College of Behavioral & Social Sciences
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The collections in this community comprise faculty research works, as well as graduate theses and dissertations..
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Item Values in American Hearing Healthcare(2024) Menon, Katherine Noel; Hoover, Eric C; Hearing and Speech Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The long-term objective of this research is to create a more inclusive, patient-centered hearing healthcare system that aligns with all stakeholders’ diverse values and needs. This dissertation explores the values shaping hearing healthcare through three complementary studies. Chapter 2 analyzes the introduction of over-the-counter (OTC) hearing aids, revealing a values shift from traditional audiology’s focus on accuracy, safety, and subjective benefit to prioritizing access and affordability. Implementing an OTC service delivery model for hearing healthcare promoted values different from those of traditional audiology. Still, the creation of OTC offers affordances that enable us to create more patient-centered hearing healthcare systems to reflect stakeholders’ values. Chapter 3 validates a comprehensive list of values in audiology through a national survey of audiologists, confirming alignment with best-practice guidelines. Previous work developed a codebook of values based on textual documents representing best practices in traditional audiology, and it was essential to validate these findings by directly engaging with audiologists. Chapter 4 develops a codebook based on the values of individuals with hearing difficulties, categorizing their concerns into Material, Social, and Healthcare domains. Results from this study highlight the importance of considering the values of individuals with hearing loss, which encompasses not only the use of hearing aids and affordable hearing healthcare but also concerns regarding the effectiveness, usefulness, and social implications of hearing aids. Together, these studies underscore the balance between efforts to improve accessibility and the need to maintain patient-centered outcomes, suggesting that future research should focus on understanding how values intersect with the daily lives and decision-making processes of all people with difficulty hearing.Item Determining the Mechanisms of Spoken Language Processing Delay for Children with Cochlear Implants(2023) Blomquist, Christina Marie; Edwards, Jan R; Newman, Rochelle S; Hearing and Speech Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The long-term objective of this project was to better understand how shorter auditory experience and spectral degradation of the cochlear implant (CI) signal impact spoken language processing in deaf children with CIs. The specific objective of this research was to utilize psycholinguistic methods to investigate the mechanisms underlying observed delays in spoken word recognition and the access of networks of semantically related words in the lexicon, which are both vital components for efficient spoken language comprehension. The first experiment used eye-tracking to investigate the contributions of early auditory deprivation and the degraded CI signal to spoken word recognition delays in children with CIs. Performance of children with CIs was compared to various typical hearing (TH) control groups matched for either chronological age or hearing age, and who heard either clear or vocoded speech. The second experiment investigated semantic processing in the face of a spectrally degraded signal (TH adult listeners presented with vocoded speech) by recording event-related potentials, specifically the N400. Results children with CIs show slower lexical access and less immediate lexical competition, and while early hearing experience supports more efficient recognition, much of these observed delays can be attributed to listening to a degraded signal in the moment, as children with TH demonstrate similar patterns of processing when presented with vocoded speech. However, some group differences remain, specifically children with CIs show slower speed of lexical access and longer-lasting competition, suggesting potential effects of learning from a degraded speech signal. With regards to higher-level semantic processing, TH adult listeners demonstrate more limited access of semantic networks when presented with a degraded speech signal. This finding suggests that uncertainty due the degraded speech signal may lead to less immediate cascading processing at both the word-level and higher-level semantic processing. Clinically, these results highlight the importance of early cochlear implantation and maximizing access to spectral detail in the speech signal for children with CIs. Additionally, it is possible that some of the delays in spoken language processing are the result of an alternative listening strategy that may be engaged to reduce the chance of incorrect predictions, thus preventing costly revision processes.Item SPECTRAL CONTRASTS PRODUCED BY CHILDREN WITH COCHLEAR IMPLANTS: INVESTIGATING THE IMPACT OF SIGNAL DEGRADATION ON SPEECH ACQUISITION(2022) Johnson, Allison Ann; Edwards, Jan; Hearing and Speech Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The primary objective of this dissertation was to assess four consonants, /t/, /k/, /s/, and /ʃ/, produced by young children with cochlear implants (CIs). These consonants were chosen because they comprise two place-of-articulation contrasts, which are cued auditorily by spectral information in English, and they cover both early-acquired (/t/, /k/) and late-acquired (/s/, /ʃ/) manners of articulation. Thus, the auditory-perceptual limitations imposed by CIs is likely to impact acquisition of these sounds: because spectral information is particularly distorted, children have limited access to the cues that differentiate these sounds.Twenty-eight children with CIs and a group of peers with normal hearing (NH) who were matched in terms of age, sex, and maternal education levels participated in this