Mark Hedrick

Background/Objectives: Children’s perception of phonemes differs from that of adults. Our purpose was to examine whether children’s perception of vowels differs from that of adults because of differential emphasis on vowel segments (steady-state or transition), degree of coarticulation, or amount of information to make a perceptual judgment of the vowel. Methods: A, between-group cross-sectional design was employed. Twenty-four children aged four to nine years and 17 adults (aged 18 to 53) participated. Stimuli were three naturally produced syllables (/bɑ/, /bi/ and /bu/), presented in the sound field in entirety or segmented to isolate the formant transition or the vowel static formant center. Participants selected the vowel presented by choosing from corresponding pictures on a computer screen. Results: The data from children showed consistently less accuracy for vowel identification than adults for whole syllable and all segments except full transitions. Conclusions: Children were more attuned to acoustic change or contrast to enable vowel perception than adults, yet needed more extensive change before reaching adult performance.

Purpose: Cognitive decline may affect how older listeners tolerate noise. Our purpose was to determine which cognitive variables are associated with older adults' acceptance of background noise, as measured by the acceptable noise level (ANL). Method: Fifteen adults with hearing within normal limits, aged 50–72 years, were administered the following tests: the ANL, the digit span and letter–number sequencing subtests of the Wechsler Adult Intelligence Scale–Fourth Edition, the auditory attention subtest from the Woodcock–Johnson Tests of Cognitive Abilities, the Hearing in Noise Test (HINT), and the operation span test. We then compared data from the older adults with an earlier data set obtained from younger adults with normal hearing, aged 20–29 years. Results: Older adults had significantly larger ANL values (were less tolerant of noise) than younger adults, and older adults scored significantly lower on auditory attention than the younger adults. There was no significant relation between scores on the HINT test and the ANL scores. Conclusions: Older adults' reduced attention control may make them less tolerant of noise than younger adults. Older adults who are not yet hearing aid candidates may still be more adversely affected by noise and may benefit from auditory rehabilitation–related tools to address noise.

Purpose: There is evidence from past animal work that the neural signal-to-noise ratio (SNR) is modulated through the action of the medial olivocochlear reflex (MOCR). This is commonly referred to as unmasking. However, evidence of unmasking in humans is limited, perhaps due to the traditional approach of measuring the MOCR using otoacoustic emissions—a preneural metric. The amplitudes and latencies of the late latency response (LLR) are sensitive to changes in SNR and may provide a means to noninvasively evaluate MOCR unmasking at the neural level. The purpose of this study was to investigate MOCR-mediated enhancement of ipsilateral noise in humans using the LLR. Method: Fifty normal-hearing adults were recruited. The LLR was measured for a 60 dB SPL, 1-kHz tone in both ipsilateral quiet and ipsilateral noise, with and without presentation of contralateral noise. For the ipsilateral noise conditions, the noise was presented at three different levels to achieve SNRs of +5 dB, +15 dB, and +25 dB. The contralateral noise was always 60 dB SPL white noise. LLR latencies (P1, N1, and P2) and interpeak amplitudes (P1-N1 and N1-P2) were measured for all conditions. In addition, otoacoustic emissions (OAEs) for a 1-kHz tone burst were measured in ipsilateral quiet both with and without contralateral noise. The same contralateral noise was used for both OAEs and LLRs. Results: For the ipsilateral noise conditions, SNR had a significant effect on LLR latencies and interpeak amplitudes: Latencies decreased, and amplitudes increased as SNR improved. The presentation of contralateral noise had a significant effect on P1 and N1 latencies, both of which decreased. LLR interpeak amplitudes significantly increased upon the presentation of contralateral noise. For the ipsilateral quiet condition, there were no significant effects of contralateral noise on LLR metrics. Though OAE magnitudes were significantly reduced upon presentation of contralateral noise, consistent significant relationships between OAE magnitude changes and changes in the LLR metrics were not found. Conclusion: Findings suggest that the presentation of contralateral noise enhances the neural response to an ipsilateral noise, potentially through MOC efferent feedback. Supplemental Material: https://doi.org/10.23641/asha.29441903

