Factors Influencing the Korean Version of the Digit-in-Noise Test.

BACKGROUND AND OBJECTIVES: The digits-in-noise (DIN) test was developed as a simple and time-efficient hearing-in-noise test worldwide. The Korean version of the DIN (K-DIN) test was previously validated for both normal-hearing and hearing-impaired listeners. This study aimed to explore the factors influencing the outcomes of the K-DIN test further by analyzing the threshold (representing detection ability) and slope (representing test difficulty) parameters for the psychometric curve fit. Subjects and. METHODS: In total, 35 young adults with normal hearing participated in the K-DIN test under the following four experimental conditions: 1) background noise (digit-shaped vs. pink noise); 2) gender of the speaker (male vs. female); 3) ear side (right vs. left); and 4) digit presentation levels (55, 65, 75, and 85 dB). The digits were presented using the method of constant stimuli procedure. Participant responses to the stimulus trials were used to fit a psychometric function, and the threshold and slope parameters were estimated according to pre-determined criteria. The accuracy of fit performance was determined using the root-mean-square error calculation. RESULTS: The listener's digit detection ability (threshold) was slightly better with pink noise than with digit-shaped noise, with similar test difficulties (slopes) across the digits. Gender and the tested ear side influenced neither the detection ability nor the task difficulty. Additionally, lower presentation levels (55 and 65 dB) elicited better thresholds than the higher presentation levels (75 and 85 dB); however, the test difficulty varied slightly across the presentation levels. CONCLUSIONS: The K-DIN test can be influenced by stimulus factors. Continued research is warranted to understand the accuracy and reliability of the test better, especially for its use as a promising clinical measure.

Systematic Review and Meta-Analysis of the Application of Virtual Reality in Hearing Disorders.

BACKGROUND AND OBJECTIVES: Trendy technologies, such as artificial intelligence, virtual reality (VR), and augmented reality (AR) are being increasingly used for hearing loss, tinnitus, and vestibular disease. Thus, we conducted this systematic review and meta-analysis to identify the possible benefits of the use of VR and AR technologies in patients with hearing loss, tinnitus, and/or vestibular dysfunction, with the aim of suggesting potential applications of these technologies for both researchers and clinicians. MATERIALS AND METHODS: Published articles from 1968 to 2022 were gathered from six electronic journal databases. Applying our specified inclusion and/or exclusion criteria, 23 studies were analyzed. As only one article on hearing loss and two articles on tinnitus were found, 20 studies on vestibular dysfunction were only finally included for the meta-analysis. Standardized mean differences (SMDs) were chosen as estimates to compare the studies. A funnel plot and Egger's regression analysis were used to identify any risk of bias. RESULTS: High heterogeneity (I2: 83%, τ2: 0.5431, p<0.01) was identified across the studies on vestibular dysfunction. VR-based rehabilitation was significantly effective for individuals with vestibular disease (SMDs: 0.03, 95% confidence interval [CI]: -0.08 to 0.15, p<0.05). A subgroup analysis revealed that only improvement in the subjective questionnaire was meaningful and statistically significant (SMDs: -0.66, 95% CI: -1.10 to -0.22). CONCLUSIONS: VR-based vestibular rehabilitation showed potential for subjective rating measures like Dizziness Handicap Index. The negative effect of aging on vestibular disease was indirectly confirmed. More clinical trials and an evidence-based approach are needed to confirm the implementation of state-of-the-art technology for hearing loss and tinnitus, representative diseases in neurotology.

Analysis of the Knowledge, Attitudes, and Practice Model of Healthcare Professionals on Hearing Loss at Elderly Dementia Residences in Korea.

