Relating Suprathreshold Auditory Processing Abilities to Speech Understanding in Competition

Individual differences elucidate the perceptual benefits associated with robust temporal fine-structure processing

The auditory system is unique among sensory systems in its ability to phase lock to and precisely follow very fast cycle-by-cycle fluctuations in the phase of sound-driven cochlear vibrations. Yet, the perceptual role of this temporal fine structure (TFS) code is debated. This fundamental gap is attributable to our inability to experimentally manipulate TFS cues without altering other perceptually relevant cues. Here, we circumnavigated this limitation by leveraging individual differences across 200 participants to systematically compare variations in TFS sensitivity to performance in a range of speech perception tasks. TFS sensitivity was assessed through detection of interaural time/phase differences, while speech perception was evaluated by word identification under noise interference. Results suggest that greater TFS sensitivity is not associated with greater masking release from fundamental-frequency or spatial cues but appears to contribute to resilience against the effects of reverberation. We also found that greater TFS sensitivity is associated with faster response times, indicating reduced listening effort. These findings highlight the perceptual significance of TFS coding for everyday hearing.

The Audible Contrast Threshold (ACT) test: A clinical spectro-temporal modulation detection test

Over the last decade, multiple studies have shown that hearing-impaired listeners' speech-in-noise reception ability, measured with audibility compensation, is closely associated with performance in spectro-temporal modulation (STM) detection tests. STM tests thus have the potential to provide highly relevant beyond-the-audiogram information in the clinic, but the available STM tests have not been optimized for clinical use in terms of test duration, required equipment, and procedural standardization. The present study introduces a quick-and-simple clinically viable STM test, named the Audible Contrast Threshold (ACT™) test. First, an experimenter-controlled STM measurement paradigm was developed, in which the patient is presented bilaterally with a continuous audibility-corrected noise via headphones and asked to press a pushbutton whenever they hear an STM target sound in the noise. The patient's threshold is established using a Hughson-Westlake tracking procedure with a three-out-of-five criterion and then refined by post-processing the collected data using a logistic function. Different stimulation paradigms were tested in 28 hearing-impaired participants and compared to data previously measured in the same participants with an established STM test paradigm. The best stimulation paradigm showed excellent test-retest reliability and good agreement with the established laboratory version. Second, the best stimulation paradigm with 1-second noise "waves" (windowed noise) was chosen, further optimized with respect to step size and logistic-function fitting, and tested in a population of 25 young normal-hearing participants using various types of transducers to obtain normative data. Based on these normative data, the "normalized Contrast Level" (in dB nCL) scale was defined, where 0 ± 4 dB nCL corresponds to normal performance and elevated dB nCL values indicate the degree of audible contrast loss. Overall, the results of the present study suggest that the ACT test may be considered a reliable, quick-and-simple (and thus clinically viable) test of STM sensitivity. The ACT can be measured directly after the audiogram using the same set up, adding only a few minutes to the process.

Effects of Temporal Processing on Speech-in-Noise Perception in Middle-Aged Adults

Auditory temporal processing is a vital component of auditory stream segregation, or the process in which complex sounds are separated and organized into perceptually meaningful objects. Temporal processing can degrade prior to hearing loss, and is suggested to be a contributing factor to difficulties with speech-in-noise perception in normal-hearing listeners. The current study tested this hypothesis in middle-aged adults-an under-investigated cohort, despite being the age group where speech-in-noise difficulties are first reported. In 76 participants, three mechanisms of temporal processing were measured: peripheral auditory nerve function using electrocochleography, subcortical encoding of periodic speech cues (i.e., fundamental frequency; F0) using the frequency following response, and binaural sensitivity to temporal fine structure (TFS) using a dichotic frequency modulation detection task. Two measures of speech-in-noise perception were administered to explore how contributions of temporal processing may be mediated by different sensory demands present in the speech perception task. This study supported the hypothesis that temporal coding deficits contribute to speech-in-noise difficulties in middle-aged listeners. Poorer speech-in-noise perception was associated with weaker subcortical F0 encoding and binaural TFS sensitivity, but in different contexts, highlighting that diverse aspects of temporal processing are differentially utilized based on speech-in-noise task characteristics.