Hearing loss represents a multifaceted and pervasive challenge that deeply impacts various aspects of an individual’s life, spanning psychological, emotional, social, and economic realms. Understanding the molecular underpinnings that orchestrate hearing loss remains paramount in the quest for effective therapeutic strategies. This review aims to expound upon the physiological, biochemical, and molecular aspects of hearing loss, with a specific focus on its correlation with diabetes. Within this context, phytochemicals have surfaced as prospective contenders in the pursuit of potential adjuvant therapies. These compounds exhibit noteworthy antioxidant and anti-inflammatory properties, which hold the potential to counteract the detrimental effects induced by oxidative stress and inflammation—prominent contributors to hearing impairment. Furthermore, this review offers an up-to-date exploration of the diverse molecular pathways modulated by these compounds. However, the dynamic landscape of their efficacy warrants recognition as an ongoing investigative topic, inherently contingent upon specific experimental models. Ultimately, to ascertain the genuine potential of phytochemicals as agents in hearing loss treatment, a comprehensive grasp of the molecular mechanisms at play, coupled with rigorous clinical investigations, stands as an imperative quest.

Reaction times for correct vowel identification were measured to determine the effects of intertrial intervals, vowel, and cue type. Thirteen adults with normal hearing, aged 20–38 years old, participated. Stimuli included three naturally produced syllables (/ba/ /bi/ /bu/) presented whole or segmented to isolate the formant transition or static formant center. Participants identified the vowel presented via loudspeaker by mouse click. Results showed a significant effect of intertrial intervals, no significant effect of cue type, and a significant vowel effect—suggesting that feedback occurs, vowel identification may depend on cue duration, and vowel bias may stem from focal structure.

We sought to determine the effects of classroom loudspeaker position, model of loudspeaker, and talker accent on mental effort or cognitive load, word clarity, sound quality, and word recognition. Thirty-one typically-developed university students whose native language is English rated and transcribed recorded sentences produced by a native English talker and a native Dutch talker speaking English. The listeners were seated in acoustically pre-calibrated locations in a classroom and were presented 10 sentences at conversational level in each of four randomized conditions: from a conventional classroom loudspeaker in front or mounted above them, and from a loudspeaker optimized for speech reproduction placed in front or mounted above them. At the front of the classroom was a muted video recording of one of the talkers delivering an online lecture. Results showed front-located speakers yielded less cognitive effort, better sound quality, and better word clarity—showing importance of congruence of loudspeaker/talker position.

ID 14554 Poster Board 60 It is estimated that by 2050 nearly 2.5 billion people are projected to have some degree of hearing loss and at least 700 million will require hearing rehabilitation. Hearing loss can be classified into three groups: sensorineural, conductive, and mixed. Sensorineural hearing loss (SNHL) arises from the inability of the inner ear to convert fluid waves into neural electric signals because of injury to cochlear hair cells resulting in hair cell death. In addition, systemic chronic inflammation implicated in other pathologies may exacerbate cell death leading to SNHL. Phytochemicals have emerged as a possible solution because of the growing evidence of their anti-inflammatory, antioxidant, and anti-apoptotic properties. Ginseng and its bioactive molecules, ginsenosides, exhibit effects that suppress pro-inflammatory signaling, reactive oxygen species (ROS) generation, and protect against apoptosis. In the current study, we investigated the effects of ginsenoside Rc (G-Rc) on UB/OC-2 primary murine sensory hair cell survival and homeostasis in response to palmitate-induced injury. We demonstrated that at a human equivalent dose G-Rc promoted UB/OC-2 cell survival and cell cycle progression. Additionally, G-Rc enhanced the differentiation of UB/OC-2 cells into functional sensory hair cells. Importantly, G-Rc alleviated inflammation, oxidative stress, ER stress, and apoptosis induced by palmitate. The current study offers novel insights into the effects of G-Rc as a potential adjuvant for SNHL and warrants further studies elucidating the molecular mechanisms mediating the beneficial effects of G-Rc on cochlear hair cells.

