Validating a Rapid, Automated Test of Spatial Release From Masking

Speech-in-Noise Testing: An Introduction for Audiologists

Speech-in-noise testing has been proposed as a useful part of the audiometric test battery dating back to the earliest years of the field of audiology. Many speech-in-noise tests have been developed and used to varying degrees. However, multiple barriers have prevented speech-in-noise testing from being used widely in the clinic. The purpose of this article is to provide a resource to audiologists and other hearing health professionals who want to know (1) what tests are available for use, (2) the rationale behind specific tests, and (3) important considerations when selecting one or more tests to use clinically. In addition, data are presented for four speech-in-noise tests with the purpose of comparing outcomes as a function of age and hearing status. The four tests (QuickSIN, Words in Noise [WIN], Listening in Spatialized Noise-Sentences [LiSN-S], and Coordinate Response Measure [CRM]) were completed by 30 individuals from three groups: 10 young adults with normal hearing, 10 older adults with normal hearing, and 10 older adults with hearing loss. The results suggest that, despite significant differences in performance between groups, group overlap was present such that some individuals from one group performed similar to some individuals of other groups; therefore, individual performance was more important than associated group. When selecting an appropriate speech-in-noise test to use clinically, audiologists should carefully consider the purpose of their testing and the type of information they desire as an outcome. A quick-resource table and appendix is provided to aid audiologists and other health professionals in their selection of an appropriate speech-in-noise test.

Effects of Gamification on Assessment of Spatial Release From Masking

PURPOSE

Difficulty understanding speech in noise is a common communication problem. Clinical tests of speech in noise differ considerably from real-world listening and offer patients limited intrinsic motivation to perform well. In order to design a test that captures motivational aspects of real-world communication, this study investigated effects of gamification, or the inclusion of game elements, on a laboratory spatial release from masking test.

METHOD

Fifty-four younger adults with normal hearing completed a traditional laboratory and a gamified test of spatial release from masking in counterbalanced order. Masker level adapted based on performance, with the traditional test ending after 10 reversals and the gamified test ending when participants solved a visual puzzle. Target-to-masker ratio thresholds (TMRs) with colocated maskers, separated maskers, and estimates of spatial release were calculated after the 10th reversal for both tests and from the last six reversals of the adaptive track from the gamified test.

RESULTS

Thresholds calculated from the 10th reversal indicated no significant differences between the traditional and gamified tests. A learning effect was observed with spatially separated maskers, such that TMRs were better for the second test than the first, regardless of test order. Thresholds calculated from the last six reversals of the gamified test indicated better TMRs in the separated condition compared to the traditional test.

CONCLUSIONS

Adding gamified elements to a traditional test of spatial release from masking did not negatively affect test validity or estimates of spatial release. Participants were willing to continue playing the gamified test for an average of 30.2 reversals of the adaptive track. For some listeners, performance in the separated condition continued to improve after the 10th reversal, leading to better TMRs and greater spatial release from masking at the end of the gamified test compared to the traditional test.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.22028789.

Development and validation of a Spanish-language spatial release from masking task in a Mexican population

This study validates a new Spanish-language version of the Coordinate Response Measure (CRM) corpus using a well-established measure of spatial release from masking (SRM). Participants were 96 Spanish-speaking young adults without hearing complaints in Mexico City. To present the Spanish-language SRM test, we created new recordings of the CRM with Spanish-language Translations and updated the freely available app (PART; https://ucrbraingamecenter.github.io/PART_Utilities/) to present materials in Spanish. In addition to SRM, we collected baseline data on a battery of non-speech auditory assessments, including detection of frequency modulations, temporal gaps, and modulated broadband noise in the temporal, spectral, and spectrotemporal domains. Data demonstrate that the newly developed speech and non-speech tasks show similar reliability to an earlier report in English-speaking populations. This study demonstrates an approach by which auditory assessment for clinical and basic research can be extended to Spanish-speaking populations for whom testing platforms are not currently available.

