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.

Establishment of Normative Data for Auditory Brainstem Responses in White Noise Condition / 대한이비인후과학회지

Background and Objectives@#Recently, researchers have been interested in auditory brainstem response (ABR) under noisy condition for better diagnosis of the hidden hearing loss. However, there is no normative data conducted from a simple noise condition for the clinical setting yet. The purpose of the present study was to compare the data of ABR under quiet condition with those under noisy conditions and to confirm the feasibility of these data in the clinic.Subjects and Method A total of 104 young listeners with normal hearing (53 female and 51 male) participated. After completing the hearing screening tests, they were given the ABR measure with 75 dB nHL click stimulus under quiet condition, and with a level of 85 dB nHL white noise via a speaker. Absolute latencies and amplitudes of the waves were statistically compared against test condition and gender. @*Results@#There was a significant difference of the latency and amplitude between the quiet and noisy conditions. Under the noise, the absolute latencies of the waves I-V were delayed, and their amplitudes were smaller compared to the quiet condition. Such patterns were revealed in both female and male subjects. However, the females had shorter latencies and larger amplitudes than the male participants regardless of noise. @*Conclusion@#We confirmed stable ABR data using simple white noise setting. In the following study, patients with various pathologies should be applied for the ABR under noisy condition and have their data standardized according to sensitivity and specificity.

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.

A Review of Music Perception with Cochlear Implantation / 대한이비인후과학회지

With a high sound quality stimulated by the electrical device and a large inclusion in medical insurance, the number of cochlear implant recipients has been rapidly increased in Korea. Today, it is not surprising that early implanted young children with congenital deafness show a similar performance to their normal hearing peers in speech perception. However, the cochlear implant users still have a trouble to enjoy music. This review study aims to introduce briefly about acoustic components that required to perceive the music and understand a relationship between cochlear implantation and temporal fine structure. For the pediatric implant users who have less experience on acoustical sound features but are much familiar with the electrically stimulated sound, perceiving the music seems to be challengeable due to the lack of temporal fine resolution related to pitch and timbre among various components of music. Four representative test batteries for evaluating the recipients' ability of the music perception were mentioned and effective auditory music trainings were discussed with analysis of related investigations. Unlike hearing aids users who usually depend on fitting algorism for better music quality, the cochlear implant users need systematic training to improve their music perception ability. In conclusion, advancement of speech processing technology which can provide accurate information about the temporal fine structure of incoming music to the recipients needs to be developed. Also, a practical application of music training should be recommended as a part of auditory training for the cochlear implant users.

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.

A Review of Music Perception with Cochlear Implantation / 대한이비인후과학회지

With a high sound quality stimulated by the electrical device and a large inclusion in medical insurance, the number of cochlear implant recipients has been rapidly increased in Korea. Today, it is not surprising that early implanted young children with congenital deafness show a similar performance to their normal hearing peers in speech perception. However, the cochlear implant users still have a trouble to enjoy music. This review study aims to introduce briefly about acoustic components that required to perceive the music and understand a relationship between cochlear implantation and temporal fine structure. For the pediatric implant users who have less experience on acoustical sound features but are much familiar with the electrically stimulated sound, perceiving the music seems to be challengeable due to the lack of temporal fine resolution related to pitch and timbre among various components of music. Four representative test batteries for evaluating the recipients' ability of the music perception were mentioned and effective auditory music trainings were discussed with analysis of related investigations. Unlike hearing aids users who usually depend on fitting algorism for better music quality, the cochlear implant users need systematic training to improve their music perception ability. In conclusion, advancement of speech processing technology which can provide accurate information about the temporal fine structure of incoming music to the recipients needs to be developed. Also, a practical application of music training should be recommended as a part of auditory training for the cochlear implant users.

Current Developments and Challenge of Implantable Bone Conduction Hearing Aids / 대한이비인후과학회지

It is acknowledged that implantable bone conduction hearing aids such as a bone anchored hearing aid provide benefit and satisfaction to patients with unilateral hearing loss in terms of sound localization and speech perception under noise circumstances. This review paper introduces current models of the implantable bone conduction hearing aids, their candidacy, brief surgical procedures, and general audiological examinations. A table summary was used for nine published research papers which have very similar results by three points, i.e., no change in ability of sound localization, better performance of Hearing-In-Noise Test, and improved satisfaction of sound quality using questionnaires after the implantation. Unfortunately, systematic fitting strategy for users of the implantable bone conduction hearing aids has not been either studied or developed yet. Futhermore, there is no scientific based approach of reason why the implantation has no benefit in sound localization but still provides better performance for speech perception in noise. In conclusion, specific and effective fitting strategy of the current implantable bone conduction hearing aids should be developed and also support effect of the implantation with sensitivity and specificity for both clinicians and patients while accompanying their advanced technology.

Current Developments and Challenge of Implantable Bone Conduction Hearing Aids / 대한이비인후과학회지

It is acknowledged that implantable bone conduction hearing aids such as a bone anchored hearing aid provide benefit and satisfaction to patients with unilateral hearing loss in terms of sound localization and speech perception under noise circumstances. This review paper introduces current models of the implantable bone conduction hearing aids, their candidacy, brief surgical procedures, and general audiological examinations. A table summary was used for nine published research papers which have very similar results by three points, i.e., no change in ability of sound localization, better performance of Hearing-In-Noise Test, and improved satisfaction of sound quality using questionnaires after the implantation. Unfortunately, systematic fitting strategy for users of the implantable bone conduction hearing aids has not been either studied or developed yet. Futhermore, there is no scientific based approach of reason why the implantation has no benefit in sound localization but still provides better performance for speech perception in noise. In conclusion, specific and effective fitting strategy of the current implantable bone conduction hearing aids should be developed and also support effect of the implantation with sensitivity and specificity for both clinicians and patients while accompanying their advanced technology.

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.