ABSTRACT
Background and Objectives@#Recently, the improvement of music perception abilities for emotional stability and high quality of life has become important for the hearing loss group. This study aimed to examine and compare the music perception abilities of the normal hearing (NH) and hearing amplification system (HAS) groups to find the needs and methods of music rehabilitation. @*Subjects and Methods@#The data were collected from 15 NH adults (33.1±11.4 years) and 15 HAS adults (38.7±13.4 years), of whom eight wore cochlear implant [CI] systems and seven wore CI and hearing aid systems depending on pitch, melody, rhythm, timbre, emotional reaction, and harmony perception tests. A mismatch negativity test was also conducted, and attitudes toward and satisfaction with listening to music were measured. @*Results@#The correction percentages for the NH and HAS groups were 94.0%±6.1% and 75.3%±23.2% in the pitch test; 94.0%±7.1% and 30.3%±25.9% in the melody test; 99.3%±1.8% and 94.0%± 7.6% in the rhythm test; 78.9%±41.8% and 64.4%±48.9% in the timbre test; 96.7%±10.4% and 81.7%±16.3% in the emotional reaction test; and 85.7%±14.1% and 58.4%±13.9% in the harmony test, respectively, showing statistical significance (p<0.05). For the mismatch negativity test, the area of the waveform was smaller in the HAS groups than in the NH groups, with 70 dB of stimulation showing no statistical significance. The response rates for satisfaction with listening to music were 80% and 93.3% for the NH and HAS groups, showing no statistical significance. @*Conclusions@#Although the HAS group showed lower music perception ability than the NH group overall, they showed a strong desire for music listening. Also, the HAS group revealed a higher degree of satisfaction even when listening to unfamiliar music played with unusual instruments. It is suggested that systematic and constant musical rehabilitation based on musical elements and different listening experiences will improve music perception qualities and abilities for HAS users.
ABSTRACT
Purpose@#This study investigated clinical competency, COVID-19-related anxiety, coping strategies, self-efficacy, and perceived stress among graduating nursing students during the COVID-19 pandemic. @*Methods@#We conducted a cross-sectional survey. Participants were recruited from universities located in four major cities in South Korea. General demographic information, clinical competency, self-efficacy, perceived stress, COVID-19-related anxiety, and coping strategies were assessed using reliable questionnaires. Descriptive statistics, correlations, and multiple regression tests were used to analyze the data. @*Results@#The mean clinical competency, self-efficacy, perceived stress, adaptive coping, and maladaptive coping were 138.16 ± 18.34, 83.85 ±14.02, 21.37 ± 5.79, 53.15 ± 4.64, and 30.98 ± 6.73, respectively. COVID-19-related anxiety was reported by 4.3% of participants. Clinical competency was significantly positively correlated with self-efficacy (r = .44, p < .001) and adaptive coping (r = .20, p = .035) and was significantly negatively correlated with maladaptive coping (r = .20, p = .035). The predictors of clinical competency were self-efficacy (β = .434, p < .001) and adaptive coping (β = .173, p < .039), which explained 23% of the variance in clinical competency. @*Conclusion@#Self-efficacy and adaptive coping strategies are significant predictors of clinical competence during the pandemic. Planning and implementing various curricular and non-curricular activities to increase senior students' self-efficacy and adaptive coping strategies will help prepare competent nursing graduates for the pandemic when they enter the nursing workforce.
ABSTRACT
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.
ABSTRACT
Purpose@#This study aimed to investigate the influence of workplace violence experience on depression among female caregivers in Korea. @*Methods@#This study was a secondary data analysis of data from the 5th Korean Working Conditions Survey (KWCS). The study sample consisted of 484 female caregivers. IBM SPSS 25.0 was used for complex sample analysis, which considered sampling the weights of variables. Based on the survey questions, we used complex sample cross-tabulation and the complex sample general linear model (CSGLM). @*Results@#About 10.1% of female caregivers experienced workplace violence. The factors influencing workplace violence experience on depression were organizational justice (p=.048) and illness (p=.004). However, in cases with no violence, the influencing factors were psychological work environment (p=.001), work environment satisfaction (p=.024), and work engagement (p=.004). @*Conclusion@#Caregivers are vulnerable to workplace violence. Therefore, it is necessary to formulate a policies such as organizational justice, work environment satisfaction, and work engagement to improve the working environment.
