Strukturen des maltesischen Mediensystems

Strukturen des maltesischen Mediensystems : Arbeitsbedingungen u. publizist. Umfeld maltes. Journalisten. - Augsburg, 1988. - XIX, 185 S. - (ABAKUS ; 8

Open Versus Closed Hearing-Aid Fittings: A Literature Review of Both Fitting Approaches

One of the main issues in hearing-aid fittings is the abnormal perception of the user’s own voice as too loud, “boomy,” or “hollow.” This phenomenon known as the occlusion effect be reduced by large vents in the earmolds or by open-fit hearing aids. This review provides an overview of publications related to open and closed hearing-aid fittings. First, the occlusion effect and its consequences for perception while using hearing aids are described. Then, the advantages and disadvantages of open compared with closed fittings and their impact on the fitting process are addressed. The advantages include less occlusion, improved own-voice perception and sound quality, and increased localization performance. The disadvantages associated with open-fit hearing aids include reduced benefits of directional microphones and noise reduction, as well as less compression and less available gain before feedback. The final part of this review addresses the need for new approaches to combine the advantages of open and closed hearing-aid fittings

Effect of Hearing Aid Directionality and Remote Microphone on Speech Intelligibility in Complex Listening Situations

Remote microphones (RMs) have been developed to support hearing aid (HA) users in understanding distant talkers. In traditional clinical applications, a drawback of these systems is the deteriorated speech intelligibility in the near field. This study investigates advantages and disadvantages of clinical RM usage and the effects of different directionality settings of the HAs in complex listening situations in the laboratory. Speech intelligibility was investigated in 15 experienced severely hearing impaired participants in a noisy environment using a dual-task test paradigm where the tasks were presented from either a near field or a far field loudspeaker. Primary and secondary tasks were presented simultaneously so attention had to be shared on both tasks. In a second experiment, two speech intelligibility tests were presented from either the near field or the far field loudspeaker. The tests were interleaved to simulate a complex listening situation with shifting attention. Directional HA microphones yielded better performance than omnidirectional microphones (both combined with a RM) in near field when analyzing both tasks of the dual-task experiment separately. Furthermore, the integrated dual-task test results showed better performance with directional HA microphones compared with the omnidirectional setting (both cases in combination with a RM). These findings were confirmed by the results of the interleaved speech intelligibility test

A preliminary investigation into hearing aid fitting based on automated real-ear measurements integrated in the fitting software: test-retest reliability, matching accuracy and perceptual outcomes

OBJECTIVE: The recent integration of automated real-ear measurements (REM) in the fitting software facilitates the hearing aid fitting process. Such a fitting strategy, TargetMatch (TM), was evaluated. Test-retest reliability and matching accuracy were quantified, and compared to a REM-based fitting with manual adjustment. Also, it was investigated whether TM leads to better perceptual outcomes compared to a FirstFit (FF) approach, using software predictions only. Design and study sample: Ten hearing impaired participants were enrolled in a counterbalanced single-blinded cross-over study comparing TM and FF. Aided audibility, speech intelligibility and real-life benefits were assessed. Repeated measurements of both TM and REMs with manual adjustment were performed. RESULTS: Compared to a REM-based fitting with manual adjustment, TM had higher test-retest reliability. Also, TM outperformed the other fitting strategies in terms of matching accuracy. Compared to a FF, improved aided audibility and real-life benefits were found. Speech intelligibility did not improve. CONCLUSIONS: Preliminary data suggest that automated REMs increase the likelihood of meeting amplification targets compared with a FF. REMs integrated in the fitting software provide additional reliability and accuracy compared to traditional REMs. Findings need to be verified in a larger and more varied sample.status: publishe

Insitu-Messung integriert in der Anpsssoftware (TargetMatch): Wiederholbarkeit, Genauigkeit und perzeptive Ergebnisse

status: publishe

Gas-Phase Enantioselectivity of Chiral N-Linked Peptidoresorc[4]arene Isomers toward Dipeptides

Botta B, Fraschetti C, D'Acquarica I, et al. Gas-Phase Enantioselectivity of Chiral N-Linked Peptidoresorc[4]arene Isomers toward Dipeptides. Journal of Physical Chemistry A. 2009;113(52):14625-14629.The gas-phase enantioselectivity of cone N-linked peptidoresorc[4]arenes (generally symbolized as M) toward the homologue dipeptides (generally symbolized as A) has been evaluated by measuring the kinetics of the A release from the diastereomeric [M center dot H center dot A](+) complexes induced by (R)-(-)-2-butylamine (B). In most cases investigated, the heterochiral [M center dot H center dot A](+) complexes, namely those wherein the configuration of the A guest is opposite to that or the host M pendants, react faster (up to 5 times) than the homochiral analogues, wherein guest A guest has the same Configuration of the host M pendants. The kinetic results, discussed in the light of previous MS and NMR evidence, indicate that both the efficiency and the enantioselectivity of the guest exchange reaction depend essentially on the Structure and the relative stability of the diastereomeric [M center dot H center dot A](+) complexes. These, in turn, depend oil the functional groups and the configuration of both the guest and the host pendants. The absence of any significant effects of the B configuration indicates that, in all systems investigated, the dipeptide guest A is predominantly located outside the host chiral cavity

Electrophysiological correlates of listening effort: neurodynamical modeling and measurement

An increased listing effort represents a major problem in humans with hearing impairment. Neurodiagnostic methods for an objective listening effort estimation might support hearing instrument fitting procedures. However the cognitive neurodynamics of listening effort is far from being understood and its neural correlates have not been identified yet. In this paper we analyze the cognitive neurodynamics of listening effort by using methods of forward neurophysical modeling and time-scale electroencephalographic neurodiagnostics. In particular, we present a forward neurophysical model for auditory late responses (ALRs) as large-scale listening effort correlates. Here endogenously driven top–down projections related to listening effort are mapped to corticothalamic feedback pathways which were analyzed for the selective attention neurodynamics before. We show that this model represents well the time-scale phase stability analysis of experimental electroencephalographic data from auditory discrimination paradigms. It is concluded that the proposed neurophysical and neuropsychological framework is appropriate for the analysis of listening effort and might help to develop objective electroencephalographic methods for its estimation in future