Due to a lack of knowledge about age-related hearing loss, its early identification and appropriate intervention are not being carried out in the field of dementia care. Since the untreated hearing loss of the elderly leads to a more rapid cognitive decline, the present study aimed to understand the hearing-related knowledge, attitudes, and practices of healthcare professionals in long-term care (LTC) facilities in Korea. A total of 557 workers (104 facility managers and 453 healthcare professionals) in residential LTC participated in this cross-sectional multicenter survey study. The Korean version of the knowledge, attitudes, and practice (KAP) on-line survey with a five-point scale or yes/no response was applied as the experimental tool. The results of structural equation modeling showed that knowledge significantly affected the attitudes and health-seeking practices of the facility manager, and allied healthcare professionals demonstrated similar results, which showed the significant effects of that knowledge on attitudes and health-seeking practices. This clearly indicated that sufficient knowledge is the driving force for the health-seeking practices and positive attitudes of both the facility manager and the healthcare professionals. Thus, we suggest that a further step, such as the development of comprehensive and professional guidelines regarding hearing care information for these professionals in residential LTC facilities, should be followed, and believe that this effort could lead to improving hearing-related knowledge, attitudes, and practices in order to clinically and politically care for the elderly population.

Relationship between Nutrient Intake and Hearing Loss According to the Income Level of Working-Aged Adults: A Korean National Health and Nutrition Survey.

The relationship between hearing impairment and nutrition has been extensively investigated; however, few studies have focused on this topic in working-age adults by income level. Herein, we aimed to determine the differences in hearing impairment among working-age adults by income level and identify the nutritional factors that affect hearing loss in various socioeconomic groups. Seven-hundred-and-twenty participants had hearing impairment, while 10,130 had normal hearing. After adjustment for propensity score matching, income and smoking status were identified as significant variables. By assessing the relationship between hearing impairment and nutrient intake by income level using multiple regression analyses, significant nutrients differed for each income category. Carbohydrate and vitamin C levels were significant in the low-income group; protein, fat, and vitamin B1 levels were significant in the middle-income group; and carbohydrates were significant in the high-income group. Income was significantly associated with hearing impairment in working-age adults. The proportion of individuals with hearing impairment increased as income decreased. The association between hearing impairment and nutritional intake also differed by income level. Our findings may enable the establishment of health policies for preventing hearing impairment in working-age adults by income level.

Effects of Natural Versus Synthetic Consonant and Vowel Stimuli on Cortical Auditory-Evoked Potential.

BACKGROUND AND OBJECTIVES: Natural and synthetic speech signals effectively stimulate cortical auditory evoked potential (CAEP). This study aimed to select the speech materials for CAEP and identify CAEP waveforms according to gender of speaker (GS) and gender of listener (GL). SUBJECTS AND METHODS: Two experiments including a comparison of natural and synthetic stimuli and CAEP measurement were performed of 21 young announcers and 40 young adults. Plosive /g/ and /b/ and aspirated plosive /k/ and /p/ were combined to /a/. Six bisyllables-/ga/-/ka/, /ga/-/ba/, /ga/-/pa/, /ka/-/ba/, /ka/-/pa/, and /ba/-/pa/-were formulated as tentative forwarding and backwarding orders. In the natural and synthetic stimulation mode (SM) according to GS, /ka/ and /pa/ were selected through the first experiment used for CAEP measurement. RESULTS: The correction rate differences were largest (74%) at /ka/-/ pa/ and /pa/-/ka/; thus, they were selected as stimulation materals for CAEP measurement. The SM showed shorter latency with P2 and N1-P2 with natural stimulation and N2 with synthetic stimulation. The P2 amplitude was larger with natural stimulation. The SD showed significantly larger amplitude for P2 and N1-P2 with /pa/. The GS showed shorter latency for P2, N2, and N1-P2 and larger amplitude for N2 with female speakers. The GL showed shorter latency for N2 and N1-P2 and larger amplitude for N2 with female listeners. CONCLUSIONS: Although several variables showed significance for N2, P2, and N1-P2, P1 and N1 did not show any significance for any variables. N2 and P2 of CAEP seemed affected by endogenous factors.

The value of having an initial word recognition score for a precise prognosis of idiopathic sudden sensorineural hearing loss.