Defining functional spatial boundaries using a spatial release from masking task

The classic spatial release from masking (SRM) task measures speech recognition thresholds for discrete separation angles between a target and masker. Alternatively, this study used a modified SRM task that adaptively measured the spatial-separation angle needed between a continuous male target stream (speech with digits) and two female masker streams to achieve a specific SRM. On average, 20 young normal-hearing listeners needed less spatial separation for 6 dB release than 9 dB release, and the presence of background babble reduced across-listener variability on the paradigm. Future work is needed to better understand the psychometric properties of this adaptive procedure.

Relating Suprathreshold Auditory Processing Abilities to Speech Understanding in Competition

(1) Background: Difficulty hearing in noise is exacerbated in older adults. Older adults are more likely to have audiometric hearing loss, although some individuals with normal pure-tone audiograms also have difficulty perceiving speech in noise. Additional variables also likely account for speech understanding in noise. It has been suggested that one important class of variables is the ability to process auditory information once it has been detected. Here, we tested a set of these “suprathreshold” auditory processing abilities and related them to performance on a two-part test of speech understanding in competition with and without spatial separation of the target and masking speech. Testing was administered in the Portable Automated Rapid Testing (PART) application developed by our team; PART facilitates psychoacoustic assessments of auditory processing. (2) Methods: Forty-one individuals (average age 51 years), completed assessments of sensitivity to temporal fine structure (TFS) and spectrotemporal modulation (STM) detection via an iPad running the PART application. Statistical models were used to evaluate the strength of associations between performance on the auditory processing tasks and speech understanding in competition. Age and pure-tone-average (PTA) were also included as potential predictors. (3) Results: The model providing the best fit also included age and a measure of diotic frequency modulation (FM) detection but none of the other potential predictors. However, even the best fitting models accounted for 31% or less of the variance, supporting work suggesting that other variables (e.g., cognitive processing abilities) also contribute significantly to speech understanding in noise. (4) Conclusions: The results of the current study do not provide strong support for previous suggestions that suprathreshold processing abilities alone can be used to explain difficulties in speech understanding in competition among older adults. This discrepancy could be due to the speech tests used, the listeners tested, or the suprathreshold tests chosen. Future work with larger numbers of participants is warranted, including a range of cognitive tests and additional assessments of suprathreshold auditory processing abilities.

Can visual capture of sound separate auditory streams?

In noisy contexts, sound discrimination improves when the auditory sources are separated in space. This phenomenon, named Spatial Release from Masking (SRM), arises from the interaction between the auditory information reaching the ear and spatial attention resources. To examine the relative contribution of these two factors, we exploited an audio-visual illusion in a hearing-in-noise task to create conditions in which the initial stimulation to the ears is held constant, while the perceived separation between speech and masker is changed illusorily (visual capture of sound). In two experiments, we asked participants to identify a string of five digits pronounced by a female voice, embedded in either energetic (Experiment 1) or informational (Experiment 2) noise, before reporting the perceived location of the heard digits. Critically, the distance between target digits and masking noise was manipulated both physically (from 22.5 to 75.0 degrees) and illusorily, by pairing target sounds with visual stimuli either at same (audio-visual congruent) or different positions (15 degrees offset, leftward or rightward: audio-visual incongruent). The proportion of correctly reported digits increased with the physical separation between the target and masker, as expected from SRM. However, despite effective visual capture of sounds, performance was not modulated by illusory changes of target sound position. Our results are compatible with a limited role of central factors in the SRM phenomenon, at least in our experimental setting. Moreover, they add to the controversial literature on the limited effects of audio-visual capture in auditory stream separation.

Effect of Masker Head Orientation, Listener Age, and Extended High-Frequency Sensitivity on Speech Recognition in Spatially Separated Speech

OBJECTIVES

Masked speech recognition is typically assessed as though the target and background talkers are all directly facing the listener. However, background speech in natural environments is often produced by talkers facing other directions, and talker head orientation affects the spectral content of speech, particularly at the extended high frequencies (EHFs; >8 kHz). This study investigated the effect of masker head orientation and listeners' EHF sensitivity on speech-in-speech recognition and spatial release from masking in children and adults.

