Ian Phillips

Purpose: Some bilinguals may exhibit lower performance when recognizing speech in noise (SiN) in their second language (L2) compared to monolinguals in their first language. Poorer performance has been found mostly for late bilinguals (L2 acquired after childhood) listening to sentences containing linguistic context and less so for simultaneous/early bilinguals (L2 acquired during childhood) and when testing context-free stimuli. However, most previous studies tested younger participants, meaning little is known about interactions with age; the purpose of this study was to address this gap. Method: Context-free SiN understanding was measured via the Modified Rhyme Test (MRT) in 3,803 young and middle-aged bilingual and monolingual adults (ages 18–57 years; 19.6% bilinguals, all L2 English) with normal to near-normal hearing. Bilingual adults included simultaneous ( n = 462), early ( n = 185), and late ( n = 97) bilinguals. Performance on the MRT was measured with both accuracy and response time. A self-reported measure of current English use was also collected for bilinguals to evaluate its impact on MRT performance. Results: Current age impacted MRT accuracy scores differently for each listener group. Relative to monolinguals, simultaneous and early bilinguals showed decreased performance with older age. Response times slowed with increasing current age at similar rates for all groups, despite faster overall response times for monolinguals. Among all bilingual listeners, greater current English language use predicted higher MRT accuracy. For simultaneous bilinguals, greater English use was associated with faster response times. Conclusions: SiN outcomes in bilingual adults are impacted by age at time of testing and by fixed features of their language history (i.e., age of acquisition) as well as language practices, which can shift over time (i.e., current language use). Results support routine querying of language history and use in the audiology clinic. Supplemental Material: https://doi.org/10.23641/asha.28405430

Purpose: Some bilinguals may exhibit lower performance when understanding speech in noise (SIN) in their second language (L2) compared to monolinguals in their first language. Poorer performance has been found mostly for late bilinguals (L2 acquired after childhood) listening to sentences containing linguistic context, and less so for simultaneous/early bilinguals (L2 acquired during childhood) and when testing context-free stimuli. However, most previous studies tested younger participants, meaning little is known about interactions with age; the purpose of this study was to address this gap.Method: Context-free SIN understanding was measured via the Modified Rhyme Test (MRT) in 3836 young and middle-aged bilingual and monolingual adults (ages 18–57; 19.5% bilinguals, all L2 English) with normal to near-normal hearing. Bilingual adults included simultaneous (n = 466), early (n = 185), and late (n = 97) bilinguals. Performance on the MRT was measured with both accuracy and response time. A self-reported measure of current English use was also collected for bilinguals to evaluate its impact on MRT performance.Results: Age impacted MRT accuracy scores differently for each listener group. Relative to monolinguals, simultaneous and early bilinguals showed decreased performance with older age. Response times slowed with older age at similar rates for all groups, despite faster overall response times for monolinguals. Among all bilingual listeners, greater current English language use predicted higher MRT accuracy. For simultaneous bilinguals, greater English use was associated with faster response times. Conclusions: Speech-in-noise outcomes in bilingual adults are impacted not only by fixed features of their language history (i.e. age of acquisition) but also by language practices which can shift over time (i.e. current language use), supporting routine querying of language history and use in the Audiology clinic.

Transcutaneous auricular vagus nerve stimulation (taVNS) is a neuromodulatory technique that may have numerous potential health and human performance benefits. However, optimal stimulation parameters for maximizing taVNS efficacy are unknown. Progress is impeded by disagreement on the identification of a biomarker that reliably indexes activation of neuromodulatory systems targeted by taVNS, including the locus coeruleus‐norepinephrine (LC‐NE) system. Pupil size varies with LC‐NE activity and is one potential taVNS biomarker that has shown inconsistent sensitivity to taVNS in prior studies. The present study examined the relationship between pupil size and taVNS using stimulation parameters that have shown promising behavioral effects in prior studies but have received comparatively little attention. Participants received trains of 50 μs taVNS pulses delivered continuously below perceptual threshold at 300 Hz to the left external acoustic meatus (EAM) while pupil size was recorded during a pupillary light reflex task. Analysis of pupil size using generalized additive mixed modeling (GAMM) revealed a non‐linear relationship between taVNS intensity and pupil diameter. Active taVNS increased pupil size during stimulation for participants who received taVNS between 2 and approximately 4.8 mA, but not for participants who received higher‐intensity taVNS (up to 8.1 mA). In addition, taVNS effects persisted in subsequent blocks, mitigating decreases in pupil size over the course of the task. These findings suggest 300 Hz taVNS activates the LC‐NE system when applied to the EAM, but its effects may be counteracted at higher intensities.