ABSTRACT
Purpose@#This study aimed to investigate the influence of workplace violence experience on depression among female caregivers in Korea. @*Methods@#This study was a secondary data analysis of data from the 5th Korean Working Conditions Survey (KWCS). The study sample consisted of 484 female caregivers. IBM SPSS 25.0 was used for complex sample analysis, which considered sampling the weights of variables. Based on the survey questions, we used complex sample cross-tabulation and the complex sample general linear model (CSGLM). @*Results@#About 10.1% of female caregivers experienced workplace violence. The factors influencing workplace violence experience on depression were organizational justice (p=.048) and illness (p=.004). However, in cases with no violence, the influencing factors were psychological work environment (p=.001), work environment satisfaction (p=.024), and work engagement (p=.004). @*Conclusion@#Caregivers are vulnerable to workplace violence. Therefore, it is necessary to formulate a policies such as organizational justice, work environment satisfaction, and work engagement to improve the working environment.
ABSTRACT
Background and Objectives@#This study aimed to investigate the occupational performance of Korean workers with and without hearing loss and analyze the hearing-related difficulties in the working environment. @*Subjects and Methods@#The Amsterdam checklist for hearing and work was used for the analyses and the occupational environments of the Korean workers were investigated. Out of 129 total participants, 86 workers experienced severe to profound hearing loss and 43 had the normal hearing ability. The hearing-impaired workers were recruited from two leading vocational centers and normal-hearing workers were their colleagues. @*Results@#The hearing-impaired workers were found to take fewer sick leaves and exhibited higher rates of permanent job statuses compared to the normal-hearing workers. Workers with hearing loss rarely detected background sound; however, they could perceive reverberation more frequently. They felt more satisfied with their careers than the normal hearing workers as they received social support and needed to put their effort into hearing for most hearing activities. Furthermore, the effort in hearing increased with the increase in job demand, job control, social support, and career satisfaction. The working hours per week increased with the increase in age, education level, job demand, job control, and social support. Different trends were observed in 9 out of 12 variables while comparing the data from the present study with that obtained from the hearing-impaired workers of the Netherlands, indicating a large difference between countries. @*Conclusions@#Although the hearing-impaired Korean workers operate diligently with good job positions, it is necessary to enhance their acoustic environment and provide them social support. Considering the cultural background of the hearing-impaired workers, the development of suitable vocational rehabilitation programs and specific questionnaires is strongly recommended worldwide.
ABSTRACT
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.
ABSTRACT
PURPOSE: This purpose of this study was to identify both good teaching and desirable teaching behaviors perceived by nursing students.METHODS: A cross-sectional descriptive design was used. A convenience sample of 324 nursing students was selected and they completed self-reported questionnaires from November 1 to December 30, 2015.RESULTS: Among 4 perspectives of good teaching (traditional, systemic, interaction, and constructionism), the traditional perspective was perceived as the highest form of good teaching, while the systemic perspective was perceived as the lowest. Meanwhile, disclosure and clarity were perceived as the highest desirable teaching behaviors. Regardless of students' perspective of good teaching, all 4 perspectives of good teaching were positively related with clarity, enthusiasm, interaction, organization, and disclosure as desirable teaching behaviors independently.CONCLUSIONS: Nursing students perceived that the highest perspective of good teaching was the traditional perspective. Meanwhile, they perceived that clarity, enthusiasm, interaction, organization, and disclosure were desirable teaching behaviors regardless of their perspective of good teaching. Further study will be needed to perceive nursing faculty's awareness of good teaching and desirable teaching behaviors to identify the difference of awareness between nursing students and faculty.
Subject(s)
Humans , Disclosure , Education, Nursing , Nursing , Students, NursingABSTRACT
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.
Subject(s)
Child , Humans , Acoustics , Cochlear Implantation , Cochlear Implants , Deafness , Hearing , Hearing Aids , Insurance , Korea , Music , Perception , Pitch Perception , Speech PerceptionABSTRACT
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.
ABSTRACT
BACKGROUND AND OBJECTIVES: Changes in distortion product otoacoustic emission (DPOAE) caused by contralateral suppression (CS) allow the function of the auditory efferent system to be evaluated. Parameters affording maximum CS are preferred in terms of clinical application. Our objective was to evaluate the effects of primary levels and frequencies on DPOAE-mediated CS. SUBJECTS AND METHODS: Sixteen subjects with normal hearing participated. DPOAEs were recorded with and without contralateral acoustic stimulation; we delivered broadband noise of 65 dB SPL at f2 frequencies between 1,000 Hz and 6,727 Hz, at 8 pt/octave. The L2 was varied between 40 dB SPL and 80 dB SPL in 10-dB steps. RESULTS: L2 did not significantly affect DPOAE-mediated CS. Higher L2 levels significantly reduced the fine structure depth of both the baseline and suppressed DPOAE datasets. The amount of CS was greatly affected by the f2 frequency; lower and higher frequency ranges afforded significantly stronger suppression than did mid-frequencies within the studied range. CONCLUSIONS: Our findings suggest that DPOAE CS should be measured over a wide range of frequencies as the amount of CS seems to be highly dependent on f2. The use of a higher L2 level may be optimal when it is sought to evoke strong DPOAE-mediated suppression while simultaneously minimizing DPOAE fine structure. Our findings may assist in optimization of clinical procedures evaluating the integrity of the auditory efferent system.