DESIGN

Participants were 5- to 7-year-olds (n = 15) and adults (n = 34), all with normal hearing up to 8 kHz and a range of EHF hearing thresholds. Speech reception thresholds (SRTs) were measured for target sentences recorded from a microphone directly in front of the talker's mouth and presented from a loudspeaker directly in front of the listener, simulating a target directly in front of and facing the listener. The maskers were two streams of concatenated words recorded from a microphone located at either 0° or 60° azimuth, simulating masker talkers facing the listener or facing away from the listener, respectively. Maskers were presented in one of three spatial conditions: co-located with the target, symmetrically separated on either side of the target (+54° and -54° on the horizontal plane), or asymmetrically separated to the right of the target (both +54° on the horizontal plane).

RESULTS

Performance was poorer for the facing than for the nonfacing masker head orientation. This benefit of the nonfacing masker head orientation, or head orientation release from masking (HORM), was largest under the co-located condition, but it was also observed for the symmetric and asymmetric masker spatial separation conditions. SRTs were positively correlated with the mean 16-kHz threshold across ears in adults for the nonfacing conditions but not for the facing masker conditions. In adults with normal EHF thresholds, the HORM was comparable in magnitude to the benefit of a symmetric spatial separation of the target and maskers. Although children benefited from the nonfacing masker head orientation, their HORM was reduced compared to adults with normal EHF thresholds. Spatial release from masking was comparable across age groups for symmetric masker placement, but it was larger in adults than children for the asymmetric masker.

CONCLUSIONS

Masker head orientation affects speech-in-speech recognition in children and adults, particularly those with normal EHF thresholds. This is important because masker talkers do not all face the listener under most natural listening conditions, and assuming a midline orientation would tend to overestimate the effect of spatial separation. The benefits associated with EHF audibility for speech-in-speech recognition may warrant clinical evaluation of thresholds above 8 kHz.

Towards Child-Appropriate Virtual Acoustic Environments: A Database of High-Resolution HRTF Measurements and 3D-Scans of Children

Head-related transfer functions (HRTFs) play a significant role in modern acoustic experiment designs in the auralization of 3-dimensional virtual acoustic environments. This technique enables us to create close to real-life situations including room-acoustic effects, background noise and multiple sources in a controlled laboratory environment. While adult HRTF databases are widely available to the research community, datasets of children are not. To fill this gap, children aged 5-10 years old were recruited among 1st and 2nd year primary school children in Aachen, Germany. Their HRTFs were measured in the hemi-anechoic chamber with a 5-degree × 5-degree resolution. Special care was taken to reduce artifacts from motion during the measurements by means of fast measurement routines. To complement the HRTF measurements with the anthropometric data needed for individualization methods, a high-resolution 3D-scan of the head and upper torso of each participant was recorded. The HRTF measurement took around 3 min. The children's head movement during that time was larger compared to adult participants in comparable experiments but was generally kept within 5 degrees of rotary and 1 cm of translatory motion. Adult participants only exhibit this range of motion in longer duration measurements. A comparison of the HRTF measurements to the KEMAR artificial head shows that it is not representative of an average child HRTF. Difference can be seen in both the spectrum and in the interaural time delay (ITD) with differences of 70 μs on average and a maximum difference of 138 μs. For both spectrum and ITD, the KEMAR more closely resembles the 95th percentile of range of children's data. This warrants a closer look at using child specific HRTFs in the binaural presentation of virtual acoustic environments in the future.