project. The experiment required children to repeat familiar words with initial /t/, /k/, /s/, or /ʃ/ following an auditory model and picture prompt. To create in-depth speech profiles and examine variability both within and across children, target consonants were elicited many times in front-vowel and back-vowel contexts. Patterns of accuracy and errors were analyzed based on transcriptions. Acoustic robustness of contrast was analyzed based on correct productions. Centroid frequencies were calculated from the release-burst spectra for /t/ and /k/ and the fricative noise spectra for /s/ and /ʃ/. Results showed that children with CIs demonstrated patterns not observed in children with NH. Findings provide evidence that for children with CIs, speech acquisition is not simply delayed due to a period of auditory deprivation prior to implantation. Idiosyncratic patterns in speech production are explained in-part by the limitations of CI’s speech-processing algorithms. The first chapter of this dissertation provides a general introduction. The second chapter includes a validation study for a measure to differentiate /t/ and /k/ in adults’ productions. The third chapter analyzes accuracy, errors, and spectral features of /t/ and /k/ across groups of children with and without CIs. The fourth chapter analyzes /s/ and /ʃ/ across groups of children, as well as the spectral robustness of both the /t/-/k/ and the /s/-/ʃ/ contrasts across adults and children. The final chapter discusses future directions for research and clinical applications for speech-language pathologists.Item INFLUENCE OF SUPPORTIVE CONTEXT AND STIMULUS VARIABILITY ON RAPID ADAPTATION TO NON-NATIVE SPEECH(2021) Bieber, Rebecca; Gordon-Salant, Sandra; Anderson, Samira; Hearing and Speech Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Older listeners, particularly those with age-related hearing loss, report a high level of difficulty in perception of non-native speech when queried in clinical settings. In an increasingly global society, addressing these challenges is an important component of providing auditory care and rehabilitation to this population. Prior literature shows that younger listeners can quickly adapt to both unfamiliar and challenging auditory stimuli, improving their perception over a short period of exposure. Prior work has suggested that a protocol including higher variability of the speech materials may be most beneficial for learning; variability within the stimuli may serve to provide listeners with a larger range of acoustic information to map onto higher level lexical representations. However, there is also evidence that increased acoustic variability is not beneficial for all listeners. Listeners also benefit from the presence of semantic context during speech recognition tasks. It is less clear, however, whether older listeners derive more benefit than younger listeners from supportive context; some studies find increased benefit for older listeners, while others find that the context benefit is similar in magnitude across age groups.This project comprises a series of experiments utilizing behavioral and electrophysiologic measures designed to examine the contributions of acoustic variability and semantic context in relation to speech recognition during the course of rapid adaptation to non-native English speech. Experiment 1 examined the effects of increasing stimulus variability on behavioral measures of rapid adaptation. The results of the study indicated that stimulus variability impacted overall levels of recognition, but did not affect rate of adaptation. This was confirmed in Experiment 2, which also showed that degree of semantic context influenced rate of adaptation, but not overall performance levels. In Experiment 3, younger and older normal-hearing adults showed similar rates of adaptation to a non-native talker regardless of context level, though talker accent and context level interacted to the detriment of older listeners’ speech recognition. When cortical responses were examined, younger and older normal-hearing listeners showed similar predictive processing effects for both native and non-native speech.Item Effects of Age, Hearing Loss and Cognition on Discourse Comprehension and Speech Intelligibility Performance(2020) Schurman, Jaclyn; Gordon-Salant, Sandra; Hearing and Speech Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Discourse comprehension requires listeners to interpret the meaning of an incoming message, integrate the message into memory and use the information to respond appropriately. Discourse comprehension is a skill required to effectively communicate with others in real time. The overall goal of this research is to determine the relative impact of multiple environmental and individual factors on discourse comprehension performance for younger and older adults with and without hearing loss using a clinically feasible testing approach. Study 1 focused on the impact of rapid speech on discourse comprehension performance for younger and older adults with and without hearing loss. Study 2 focused on the impact of background noise and masker type on discourse comprehension performance for younger and older adults with and without hearing loss. The influences of cognitive function and speech intelligibility were also of interest. The impact of these factors was measured using a self-selection paradigm in both studies. Listeners were required to self-select a time-compression ratio or signal-to-noise ratio (SNR) where they could understand and effectively answer questions about the discourse comprehension passages. Results showed that comprehension accuracy performance was held relatively constant across groups and conditions, but the time-compression ratios and SNRs varied significantly. Results in both studies demonstrated significant effects of age and hearing loss on the self-selection of listening rate and SNR. This result suggests that older adults are at a disadvantage for rapid speech and in the presence of background noise during a discourse comprehension task compared to younger adults. Older adults with hearing loss showed an additional disadvantage compared to older normal-hearing listeners for both difficult discourse comprehension tasks. Cognitive function, specifically processing speed and working memory, was shown to predict self-selected time-compression ratio and SNR. Understanding the effects of age, hearing loss and cognitive decline on discourse comprehension performance may eventually help mitigate these effects in real world listening situations.Item Effects of talker familiarity on speech understanding and cognitive effort in complex environments.