Subject(s)
Acoustic Stimulation , Dataset , Hearing , NoiseABSTRACT
BACKGROUND AND OBJECTIVES: Although Ling 6 sounds are often used in the rehabilitation process, its acoustic features have not been fully analyzed and represented in cortical responses. Current study was aimed to analyze acoustic features according to gender and emotional statuses of core vowels of Ling 6 sounds, /u/, /a/, and /i/. Cortical auditory evoked potentials (CAEPs) were also observed in those vowels. SUBJECTS AND METHODS: Vowel sounds /u/, /a/, and /i/ out of Ling 6 sounds representing low, middle and high frequencies were recorded from normal 20 young adults. The participants watched relevant videos for 4-5 minutes in order for them to sympathize emotions with anger (A), happiness (H), and sadness (S) before producing vowels. And without any emotional salience, neutrally production was performed. The recording was extracted for 500 ms to select pure vowel portion of production. For analysis of CAEP, the latencies and amplitudes of P1, N1, P2, N2, N1-P2 were analyzed. RESULTS: Intensities of /u/, /a/, and /i/ were 61.47, 63.38, and 60.55 dB. The intensities of neutral (N), H, A, S were 60.60, 65.43, 64.21, and 55.75 dB for vowel /u/, vowel /a/ were 61.80, 68.98, 66.50, and 56.23 dB, and vowel /i/ were 59.34, 64.90, 61.90, and 56.05 dB. The statistical significances for vowel and emotion were found but not for gender. The fundamental frequency (F0) of vowels for N, A, H, and S were 168.04, 174.93, 182.72, and 149.76 Hz and the first formant were 743.75, 815.59, 823.32, and 667.62 Hz. The statistical significance of F0 was found by vowel, emotion, and gender. The latencies and amplitudes of CAEP components did not show any statistical significance according to vowel. CONCLUSIONS: Ling 6 sounds should be produced consistently in the rehabilitation process for considering their difference of intensities and frequencies according to speaker’s emotions and gender. The vowels seemed to be interpreted as tonal stimuli for CAEP components of this study with similar acoustic features among them. Careful selection of materials is necessary to observe meaningful conclusion of CAEP measurement with vowel stimuli.
Subject(s)
Humans , Young Adult , Acoustics , Anger , Evoked Potentials, Auditory , Happiness , RehabilitationABSTRACT
BACKGROUND AND OBJECTIVES: To prevent noise induced hearing losses caused by listening to music with personal listening devices for young adults, this study was aimed to measure output levels of an MP3 and to identify preferred listening levels (PLLs) depending on earphone types, music genres, and listening durations. SUBJECTS AND METHODS: Twenty-two normal hearing young adults (mean=18.82, standard deviation=0.57) participated. Each participant was asked to select his or her most PLLs when listened to Korean ballade or dance music with an earbud or an over-the-ear earphone for 30 or 60 minutes. One side of earphone was connected to the participant’s better ear and the other side was connected to a sound level meter via a 2 or 6 cc-couplers. Depending on earphone types, music genres, and listening durations, loudness A-weighted equivalent (LAeq) and loudness maximum time-weighted with A-frequency sound levels in dBA were measured. RESULTS: Neither main nor interaction effects of the PLLs among the three factors were significant. Overall output levels of earbuds were about 10-12 dBA greater than those of over-the-ear earphones. The PLLs were 1.73 dBA greater for earbuds than over-the-ear earphones. The average PLL for ballad was higher than for dance music. The PLLs at LAeq for both music genres were the greatest at 0.5 kHz followed by 1, 0.25, 2, 4, 0.125, 8 kHz in the order. CONCLUSIONS: The PLLs were not different significantly when listening to Korean ballad or dance music as functions of earphone types, music genres, and listening durations. However, over-the-ear earphones seemed to be more suitable to prevent noise induce hearing loss when listening to music, showing lower PLLs, possibly due to isolation from the background noise by covering ears.