Impaired Binaural Hearing in Adults: A Selected Review of the Literature

Despite over 100 years of study, there are still many fundamental questions about binaural hearing that remain unanswered, including how impairments of binaural function are related to the mechanisms of binaural hearing. This review focuses on a number of studies that are fundamental to understanding what is known about the effects of peripheral hearing loss, aging, traumatic brain injury, strokes, brain tumors, and multiple sclerosis (MS) on binaural function. The literature reviewed makes clear that while each of these conditions has the potential to impair the binaural system, the specific abilities of a given patient cannot be known without performing multiple behavioral and/or neurophysiological measurements of binaural sensitivity. Future work in this area has the potential to bring awareness of binaural dysfunction to patients and clinicians as well as a deeper understanding of the mechanisms of binaural hearing, but it will require the integration of clinical research with animal and computational modeling approaches.

Speech intelligibility with various head-related transfer functions: A computational modelling approach

Speech intelligibility (SI) is known to be affected by the relative spatial position between target and interferers. The benefit of a spatial separation is, along with other factors, related to the head-related transfer function (HRTF). The HRTF is individually different and thus, the cues that affect SI might also be different. In the current study, an auditory model was employed to predict SI with various HRTFs and at different angles on the horizontal plane. The predicted SI threshold was found to be largely different across HRTFs. Thus, individual listeners might have different access to SI cues, dependent on their HRTF.

Reliability and critical differences for an implementation of the coordinate response measure in speech-shaped noise

This study established test-retest reliability and critical differences for an implementation of the coordinate response measure (CRM) for the purpose of detecting significant changes in task performance. In normal-hearing adults, speech stimuli were presented monaurally at 50 dB sound pressure level in speech-shaped noise at signal-to-noise ratios (SNRs) of -12, -9, and -6 dB. Two runs were obtained. Intrasubject and intersubject variability were examined. Performance increased significantly with increasing SNR and in the second run. High variability was observed at each SNR. Critical differences indicated that only large changes in performance would be significant for the CRM as implemented in this study.

Comparing Spatial Release From Masking Using Traditional Methods and Portable Automated Rapid Testing iPad App

Purpose The purpose of this study was to compare speech identification abilities of individuals of various ages and hearing abilities using traditional methods and Portable Automated Rapid Testing (PART) iPad app. Method Speech identification data were collected using three techniques: over headphones using a virtual speaker array, using PART iPad app (UCR Brain Game Center, 2018), and using loudspeaker presentation in a sound-attenuated room. For all three techniques, Coordinate Response Measure sentences were used as the stimuli and "Charlie" was used as the call sign. A progressive tracking procedure was used to estimate the speech identification thresholds for listeners with varying hearing thresholds. The target sentence was always presented at 0° azimuth angle, whereas the maskers were colocated (0°) with the target or symmetrically spatially separated by ±15°, ±30°, or ±45°. Results Data analysis revealed similar speech identification thresholds for the iPad and headphone conditions and slightly poorer thresholds for the loudspeaker array condition across participant groups. This was true for all spatial separations between the target and the maskers. Conclusion Strong correlation between the headphone and iPad data presented in this study indicated that the spatial release from masking module in the PART iPad app can be used as a clinical tool to assess spatial processing ability prior to audiologic evaluation in the clinic and can also be used to make recommendations for and to track progress with aural rehabilitation programs over time.

Age-Related Deficits in Electrophysiological and Behavioral Measures of Binaural Temporal Processing

Binaural processing, particularly the processing of interaural phase differences, is important for sound localization and speech understanding in background noise. Age has been shown to impact the neural encoding and perception of these binaural temporal cues even in individuals with clinically normal hearing sensitivity. This work used a new electrophysiological response, called the interaural phase modulation-following response (IPM-FR), to examine the effects of age on the neural encoding of interaural phase difference cues. Relationships between neural recordings and performance on several behavioral measures of binaural processing were used to determine whether the IPM-FR is predictive of interaural phase difference sensitivity and functional speech understanding deficits. Behavioral binaural frequency modulation detection thresholds were measured to assess sensitivity to interaural phase differences while spatial release-from-masking thresholds were used to assess speech understanding abilities in spatialized noise. Thirty adults between the ages of 35 to 74 years with normal low-frequency hearing thresholds were used in this study. Data showed that older participants had weaker neural responses to the interaural phase difference cue and were less able to take advantage of binaural cues for speech understanding compared to younger participants. Results also showed that the IPM-FR was predictive of performance on the binaural frequency modulation detection task, but not on the spatial release-from-masking task after accounting the effects of age. These results confirm previous work that showed that the IPM-FR reflects age-related declines in binaural temporal processing and provide further evidence that this response may represent a useful objective tool for assessing binaural function. However, further research is needed to understand how the IPM-FR is related to speech understanding abilities.

