The Costs (and Benefits?) of Effortful Listening for Older Adults: Insights from Simultaneous Electrophysiology, Pupillometry, and Memory.

Although the impact of acoustic challenge on speech processing and memory increases as a person ages, older adults may engage in strategies that help them compensate for these demands. In the current preregistered study, older adults (n = 48) listened to sentences-presented in quiet or in noise-that were high constraint with either expected or unexpected endings or were low constraint with unexpected endings. Pupillometry and EEG were simultaneously recorded, and subsequent sentence recognition and word recall were measured. Like young adults in prior work, we found that noise led to increases in pupil size, delayed and reduced ERP responses, and decreased recall for unexpected words. However, in contrast to prior work in young adults where a larger pupillary response predicted a recovery of the N400 at the cost of poorer memory performance in noise, older adults did not show an associated recovery of the N400 despite decreased memory performance. Instead, we found that in quiet, increases in pupil size were associated with delays in N400 onset latencies and increased recognition memory performance. In conclusion, we found that transient variation in pupil-linked arousal predicted trade-offs between real-time lexical processing and memory that emerged at lower levels of task demand in aging. Moreover, with increased acoustic challenge, older adults still exhibited costs associated with transient increases in arousal without the corresponding benefits.

Within-talker and within-session stability of acoustic characteristics of conversational and clear speaking stylesa).

In speech production research, talkers often perform a speech task several times per recording session with different speaking styles or in different environments. For example, Lombard speech studies typically have talkers speak in several different noise conditions. However, it is unknown to what degree simple repetition of a speech task affects speech acoustic characteristics or whether repetition effects might offset or exaggerate effects of speaking style or environment. The present study assessed speech acoustic changes over four within-session repetitions of a speech production taskset performed with two speaking styles recorded in separate sessions: conversational and clear speech. In each style, ten talkers performed a set of three speech tasks four times. Speaking rate, median fundamental frequency, fundamental frequency range, and mid-frequency spectral energy for read sentences were measured and compared across test blocks both within-session and between the two styles. Results indicate that statistically significant changes can occur from one repetition of a speech task to the next, even with a brief practice set and especially in the conversational style. While these changes were smaller than speaking style differences, these findings support using a complete speech set for training while talkers acclimate to the task and to the laboratory environment.

Using a novel in-mask non-invasive ventilator microphone to improve talker intelligibility in healthy and hospitalised adults.

Purpose: Non-invasive ventilation (NIV) provides respiratory support without invasive endotracheal intubation but can hinder patients' ability to communicate effectively. The current study presents preliminary results using a novel in-mask ventilator microphone to enhance talker intelligibility while receiving NIV.Method: A proof-of-concept study assessed sentence intelligibility of five healthy adult talkers using a prototype model of the microphone under continuous positive airway pressure (CPAP; 5/5 cm H2O) and bilevel positive airway pressure (BiPAP; 8/4 cm H2O) ventilator conditions. A pilot study then assessed intelligibility, subjective comprehensibility and naturalness, and patient- and conversation partner-reported communication outcomes for eight patients undergoing therapeutic NIV while being treated in an intensive care unit (ICU).Result: Intelligibility increased significantly with the microphone on in the BiPAP condition for healthy volunteers. For patients undergoing NIV in an ICU, intelligibility, comprehensibility, and patient and conversation partner ratings of conversation satisfaction significantly improved with the microphone on. Patients with lower baselines without the microphone in certain measures (intelligibility, comprehensibility) generally showed a greater microphone benefit than patients with higher baselines.Conclusion: Use of a novel microphone integrated into NIV improved intelligibility during ventilation for both healthy volunteers and patients undergoing therapeutic NIV. Additional clinical studies will define precise benefits and implications of such improved intelligibility.

Perceived Anger in Clear and Conversational Speech: Contributions of Age and Hearing Loss.