Aging affects auditory contributions to focus perception in Jianghuai Mandarina)

Speakers can place their prosodic prominence on any locations within a sentence, generating focus prosody for listeners to perceive new information. This study aimed to investigate age-related changes in the bottom-up processing of focus perception in Jianghuai Mandarin by clarifying the perceptual cues and the auditory processing abilities involved in the identification of focus locations. Young, middle-aged, and older speakers of Jianghuai Mandarin completed a focus identification task and an auditory perception task. The results showed that increasing age led to a decrease in listeners' accuracy rate in identifying focus locations, with all participants performing the worst when dynamic pitch cues were inaccessible. Auditory processing abilities did not predict focus perception performance in young and middle-aged listeners but accounted significantly for the variance in older adults' performance. These findings suggest that age-related deteriorations in focus perception can be largely attributed to declined auditory processing of perceptual cues. Poor ability to extract frequency modulation cues may be the most important underlying psychoacoustic factor for older adults' difficulties in perceiving focus prosody in Jianghuai Mandarin. The results contribute to our understanding of the bottom-up mechanisms involved in linguistic prosody processing in aging adults, particularly in tonal languages.

Testing the Informativeness of Diverse Measures of Auditory Processing for Clinical Audiological Practice in Middle-Aged Adults in Mexico

PURPOSE

Standard clinical audiologic assessment is limited in its ability to capture variance in self-reported hearing difficulty. Additionally, the costs associated with clinical testing in audiology create financial barriers for hearing health care in developing countries like Mexico. This study used an open-source Spanish-language tool called PART (Portable Automated Rapid Testing) to test the hypothesis that a battery of assessments of auditory processing can complement standard clinical audiological assessment to better capture the variance of self-reported hearing difficulty.

METHOD

Forty-three adults between 40 and 69 years of age were tested in Mexico City using a traditional clinical pure-tone audiogram, cognitive screening, and a battery of PART-based auditory processing assessments including a speech-on-speech competition spatial release from masking task. Results were compared to self-reported hearing difficulty, assessed with a Spanish-language adaptation of the Hearing Handicap Inventory for the Elderly-Screening Version (HHIE-S).

RESULTS

Several measures from the PART battery exhibited stronger correlations with self-reported hearing difficulties than the pure-tone audiogram. The spatial release from masking task best captured variance in HHIE-S scores and remained significant after controlling for the effects of age, audibility, and cognitive score.

CONCLUSIONS

The spatial release from masking task can complement traditional clinical measures to better account for patient's self-reported hearing difficulty. Open-source access to this test in PART supports its implementation for Spanish speakers in clinical settings around the world at low cost.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.24470140.

Validation of the adaptive scan method in the quest for time-efficient methods of testing auditory processes

A major barrier to the clinical application of psychophysical testing of central auditory processes is the time required to obtain precise estimates of different listening abilities. In this study, we validate a novel adaptive scan (AS) method of threshold estimation that is designed to adapt on a range of values around threshold rather than on a single threshold value. This method has the advantage of providing the listener with greater familiarity with the stimulus characteristics near threshold while maintaining precise measurement and increasing time-efficiency. Additionally, we explore the time-efficiency of AS through comparison with two more conventional adaptive algorithms and the method of constant stimuli in two common psychophysical tasks: the detection of a gap in noise and the detection of a tone in noise. Seventy undergraduates without hearing complaints were tested using all four methods. The AS method provided similar threshold estimates with similar precision to those from the other adaptive methods and, thus, it is a valid adaptive method of psychophysical testing. We also provide an analysis of the AS method based on precision metrics to propose a shortened version of the algorithm that maximizes the time/precision tradeoff and can achieve similar thresholds to the adaptive methods tested in the validation. This work lays the foundation for using AS across a wide variety of psychophysical assessments and experimental situations where different levels of precision and/or time-efficiency may be required.

Remote auditory assessment using Portable Automated Rapid Testing (PART) and participant-owned devices

Remote testing of auditory function can be transformative to both basic research and hearing healthcare; however, historically, many obstacles have limited remote collection of reliable and valid auditory psychometric data. Here, we report performance on a battery of auditory processing tests using a remotely administered system, Portable Automatic Rapid Testing. We compare a previously reported dataset collected in a laboratory setting with the same measures using uncalibrated, participant-owned devices in remote settings (experiment 1, n = 40) remote with and without calibrated hardware (experiment 2, n = 36) and laboratory with and without calibrated hardware (experiment 3, n = 58). Results were well-matched across datasets and had similar reliability, but overall performance was slightly worse than published norms. Analyses of potential nuisance factors such as environmental noise, distraction, or lack of calibration failed to provide reliable evidence that these factors contributed to the observed variance in performance. These data indicate feasibility of remote testing of suprathreshold auditory processing using participants' own devices. Although the current investigation was limited to young participants without hearing difficulties, its outcomes demonstrate the potential for large-scale, remote hearing testing of more hearing-diverse populations both to advance basic science and to establish the clinical viability of auditory remote testing.