Portable Automated Rapid Testing (PART) for auditory assessment: Validation in a young adult normal-hearing population

This study aims to determine the degree to which Portable Automated Rapid Testing (PART), a freely available program running on a tablet computer, is capable of reproducing standard laboratory results. Undergraduate students were assigned to one of three within-subject conditions that examined repeatability of performance on a battery of psychoacoustical tests of temporal fine structure processing, spectro-temporal amplitude modulation, and targets in competition. The repeatability condition examined test/retest with the same system, the headphones condition examined the effects of varying headphones (passive and active noise-attenuating), and the noise condition examined repeatability in the presence of recorded cafeteria noise. In general, performance on the test battery showed high repeatability, even across manipulated conditions, and was similar to that reported in the literature. These data serve as validation that suprathreshold psychoacoustical tests can be made accessible to run on consumer-grade hardware and perform in less controlled settings. This dataset also provides a distribution of thresholds that can be used as a normative baseline against which auditory dysfunction can be identified in future work.

Spatial Release from Masking Using Clinical Corpora: Sentence Recognition in a Colocated or Spatially Separated Speech Masker

BACKGROUND

Speech recognition in complex multisource environments is challenging, particularly for listeners with hearing loss. One source of difficulty is the reduced ability of listeners with hearing loss to benefit from spatial separation of the target and masker, an effect called spatial release from masking (SRM). Despite the prevalence of complex multisource environments in everyday life, SRM is not routinely evaluated in the audiology clinic.

PURPOSE

The purpose of this study was to demonstrate the feasibility of assessing SRM in adults using widely available tests of speech-in-speech recognition that can be conducted using standard clinical equipment.

RESEARCH DESIGN

Participants were 22 young adults with normal hearing. The task was masked sentence recognition, using each of five clinically available corpora with speech maskers. The target always sounded like it originated from directly in front of the listener, and the masker either sounded like it originated from the front (colocated with the target) or from the side (separated from the target). In the real spatial manipulation conditions, source location was manipulated by routing the target and masker to either a single speaker or to two speakers: one directly in front of the participant, and one mounted in an adjacent corner, 90° to the right. In the perceived spatial separation conditions, the target and masker were presented from both speakers with delays that made them sound as if they were either colocated or separated.

RESULTS

With real spatial manipulations, the mean SRM ranged from 7.1 to 11.4 dB, depending on the speech corpus. With perceived spatial manipulations, the mean SRM ranged from 1.8 to 3.1 dB. Whereas real separation improves the signal-to-noise ratio in the ear contralateral to the masker, SRM in the perceived spatial separation conditions is based solely on interaural timing cues.

CONCLUSIONS

The finding of robust SRM with widely available speech corpora supports the feasibility of measuring this important aspect of hearing in the audiology clinic. The finding of a small but significant SRM in the perceived spatial separation conditions suggests that modified materials could be used to evaluate the use of interaural timing cues specifically.