A previous investigation demonstrated differences between younger adult normal-hearing listeners and older adult hearing-impaired listeners in the perceived emotion of clear and conversational speech. Specifically, clear speech sounded angry more often than conversational speech for both groups, but the effect was smaller for the older listeners. These listener groups differed by two confounding factors, age (younger vs. older adults) and hearing status (normal vs. impaired). The objective of the present study was to evaluate the contributions of aging and hearing loss to the reduced perception of anger in older adults with hearing loss. We investigated perceived anger in clear and conversational speech in younger adults with and without a simulated age-related hearing loss, and in older adults with normal hearing. Younger adults with simulated hearing loss performed similarly to normal-hearing peers, while normal-hearing older adults performed similarly to hearing-impaired peers, suggesting that aging was the primary contributor to the decreased anger perception seen in previous work. These findings confirm reduced anger perception for older adults compared to younger adults, though the significant speaking style effect-regardless of age and hearing status-highlights the need to identify methods of producing clear speech that is emotionally neutral or positive.

Text Captioning Buffers Against the Effects of Background Noise and Hearing Loss on Memory for Speech.

OBJECTIVE: Everyday speech understanding frequently occurs in perceptually demanding environments, for example, due to background noise and normal age-related hearing loss. The resulting degraded speech signals increase listening effort, which gives rise to negative downstream effects on subsequent memory and comprehension, even when speech is intelligible. In two experiments, we explored whether the presentation of realistic assistive text captioned speech offsets the negative effects of background noise and hearing impairment on multiple measures of speech memory. DESIGN: In Experiment 1, young normal-hearing adults (N = 48) listened to sentences for immediate recall and delayed recognition memory. Speech was presented in quiet or in two levels of background noise. Sentences were either presented as speech only or as text captioned speech. Thus, the experiment followed a 2 (caption vs no caption) × 3 (no noise, +7 dB signal-to-noise ratio, +3 dB signal-to-noise ratio) within-subjects design. In Experiment 2, a group of older adults (age range: 61 to 80, N = 31), with varying levels of hearing acuity completed the same experimental task as in Experiment 1. For both experiments, immediate recall, recognition memory accuracy, and recognition memory confidence were analyzed via general(ized) linear mixed-effects models. In addition, we examined individual differences as a function of hearing acuity in Experiment 2. RESULTS: In Experiment 1, we found that the presentation of realistic text-captioned speech in young normal-hearing listeners showed improved immediate recall and delayed recognition memory accuracy and confidence compared with speech alone. Moreover, text captions attenuated the negative effects of background noise on all speech memory outcomes. In Experiment 2, we replicated the same pattern of results in a sample of older adults with varying levels of hearing acuity. Moreover, we showed that the negative effects of hearing loss on speech memory in older adulthood were attenuated by the presentation of text captions. CONCLUSIONS: Collectively, these findings strongly suggest that the simultaneous presentation of text can offset the negative effects of effortful listening on speech memory. Critically, captioning benefits extended from immediate word recall to long-term sentence recognition memory, a benefit that was observed not only for older adults with hearing loss but also young normal-hearing listeners. These findings suggest that the text captioning benefit to memory is robust and has potentially wide applications for supporting speech listening in acoustically challenging environments.

Examining vocal attractiveness through articulatory working space.

Robust gender differences exist in the acoustic correlates of clearly articulated speech, with females, on average, producing speech that is acoustically and phonetically more distinct than that of males. This study investigates the relationship between several acoustic correlates of clear speech and subjective ratings of vocal attractiveness. Talkers were recorded producing vowels in /bVd/ context and sentences containing the four corner vowels. Multiple measures of working vowel space were computed from continuously sampled formant trajectories and were combined with measures of speech timing known to co-vary with clear articulation. Partial least squares regression (PLS-R) modeling was used to predict ratings of vocal attractiveness for male and female talkers based on the acoustic measures. PLS components that loaded on size and shape measures of working vowel space-including the quadrilateral vowel space area, convex hull area, and bivariate spread of formants-along with measures of speech timing were highly successful at predicting attractiveness in female talkers producing /bVd/ words. These findings are consistent with a number of hypotheses regarding human attractiveness judgments, including the role of sexual dimorphism in mate selection, the significance of traits signalling underlying health, and perceptual fluency accounts of preferences.

Intelligibility of British- and American-Accented Sentences for American Younger and Older Listeners With and Without Hearing Loss.

