How Hearing Impairment Affects Sentence Comprehension: Using Eye Fixations to Investigate the Duration of Speech Processing

The main objective of this study was to investigate the extent to which hearing impairment influences the duration of sentence processing. An eye-tracking paradigm is introduced that provides an online measure of how hearing impairment prolongs processing of linguistically complex sentences; this measure uses eye fixations recorded while the participant listens to a sentence. Eye fixations toward a target picture (which matches the aurally presented sentence) were measured in the presence of a competitor picture. Based on the recorded eye fixations, the single target detection amplitude, which reflects the tendency of the participant to fixate the target picture, was used as a metric to estimate the duration of sentence processing. The single target detection amplitude was calculated for sentence structures with different levels of linguistic complexity and for different listening conditions: in quiet and in two different noise conditions. Participants with hearing impairment spent more time processing sentences, even at high levels of speech intelligibility. In addition, the relationship between the proposed online measure and listener-specific factors, such as hearing aid use and cognitive abilities, was investigated. Longer processing durations were measured for participants with hearing impairment who were not accustomed to using a hearing aid. Moreover, significant correlations were found between sentence processing duration and individual cognitive abilities (such as working memory capacity or susceptibility to interference). These findings are discussed with respect to audiological applications

Continuous Assessment and Modeling of Speech~ansmission Quality

Abstract: This paper addresses the question whether subjects are able to assess the perceived time-vaying quality of speech material continuously. .4 method motivated by de Ridder and Hamberg [J. Opt. Sot. Am. A, 12, 2j73-2577 (1995)] is introduced which is characterized by a subjective continuous rating of the perceived speech quality by moving a slider along a graphical scale. The usability of this method is illustrated with an experiment in which different sequences of sentences were degraded in quality with a llodulated h-oise Reference Unit. The modulation depth was varied with time and the subjects task was to assess the perceived quality. The results indicate that subjects can monitor speech quality variations very accurately with a delay of approximately 1 s. An objective speech quality estimation procedure which uses a psychoacoustic model is also shown to predict these time-varying judgments

Comparing eye tracking with electrooculography for measuring individual sentence comprehension duration

The aim of this study was to validate a procedure for performing the audio-visual paradigm introduced by Wendt et al. (2015) with reduced practical challenges. The original paradigm records eye fixations using an eye tracker and calculates the duration of sentence comprehension based on a bootstrap procedure. In order to reduce practical challenges, we first reduced the measurement time by evaluating a smaller measurement set with fewer trials. The results of 16 listeners showed effects comparable to those obtained when testing the original full measurement set on a different collective of listeners. Secondly, we introduced electrooculography as an alternative technique for recording eye movements. The correlation between the results of the two recording techniques (eye tracker and electrooculography) was r = 0.97, indicating that both methods are suitable for estimating the processing duration of individual participants. Similar changes in processing duration arising from sentence complexity were found using the eye tracker and the electrooculography procedure. Thirdly, the time course of eye fixations was estimated with an alternative procedure, growth curve analysis, which is more commonly used in recent studies analyzing eye tracking data. The results of the growth curve analysis were compared with the results of the bootstrap procedure. Both analysis methods show similar processing durations

Der Exzellenzcluster Hearing4all : Von der medizinischen Grundlagenforschung bis zu Hi-Tech-Lösungen für jedes Ohr

Bereits seit 2012 arbeiten Forscherinnen und Forscher der Carl von Ossietzky Universität Oldenburg, der Medizinischen Hochschule Hannover und der Leibniz Universität Hannover im Rahmen des Exzellenzclusters Hearing4all intensiv, interdisziplinär und erfolgreich zusammen. Im Jahr 2018 konnte sich dieser Verbund aus den drei Universitäten samt angeschlossener Forschungsinstitutionen im „Auditory Valley Hannover – Oldenburg“ erneut in der Exzellenzstrategie durchsetzen: Mit Hearing4all 2.0 kann in den nächsten sieben Jahren auf das bisher Geleistete aufgebaut werden, um weitere Ziele zum Wohle hörgeschädigter Menschen zu verfolgen

Comparison of nitrogen fertilization methods and rates for subsurface drip irrigated corn in the semi-arid Great Plains