A Comparison of Behavioral Methods for Indexing the Auditory Processing of Temporal Fine Structure Cues

Purpose Growing evidence supports the inclusion of perceptual tests that quantify the processing of temporal fine structure (TFS) in clinical hearing assessment. Many tasks have been used to evaluate TFS in the laboratory that vary greatly in the stimuli used and whether the judgments require monaural or binaural comparisons of TFS. The purpose of this study was to compare laboratory measures of TFS for inclusion in a battery of suprathreshold auditory tests. A subset of available TFS tasks were selected on the basis of potential clinical utility and were evaluated using metrics that focus on characteristics important for clinical use. Method TFS measures were implemented in replication of studies that demonstrated clinical utility. Monaural, diotic, and dichotic measures were evaluated in 11 young listeners with normal hearing. Measures included frequency modulation (FM) tasks, harmonic frequency shift detection, interaural phase difference (TFS-low frequency), interaural time difference (ITD), monaural gap duration discrimination, and tone detection in noise with and without a difference in interaural phase (N0S0, N0Sπ). Data were compared with published results and evaluated with metrics of consistency and efficiency. Results Thresholds obtained were consistent with published data. There was no evidence of predictive relationships among the measures consistent with a homogenous group. The most stable tasks across repeated testing were TFS-low frequency, diotic and dichotic FM, and N0Sπ. Monaural and diotic FM had the lowest normalized variance and were the most efficient accounting for differences in total test duration, followed by ITD. Conclusions Despite a long stimulus duration, FM tasks dominated comparisons of consistency and efficiency. Small differences separated the dichotic tasks FM, ITD, and N0Sπ. Future comparisons following procedural optimization of the tasks will evaluate clinical efficiency in populations with impairment.

The effects of auditory spatial training on informational masking release in elderly listeners: a study protocol for a randomized clinical trial

Background: Regarding the strong auditory spatial plasticity capability of the central auditory system and the effect of short-term and long-term rehabilitation programs in elderly people, it seems that an auditory spatial training can help this population in informational masking release and better track speech in noisy environments. The main purposes of this study are developing an informational masking measurement test and an auditory spatial training program. Protocol: This study will be conducted in two parts. Part 1: develop and determine the validity of an informational masking measurement test by recruiting two groups of young (n=50) and old (n=50) participants with normal hearing who have no difficulty in understanding speech in noisy environments. Part 2 (clinical trial): two groups of 60-75-year-olds with normal hearing, who complain about difficulty in speech perception in noisy environments, will participate as control and intervention groups to examine the effect of auditory spatial training. Intervention: 15 sessions of auditory spatial training. The informational masking measurement test and Speech, Spatial and Qualities of Hearing Scale will be compared before intervention, immediately after intervention, and five weeks after intervention between the two groups. Discussion: Since auditory training programs do not deal with informational masking release, an auditory spatial training will be designed, aiming to improve hearing in noisy environments for elderly populations. Trial registration: Iranian Registry of Clinical Trials ( IRCT20190118042404N1) on 25 th February 2019.

Effects of Acquired Aphasia on the Recognition of Speech Under Energetic and Informational Masking Conditions

Persons with aphasia (PWA) often report difficulty understanding spoken language in noisy environments that require listeners to identify and selectively attend to target speech while ignoring competing background sounds or “maskers.” This study compared the performance of PWA and age-matched healthy controls (HC) on a masked speech identification task and examined the consequences of different types of masking on performance. Twelve PWA and 12 age-matched HC completed a speech identification task comprising three conditions designed to differentiate between the effects of energetic and informational masking on receptive speech processing. The target and masker speech materials were taken from a closed-set matrix-style corpus, and a forced-choice word identification task was used. Target and maskers were spatially separated from one another in order to simulate real-world listening environments and allow listeners to make use of binaural cues for source segregation. Individualized frequency-specific gain was applied to compensate for the effects of hearing loss. Although both groups showed similar susceptibility to the effects of energetic masking, PWA were more susceptible than age-matched HC to the effects of informational masking. Results indicate that this increased susceptibility cannot be attributed to age, hearing loss, or comprehension deficits and is therefore a consequence of acquired cognitive-linguistic impairments associated with aphasia. This finding suggests that aphasia may result in increased difficulty segregating target speech from masker speech, which in turn may have implications for the ability of PWA to comprehend target speech in multitalker environments, such as restaurants, family gatherings, and other everyday situations.