BACKGROUND: Older adults with hearing loss often report difficulty understanding British-accented speech, such as in television or movies, after having understood such speech in the past. A few studies have examined the intelligibility of various United States regional and non-U.S. varieties of English for American listeners, but only for young adults with normal hearing. PURPOSE: This preliminary study sought to determine whether British-accented sentences were less intelligible than American-accented sentences for American younger and older adults with normal hearing and for older adults with hearing loss. RESEARCH DESIGN: A mixed-effects design, with talker accent and listening condition as within-subjects factors and listener group as a between-subjects factor. STUDY SAMPLE: Three listener groups consisting of 16 young adults with normal hearing, 15 older adults with essentially normal hearing, and 22 older adults with sloping sensorineural hearing loss. DATA COLLECTION AND ANALYSIS: Sentences produced by one General American English speaker and one British English speaker were presented to listeners at 70 dB sound pressure level in quiet and in babble. Signal-to-noise ratios for the latter varied among the listener groups. Responses were typed into a textbox and saved on each trial. Effects of accent, listening condition, and listener group were assessed using linear mixed-effects models. RESULTS: American- and British-accented sentences were equally intelligible in quiet, but intelligibility in noise was lower for British-accented sentences than American-accented sentences. These intelligibility differences were similar for all three groups. CONCLUSION: British-accented sentences were less intelligible than those produced by an American talker, but only in noise.

Does Time Compression Decrease Intelligibility for Female Talkers More Than for Male Talkers?

Purpose This preliminary investigation compared effects of time compression on intelligibility for male versus female talkers. We hypothesized that time compression would have a greater effect for female talkers. Method Sentence materials from four talkers (two males) were time compressed, and original-speed and time-compressed speech materials were presented in a background of 12-talker babble to young adult listeners with normal hearing. Each talker/processing condition was heard by eight listeners (total N = 64). Generalized linear mixed-effects models were used to determine the effects of and interaction between processing condition and talker sex on keyword intelligibility. Additional post hoc analyses examined whether processing condition effects were related to talker vowel space and word frequency. Results For original-speed sentences, female and male talkers were essentially equally intelligible. Time compression reduced intelligibility for all talkers, but the effect was significantly greater for the female talkers. Supplementary analyses revealed that the effect of time compression depended on both talker vowel space and word frequency: The detrimental effect decreased significantly as word frequency and vowel space increased. Word frequency effects were also greater overall for talkers with larger vowel spaces. Conclusions While the small talker sample limits conclusions about the effects of talker sex, the secondary analyses suggest that intelligibility of talkers with larger vowel spaces is less susceptible to the negative effect of time compression, especially for high-frequency words.

The Effect of Clear Speech on Temporal Metrics of Rhythm in Spanish-Accented Speakers of English.

This paper presents a comparative analysis of temporal rhythm in native American English talkers and Spanish-accented English talkers producing clear (hyperarticulated) speech and typical, conversational-style speech. Five acoustic measures of comparative vocalic and consonantal interval duration ("temporal metrics") were obtained from speech samples of 40 adult men and women (half native and half Spanish-accented talkers). In conversational-style speech, vocalic-based metrics differed significantly between native and Spanish-accented talkers, consistent with phonotactic differences between the two native languages. In clear speech, however, all metric values from the Spanish-accented talkers became more English-like and no longer differed significantly from those observed in the native English talkers. Post-hoc analysis revealed that native English talkers increased the duration of both weak and strong vowels in clear speech, whereas the Spanish-accented talkers increased the duration of strong vowels without changing the duration of weak vowels. Listener ease of understanding, as perceived by monolingual English speakers, was significantly improved in clear- compared with conversational-style speech for all talkers. The acoustic data help to explain the changes that result from use of clear speech in nonnative speakers. Together with the improved listener ease of understanding, these data strongly support the further exploration of clear speech as a clinical tool to improve prosody and hence, interpersonal communication, in nonnative speakers.

Talker Differences in Clear and Conversational Speech: Perceived Sentence Clarity for Young Adults With Normal Hearing and Older Adults With Hearing Loss.

