Naveen K. Nagaraj

Audiology Students’ Perception of Hybrid Simulation Experiences: Qualitative Evaluation of Debriefing Sessions

Simulation-based research is still new in the audiology field and requires more research to better understand students’ perspectives on standardized patients/parents (SPs) and manikins use. There is also limited research about debriefing practices in audiology. This qualitative study used a baby simulator and SPs to evaluate audiology students’ reflection during three debriefing sessions conducted at the University of Arkansas for Medical Science (UAMS) Simulation Center. Seventeen Doctor of Audiology (AuD) students participated in the simulation event, and the data were collected using the transcripts of videotaped debriefing sessions. The qualitative content analysis of the transcripts revealed eight sub-themes: support, compassion, respect, teamwork, limited academic knowledge and practice, insufficient communication skills, low self-confidence, and undesirable emotional reactions. These items, in turn, fell under two main themes of Qualification and Lack of Preparation. Both main themes were included in one core category named Professional Dispositions and Competencies. Study findings indicated that audiology students demonstrated both promising professional dispositions and competencies as well as characteristics that may hinder students from developing their professional abilities. Thus, audiology programs will benefit from simulation use, including debriefing sessions, to emphasize professional efficiency.

No evidence of relation between working memory and perception of interrupted speech in young adults.

Understanding interrupted speech requires top-down linguistic and cognitive restoration mechanisms. To investigate the relation between working memory (WM) and perception of interrupted speech, 20 young adults were asked to recognize sentences interrupted at 2 Hz, 8 Hz, and a combination of 2 and 8 Hz. WM was measured using automated reading and operation span tasks. Interestingly, the results presented here revealed no statistical relation between any of the interrupted speech recognition scores and WM scores. This finding is in agreement with previous findings that suggest greater reliance on linguistic factors relative to cognitive factors during perception of interrupted speech.

Working Memory and Auditory Processing in School-Age Children

Purpose Our goal is to present the relationships between working memory (WM) and auditory processing abilities in school-age children. Review and Discussion We begin with an overview of auditory processing, the conceptualization of auditory processing disorder, and the assessment of auditory processing abilities in children. Next, we describe a model of WM and a model of auditory processing followed by their comparison. Evidence for the relationships between WM and auditory processing abilities in school-age children follows. Specifically, we present evidence for the association (or lack thereof) between WM/attention and auditory processing test performance. Clinical Implications In conclusion, we describe a new framework for understanding auditory processing abilities in children based on integrated evidence from cognitive science, hearing science, and language science. We also discuss clinical implications in children that could inform future research.

Children's Speech Perception in Noise: Evidence for Dissociation From Language and Working Memory

Purpose We examined the association between speech perception in noise (SPIN), language abilities, and working memory (WM) capacity in school-age children. Existing studies supporting the Ease of Language Understanding (ELU) model suggest that WM capacity plays a significant role in adverse listening situations. Method Eighty-three children between the ages of 7 to 11 years participated. The sample represented a continuum of individual differences in attention, memory, and language abilities. All children had normal-range hearing and normal-range nonverbal IQ. Children completed the Bamford-Kowal-Bench Speech-in-Noise Test (BKB-SIN; Etymotic Research, 2005), a selective auditory attention task, and multiple measures of language and WM. Results Partial correlations (controlling for age) showed significant positive associations among attention, memory, and language measures. However, BKB-SIN did not correlate significantly with any of the other measures. Principal component analysis revealed a distinct WM factor and a distinct language factor. BKB-SIN loaded robustly as a distinct 3rd factor with minimal secondary loading from sentence recall and short-term memory. Nonverbal IQ loaded as a 4th factor. Conclusions Results did not support an association between SPIN and WM capacity in children. However, in this study, a single SPIN measure was used. Future studies using multiple SPIN measures are warranted. Evidence from the current study supports the use of BKB-SIN as clinical measure of speech perception ability because it was not influenced by variation in childrens language and memory abilities. More large-scale studies in school-age children are needed to replicate the proposed role played by WM in adverse listening situations.

Role of working memory and lexical knowledge in perceptual restoration of interrupted speech

The role of working memory (WM) capacity and lexical knowledge in perceptual restoration (PR) of missing speech was investigated using the interrupted speech perception paradigm. Speech identification ability, which indexed PR, was measured using low-context sentences periodically interrupted at 1.5 Hz. PR was measured for silent gated, low-frequency speech noise filled, and low-frequency fine-structure and envelope filled interrupted conditions. WM capacity was measured using verbal and visuospatial span tasks. Lexical knowledge was assessed using both receptive vocabulary and meaning from context tests. Results showed that PR was better for speech noise filled condition than other conditions tested. Both receptive vocabulary and verbal WM capacity explained unique variance in PR for the speech noise filled condition, but were unrelated to performance in the silent gated condition. It was only receptive vocabulary that uniquely predicted PR for fine-structure and envelope filled conditions. These findings suggest that the contribution of lexical knowledge and verbal WM during PR depends crucially on the information content that replaced the silent intervals. When perceptual continuity was partially restored by filler speech noise, both lexical knowledge and verbal WM capacity facilitated PR. Importantly, for fine-structure and envelope filled interrupted conditions, lexical knowledge was crucial for PR.