Purpose: The purpose of this study was to explore potential differences in suprathreshold auditory function among native and nonnative speakers of English as a function of age. Method: Retrospective analyses were performed on three large data sets containing suprathreshold auditory tests completed by 5,572 participants who were self-identified native and nonnative speakers of English between the ages of 18–65 years, including a binaural tone detection test, a digit identification test, and a sentence recognition test. Results: The analyses show a significant interaction between increasing age and participant group on tests involving speech-based stimuli (digit strings, sentences) but not on the binaural tone detection test. For both speech tests, differences in speech recognition emerged between groups during early adulthood, and increasing age had a more negative impact on word recognition for nonnative compared to native participants. Age-related declines in performance were 2.9 times faster for digit strings and 3.3 times faster for sentences for nonnative participants compared to native participants. Conclusions: This set of analyses extends the existing literature by examining interactions between aging and self-identified native English speaker status in several auditory domains in a cohort of adults spanning young adulthood through middle age. The finding that older nonnative English speakers in this age cohort may have greater-than-expected deficits on speech-in-noise perception may have clinical implications on how these individuals should be diagnosed and treated for hearing difficulties.

Transcutaneous auricular vagus nerve stimulation (taVNS) is a neuromodulatory technique that may have numerous potential health and human performance benefits. However, optimal stimulation parameters for maximizing taVNS efficacy are unknown. Progress is impeded by disagreement on the identification of a biomarker that reliably indexes activation of neuromodulatory systems targeted by taVNS, including the locus coeruleus-norepinephrine (LC-NE) system. Pupil size varies with LC-NE activity and is one potential taVNS biomarker that has shown inconsistent sensitivity to taVNS in prior studies. The present study examined the relationship between pupil size and taVNS using stimulation parameters that have shown promising behavioral effects in prior studies but have received comparatively little attention. Participants received 30-second trains of 50 μs taVNS pulses delivered below perceptual threshold at 300 Hz to the left external acoustic meatus (EAM) while pupil size was recorded during a pupillary light reflex task. Analysis of pupil size using generalized additive mixed modelling (GAMM) revealed a nonlinear relationship between taVNS intensity and pupil diameter. Active taVNS increased pupil size during stimulation for participants who received taVNS between 2 and approximately 4.8 mA, but not for participants who received higher intensity taVNS (up to 8.1 mA). In addition, taVNS effects persisted in subsequent blocks, mitigating decreases in pupil size over the course of the task. These findings suggest 300 Hz taVNS activates the LC-NE system when applied to the EAM, but its effects may be counteracted at higher intensities.

Purpose: The purpose of this study was to explore potential differences in suprathreshold auditory function among native and nonnative speakers of English as a function of age. Method: Retrospective analyses were performed on three large datasets containing suprathreshold auditory tasks completed by 5572 participants who were self-identified native and nonnative speakers of English between the ages of 18–65, including a binaural tone detection task, a digit identification task, and a sentence recognition task.Results: The analyses show a significant interaction between increasing age and participant group on tasks involving speech-based stimuli (digit strings, sentences) but not on the binaural tone detection task. For both speech tasks, differences in speech recognition emerged between groups during early adulthood and increasing age had a more negative impact on word recognition for nonnative compared to native participants. Age-related declines in performance were 2.9 times faster for digit strings and 3.3 times faster for sentences for nonnative participants compared to native participants. Conclusions: This set of analyses extends the existing literature by examining interactions between aging and language background in several auditory domains in a cohort of adults spanning young adulthood through middle age. The finding that older nonnative English speakers in this age cohort may have greater than expected deficits on speech-in-noise perception may have clinical implications on how these individuals should be diagnosed and treated for hearing difficulties.