OBJECTIVE: Although the hearing thresholds of patients with idiopathic sudden sensorineural hearing loss (ISSNHL) closely relate to the prognosis that results in progressive floor effects, many studies have usually used hearing thresholds as the main outcome of the measurement of prognostic factors. The present study aimed to identify the prognostic factors related to initial hearing tests and speculates the effects of word recognition score (WRS) on the prognoses for patients with ISSNHL. METHODS: Between March 2011 and November 2020, we retrospectively reviewed chart profiles of 2,636 ISSNHL patients. The 180 patients who met the inclusion criteria were asked to participate in the present study. Based on their initial WRS, all these patients were divided into good WRS (GW) and poor WRS (PW) groups with 52% as the cut-off points. Demographic, clinical, and audiological variables, such as age, onset time, duration of treatment, gender, ear side, comorbidities (i.e., hypertension, diabetes mellitus, tinnitus, dizziness), hearing configuration (i.e., ascending, descending, flat, irregular, and profound), treatment options (i.e., systemic corticosteroid therapy per oral, intratympanic steroid injection, and hyperbaric oxygen therapy), and WRS were analyzed as being underlying prognostic factors. RESULTS: Both groups showed significantly different distributions for hearing thresholds and hyperbaric oxygen therapy (HBOT) as general characteristics. The results of a multivariate logistic regression analysis showed that the odds ratio (OR) of age (OR: 0.96, 95% CI: 0.59 - 24.25), duration of treatment (OR: 0.98, 95% CI: 0.96 - 1.00), ascending configuration (OR: 4.97, 95% CI: 1.64 - 16.62), irregular configuration (OR: 4.58, 95% CI: 1.62 - 13.79), and WRS (OR: 1.01, 95% CI: 1.00 - 1.02) were the significant prognostic factors for all the patients. Further analysis of those patients with WRS under 52% cut-off points showed that an ascending configuration (OR: 5.87, 95% CI: 1.18 - 35.99), irregular configuration (OR: 8.03, 95% CI: 1.69 - 46.30), and WRS (OR: 1.05, 95% CI: 1.01 - 1.10) significantly affected the prognosis. As the initial WRS of ISSNHL patients decreased, the OR of the WRS itself increased. These results suggested that the importance of WRS as the prognostic factor was stressed for PW patients. CONCLUSION: The age, duration of treatment, initial hearing configuration (ascending and irregular types), and WRS were the significant prognostic factors for patients with ISSNHL. It was learned that WRS could be a remarkable prognostic factor to consider, especially for ISSNHL patients with poor WRS.

Efficacy of the Digit-in-Noise Test: A Systematic Review and Meta-Analysis.

BACKGROUND AND OBJECTIVES: Although the digit-in-noise (DIN) test is simple and quick, little is known about its key factors. This study explored the considerable components of the DIN test through a systematic review and meta-analysis. MATERIALS AND METHODS: After six electronic journal databases were screened, 14 studies were selected. For the meta-analysis, standardized mean difference was used to calculate effect sizes and 95% confidence intervals. RESULTS: The overall result of the meta-analysis showed an effect size of 2.224. In a subgroup analysis, the patient's hearing status was found to have the highest effect size, meaning that the DIN test was significantly sensitive to screen for hearing loss. In terms of the length of the presenting digits, triple digits had lower speech recognition thresholds (SRTs) than single or pairs of digits. Among the types of background noise, speech-spectrum noise provided lower SRTs than multi-talker babbling. Regarding language variance, the DIN test showed better performance in the patient's native language(s) than in other languages. CONCLUSIONS: When uniformly developed and well validated, the DIN test can be a universal tool for hearing screening.

The Effectiveness of Hearing Protection Devices: A Systematic Review and Meta-Analysis.

