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.

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.

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.

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.

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.

Better Understanding of Direct Bone-Conduction Measurement:Comparison with Frequency-Specific Bone-Conduction Tonesand Brainstem Responses

The present study aimed to compare thresholds of directbone-conduction (BC direct) with those of behaviorally measured BC pure-tone audiometry(PTA) and objectively measured BC auditory brainstem response (ABR) to confirm the clinicalfeasibility of their relationships. Subjects and Methods: Young adults with normal hearingparticipated in the study to determine the thresholds from three measurements at four testingfrequencies. In the BC direct, the vibrator of a bone-anchored hearing aid softband wasplaced on the right mastoid of each subject. In both PTA and ABR, a B71 bone oscillatorwas placed on the subject’s right mastoid. While the subject’s thresholds of BC direct andBC PTA were determined with a clinically routine 5-dB step procedure, BC ABR was conductedto determine the individual’s hearing sensitivity by a peak V of the waveform usingtone-burst and click stimuli. Results: The BC direct showed a different pattern between lowand high frequencies. Precisely, its thresholds were 13.25 and 12.25 dB HL at 0.5 and 1kHz, respectively, but 19 and 19.75 dB HL at 2 and 4 kHz, respectively. A significant positivecorrelation existed between BC direct and PTA at 1 kHz, which was also correlated withABR. Conclusions: Based on the current data, the thresholds of BC direct were similar toBC PTA at low frequencies and BC ABR at high frequencies. The thresholds of BC directmight be predictable at approximately 5 dB higher (or lower) than that in PTA, although alarge data set is required for standardization. J Audiol Otol 2020;24(2):85-90

Types of Hearing Protection Devices and Application / 대한이비인후과학회지

Since noise-induced hearing loss (NIHL) is one of prevalent issues in the occupational settings, hearing protection device (HPD) has been widely used to reduce noise exposure levels and to prevent developing NIHL. This review study aimed to introduce several types of the HPD in terms of current trends, its variety and functions, and application. Including a brief history of the HPD, we explain its two types, i.e., passive and active functions, in the first part of main body. The passive HPD has a flat attenuation across the overall frequency range, whereas the active HPD effectively preserves communication components such as meaningful speech with low intensity stimuli while filtering out the high levels of noise. In the second part of the main body, we discuss some negative issues of hearing functions when users are wearing the HPD. In detail, the active HPD does not much degrade the hearing performance for speech detection/recognition and sound source localization compared to the passive HPD. Rather, reduced sound (or music) quality is improved with active one in general. In the final part, we mention that although various applications in the special fields such as factory, mining, army, airplane, and music have been demonstrated, the usage and awareness of HPD in occupational aspect may not follow its fast technological development. Furthermore, most people do not know about either importance or use method of HPD in the non-occupational setting. For these reasons, we conclude that hearing professionals have to access the latest trends of the HPD and to increase their knowledge on it, and thus they should provide the best HPD prescription for the public as well as employees who have to protect their ears from hazard noise impacts.

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.

Proximity Analysis of Web-Based Auditory Training Programs: Toward Listening and Customized Learning Exercises for Aural Rehabilitation / 대한이비인후과학회지

Aural rehabilitation is defined as a comprehensive service which includes hearing aid fitting, hearing aid orientation, auditory training, and informational/educational counseling for people with hearing loss in order to reduce deficits of auditory function, difficulty in communication, and limited social activity, and ultimately to enhance their quality of life. Although it is well known that auditory training among a large scope of the aural rehabilitation is critical to improve residual hearing of hearing-impaired adults and/or older adults, there are some limitations to conduct it in the clinic in terms of time consuming and individual difference. In this review paper, we introduce two of the most popular web-based auditory training programs, namely Listening and Communication Enhancement And customized learning: Exercises for Aural Rehabilitation. The paper analyzes their purpose, contents, effect (or benefit) of auditory training, and clinical application, while arguing their pros and cons. In conclusion, we discuss a necessary of developing auditory training platforms for the hearing-impaired adults and older adults, and then of forging systematic web-based auditory training tools with a low-cost and high efficiency because aging population is rapidly increasing in Korea.

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.