(2020) Cohen, Julie; Gordon-Salant, Sandra; Brungart, Douglas S.; Hearing and Speech Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The long-term goal of this project is to understand the cognitive mechanisms responsible for familiar voice (FV) benefit in real-world environments, and to develop means to exploit the FV benefit to increase saliency of attended speech for older adults with hearing loss. Older adults and those with hearing loss have greater difficulty in noisy environments than younger adults, due in part to a reduction in available cognitive resources. When older listeners are in a challenging environment, their reduced cognitive resources (i.e., working memory and inhibitory control) can result in increased listening effort to maintain speech understanding performance. Both younger and older listeners were tested in this study to determine if the familiar voice benefit varies with listener age under various listening conditions. Study 1 examined whether a FV improves speech understanding and working memory during a dynamic speech understanding task in a real-world setting for couples of younger and older adults. Results showed that both younger and older adults exhibited a talker familiarity benefit to speech understanding performance, but performance on a test of working memory capacity did not vary as a function of talker familiarity. Study 2 examined if a FV improves speech understanding in a simulated cocktail-party environment in a lab setting by presenting multi-talker stimuli that were either monotic or dichotic. Both YNH and ONH groups exhibited a familiarity benefit in monotic and dichotic listening conditions. However, results also showed that talker familiarity benefit in the monotic conditions varied as a function of talker identification accuracy. When the talker identification was correct, speech understanding was similar when listening to a familiar masker or when both voices were unfamiliar. However, when talker identification was incorrect, listening to a familiar masker resulted in a decline in speech understanding. Study 3 examined if a FV improves performance on a measure of auditory working memory. ONH listeners with higher working memory capacity exhibited a benefit in performance when listening to a familiar vs. unfamiliar target voice. Additionally, performance on the 1-back test varied as a function of working memory capacity and inhibitory control. Taken together, talker familiarity is a beneficial cue that both younger and older adults can utilize when listening in complex environments, such as a restaurant or a crowded gathering. Listening to a familiar voice can improve speech understanding in noise, particularly when the noise is composed of speech. However, this benefit did not impact performance on a high memory load task. Understanding the role that familiar voices may have on the allocation of cognitive resources could result in improved aural rehabilitation strategies and may ultimately facilitate improvements in partner communication in complex real-world environments.Item EFFECTS OF INTERRUPTING NOISE AND SPEECH REPAIR MECHANISMS IN ADULT COCHLEAR-IMPLANT USERS(2020) Jaekel, Brittany Nicole; Goupell, Matthew J; Newman, Rochelle S; Hearing and Speech Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The long-term objective of this project is to help cochlear-implant (CI) users achieve better speech understanding in noisy, real-world listening environments. The specific objective of the proposed research is to evaluate why speech repair (“restoration”) mechanisms are often atypical or absent in this population. Restoration allows for improved speech understanding when signals are interrupted with noise, at least among normal-hearing listeners. These experiments measured how CI device factors like noise-reduction algorithms and compression and listener factors like peripheral auditory encoding and linguistic skills affected restoration mechanisms. We hypothesized that device factors reduce opportunities to restore speech; noise in the restoration paradigm must act as a plausible masker in order to prompt the illusion of intact speech, and CIs are designed to attenuate noise. We also hypothesized that CI users, when listening with an ear with better peripheral auditory encoding and provided with a semantic cue, would show improved restoration ability. The interaction of high-quality bottom-up acoustic information with top-down linguistic knowledge is integral to the restoration paradigm, and thus restoration could be possible if CI users listen to noise-interrupted speech with a “better ear” and have opportunities to utilize their linguistic knowledge. We found that CI users generally failed to restore speech regardless of device factors, ear presentation, and semantic cue availability. For CI users, interrupting noise apparently serves as an interferer rather than a promoter of restoration. The most common concern among CI users is difficulty understanding speech in noisy listening conditions; our results indicate that one reason for this difficulty could be that CI users are unable to utilize tools like restoration to process noise-interrupted speech effectively.Item Auditory Temporal Processing Ability in Cochlear-Implant Users: The Effects of Age and Peripheral Neural Survival(2019) Shader, Maureen Joyce; Goupell, Matthew J; Hearing and Speech Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Cochlear implants (CIs) are a valuable tool in