Normative Data for a Rapid, Automated Test of Spatial Release From Masking

Purpose

The purpose of this study is to report normative data and predict thresholds for a rapid test of spatial release from masking for speech perception. The test is easily administered and has good repeatability, with the potential to be used in clinics and laboratories. Normative functions were generated for adults varying in age and amounts of hearing loss.

Method

The test of spatial release presents a virtual auditory scene over headphones with 2 conditions: colocated (with target and maskers at 0°) and spatially separated (with target at 0° and maskers at ± 45°). Listener thresholds are determined as target-to-masker ratios, and spatial release from masking (SRM) is determined as the difference between the colocated condition and spatially separated condition. Multiple linear regression was used to fit the data from 82 adults 18–80 years of age with normal to moderate hearing loss (0–40 dB HL pure-tone average [PTA]). The regression equations were then used to generate normative functions that relate age (in years) and hearing thresholds (as PTA) to target-to-masker ratios and SRM.

Results

Normative functions were able to predict thresholds with an error of less than 3.5 dB in all conditions. In the colocated condition, the function included only age as a predictive parameter, whereas in the spatially separated condition, both age and PTA were included as parameters. For SRM, PTA was the only significant predictor. Different functions were generated for the 1st run, the 2nd run, and the average of the 2 runs. All 3 functions were largely similar in form, with the smallest error being associated with the function on the basis of the average of 2 runs.

Conclusion

With the normative functions generated from this data set, it would be possible for a researcher or clinician to interpret data from a small number of participants or even a single patient without having to first collect data from a control group, substantially reducing the time and resources needed.

Supplemental Material

https://doi.org/10.23641/asha.7080878

Does the semantic content or syntactic regularity of masker speech affect speech-on-speech recognition?

Speech-on-speech recognition differs substantially across stimuli, but it is unclear what role linguistic features of the masker play in this variability. The linguistic similarity hypothesis suggests similarity between sentence-level semantic content of the target and masker speech increases masking. Sentence recognition in a two-talker masker was evaluated with respect to semantic content and syntactic structure of the masker (experiment 1) and linguistic similarity of the target and masker (experiment 2). Target and masker sentences were semantically meaningful or anomalous. Masker syntax was varied or the same across sentences. When other linguistic features of the masker were controlled, variability in syntactic structure across masker tokens was only relevant when the masker was played continuously (as opposed to gated); when played continuously, sentence-recognition thresholds were poorer with variable than consistent masker syntax, but this effect was small (0.5 dB). When the syntactic structure of the masker was held constant, semantic meaningfulness of the masker did not increase masking, and at times performance was better for the meaningful than the anomalous masker. These data indicate that sentence-level semantic content of the masker speech does not influence speech-on-speech masking. Further, no evidence that similarities between target/masker sentence-level semantic content increases masking was found.

Development and validation of Portable Automated Rapid Testing (PART) measures for auditory research

The current state of consumer-grade electronics means that researchers, clinicians, students, and members of the general public across the globe can create high-quality auditory stimuli using tablet computers, built-in sound hardware, and calibrated consumer-grade headphones. Our laboratories have created a free application that supports this work: PART (Portable Automated Rapid Testing). PART has implemented a range of psychoacoustical tasks including: spatial release from speech-on-speech masking, binaural sensitivity, gap discrimination, temporal modulation, spectral modulation, and spectrotemporal modulation (STM). Here, data from the spatial release and STM tasks are presented. Data were collected across the globe on tablet computers using applications available for free download, built-in sound hardware, and calibrated consumer-grade headphones. Spatial release results were as good or better than those obtained with standard laboratory methods. Spectrotemporal modulation thresholds were obtained rapidly and, for younger normal hearing listeners, were also as good or better than those in the literature. For older hearing impaired listeners, rapid testing resulted in similar thresholds to those reported in the literature. Listeners at five different testing sites produced very similar STM thresholds, despite a variety of testing conditions and calibration routines. Download Spatial Release, PART, and Listen: An Auditory Training Experience for free at https://bgc.ucr.edu/games/.