In semi?arid areas such as western Nebraska, interest in subsurface drip irrigation (SDI) for corn is increasing due to restricted irrigation allocations. However, crop response quantification to nitrogen (N) applications with SDI and the environmental benefits of multiple in?season (IS) SDI N applications instead of a single early?season (ES) surface application are lacking. The study was conducted in 2004, 2005, and 2006 at the University of Nebraska?Lincoln West Central Research and Extension Center in North Platte, Nebraska, comparing two N application methods (IS and ES) and three N rates (128, 186, and 278 kg N ha-1) using a randomized complete block design with four replications. No grain yield or biomass response was observed in 2004. In 2005 and 2006, corn grain yield and biomass production increased with increasing N rates, and the IS treatment increased grain yield, total N uptake, and gross return after N application costs (GRN) compared to the ES treatment. Chlorophyll meter readings taken at the R3 corn growth stage in 2006 showed that less N was supplied to the plant with ES compared to the IS treatment. At the end of the study, soil NO3-N masses in the 0.9 to 1.8 m depth were greater under the IS treatment compared to the ES treatment. Results suggested that greater losses of NO3-N below the root zone under the ES treatment may have had a negative effect on corn production. Under SDI systems, fertigating a recommended N rate at various corn growth stages can increase yields, GRN, and reduce NO3-N leaching in soils compared to concentrated early?season applications

Exploring Differences in Speech Processing Among Older Hearing-Impaired Listeners With or Without Hearing Aid Experience: Eye-Tracking and fMRI Measurements

Recently, evidence has been accumulating that untreated hearing loss can lead to neurophysiological changes that affect speech processing abilities in noise. To shed more light on how aiding may impact these effects, this study explored the influence of hearing aid (HA) experience on the cognitive processes underlying speech comprehension. Eye-tracking and functional magnetic resonance imaging (fMRI) measurements were carried out with acoustic sentence-in-noise (SiN) stimuli complemented by pairs of pictures that either correctly (target picture) or incorrectly (competitor picture) depicted the sentence meanings. For the eye-tracking measurements, the time taken by the participants to start fixating the target picture (the ‘processing time’) was measured. For the fMRI measurements, brain activation inferred from blood-oxygen-level dependent responses following sentence comprehension was measured. A noise-only condition was also included. Groups of older hearing-impaired individuals matched in terms of age, hearing loss, and working memory capacity with (eHA; N = 13) or without (iHA; N = 14) HA experience participated. All acoustic stimuli were presented via earphones with individual linear amplification to ensure audibility. Consistent with previous findings, the iHA group had significantly longer (poorer) processing times than the eHA group, despite no differences in speech recognition performance. Concerning the fMRI measurements, there were indications of less brain activation in some right frontal areas for SiN relative to noise-only stimuli in the eHA group compared to the iHA group. Together, these results suggest that HA experience leads to faster speech-in-noise processing, possibly related to less recruitment of brain regions outside the core sentence-comprehension network. Follow-up research is needed to substantiate the findings related to changes in cortical speech processing with HA use

Predicting combined effect of reverberation and noise on binaural speech recognition in real classroom acoustics

Background: Good acoustics in classrooms is necessary to guarantee appropriate communication, teaching and learning practices. This work focuses on investigating the influence of reverberation and noise in real classrooms on binaural speech recognition. Material and Methods: Five experiments were designed based on realistic receiver positions in two representative Italian classrooms, one with an acoustical treatment and one without, where room impulse responses were measured at the ears of a head and torso simulator. In each room, interfering noise sources were placed at different distances and azimuths with respect to the receivers to account for binaural cues in speech recognition, namely at 0°, 120° and 180°. Babble noise was recorded in real classrooms during a break between lessons. The respective impulse responses were convolved with speech signals of the simplified Italian matrix test. This was presented via headphone to a group of adult normal-hearing listeners. Speech recognition was measured adaptively converging to a signal-to-noise ratio yielding 80% correct recognition scores (SRT80). For the classroom with a poor acoustics, several solutions for treatment were simulated using CATT-Acoustics®, including the adjustment of the absorption and scattering coefficients of surfaces to reach an optimum reverberation time. The effectiveness of these acoustic treatments was also evaluated in terms of speech recognition enhancement using the Binaural Speech Intelligibility Model (Rennies et al., 2013)