear implant (CI) speech processor, noise reduction (NR) is a critical component for enabling CI users to attain improved speech perception under noisy conditions. Identifying an effective NR approach has long been a key topic in CI research. METHOD: Recently, a deep denoising autoencoder (DDAE) based NR approach was proposed and shown to be effective in restoring clean speech from noisy observations. It was also shown that DDAE could provide better performance than several existing NR methods in standardized objective evaluations. Following this success with normal speech, this paper further investigated the performance of DDAE-based NR to improve the intelligibility of envelope-based vocoded speech, which simulates speech signal processing in existing CI devices. RESULTS: We compared the performance of speech intelligibility between DDAE-based NR and conventional single-microphone NR approaches using the noise vocoder simulation. The results of both objective evaluations and listening test showed that, under the conditions of nonstationary noise distortion, DDAE-based NR yielded higher intelligibility scores than conventional NR approaches. CONCLUSION AND SIGNIFICANCE: This study confirmed that DDAE-based NR could potentially be integrated into a CI processor to provide more benefits to CI users under noisy conditions.

A Dual-Mode Magnetic-Acoustic System for Monitoring Fluid Intake Behavior in Animals.

We have developed an unobtrusive magnetic-acoustic fluid intake monitoring (MAFIM) system using a conventional stainless-steel roller-ball nipple to measure licking and drinking behavior in animals. Movements of a small permanent magnetic tracer attached to stainless-steel roller balls that operate as a tongue-actuated valve are sensed by a pair of three-axial magnetometers, and transformed into a time-series indicating the status of the ball (up or down), using a Gaussian mixture model based data-driven classifier. The sounds produced by the rise and fall of the roller balls are also recorded and classified to substantiate the magnetic data by an independent modality for a more robust solution. The operation of the magnetic and acoustic sensors is controlled by an embedded system, communicating via Universal Serial Bus (USB) with a custom-designed user interface, running on a PC. The MAFIM system has been tested in vivo with minipigs, accurately measuring various drinking parameters and licking patterns without constraints imposed by current lick monitoring systems, such as nipple access, animal-nipple contact, animal training, and complex parameter settings.

[Noise level in the NICU: Impact of monitoring equipment]. / Nuisances sonores en réanimation néonatale : impact d'un outil de monitorage.

BACKGROUND: The sound level in the neonatal intensive care unit (NICU) may induce adverse effects for neonates, their family, and the staff. This study evaluated the sound level in a NICU before and after the implementation of an educational program. MATERIAL AND METHODS: A baseline audit determined the most exposed area of the NICU and the most exposed periods over 24 h. Then an educational program started, including sound level measurement methods, side effects for neonates, results from the baseline audit, and new visual monitoring equipment (SoundEar®). Sound levels were measured before, 1, 2, and 3 months after starting the educational program and the use of SoundEar®. The NICU staff was blind to the periods of sound level measurements. RESULTS: The base noise level was high, especially near the central part of the NICU and during transmission time (mean Leq: 60.6±3.6dB(A); sound peaks: 94.8±6.8dB(A)). A decrease in the sound level (P<0.001) was found 1 and 2, but not 3 months after starting the educational program. It remained high compared to the guidelines. CONCLUSION: Human activity was responsible for most of the sound level. An educational program was effective in reducing the sound level, but did not reach the guideline's target. The continuous use of sound-monitoring equipment after starting the project reduced the sound level for 2 months, but no longer. Therefore, a continuous educational program about the sound level in the NICU including feedback monitoring every 2-3 months should be encouraged.

Development and evaluation of wheel-controlled pitch-adjustable electrolarynx.

Tone is important in tonal languages, especially in Mandarin. However, there is presently no commercially available electrolarynx (EL) for laryngectomized Mandarin speakers. Moreover, few studies have focused on this area. Our purpose is to design an EL that produces the four Mandarin tones and to evaluate its performance. We designed a wheel-controlled pitch-adjustable EL and manufactured a prototype (Wheel-EL). Using monosyllables, disyllabic segments, and frequently used phrases, we evaluated speech produced by Wheel-EL and by monotone (M-TruTone) and variable-frequency modes (V-TruTone) of the commercially available TruTone EL. The pitch contours of the high-level (HL), middle-rising (MR), and falling-rising (FR) tones produced by Wheel-EL most closely matched the natural speech characteristics of a native speaker. However, redundant sounds were generated in the high-falling (HF) tone. The statistical accuracy of Wheel-EL's tone and word perception was significantly higher than that of other EL types. However, no significant differences existed in acceptability among the three EL speech types. Wheel-EL produces better HL, MR, and FR tones in Mandarin than either M-TruTone or V-TruTone. Nevertheless, redundant sounds affect HF phonation. Accurate tone judgment can improve the intelligibility of EL speech in Mandarin but has no obvious effect on acceptability.

A MEMS Condenser Microphone-Based Intracochlear Acoustic Receiver.

GOAL: Intracochlear sound pressure (ICSP) measurements are limited by the small dimensions of the human inner ear and the requirements imposed by the liquid medium. A robust intracochlear acoustic receiver (ICAR) for repeated use with a simple data acquisition system that provides the required high sensitivity and small dimensions does not yet exist. The work described in this report aims to fill this gap and presents a new microelectromechanical systems (MEMS) condenser microphone (CMIC)-based ICAR concept suitable for ICSP measurements in human temporal bones. METHODS: The ICAR head consisted of a passive protective diaphragm (PD) sealing the MEMS CMIC against the liquid medium, enabling insertion into the inner ear. The components of the MEMS CMIC-based ICAR were expressed by a lumped element model (LEM) and compared to the performance of successfully fabricated ICARs. RESULTS: Good agreement was achieved between the LEM and the measurements with different sizes of the PD. The ICSP measurements in a human cadaver temporal bone yielded data in agreement with the literature. CONCLUSION: Our results confirm that the presented MEMS CMIC-based ICAR is a promising technology for measuring ICSP in human temporal bones in the audible frequency range. SIGNIFICANCE: A sensor for evaluation of the biomechanical hearing process by quantification of ICSP is presented. The concept has potential as an acoustic receiver in totally implantable cochlear implants.