To prevent intensive noise exposure in advance and be safely controlled during such exposure, hearing protection devices (HPDs) have been widely used by workers. The present study evaluates the effectiveness of these HPDs, partitioned into three different outcomes, such as sound attenuation, sound localization, and speech perception. Seven electronic journal databases were used to search for published articles from 2000 to 2021. Based on inclusion criteria, 20 articles were chosen and then analyzed. For a systematic review and meta-analysis, standardized mean differences (SMDs) and effect size were calculated using a random-effect model. The funnel plot and Egger's regression analysis were conducted to assess the risk of bias. From the overall results of the included 20 articles, we found that the HPD function performed significantly well for their users (SMDs: 0.457, 95% confidence interval (CI): 0.034-0.881, p < 0.05). Specifically, a subgroup analysis showed a meaningful difference in sound attenuation (SMDs: 1.080, 95% CI: 0.167-1.993, p < 0.05) when to wear and not to wear HPDs, but indicated no significance between the groups for sound localization (SMDs: 0.177, 95% CI: 0.540-0.894, p = 0.628) and speech perception (SMDs: 0.366, 95% CI: -0.100-1.086, p = 0.103). The HPDs work well for their originally designated purposes without interfering to find the location of the sound sources and for talking between the workers. Taking into account various factors, such as the characteristics of the users, selection of appropriate types, and fitting methods for wearing in different circumstances, seems to be necessary for a reliable systematic analysis in terms of offering the most useful information to the workers.

Age-Related Difficulty of Listening Effort in Elderly.

The present study identifies the combined effects of aging and listening environment related factors, such as directionality, types of stimuli, and the presence of background noise. A total of 50 listeners with normal hearing (25 older adults and 25 young adults) participated in a series of tasks. The detection task using tone and speech and a speech segregation task with two levels of background noise were conducted while sound was randomly presented via eight directional speakers. After completing each task, a subjective questionnaire using a seven-point Likert scale was asked to measure the amount of the subjects' listening effort in terms of speech, spatial, and hearing quality. As expected, the amount of listening effort required in all the experiments for the older group was significantly higher than for their young counterparts. The effects of aging and types of stimuli (tone and speech) also showed different patterns of listening effort for the older adults and younger adults. The combined interaction of aging, directionality, and presence of background noise led to a significantly different amount of listening effort for the older group (90.1%) compared to the younger group (53.1%), even in the same listening situation. These current results, when summarized, indicated weak tone detection ability at high frequencies occurred in the elderly population but the elderly could improve their ability by using speech sounds with broad-band spectrum energy. We suggest that a warning signal when using speech rather than a single tone is more advantageous for the elderly in a public environment. It is also better to converse with the elderly by avoiding situations where noise from behind can interrupt.

Audiological benefits and performance improvements of Baha® attract implantation in patients with unilateral hearing loss.

OBJECTIVES: To evaluate the overall functional and audiological benefits in unilateral hearing loss, as well as performance improvements with Cochlear™ Baha® Attract System with Baha® 5 sound processor. METHODS: We performed a prospective study. Fourteen consecutive adult patients with unilateral hearing loss who were audiologically eligible for Baha® Attract were included in this study. All patients were followed-up, and a series of tests were performed in the sound field before surgery, one, two, three, and 6 months after surgery. RESULTS: Patients were categorized based on their hearing impairment type and severity. Ten patients had conductive hearing loss (CHL), or mixed hearing loss (MHL), and four patients had sensorineural hearing loss (SNHL). The hearing threshold in the sound field aided with Baha® Attract was similar to the preoperative bone conduction hearing threshold of the better ear. The results of the speech audiometry improved post-operatively, but they did not match that of the better ear before surgery. The overall score of the hearing-in-noise test was gradually improved from one month to 6 months after surgery. The results of the sound localization test for SNHL patients were not as good as those for CHL or MHL. All the questionnaires demonstrated additional benefits that implied performance improvements. CONCLUSIONS: The Baha® Attract provides enough auditory benefits and performance improvements for hearing impaired patients, though there are different benefits according to the type of hearing loss. Clinicians need to counsel the unilateral hearing loss patients for Baha® Attract System carefully, according to their type of hearing loss.

Effect of Speech Degradation and Listening Effort in Reverberating and Noisy Environments Given N400 Responses.

