BACKGROUND: Binaural hearing enables better speech comprehension in noisy environments and is necessary for acoustic spatial orientation. This study investigates speech discrimination in noise with separated signal sources and measures sound localization. The aim was to study characteristics and reproducibility of two selected measurement techniques which seem to be suitable for description of the aforementioned aspects of binaural hearing.
METHODS: Speech reception thresholds (SRT) in noise and test-retest reliability were collected from 55 normal-hearing adults for a spatial setup of loudspeakers with angles of ± 45° and ± 90° using the Oldenburg sentence test. The investigations of sound localization were conducted in a semicircle and fullcircle setup (7 and 12 equidistant loudspeakers).
RESULTS: SRT (S-45N45: -14.1 dB SNR; S45N-45: -16.4 dB SNR; S0N90: -13.1 dB SNR; S0N-90: -13.4 dB SNR) and test-retest reliability (4 to 6 dB SNR) were collected for speech intelligibility in noise with separated signals. The procedural learning effect for this setup could only be mitigated with 120 training sentences. Significantly smaller SRT values, resulting in better speech discrimination, were found for the test situation of the right compared to the left ear. RMS values could be gathered for sound localization in the semicircle (1,9°) as well as in the fullcircle setup (11,1°). Better results were obtained in the retest of the fullcircle setup.
CONCLUSIONS: When using the Oldenburg sentence test in noise with spatially separated signals, it is mandatory to perform a training session of 120 sentences in order to minimize the procedural learning effect. Ear-specific SRT values for speech discrimination in noise with separated signal sources are required, which is probably due to the right-ear advantage. A training is recommended for sound localization in the fullcircle setup.
UNASSIGNED: HINTERGRUND: Binaurales Hören ermöglicht das bessere Sprachverstehen in geräuschvollen Umgebungen und stellt eine Voraussetzung für die akustische Raumorientierung dar. Deshalb soll im Rahmen dieser Studie das Sprachverstehen im Störschall bei separierten Signalquellen und das Richtungshören untersucht werden. Ziel war es dabei, Kennwerte und Reproduzierbarkeiten für zwei ausgewählte Testverfahren, welche für die Beschreibung der beiden genannten Aspekte des binauralen Hörens als geeignet scheinen, zu erheben.
METHODS: Bei 55 normalhörenden Erwachsenen wurden die Sprachverständlichkeitsschwellen im Störschall („speech reception thresholds“ [SRT]) und die Test-Retest-Reliabilität bei räumlich getrennten Signalquellen im 45°- und 90°-Winkel für den Oldenburger Satztest erhoben. Die Untersuchung des Richtungshörens erfolgte für den Halb- und Vollkreis (7 und 12 äquidistante Lautsprecher).
UNASSIGNED: Es wurden SRT (S−45N45: −14,1 dB SNR, S45N−45: −16,4 dB SNR, S0N90: −13,1 dB SNR, S0N−90: −13,4 dB SNR) und die Test-Retest-Reliabilität (4 bis 6 dB SNR) für das Sprachverstehen im Störschall bei separierten Schallquellen erhoben. Der prozedurale Lerneffekt konnte erst bei Einsatz von 120 Trainingssätzen minimiert werden. Es wurde eine signifikant niedrigere SRT für die Prüfsituation des rechten Ohrs im Vergleich zum linken ermittelt. Für das Richtungshören im Halbkreis konnten RMS-Werte von (1,9°) und für den Vollkreis von (11,1°) erhoben werden. Hierbei zeigten sich in der Wiederholungsmessung des Vollkreises bessere Ergebnisse.
UNASSIGNED: Beim Einsatz des Oldenburger Satztests im Störschall mit separierten Signalquellen besteht die Notwendigkeit eines ausgedehnten Trainings mit mehr als 120 Sätzen, um den prozeduralen Lerneffekt zu minimieren. Es sind seitenspezifische SRT-Werte erforderlich, welche vermutlich durch den Right-Ear-Advantage-Effekt bedingt sind. Für die Durchführung des Richtungshörens im Vollkreis wird ein Training empfohlen.

Right-ear advantage refers to the observation that when two different speech stimuli are simultaneously presented to both ears, listeners report stimuli more correctly from the right ear than the left. It is assumed to result from prominent projection along the auditory pathways to the contralateral hemisphere and the dominance of the left auditory cortex for the perception of speech elements. Our study aimed to investigate the role of attention in the right-ear advantage. We recorded magnetoencephalography data while participants listened to pairs of Japanese two-syllable words (namely, \"/ta/ /ko/\" or \"/i/ /ka/\"). The amplitudes of the stimuli were modulated at 35 Hz in one ear and 45 Hz in the other. Such frequency-tagging allowed the selective quantification of left and right auditory cortex responses to left and right ear stimuli. Behavioral tests confirmed the right-ear advantage, with higher accuracy for stimuli presented to the right ear than to the left. The amplitude of the auditory steady-state response was larger when attending to the stimuli compared to passive listening. We detected a correlation between the attention-related increase in the amplitude of the auditory steady-state response and the laterality index of behavioral accuracy. The right-ear advantage in the free-response dichotic listening was also found in neural activities in the left auditory cortex, suggesting that it was related to the allocation of attention to both ears.