Purpose: The purpose of this study is to examine talker differences for subjectively rated speech clarity in clear versus conversational speech, to determine whether ratings differ for young adults with normal hearing (YNH listeners) and older adults with hearing impairment (OHI listeners), and to explore effects of certain talker characteristics (e.g., gender) on perceived clarity. Relationships among clarity ratings and other speech perceptual and acoustic measures were also explored. Method: Twenty-one YNH and 15 OHI listeners rated clear and conversational sentences produced by 41 talkers on a scale of 1 (lowest possible clarity) to 7 (highest possible clarity). Results: While clarity ratings varied significantly among talkers, listeners rated clear speech significantly clearer than conversational speech for all but 1 talker. OHI and YNH listeners gave similar ratings for conversational speech, but ratings for clear speech were significantly higher for OHI listeners. Talker gender effects differed for YNH and OHI listeners. Ratings of clear speech varied among subgroups of talkers with different amounts of experience talking to people with hearing loss. Conclusions: Perceived clarity varies widely among talkers, but nearly all produce clear speech that sounds significantly clearer than their conversational speech. Few differences were seen between OHI and YNH listeners except the effect of talker gender.

Listener estimates of talker age in a single-talker, 50-year longitudinal sample.

PURPOSE: While many studies have shown that listeners make relatively accurate age judgments from hearing talkers' voices, most have used just one age per talker. The present study evaluated listeners' age estimation abilities for a longitudinal sample: a single talker recorded over nearly five decades. METHOD: We extracted 60 samples from addresses given by a male talker over 48 years. For each sample, listeners gave a direct estimate of his age. We also asked listeners if they could identify the talker, who was known locally, from the recordings. RESULTS: While correlations between the talker's chronological age and direct estimates of age were generally strong, the relationship was particularly strong when the talker was older than 68 years, although listeners underestimated chronological age by approximately 5 years. When the talker was between 49 and 68 years, direct age estimates were less accurate and less strongly correlated with chronological age. Additionally, direct age estimates were more accurate when listeners recognized the talker. CONCLUSIONS: Corroborating cross-sectional studies, our listeners overestimated the talker's age when he was younger and underestimated it when he was older. However, the crossover between overestimation and underestimation, the point where estimated and chronological ages were equal, occurred at a later talker age for this longitudinal study than in previous cross-sectional studies. Additionally, listeners who recognized the talker made more accurate age estimates when the talker's chronological age was near the age where they would have known him. We propose future studies explore the relationship between familiarity and estimated age.

Judgments of Emotion in Clear and Conversational Speech by Young Adults With Normal Hearing and Older Adults With Hearing Impairment.

Purpose: In this study, we investigated the emotion perceived by young listeners with normal hearing (YNH listeners) and older adults with hearing impairment (OHI listeners) when listening to speech produced conversationally or in a clear speaking style. Method: The first experiment included 18 YNH listeners, and the second included 10 additional YNH listeners along with 20 OHI listeners. Participants heard sentences spoken conversationally and clearly. Participants selected the emotion they heard in the talker's voice using a 6-alternative, forced-choice paradigm. Results: Clear speech was judged as sounding angry and disgusted more often and happy, fearful, sad, and neutral less often than conversational speech. Talkers whose clear speech was judged to be particularly clear were also judged as sounding angry more often and fearful less often than other talkers. OHI listeners reported hearing anger less often than YNH listeners; however, they still judged clear speech as angry more often than conversational speech. Conclusions: Speech spoken clearly may sound angry more often than speech spoken conversationally. Although perceived emotion varied between YNH and OHI listeners, judgments of anger were higher for clear speech than conversational speech for both listener groups. Supplemental Materials: https://doi.org/10.23641/asha.5170717.

Listener estimations of talker age: A meta-analysis of the literature.

Numerous studies, most of them cross-sectional studies using one sample per talker, have demonstrated that listeners make relatively accurate age judgments from hearing talkers' voices. The current study analyzed the results of several such direct age estimation studies to characterize better the perception of talker age over a larger number of individuals. A review of the direct age estimation literature was performed. Data sets from seven papers were reconstituted, and an analysis of the combined data (meta-analysis) including 530 data points was conducted. The reconstituted and combined data included talkers aged 10-90. Listeners appeared to overestimate age when talkers were younger and to underestimate it when talkers were older.

Acoustic correlates of vowel intelligibility in clear and conversational speech for young normal-hearing and elderly hearing-impaired listeners.