By 2050, at least 700 million people will require hearing therapy while 2.5 billion are projected to suffer from hearing loss. Sensorineural hearing loss (SNHL) arises from the inability of the inner ear to convert fluid waves into neural electric signals because of injury to cochlear hair cells that has resulted in their death. In addition, systemic chronic inflammation implicated in other pathologies may exacerbate cell death leading to SNHL. Phytochemicals have emerged as a possible solution because of the growing evidence of their anti-inflammatory, antioxidant, and anti-apoptotic properties. Ginseng and its bioactive molecules, ginsenosides, exhibit effects that suppress pro-inflammatory signaling and protect against apoptosis. In the current study, we investigated the effects of ginsenoside Rc (G-Rc) on UB/OC-2 primary murine sensory hair cell survival in response to palmitate-induced injury. G-Rc promoted UB/OC-2 cell survival and cell cycle progression. Additionally, G-Rc enhanced the differentiation of UB/OC-2 cells into functional sensory hair cells and alleviated palmitate-induced inflammation, endoplasmic reticulum stress, and apoptosis. The current study offers novel insights into the effects of G-Rc as a potential adjuvant for SNHL and warrants further studies elucidating the molecular mechanisms.

Purpose: The purpose of this study was to determine whether the speech-evoked auditory brainstem responses (sABRs) obtained by stimulating the ear with normal sensitivity in children with unilateral hearing loss (UHL) were different from that of children with normal hearing (NH), and to explore correlations between the sABR findings and measures of reading. Method: Eleven children with UHL and 11 children with NH were tested via the BioMARK sABR protocol using the syllable /da/; latency and amplitudes of Waves V, A, C, D, E, F, and O were measured. Participants also were tested on the Phonemic Synthesis Test (PST) and the Woodcock Reading Mastery Test–Revised (WRMT-R), particularly the Reading Readiness, Basic Skills, and Comprehension subtests. Results: Multivariate analysis of variance testing showed a significantly higher amplitude for Wave A for the NH group as compared to the UHL group. Separate ANOVAs also found significantly lower scores for the UHL group compared to the NH group on Basic Skills and Comprehension subtests of the Woodcock. Significant positive Spearman rho correlations were found for the UHL group between wave amplitudes for V, A, and O and the Reading Readiness score, and between wave amplitudes for V, A, D, and O and the Reading Comprehension score. A significant correlation also was found between the Total Reading score and wave amplitudes for V and A. No such correlations were found between wave amplitude and Woodcock scores for the NH group. Further testing of the UHL data found significant relationships between the pure-tone average of the hearing loss ear and the Basic Skills, Comprehension, and Total Reading scores from the WRMT-R. There was also a significant correlation between the PST score and Wave C amplitude. Conclusion: There may be a connection between speech encoding and measures of reading in children with UHL.

Objective: The aim of this study was to determine the relation between the acceptable noise level (ANL) and cognitive measures of auditory attention and working memory. Design: Young adults were administered the following tests: the ANL, the Digit Span and Letter–Number Sequencing subtests of the Wechsler Adult Intelligence Scale–Fourth Edition, the Auditory Attention subtest from the Woodcock-Johnson Tests of Cognitive Abilities, the Hearing in Noise Test (HINT), and the operation span (OSPAN) test. A correlation matrix was constructed using Pearson coefficients. Study sample: Twenty-four young adults aged 20–29 years with normal hearing participated in the study. Results: No significant relationships were found among the ANL and the different cognitive tasks, nor was there a significant relation found between the ANL and the HINT. However, significant relationships were found between individual cognitive tasks. There was a significant relation found between selective attention and the most comfortable level of presentation of a story. Conclusion: Selective attention may be a key cognitive function in acceptance of background noise.