BACKGROUND AND OBJECTIVES: In distracting listening conditions, individuals need to pay extra attention to selectively listen to the target sounds. To investigate the amount of listening effort required in reverberating and noisy backgrounds, a semantic mismatch was examined. SUBJECTS AND METHODS: Electroencephalography was performed in 18 voluntary healthy participants using a 64-channel system to obtain N400 latencies. They were asked to listen to sounds and see letters in 2 reverberated×2 noisy paradigms (i.e., Q-0 ms, Q-2000 ms, 3 dB-0 ms, and 3 dB-2000 ms). With auditory-visual pairings, the participants were required to answer whether the auditory primes and letter targets did or did not match. RESULTS: Q-0 ms revealed the shortest N400 latency, whereas the latency was significantly increased at 3 dB-2000 ms. Further, Q-2000 ms showed approximately a 47 ms delayed latency compared to 3 dB-0 ms. Interestingly, the presence of reverberation significantly increased N400 latencies. Under the distracting conditions, both noise and reverberation involved stronger frontal activation. CONCLUSIONS: The current distracting listening conditions could interrupt the semantic mismatch processing in the brain. The presence of reverberation, specifically a 2000 ms delay, necessitates additional mental effort, as evidenced in the delayed N400 latency and the involvement of the frontal sources in this study.

Development of the Hearing Rehabilitation for Older Adults (HeRO) Healthcare Mobile Application and Its Likely Utility for Elderly Users.

The present study aimed to develop a healthcare application for the elderly who suspect or know they have a hearing loss, namely, the Hearing Rehabilitation for Older Adults (HeRO), which is available in a mobile device, and then to confirm its probability of acceptance among elderly users. Under a web server system, HeRO which had four types of tailored training for the aged auditory system (i.e., syllable, sentence, discourse, working memory) and a self-reported questionnaire to screen amount of the hearing loss was completed for the elderly. To verify whether the HeRO contents and functions were user-friendly to the elderly users, the technology acceptance model (TAM) was used. Forty-four older adults were asked to use the developed application for 10 days and then respond to a TAM questionnaire with 25 items. The Cronbach's α coefficient of each subcategory was very high. The construct validity of all subcategories showed high eigenvalues using principal component analysis. Furthermore, our regression model statistically supported a persuasive intention to use the healthcare application because the elderly readily accept it and find it easy to manipulate. We expect the current technology to be applied to the general public as well as the elderly who want to explore digital health.

Use of Personal Listening Devices and Knowledge/Attitude for Greater Hearing Conservation in College Students: Data Analysis and Regression Model Based on 1009 Respondents.

Given the concern regarding increased hearing loss in young people who use personal listening devices (PLDs), the present study analyzes the experience of PLDs among college students to identify their knowledge of and attitude toward hearing conservation. It also explains their relationship between knowledge of hearing loss and attitude-related hearing conservation as a questionnaire response using a regression model. A total of 1009 Korean college students responded to an online questionnaire. As a survey tool, the Personal Listening Device and Hearing Questionnaire was adapted as a Korean version with 78 modified items under 9 categories. Using principal component analysis, specific factors were extracted, and their relationships and paths were confirmed using multiple regression analysis. The results of the knowledge category of the questionnaire indicate that most respondents knew how to maintain healthy hearing and understood the signs of hearing loss. Regardless, many college students habitually use PLDs at high levels in noisy environments; they do not recognize how to prevent hearing loss. Even though they continue their current use pattern for PLDs, they also had a positive attitude toward receiving more information about hearing conservation. According to the regression model, the students' self-reported hearing deficits were due to the volume rather than the frequent use. Interestingly, knowledge about hearing loss may encourage students to develop a positive attitude toward reasonable restriction of PLD use. When PLD users have detailed knowledge about the hearing loss provided by professionals, we believe that most will avoid serious hearing problems and its risks and maintain a judicious attitude toward their own conservation.

Better Understanding of Direct Bone-Conduction Measurement: Comparison with Frequency-Specific Bone-Conduction Tones and Brainstem Responses.