Subject(s)
Humans , Young Adult , Dancing , Ear , Hearing , Hearing Loss , MP3-Player , Music , NoiseABSTRACT
Listening effort is defined as a listener's mental exertion required to understand a speaker's auditory message, especially when distracting conditions are present. This review paper analyzed several subjective scaling tools used to measure the listening effort in order to suggest the best tool for use with hearing-impaired listeners who have to expend much effort even in everyday life. We first explained the importance of measuring listening effort and discussed various kinds of measurements. We then analyzed and categorized 15 recently published articles (i.e., from 2014 to 2016) into three topics: performance and listening effort, listening effort and fatigue, and clinical implication of listening effort. We compared the articles in terms of pros and cons and also identified 10 tools for use in the subjective scaling. Although none of these tools were unified or standardized easily, we concluded that 7-point scale would be the most reasonable as a less time-consuming measurement for compartmentalizing the degree of listening effort. If used with objective tools for measuring the listening effort, the subjective scaling could be a powerful tool for clinical use.
Subject(s)
FatigueABSTRACT
BACKGROUND AND OBJECTIVES: Listeners with sensorineural hearing loss want to compensate for their narrow dynamic range from appropriate compression functions of hearing aids. The present study aimed to determine which compression threshold and release time of nonlinear hearing aids might affect speech recognition and speech quality judgments. SUBJECTS AND METHODS: Ten elderly listeners with symmetrical moderate-to-severe sensorineural hearing loss participated in the study. To compare two compression threshold (31 dB SPL vs. 61 dB SPL) and two release time (50 ms vs. 500 ms) conditions, subjects’ speech recognition was measured using the Korean version of the Hearing in Noise Test in both quiet and noisy situations. All subjects were also asked to rate the degree of speech quality in terms of loudness, sharpness, clarity, and background noise immediately after completing the speech recognition test. RESULTS: Although no significant difference emerged in speech recognition thresholds between the two compression thresholds in the quiet situation, the compression threshold of 31 dB SPL showed a lower (or better) signal-to-noise ratio of speech recognition compared to that of 61 dB SPL. The release times of 50 and 500 ms did not statistically differ in both quiet and noisy situations. Subjective categories were found to be louder and clearer in the 50 ms release time for quiet and noisy, respectively. CONCLUSIONS: We expect that these patterns of current results will apply for better-fitting protocol of elderly Korean hearing aid users.
Subject(s)
Aged , Humans , Hearing Aids , Hearing Loss, Sensorineural , Hearing , Judgment , Noise , Signal-To-Noise RatioABSTRACT
BACKGROUND AND OBJECTIVES: Listeners with sensorineural hearing loss want to compensate for their narrow dynamic range from appropriate compression functions of hearing aids. The present study aimed to determine which compression threshold and release time of nonlinear hearing aids might affect speech recognition and speech quality judgments. SUBJECTS AND METHODS: Ten elderly listeners with symmetrical moderate-to-severe sensorineural hearing loss participated in the study. To compare two compression threshold (31 dB SPL vs. 61 dB SPL) and two release time (50 ms vs. 500 ms) conditions, subjects’ speech recognition was measured using the Korean version of the Hearing in Noise Test in both quiet and noisy situations. All subjects were also asked to rate the degree of speech quality in terms of loudness, sharpness, clarity, and background noise immediately after completing the speech recognition test. RESULTS: Although no significant difference emerged in speech recognition thresholds between the two compression thresholds in the quiet situation, the compression threshold of 31 dB SPL showed a lower (or better) signal-to-noise ratio of speech recognition compared to that of 61 dB SPL. The release times of 50 and 500 ms did not statistically differ in both quiet and noisy situations. Subjective categories were found to be louder and clearer in the 50 ms release time for quiet and noisy, respectively. CONCLUSIONS: We expect that these patterns of current results will apply for better-fitting protocol of elderly Korean hearing aid users.
Subject(s)
Aged , Humans , Hearing Aids , Hearing Loss, Sensorineural , Hearing , Judgment , Noise , Signal-To-Noise RatioABSTRACT
BACKGROUND AND OBJECTIVES: The band-importance function (BIF) refers to a value characterizing the relative importance of different frequencies to speech intelligibility. The purpose of this study was to derive the BIF for the Korean standard sentence lists for adults (KS-SL-A). SUBJECTS AND METHODS: In this study, sentences from the KS-SL-A were used as the speech material. Twenty-six normal-hearing Korean listeners participated and intelligibility scores in 8 filters with 3 signal-to-noise ratio conditions were obtained. Based on the intelligibility score percentages, the BIF for the KS-SL-A was derived by using an established protocol. RESULTS: Band-importance weights varied across frequency bands. The most important frequency region was around 316 Hz (20.0%), and the importance of the frequency bands below the center frequency (CF) of 1,778 Hz was 59.6%. Therefore, low frequencies below the CF of 1,778 Hz were more important than high frequencies above the CF of 1,778 Hz. CONCLUSIONS: The BIF for KS-SL-A could be applied towards developing a hearing aid fitting formulae for Korean listeners.