The present investigation carried out acoustic analyses of vowels in clear and conversational speech produced by 41 talkers. Mixed-effects models were then deployed to examine relationships among acoustic and perceptual data for these vowels. Acoustic data include vowel duration, steady-state formant frequencies, and two measures of dynamic formant movement. Perceptual data consist of vowel intelligibility in noise for young normal-hearing and elderly hearing-impaired listeners, as reported by Ferguson in 2004 and 2012 [J. Acoust. Soc. Am. 116, 2365-2373 (2004); J. Speech Lang. Hear. Res. 55, 779-790 (2012)], respectively. Significant clear speech effects were observed for all acoustic metrics, although not all measures changed for all vowels and considerable talker variability was observed. Mixed-effects analyses revealed that the contribution of duration and steady-state formant information to vowel intelligibility differed for the two listener groups. This outcome is consistent with earlier research suggesting that hearing loss, and possibly aging, alters the way acoustic cues are used for identifying vowels.

Talker differences in clear and conversational speech: vowel intelligibility for older adults with hearing loss.

PURPOSE: To establish the range of talker variability for vowel intelligibility in clear versus conversational speech for older adults with hearing loss and to determine whether talkers who produced a clear speech benefit for young listeners with normal hearing also did so for older adults with hearing loss. METHOD: Clear and conversational vowels in /bVd/ context produced by 41 talkers were presented in noise for identification by 40 older (ages 65-87 years) adults with sloping sensorineural hearing loss. RESULTS: Vowel intelligibility within each speaking style and the size of the clear speech benefit varied widely among talkers. The clear speech benefit was equivalent to that enjoyed by young listeners with normal hearing in an earlier study. Most talkers who had produced a clear speech benefit for young listeners with normal hearing also did so for the older listeners with hearing loss in the present study. However, effects of talker gender differed between listeners with normal hearing and listeners with hearing loss. CONCLUSION: The clear speech vowel intelligibility benefit generated for listeners with hearing loss varied considerably among talkers. Most talkers who produced a clear speech benefit for normal-hearing listeners also produced a benefit for listeners with hearing loss.

Across-talker effects on non-native listeners' vowel perception in noise.

This study explored how across-talker differences influence non-native vowel perception. American English (AE) and Korean listeners were presented with recordings of 10 AE vowels in /bVd/ context. The stimuli were mixed with noise and presented for identification in a 10-alternative forced-choice task. The two listener groups heard recordings of the vowels produced by 10 talkers at three signal-to-noise ratios. Overall the AE listeners identified the vowels 22% more accurately than the Korean listeners. There was a wide range of identification accuracy scores across talkers for both AE and Korean listeners. At each signal-to-noise ratio, the across-talker intelligibility scores were highly correlated for AE and Korean listeners. Acoustic analysis was conducted for 2 vowel pairs that exhibited variable accuracy across talkers for Korean listeners but high identification accuracy for AE listeners. Results demonstrated that Korean listeners' error patterns for these four vowels were strongly influenced by variability in vowel production that was within the normal range for AE talkers. These results suggest that non-native listeners are strongly influenced by across-talker variability perhaps because of the difficulty they have forming native-like vowel categories.

Intelligibility of foreign-accented speech for older adults with and without hearing loss.

BACKGROUND: Numerous studies have demonstrated that the negative effect of noise and other distortions on speech understanding is greater for older adults than for younger adults. Anecdotal evidence suggests that older adults may also be disproportionately negatively affected by foreign accent. While two previous studies found no interaction between foreign accent and listener age, these studies reported no audiometric data and assessed speech understanding in quiet only. PURPOSE: To examine the effects of foreign accent, listening condition, and listener age and hearing status on word identification. RESEARCH DESIGN: A cross-sectional descriptive study. STUDY SAMPLE: Experiments 1 and 2 tested young adults with normal hearing (n = 20 and n = 5, respectively), older adults with essentially normal hearing (n = 20 and n = 10, respectively), and older adults with sloping sensorineural hearing loss (n = 20 and n = 10, respectively). DATA COLLECTION AND ANALYSIS: The intelligibility of English words produced by a native speaker of English and by a native speaker of Spanish was assessed. In Experiment 1, word intelligibility was measured in quiet, in noise (+3 dB signal-to-babble ratio, or SBR), and in a telephone filter condition. In Experiment 2, intelligibility was measured in three additional noise conditions (+6, +9, and +12 dB SBR). RESULTS: English words produced by the native speaker of English were significantly more intelligible than those produced by the native speaker of Spanish. While the negative effect of noise was significantly greater for older listeners than for younger listeners, the effect of foreign accent was independent of listener age, listener hearing status, and listening condition. CONCLUSION: The results suggest that, unlike with other forms of distortion, older adults are not disproportionately affected by foreign accent. This suggests, in turn, that talker-related distortions of the speech signal have a qualitatively different impact on speech perception than distortions that are applied to the signal after it has been produced. The nature of these different types of distortion may be a fruitful area for future investigations of speech understanding in older adults.