Pure-tone thresholds are often a poor predictor of hearing difficulties experienced by patients in audiology clinics. Approximately 25 million Americans may experience hearing difficulties despite having audiometric thresholds within normal limits. Pupil diameter increases with increasing listening effort and could provide an objective measure for determining the presence of such subclinical hearing problems. However, the cost and technical requirements of research-grade eye trackers have limited their use in audiology clinics. This study aims to determine the feasibility of using a commercially-available head mounted display (HMD) with integrated eye tracking to collect pupillometry measures during audiological testing. Pupillary data were collected for N = 46 younger normal-hearing adults while they completed clinically-relevant tests including pure tone audiometry, gaps-in-noise (GIN), dichotic digits, and speech-in-noise tests. Across tasks, task-evoked pupillary responses were generally sensitive to differences in listening demands. Results suggest audiologic testing with commercial HMD eye trackers is feasible and provides additional objective information related to listening effort that may help clinicians better understand and address patient needs. [The views expressed in this abstract are those of theauthors and do not reflect the official policy of the Department of Army/Navy/Air Force, Department of Defense, or U.S. Government.]

Some bilinguals may perform worse understanding speech in noise (SIN) in their second language (L2) compared to monolinguals. Poorer performance has been found mostly for late bilinguals (L2 acquired after childhood) listening to sentences containing linguistic context, and less so for simultaneous/early bilinguals (L2 acquired during childhood) and when testing context-free stimuli. However, most studies tested younger participants–little is known about interactions with age. This study addresses this gap by measuring context-free SIN understanding via the Modified Rhyme Test in over 2,000 normal-hearing young and middle-aged bilingual and monolingual adults (ages 18–58; 23% bilinguals, all L2 English). Data collection is ongoing. Interim analyses reveal an interaction of age and group. Word recognition accuracy decreased as age increased for simultaneous and early bilinguals, but was stable for monolinguals and late bilinguals (though worse for bilinguals than monolinguals). Response time was faster for monolinguals but all groups slowed with increasing age at similar rates. These findings suggest an exaggerated age effect for bilingual SIN understanding across early and middle adulthood. [The views expressed in this abstract are those of the author(s) and do not necessarily reflect the official policy of the Department of Defense or the U.S. Government.]

Difficulty perceiving phonological contrasts in a second language (L2) can impede initial L2 lexical learning. Such is the case for English speakers learning tonal languages, like Mandarin Chinese. Given the hypothesized role of reduced neuroplasticity in adulthood limiting L2 phonological perception, the current study examined whether transcutaneous auricular vagus nerve stimulation (taVNS), a relatively new neuromodulatory technique, can facilitate L2 lexical learning for English speakers learning Mandarin Chinese over 2 days. Using a double-blind design, one group of participants received 10 min of continuous priming taVNS before lexical training and testing each day, a second group received 500 msec of peristimulus (peristim) taVNS preceding each to-be-learned item in the same tasks, and a third group received passive sham stimulation. Results of the lexical recognition test administered at the end of each day revealed evidence of learning for all groups, but a higher likelihood of accuracy across days for the peristim group and a greater improvement in response time between days for the priming group. Analyses of N400 ERP components elicited during the same tasks indicate behavioral advantages for both taVNS groups coincided with stronger lexico-semantic encoding for target words. Comparison of these findings to pupillometry results for the same study reported in Pandža, N. B., Phillips, I., Karuzis, V. P., O'Rourke, P., and Kuchinsky, S. E. (Neurostimulation and pupillometry: New directions for learning and research in applied linguistics. Annual Review of Applied Linguistics, 40, 56–77, 2020) suggest that positive effects of priming taVNS (but not peristim taVNS) on lexico-semantic encoding are related to sustained attentional effort.