Overview of Central Auditory Processing Deficits in Older Adults

Although there are many reported age-related declines in the human body, the notion that a central auditory processing deficit exists in older adults has not always been clear. Hearing loss and both structural and functional central nervous system changes with advancing age are contributors to how we listen, hear, and process auditory information. Even older adults with normal or near normal hearing sensitivity may exhibit age-related central auditory processing deficits as measured behaviorally and/or electrophysiologically. The purpose of this article is to provide an overview of assessment and rehabilitative approaches for central auditory processing deficits in older adults. It is hoped that the outcome of the information presented here will help clinicians with older adult patients who do not exhibit the typical auditory processing behaviors exhibited by others at the same age and with comparable hearing sensitivity all in the absence of other health-related conditions.

Dominance of persistence over adaptation in forward masking

Persistence of excitation and neural adaptation are competing theories proposed to explain the mechanisms underlying psychophysical forward masking. Previous research has been directed towards finding models that accurately describe the phenomenon but cannot account for the underlying explanation. The current study was designed to determine which theory best accounts for results obtained from behavioral gap duration adjustment tasks. Thirteen adults adjusted the gap within asymmetrical noise markers to be subjectively equal to the gap within equal-intensity-noise markers. The duration of the perceived gap between the asymmetrical markers is expected to vary depending on which theory dominates perception. The persistence of excitation mechanism would lead to longer duration gaps when the second noise marker is lower in intensity than the preceding. Neural adaptation would result in matched gaps that are shorter in duration when the second noise marker was lower in level. The outcome of our data analysis is consistent with the persistence of excitation as a dominant mechanism in forward masking.

Working memory capacity and lexical knowledge in perceptual restoration of interrupted speech

Role of working memory capacity (WMC) and lexical knowledge in perceptual restoration (PR) of missing speech was investigated using the interrupted speech perception (ISP) paradigm. 75 young normal hearing listeners’ speech identification was measured using low-context sentences interrupted by silence and three noise at 1.5 Hz. Noise conditions created by manipulating the spectro-temporal content of filler noise were as follows: (1) low frequency (LF) speech shaped noise (SSN), (2) temporal fine structure filled (TFSf) noise consisting of LF TFS from the missing speech, and (3) temporal envelope filled (TEf) noise consisting of LF TE extracted from the missing speech. WMC was measured using verbal reading span and visuospatial symmetry span. Lexical knowledge was assessed using standard vocabulary and meaning from context tests. We hypothesized that during noise filled ISP conditions WM mechanism is crucial for retrieving and integrating relevant information from long-term memory. Results showed that ISP ...

Musical instrument dexterity requirements and its effects on adolescent diotic and dichotic listening performance

Research examining the human asymmetry of handedness has included exploring the relationship to the auditory modality (e.g., digit span memory; Bannatyne & Wichiarajote, 1969). Musicians whose instruments require dual dexterity have more symmetric neural processing as a result of the sensory-motor experience with their instrument (Gaser & Schlaug, 2003). Little research translates these neurological differences based on dexterity to determine if more neurologic symmetry manifests into advantages for auditory processing. This study aimed to identify perceptual advantages of instrumental training based on dexterity, during stages when the central auditory nervous system is still developing. Monaural and binaural listening tasks, as well as working memory tasks, were collected on 33 adolescent (14–18 years old) musicians split into subgroups based on their instrument dexterity requirement (mono vs. dual). The outcomes indicate that instrumental choice did not significantly impact diotic digit span performance; however, a performance asymmetry (e.g., right ear advantage) was identified for the mono dexterity group for dichotic listening tasks performance at capacity limits. Overall, the results indicate that individuals choosing musical instruments that require dual dexterity had more symmetric auditory processing which corresponds to previous evidence of more neural symmetry based on instrumental dexterity.Research examining the human asymmetry of handedness has included exploring the relationship to the auditory modality (e.g., digit span memory; Bannatyne & Wichiarajote, 1969). Musicians whose instruments require dual dexterity have more symmetric neural processing as a result of the sensory-motor experience with their instrument (Gaser & Schlaug, 2003). Little research translates these neurological differences based on dexterity to determine if more neurologic symmetry manifests into advantages for auditory processing. This study aimed to identify perceptual advantages of instrumental training based on dexterity, during stages when the central auditory nervous system is still developing. Monaural and binaural listening tasks, as well as working memory tasks, were collected on 33 adolescent (14–18 years old) musicians split into subgroups based on their instrument dexterity requirement (mono vs. dual). The outcomes indicate that instrumental choice did not significantly impact diotic digit span performanc...

Noise characteristics and their impact on working memory and listening comprehension performance

An emerging body of literature is demonstrating a significant relationship between cognition and listening performance. Noise has been shown to be detrimental to maintaining focus of attention in cognitive tasks. Noise characteristics, for a given SNR, may have differing impacts on these tasks. Fourteen normal-hearing individuals participated in an experiment designed to examine the effects of different background noises on auditory cognitive tasks while still maintaining a high-level of intelligibility (90%). Three tasks were used: a working memory span task, an attention-switching task, and a language comprehension task. The first two tasks were completed in quiet and three different types of modulated background noise, and the language comprehension task was performed in quiet and one modulated noise. Performance in both the working memory span task and attention-switching task were correlated significantly with language comprehension, suggesting that the cognitive resources tapped by these tasks are s...