Methodological variables in choral reading.

This preliminary study explored changes in prosodic variability during choral reading and investigated whether these changes are affected by the method of eliciting choral reading. Ten typical adult talkers recorded three reading materials (poetry, fiction and textbook) in three reading conditions: solo (reading aloud alone), track (reading aloud with a recording), and choral (reading aloud with another live talker). Measurements of fundamental frequency, amplitude, and vowel duration variability were performed. Compared to solo reading, choral reading featured decreased variability of fundamental frequency, amplitude, and vowel duration. In track reading, only decreased fundamental frequency variability was observed, while vowel duration variability increased. Track reading also contained significantly more errors than choral or solo reading. The reading material used did not significantly affect the prosodic features of talkers' speech, but did affect talkers' error rate. These results suggest that, in studies of choral reading as a fluency-evoking condition, track reading might not be an appropriate substitute. In addition, the text used may affect fluency in these conditions. These results also have theoretical implications for studies of how talkers manipulate and execute the prosodic features of speech.

Talker differences in clear and conversational speech: acoustic characteristics of vowels.

PURPOSE: To determine the specific acoustic changes that underlie improved vowel intelligibility in clear speech. METHOD: Seven acoustic metrics were measured for conversational and clear vowels produced by 12 talkers-6 who previously were found (S. H. Ferguson, 2004) to produce a large clear speech vowel intelligibility effect for listeners with normal hearing identifying vowels in background noise (the big benefit talkers), and 6 who produced no clear speech vowel intelligibility benefit (the no benefit talkers). RESULTS: For vowel duration and for certain measures of the overall acoustic vowel space, the change from conversational to clear speech was significantly greater for big benefit talkers than for no benefit talkers. For measures of formant dynamics, in contrast, the clear speech effect was similar for the 2 groups. CONCLUSION: These results suggest that acoustic vowel space expansion and large vowel duration increases improve vowel intelligibility. In contrast, changing the dynamic characteristics of vowels seems not to contribute to improved clear speech vowel intelligibility. However, talker variability suggested that improved vowel intelligibility can be achieved using a variety of clear speech strategies, including some apparently not measured here.

Talker differences in clear and conversational speech: vowel intelligibility for normal-hearing listeners.

Several studies have shown that when a talker is instructed to speak as though talking to a hearing-impaired person, the resulting "clear" speech is significantly more intelligible than typical conversational speech. While variability among talkers during speech production is well known, only one study to date [Gagné et al., J. Acad. Rehab. Audiol. 27, 135-158 (1994)] has directly examined differences among talkers producing clear and conversational speech. Data from that study, which utilized ten talkers, suggested that talkers vary in the extent to which they improve their intelligibility by speaking clearly. Similar variability can be also seen in studies using smaller groups of talkers [e.g., Picheny, Durlach, and Braida, J. Speech Hear. Res. 28, 96-103 (1985)]. In the current paper, clear and conversational speech materials were recorded from 41 male and female talkers aged 18 to 45 years. A listening experiment demonstrated that for normal-hearing listeners in noise, vowel intelligibility varied widely among the 41 talkers for both speaking styles, as did the magnitude of the speaking style effect. While female talkers showed a larger clear speech vowel intelligibility benefit than male talkers, neither talker age nor prior experience communicating with hearing-impaired listeners significantly affected the speaking style effect.