BACKGROUND AND OBJECTIVES: The present study aimed to compare thresholds of direct bone-conduction (BC direct) with those of behaviorally measured BC pure-tone audiometry (PTA) and objectively measured BC auditory brainstem response (ABR) to confirm the clinical feasibility of their relationships. Subjects and. METHODS: Young adults with normal hearing participated in the study to determine the thresholds from three measurements at four testing frequencies. In the BC direct, the vibrator of a bone-anchored hearing aid softband was placed on the right mastoid of each subject. In both PTA and ABR, a B71 bone oscillator was placed on the subject's right mastoid. While the subject's thresholds of BC direct and BC PTA were determined with a clinically routine 5-dB step procedure, BC ABR was conducted to determine the individual's hearing sensitivity by a peak V of the waveform using tone-burst and click stimuli. RESULTS: The BC direct showed a different pattern between low and high frequencies. Precisely, its thresholds were 13.25 and 12.25 dB HL at 0.5 and 1 kHz, respectively, but 19 and 19.75 dB HL at 2 and 4 kHz, respectively. A significant positive correlation existed between BC direct and PTA at 1 kHz, which was also correlated with ABR. CONCLUSIONS: Based on the current data, the thresholds of BC direct were similar to BC PTA at low frequencies and BC ABR at high frequencies. The thresholds of BC direct might be predictable at approximately 5 dB higher (or lower) than that in PTA, although a large data set is required for standardization.

Towards Size of Scene in Auditory Scene Analysis: A Systematic Review.

Auditory scene analysis is defined as a listener's ability to segregate a meaningful message from meaningless background noise in a listening environment. To gain better understanding of auditory perception in terms of message integration and segregation ability among concurrent signals, we aimed to systematically review the size of auditory scenes among individuals. A total of seven electronic databases were searched from 2000 to the present with related key terms. Using our inclusion criteria, 4,507 articles were classified according to four sequential steps-identification, screening, eligibility, included. Following study selection, the quality of four included articles was evaluated using the CAMARADES checklist. In general, studies concluded that the size of auditory scene increased as the number of sound sources increased; however, when the number of sources was five or higher, the listener's auditory scene analysis reached its maximum capability. Unfortunately, the score of study quality was not determined to be very high, and the number of articles used to calculate mean effect size and statistical significance was insufficient to draw significant conclusions. We suggest that study design and materials that consider realistic listening environments should be used in further studies to deep understand the nature of auditory scene analysis within various groups.

Speech Perception and Gap Detection Performance of Single-Sided Deafness under Noisy Conditions.

BACKGROUND AND OBJECTIVES: Many studies have reported no benefit of sound localization, but improved speech understanding in noise after treating patients with single-sided deafness (SSD). Furthermore, their performances provided a large individual difference. The present study aimed to measure the ability of speech perception and gap detection in noise for the SSD patients to better understand their hearing nature. SUBJECTS AND METHODS: Nine SSD patients with different onset and period of hearing deprivation and 20 young adults with normal hearing and simulated conductive hearing loss as the control groups conducted speech perception in noise (SPIN) and Gap-In-Noise (GIN) tests. The SPIN test asked how many presented sentences were understood at the +5 and -5 dB signal-to-noise ratio. The GIN test was asked to find the shortest gap in white noise with different lengths in the gap. RESULTS: Compared to the groups with normal hearing and simulated instant hearing loss, the SSD group showed much poor performance in both SPIN and GIN tests while supporting central auditory plasticity of the SSD patients. Rather than a longer period of deafness, the large individual variance indicated that the congenital SSD patients showed better performance than the acquired SSD patients in two measurements. CONCLUSIONS: The results suggested that comprehensive assessments should be implemented before any treatment of the SSD patient considering their onset time and etiology, although these findings need to be generalized with a large sample size.

Evaluation of wireless Bluetooth devices to improve recognition of speech and sentences when using a mobile phone in bone conduction device recipients.

OBJECTIVE: To evaluate the effect of a wireless Bluetooth device (WBD) in word and sentence recognition in patients with bone conduction devices (BCDs) while using mobile phones. METHODS: We performed a prospective study evaluating speech and sentence recognition in both quiet and noised conditions. A total of nine patients, audiologically eligible for BCDs, were included. Based on their hearing impairment type and severity, subjects were divided into "BCD only" and "BCD with HA" groups. The speech and sentence recognition scores of each condition were compared by nonparametric methods. RESULTS: Both the "BCD only" and "BCD with HA" groups had higher scores in the quiet condition than in the noised condition in word and sentence recognition tests, irrespective of whether the WBD was used. The benefit from using a WBD was greater in the noised condition. There were significant differences in the word recognition test results before and after using the WBD in the "BCD only" group, and in both the word and sentence recognition tests results before and after using the WBD bimodally in the noised condition in the "BCD with HA" group. CONCLUSION: WBDs improve word and sentence recognition in adult BCD bone recipients when they use mobile phones. WBD use provides additional benefits in "BCD with HA" patients in a bimodal situation.