Real-Time Control of an Articulatory-Based Speech Synthesizer for Brain Computer Interfaces.

Restoring natural speech in paralyzed and aphasic people could be achieved using a Brain-Computer Interface (BCI) controlling a speech synthesizer in real-time. To reach this goal, a prerequisite is to develop a speech synthesizer producing intelligible speech in real-time with a reasonable number of control parameters. We present here an articulatory-based speech synthesizer that can be controlled in real-time for future BCI applications. This synthesizer converts movements of the main speech articulators (tongue, jaw, velum, and lips) into intelligible speech. The articulatory-to-acoustic mapping is performed using a deep neural network (DNN) trained on electromagnetic articulography (EMA) data recorded on a reference speaker synchronously with the produced speech signal. This DNN is then used in both offline and online modes to map the position of sensors glued on different speech articulators into acoustic parameters that are further converted into an audio signal using a vocoder. In offline mode, highly intelligible speech could be obtained as assessed by perceptual evaluation performed by 12 listeners. Then, to anticipate future BCI applications, we further assessed the real-time control of the synthesizer by both the reference speaker and new speakers, in a closed-loop paradigm using EMA data recorded in real time. A short calibration period was used to compensate for differences in sensor positions and articulatory differences between new speakers and the reference speaker. We found that real-time synthesis of vowels and consonants was possible with good intelligibility. In conclusion, these results open to future speech BCI applications using such articulatory-based speech synthesizer.

Differential Intracochlear Sound Pressure Measurements in Human Temporal Bones with an Off-the-Shelf Sensor.

The standard method to determine the output level of acoustic and mechanical stimulation to the inner ear is measurement of vibration response of the stapes in human cadaveric temporal bones (TBs) by laser Doppler vibrometry. However, this method is reliable only if the intact ossicular chain is stimulated. For other stimulation modes an alternative method is needed. The differential intracochlear sound pressure between scala vestibuli (SV) and scala tympani (ST) is assumed to correlate with excitation. Using a custom-made pressure sensor it has been successfully measured and used to determine the output level of acoustic and mechanical stimulation. To make this method generally accessible, an off-the-shelf pressure sensor (Samba Preclin 420 LP, Samba Sensors) was tested here for intracochlear sound pressure measurements. During acoustic stimulation, intracochlear sound pressures were simultaneously measurable in SV and ST between 0.1 and 8 kHz with sufficient signal-to-noise ratios with this sensor. The pressure differences were comparable to results obtained with custom-made sensors. Our results demonstrated that the pressure sensor Samba Preclin 420 LP is usable for measurements of intracochlear sound pressures in SV and ST and for the determination of differential intracochlear sound pressures.

Directional Reflective Surface Formed via Gradient-Impeding Acoustic Meta-Surfaces.

Artificially designed acoustic meta-surfaces have the ability to manipulate sound energy to an extraordinary extent. Here, we report on a new type of directional reflective surface consisting of an array of sub-wavelength Helmholtz resonators with varying internal coiled path lengths, which induce a reflection phase gradient along a planar acoustic meta-surface. The acoustically reshaped reflective surface created by the gradient-impeding meta-surface yields a distinct focal line similar to a parabolic cylinder antenna, and is used for directive sound beamforming. Focused beam steering can be also obtained by repositioning the source (or receiver) off axis, i.e., displaced from the focal line. Besides flat reflective surfaces, complex surfaces such as convex or conformal shapes may be used for sound beamforming, thus facilitating easy application in sound reinforcement systems. Therefore, directional reflective surfaces have promising applications in fields such as acoustic imaging, sonic weaponry, and underwater communication.

[Normal and Adventitious Breath Sounds]. / Atemgeräusche und Atem-Nebengeräusche.

Auscultation of the lung is an inexpensive, noninvasive and easy-to-perform tool. It is an important part of the physical examination and is help ful to distinguish physiological respiratory sounds from pathophysiological events. Computerized lung sound analysis is a powerful tool for optimizing and quantifying electronic auscultation based on the specific lung sound spectral characteristics. The automatic analysis of respiratory sounds assumes that physiological and pathological sounds are reliably analyzed based on special algorithms. The development of automated long-term lungsound monitors enables objective assessment of different respiratory symptoms.

The Use of Sound Level Meter Apps in the Clinical Setting.

PURPOSE: The purpose of this study was to compare sound level meter (SLM) readings obtained using a Larson-Davis (Depew, NY) Model 831 Type 1 SLM, a RadioShack (Fort Worth, TX) SLM, and iPhone 5 (Apple, Cupertino, CA) SLM apps. METHOD: In Procedure 1, pure tones were measured in an anechoic chamber (125, 250, 500, 1000, 2000, 4000, and 8000 Hz); sound pressure levels (SPLs) ranged from 60 to 100 dB SPL in 10-dB increments. In Procedure 2, human voices were measured. Participants were 20 vocally healthy adults (7 women, 13 men; mean age = 25.1 years). The task was to sustain a vowel "ah" at 3 intensity levels: soft, habitual, and loud. Microphones were lined up equal distances from the participant's mouth, and recordings were captured simultaneously. RESULTS: Overall, the 3 SLM apps and the RadioShack SLM yielded inconsistent readings compared with the Type 1 SLM. CONCLUSION: The use of apps for SPL readings in the clinical setting is premature because all 3 apps adopted were incomparable with the Type 1 SLM.