the treatment of hearing loss and are considered a safe and effective option for adults of all ages. Nevertheless, older adults with CIs do not always achieve comparable speech recognition performance to younger adults following implantation. The mechanism(s) underlying this age limitation are unknown. It was hypothesized that older CI users would demonstrate age-related deficits in auditory temporal processing ability, which could contribute to an age limitation in CI performance. This is because the ability to accurately encode temporal information is critical to speech recognition through a CI. The current studies were aimed at identifying age-related limitations for processing temporal information using a variety of electrical stimulation parameters with the goal of identifying parameters that could mitigate the negative effects of age on CI performance. Studies 1 and 2 measured auditory temporal processing ability for non-speech signals at the single-electrode level for various electrical stimulation rates. Specifically, Study 1 measured gap detection thresholds, which constitutes a simple, static measurement of temporal processing. Study 2 measured amplitude-modulation detection thresholds, which utilized relatively more complex and dynamic signals. Peripheral neural survival was estimated on each electrode location that was tested in Studies 1 and 2. Study 3 measured phoneme recognition ability for consonant contrasts that varied in discrete temporal cues at multiple stimulation rates and envelope modulation frequencies. Results demonstrated significant effects of age and/or peripheral neural survival on temporal processing ability in each study. However, age and the degree of neural survival were often strongly correlated, with older participants exhibiting poorer neural survival compared to younger participants. This result suggested that a substantial reduction in peripheral neural survival accompanies aging in older CI users, and that these factors should be considered together, rather than separately. Parametric variation in the stimulation settings impacted performance for some participants, but this effect was not consistent across participants, nor was it predicted by age or peripheral neural survival.Item Age Effects on Perceptual Organization of Speech in Realistic Environments(2017) Bologna, William Joseph; Dubno, Judy R; Gordon-Salant, Sandra; Hearing and Speech Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Communication often occurs in environments where background sounds fluctuate and mask portions of the intended message. Listeners use envelope and periodicity cues to group together audible glimpses of speech and fill in missing information. When the background contains other talkers, listeners also use focused attention to select the appropriate target talker and ignore competing talkers. Whereas older adults are known to experience significantly more difficulty with these challenging tasks than younger adults, the sources of these difficulties remain unclear. In this project, three related experiments explored the effects of aging on several aspects of speech understanding in realistic listening environments. Experiments 1 and 2 determined the extent to which aging affects the benefit of envelope and periodicity cues for recognition of short glimpses of speech, phonemic restoration of missing speech segments, and/or segregation of glimpses with a competing talker. Experiment 3 investigated effects of age on the ability to focus attention on an expected voice in a two-talker environment. Twenty younger adults and 20 older adults with normal hearing participated in all three experiments and also completed a battery of cognitive measures to examine contributions from specific cognitive abilities to speech recognition. Keyword recognition and cognitive data were analyzed with an item-level logistic regression based on a generalized linear mixed model. Results indicated that older adults were poorer than younger adults at glimpsing short segments of speech but were able use envelope and periodicity cues to facilitate phonemic restoration and speech segregation. Whereas older adults performed poorer than younger adults overall, these groups did not differ in their ability to focus attention on an expected voice. Across all three experiments, older adults were poorer than younger adults at recognizing speech from a female talker both in quiet and with a competing talker. Results of cognitive tasks indicated that faster processing speed and better visual-linguistic closure were predictive of better speech understanding. Taken together these results suggest that age-related declines in speech recognition may be partially explained by difficulty grouping short glimpses of speech into a coherent message, which may be particularly difficult for older adults when the talker is female.Item An Exploration of Auditory Brainstem Encoding of Stop Consonants in Infants and Implications for Language Outcomes(2016) Rosner, Rachel Stein; Anderson, Samira B; Hearing and Speech Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Current trends in speech-language pathology focus on early intervention as the preferred tool for promoting the best possible outcomes in children with language disorders. Neuroimaging techniques are being studied as promising tools for flagging at-risk infants. In this study, the auditory brainstem response (ABR) to the syllables /ba/ and /ga/ was examined in 41 infants between 3 and 12 months of age as a possible tool to predict language development in toddlerhood. The MacArthur-Bates Communicative Development Inventory (MCDI) was used to assess language development at 18 months of age. The current study compared the periodicity of the responses to the stop consonants and phase differences between /ba/ and /ga/ in both at-risk and low-risk groups. The study also examined whether there are correlations among ABR measures (periodicity and phase differentiation) and language development. The study found that these measures predict language development at 18 months.