The Extended Speech Transmission Index: Predicting speech intelligibility in fluctuating noise and reverberant rooms

The Speech Transmission Index (STI) is used to predict speech intelligibility in noise and reverberant environments. However, measurements and predictions in fluctuating noises lead to inaccuracies. In the current paper, the Extended Speech Transmission Index (ESTI) is presented in order to deal with these shortcomings. Speech intelligibility in normally hearing subjects was measured using stationary and fluctuating maskers. These results served to optimize model parameters. Data from the literature were then used to verify the ESTI-model. Model outcomes were accurate for stationary maskers, maskers with artificial fluctuations, and maskers with real life non-speech modulations. Maskers with speech-like characteristics introduced systematic errors in the model outcomes, probably due to a combination of modulation masking, context effects, and informational masking

Towards measuring the Speech Transmission Index in fluctuating noise: Accuracy and limitations

In the field of room acoustics, the modulation transfer function (MTF) can be used to predict speech intelligibility in stationary noise and reverberation and can be expressed in one single value: the Speech Transmission Index (STI). One drawback of the classical STI measurement method is that it is not validated for fluctuating background noise. As opposed to the classical measurement method, the MTF due to reverberation can also be calculated using an impulse response measurement. This indirect method presents an opportunity for STI measurements in fluctuating noise, and a first prerequisite is a reliable impulse response measurement. The conditions under which the impulse response can be measured with sufficient precision were investigated in the current study. Impulse response measurements were conducted using a sweep stimulus. Two experiments are discussed with variable absorption, different levels of stationary and fluctuating background noise, and different sweep levels. Additionally, simulations with different types of fluctuating noise were conducted in an attempt to extrapolate the experimental findings to other acoustical conditions. The experiments and simulations showed that a minimum impulse-to-noise ratio of +25 dB in fluctuating noise was needed. (C) 2017 Acoustical Society of Americ

Selecting Appropriate Tests to Assess the Benefits of Bilateral Amplification With Hearing Aids

The aim of this study was to investigate the effect of bilateral hearing aids (HA) in subjects with mild and moderate-to-severe hearing loss. This study was designed as a within-subject feasibility study. Bilateral HA use was assessed using different laboratory tests on speech reception, listening effort, noise tolerance, and localization. All data were evaluated with bilateral and unilateral HA fittings. Forty experienced bilateral HA users were included with hearing impairment ranging from mild to moderate-to-severe. Subjects were stratified into two groups based on the degree of hearing loss. Speech reception in noise, listening effort, and localization tests showed a bilateral benefit for the moderate-to-severely hearing-impaired subjects. A bilateral benefit was also observed for listening effort in the mildly hearing-impaired group. The assessment of listening effort shows promise as a measure of bilateral HA benefit for mild hearing impairment. Localization and speech reception in noise tests provide additional value for larger losses. The next step is to compare experienced unilateral with bilateral HA user

Auf Tribenzotriquinacen und Fulleren basierende supramolekulare Aggregate: Baukastenprinzip funktioneller Nano-Module

Im Rahmen der vorliegenden Arbeit wurden zwei neuartige Rezeptoren synthetisiert, die eine optimierte Passform für C60 besitzen. Die anschließenden spektroskopischen Untersuchungen mit C60 haben Aufschluss über die Zusammensetzung und die jeweilige Stärke der Wirt-Gast-Komplexe in Lösung gegeben. Diese grundlegende Selbstorganisations-Strategie aufgreifend, konnte der variable Einsatz von Rezeptor-Bausteinen und funktionalisierten Fullerenen, ebenfalls mittels Komplexierungsstudien, gezeigt werden. Diese Ergebnisse geben das positive Signal, dass weitere Untersuchungen zu molekularen Ratschen und Motoren auf dieser Basis möglich und sinnvoll sind. Um elementare Erkenntnisse zur Fixierung von Tribenzotriquinacenen auf Oberflächen realisieren zu können, wurde abschließend ein am "Rückgrat" funktionalisiertes Tribenzotriquinacen synthetisiert. Dieses konnte in einer gemischten Monolage zusammen mit Hexan- bzw. Decanthiol auf Gold-(111) immobilisiert und mit einem Rastertunnelmikroskop detektiert und untersucht werden.In the present doctoral thesis two novel receptors have been synthesized that provide a structurally optimized fit for fullerene C60. The subsequent spectroscopic studies with C60 gave information about the composition and the respective strengths of the host-guest complexes in solution. By picking up this basic self-organization strategy, the variable use of receptorblock and functionalized fullerenes was demonstrated by using spectroscopic studies as well, whereby the possible feasibility of molecular ratchets and motors was confirmed. Finally, a backbone-functionalized tribenzotriquinacene was synthesized, immobilized as a mixed monolayer with hexane- or decanethiol on gold-(111) and detected and investigated with a scanning tunneling microscope to carry out basic studies on surfaces

The Effectiveness of Bilateral Cochlear Implants for Severe-to-Profound Deafness in Adults:A Systematic Review

<p>Objective: Assessment of the clinical effectiveness of bilateral cochlear implantation compared with unilateral cochlear implantation or bimodal stimulation, in adults with severe-to-profound hearing loss. In 2007, the National Institute for Health and Clinical Excellence (NICE) in the U. K. conducted a systematic review on cochlear implantation. This study forms an update of the adult part of the NICE review.</p><p>Data Sources: The electronic databases MEDLINE and Embase were searched for English language studies published between October 2006 and March 2011.</p><p>Study Selection: Studies were included that compared bilateral cochlear implantation with unilateral cochlear implantation and/or with bimodal stimulation, in adults with severe-to-profound sensorineural hearing loss. Speech perception in quiet and in noise, sound localization and lateralization, speech production, health-related quality of life, and functional outcomes were analyzed.</p><p>Data Extraction: Data extraction forms were used to describe study characteristics and the level of evidence.</p><p>Data Synthesis: The effect size was calculated to compare different outcome measures.</p><p>Conclusion: Pooling of data was not possible because of the heterogeneity of the studies. As in the NICE review, the level of evidence of the included studies was low, although some of the additional studies showed less risk of bias. All studies showed a significant bilateral benefit in localization over unilateral cochlear implantation. Bilateral cochlear implants were beneficial for speech perception in noise under certain conditions and several self-reported measures. Most speech perception in quiet outcomes did not show a bilateral benefit. The current review provides additional evidence in favor of bilateral cochlear implantation, even in complex listening situations.</p>