Cerebral lateralisation of language processing leads to a right ear advantage in normal hearing subjects. The aim of this study was to present a systematic overview of the effect of implantation side on postoperative cochlear implant performance in patients with symmetrical severe to profound sensorineural hearing loss.
PubMed, Embase and The Cochrane Library databases.
Databases were searched from database inception up to 9 January 2017 for cochlear implant and side and all synonyms. Title, abstract and full-text of retrieved articles were screened for eligibility. Then, directness of evidence and risk of bias were assessed. For the included articles, study characteristics and outcome data (hearing and language development) were extracted.
2541 unique articles were screened, of which twenty were eligible for critical appraisal. No randomised controlled trials were identified. Twelve studies with a high directness of evidence remained for data extraction. Four of six studies including children with pre-lingual sensorineural hearing loss and four of seven studies investigating adults with postlingual sensorineural hearing loss found a right ear advantage in at least one outcome measurement related to cochlear implant performance.
The available evidence on the effect of side of implantation is of low quality, as study populations and outcome measures are heterogeneous. The majority of studies reveals evidence for a right ear advantage in prelingually deafened children as well as postlingually deafened adults. In view of the present evidence and as no left ear advantage was identified, we cautiously advise implanting the cochlear implant in the right ear when other prognostic factors do not favour the left ear and sensorineural hearing loss is symmetrical.

The goal of this study was to investigate the impact of individual costs on prospective memory performance. Individual costs were assessed by contrasting participants with high costs and those with low costs. Specifically, we tested whether prospective memory performance is moderated by costs, cue-focality and intention specificity. Participants performed a dichotic listening paradigm where they had to indicate whether a word presented to one ear was abstract or concrete while ignoring the word presented to the other ear. For the prospective memory task, participants had to detect target items; half of them were presented focally to the same ear as the relevant words for the ongoing task and half of them were presented non-focally to the other ear. Moreover, half of the participants were given specific instructions and the other half were given categorical instructions. The results revealed a right-ear advantage for participants with low costs but not for participants with high costs. Moreover, the absence of costs was not necessarily accompanied by worse prospective memory performance. Given differential results under the same task conditions, we conclude that individual costs are an important factor which should be considered when investigating prospective memory processes.

The aim of the present study was to investigate the effect of ear asymmetry, order of testing, and gender on transient-evoked otoacoustic emission (TEOAE) pass rates and response levels in newborn hearing screening. The screening results of 879 newborns, of whom 387 (study group) passed screening successfully in only one ear in the first TEOAE screening, but passed screening successfully in both ears thereafter, and 492 (control group) who passed screening successfully in both ears in the first TEOAE, were retrospectively examined for pass rates and TEOAE characteristics. Results indicated a right-ear advantage, as manifested by significantly higher pass rates in the right ear (61% and 39% for right and left ears, respectively) in the study group, and in 1.75 dB greater TEOAE response amplitudes in the control group. The right-ear advantage was enhanced when the first tested ear was the right ear (76%). When the left ear was tested first, pass rates were comparable in both ears. The right-ear advantage in pass rates was similar in females versus males, but manifested in 1.5 dB higher response amplitudes in females compared with males, regardless of the tested ear and order of testing in both study and control groups. The study provides further evidence for the functional lateralization of the auditory system at the cochlear level already apparent soon after birth in both males and females. While order of testing plays a significant role in the asymmetry in pass rates, the innate right-ear advantage seems to be a more dominant contributor.

Two dichotic listening experiments examined the degree to which the right-ear advantage (REA) for linguistic stimuli is altered by a \"top-down\" variable (i.e., directed attention) in conjunction with selected \"bottom-up\" (acoustic) variables. Halwes fused dichotic words were administered to 99 right-handed adults with instructions to attend to the left or right ear, or to divide attention equally. Stimuli in Experiment 1 were presented without noise or mixed with noise that was high-pass or low-pass filtered, or unfiltered. The stimuli themselves in Experiment 2 were high-pass or low-pass filtered, or unfiltered. The initial consonants of each dichotic pair were categorized according to voice onset time (VOT) and place of articulation (PoA). White noise extinguished both the REA and selective attention, and filtered noise nullified selective attention without extinguishing the REA. Frequency filtering of the words themselves did not alter performance. VOT effects were inconsistent across experiments but PoA analyses indicated that paired velar consonants (/k/ and /g/) yield a left-ear advantage and paradoxical selective-attention results. The findings show that ear asymmetry and the effectiveness of directed attention can be altered by bottom-up variables.