Subject(s)
Adult , Humans , Hearing Aids , Signal-To-Noise Ratio , Speech Intelligibility , Weights and MeasuresABSTRACT
BACKGROUND AND OBJECTIVES: The purpose was to establish the test-retest reliability of word recognition score (WRS) using Korean standard monosyllabic word lists for adults (KS-MWL-A) recently developed based on the international standard for speech audiometry (ISO 8253-3:2012). SUBJECTS AND METHODS: Subjects consisted of 159 adults aged to 18 to 25 years with normal hearing sensitivity. WRSs were obtained in 2 dB steps from the level of speech recognition thresholds to the level of 86% correct responses or greater. After one or two weeks, retest was performed. Correlation, confidence interval (CI) and prediction interval (PI) were calculated for the reliability. RESULTS: Correlation coefficients were 0.88 for 50 test words, 0.76 for 25 and 0.61 for 10 words. Results also showed that 95% CIs and PIs were narrower for 25 and 50 test words than those for 10 test words. CONCLUSIONS: Korean WRS using the KS-MWL-A has high reliability for 25 and 50 test words, but relatively low for 10 words. It suggested that 95% CIs for each test words would be criteria for significant differences in WRS for groups and 95% PIs at each score of WRS could be utilized for a considerable difference for each individual at retest.
Subject(s)
Adult , Humans , Audiometry, Speech , HearingABSTRACT
Mass and stiffness affect on the peculiar characteristics of transmission of the middle ear and the distinctive behavior of the cochlear mechanics. Applying the principle of the mass and stiffness, the band-pass characteristic transfer function of the middle ear has been explained. The greatest transfer function of the middle ear, approximately 24-29 dB, is observed at 1-2 kHz in both cat and human species. However, at lower frequencies, the transfer function was disturbed by the stiffness of the middle ear primarily due to middle ear cavity. At higher frequencies, the transfer function was disturbed by the stiffness of the middle ear primarily due to middle ear bones. Several examples, such as an acoustic reflex, otitis media, and otosclerosis are discussed. For understanding the traveling wave of the basilar membrane, different place tuning at certain stimulus frequencies, contrastingly shaped basilar membrane to the cochlear duct, and the structural and physical characteristics of the whole cochlear partition were reviewed in terms of changing width, mass, and stiffness from the base to apex. Being about ten times wider, more massive, and one hundredfold stiffer at the base than the apex, the nature of the cochlear partition to absorb high-frequency energy changes in fluid pressure declines toward the apex. Consequently, at the base of the cochlea, high frequencies stimuli are decoded while low frequencies stimuli are decoded at the apex of the cochlea. Due to these characteristics of the cochlear partition, the direction of the traveling wave was also proved to be in the fashion of base-to-apex always.
Subject(s)
Animals , Cats , Humans , Basilar Membrane , Cochlea , Cochlear Duct , Ear, Middle , Mechanics , Otitis Media , Otosclerosis , Reflex, AcousticABSTRACT
Exposure to high levels of music that could lead to music induced hearing loss (MIHL) has been of recent interest especially for young adults, considering their excessive use of personal listening devices such as MP3 player. More attention should be drawn to MIHL for noting that early noise exposure leads to earlier onset of presbycusis. In search of appropriate and safe listening habits for young adults, this investigation was aimed to evaluate output levels and frequencies generated by the Samsung galaxy note MP3 player depending on two earphone types; ear-bud and over-the-ear earphones and three music genres; rock, hip-hop, ballade. A sound level meter was used to measure output level and frequency spectrum between 12.5 and 16000 Hz at all 1/3-octave bands. The following results can be summarized. 1) The earphone styles did not produce significant difference in output levels, but the music genres did. However, the results of music genres varied. 2) Neither earphone styles nor music genres produced significant difference in frequency response spectrum, except music genres at the volume settings we usually listen to. Additionally, volume levels should be lower than 50% for usual listening situation. Through this investigation, it was noted that the frequency range was substantial between 50 and 1000 Hz regardless of the styles of earphones and music genres, implying that we should be cautious of this frequency range when we listen to music. Researchers should give more attention to the effects of the mixture of output level and frequency spectrum, considering that the auditory system has frequency specificity from the periphery to the central to provide refined methods for protecting our ears from MIHL.