Effect of noise and reverberation on speech recognition and listening effort for older adults.

AIM: The purpose of the present study was to evaluate the speech recognition ability and degree of listening effort for older adults in noisy and reverberating environments. METHODS: A total of 80 participants (40 older and 40 younger adults) participated in a sentence recognition test under 20 conditions with four levels of background noise and five levels of reverberation time. In each condition, the degree of listening effort was self-reported using a 5-point Likert scale. RESULTS: The older and younger groups showed that both the error percentage of the sentence recognition task and scale of the listening effort increased as the background noise and reverberation time increased. In the sentence recognition task, the older group was more affected by the reverberation condition than the noisy background compared with their younger counterparts. For the listening effort, the older group had higher scales than the younger group in all conditions, thereby explaining that they required significant effort during the listening task. CONCLUSIONS: The older adults had poorer speech perception ability and required more listening effort than their younger counterparts in all conditions. Reverberation reversely significantly affected the speech recognition and listening effort for the older adults when compared with the background noise, suggesting that an appropriate level of noise and reverberation should be considered for comfort and a less stressful listening environment for the older adult population. Geriatr Gerontol Int 2018; 18: 1603-1608.

Update on Bone-Conduction Auditory Brainstem Responses: A Review.

Auditory brainstem responses (ABR) have been used as a powerful and the most common objective tool to evaluate hearing sensitivity and to diagnose the types of hearing loss and neurological disorders, through the auditory peripheral pathway to a central level of the brainstem, since 1971. Although bone-conduction (BC) ABR could be an alternative to air-conduction (AC) ABR, as the former overcomes some limitations of the latter, the majority of clinicians rarely utilize it due to a lack of knowledge and no routine test administration. This review presents the weaknesses of AC ABR that apply to all clinical population, and discusses the development of BC ABR. The optimal placements of bone oscillators to obtain favorable clinical outcomes in infants, children, and adults, and the appropriate stimuli for BC ABR are examined. While providing absolute thresholds and latencies of BC ABR based on previous studies compared to AC ABR, this review includes clinical data of infants and young children with both normal hearing in terms of maturation, and with pathology such as congenital external auditory canal atresia. We recommend the future clinical application of BC ABR for candidacy as well as for patients with BC hearing implants.

Comparison of Single-Task versus Dual-Task for Listening Effort.

BACKGROUND AND OBJECTIVES: Depending on the kind of task and/or material, listeners sometimes need to pay attention to understand communication. The present study aimed to estimate a listener's amount of effort needed to understand communication by using recognition score and response time as a function of signal-to-noise ratio (SNR) and to confirm his/ her task dependency for listening effort. SUBJECTS AND METHODS: Forty-eight young adults with normal hearing participated in the study. As stimuli, Korean Speech Perception in Noise test without a question tag and three consecutive digits were used for sentence recognition (or single-task) and arithmetic (or dual-task), respectively. Both tasks were measured in quiet and under four SNR (i.e., 0, -4, -8, -12 dB) conditions. Their outcomes were analyzed and compared in terms of percent correct and response time. RESULTS: Sentence recognition scores and arithmetic scores decreased as the level of noise increased. Response time for sentence recognition decreased as noise increased, whereas the response time for arithmetic increased as noise increased. In addition, there was a negative correlation between error percent and response time in the sentence recognition. Conversely, a positive correlation between error percent and response time appeared in the arithmetic test. CONCLUSIONS: Listening effort showed a different pattern based on the kind of task, single vs. dual, while the dual-task required greater effort from the listener.