Effect of wearing earphone to listen to music on high-frequency hearing loss in noise exposure workers / 中国职业医学

OBJECTIVE: To explore the effect of wearing earphone to listen to music on the high-frequency noise-induced hearing loss(NIHL) in noise-exposure workers. METHODS: A total of 651 male noise-exposure workers in an automobile manufacturer were selected as study subjects by using judgment sampling method. The level of noise exposure in the individuals and the pure tone hearing threshold were tested. According to the frequency of wearing earphone to listen to music after work, the subjects were divided into low-, medium-and high-frequency earphone-using groups, with 60, 436 and 155 workers in each group, respectively. The effects of wearing earphone to listen to music combined with occupational noise exposure on high-frequency NIHL were analyzed. RESULTS: The high-frequency NIHL detection rate of the study subjects was 31.3%(204/651). The detection rate of high-frequency NIHL in these three groups from low to high was low-, medium-and high-frequency earphone-using groups(P<0.01). The detection rate of high-frequency NIHL in the high-frequency earphone-using group was higher than that of the low-and medium-frequency earphone-using groups(43.2% vs 25.0%, 43.2% vs 28.0%, P<0.01). Multivariate logistic regression analysis showed that wearing earphones to listen to music was a risk factor for high-frequency NIHL in noise-exposure workers(P<0.01) after eliminating the influence of confounding factors such as age, length and level of noise-exposure, and wearing anti-noise ear plugs. The higher frequency of wearing earphone to listen to music, the higher risk of high-frequency NIHL. CONCLUSION: Wearing earphone to listen to music after work and occupational noise exposure had a synergistic effect on high-frequency NIHL in noise-exposure workers.

Analysis of Output Levels of an MP3 Player: Effects of Earphone Type, Music Genre, and Listening Duration

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.

The Effects of Noise from the Subway Cars on the Preferred Listening Volumes and Noise Exposure Using Earphones / 听力学及言语疾病杂志

Objective To investigate the effects of noise from the subway cars on the preferred listening volumes using different kinds of earphones.Methods A total of 75 subjects with normal hearing were investigated to listen the same song wearing 4 kinds of earphones: insert earphones, intra-concha earphones, supra-concha earphones, and circumaural earphones, in the semi-anechoic background and inside the Line 7 subway-cars of the Beijing subway (the mean of LAeq,1s is 80.3 dB A and then selected personally preferred listening volumes.The effects of noise in the subway cars and earphone types on the preferred listening volumes were then analyzed.Results Inside subway-cars, the preferred listening levels using insert earphones, intra-concha earphones, supra-concha earphones, circumaural earphones were 76.6±4.7, 84.3±5.0, 82.3±4.2, and 80.8±4.2 dB A, respectively.The levels were respectively 65.5±6.8, 71.9±7.1, 69.5±7.5, 67.9±7.3 dB A for those in the semi-anechoic background.The preferred listening levels increase more than 10 dB averagely when stepped into noisy subway-cars background from silent background.According to the threshold levels stipulated in the WHO, to avoid hearing impairment, the daily noise exposure duration should not exceed 134 mins when exposed to subway-cars noise and the duration should not exceed 315, 54, 85, and 120 mins respectively when wearing those 4 kinds of earphones in subway-cars.Conclusion The noise and earphones types have great effects on the preferred listening volumes.The noise exposure levels in the ear canal wearing earphones with good sound insulation and listening at highly increased volume may be lower than that without earphones.

The Optimization of Comfortable Earphone Designed by the Method of Semi -parametric / 听力学及言语疾病杂志

Objective To investigate the solutions to the comfort problem caused by traditional batch produc‐tion that cannot satisfy everyone's request .Methods The both objective and subjective evaluations were put forward to the assessment of ear comfort .The accurate data about the pinna was acquired through reverse engineering and extracting key points of the pinna by image detection method .The headphone model was built by the semi-parame‐ter design .Through the FESA study ,headphones - pinna contact pressure was assessed and relevant parameters were improved .Comfort was analyzed by contact pressure .Results The simulation contact pressure was compared before and after optimizing parameters .The results showed that the contact area of the augment cymba conchae could obtain more uniformity pressure .Conclusion The example verification shows this delivers better comfort than traditional one .The research has some reference value for the design and option comfortable headphones .

Effect of Active Noise Cancelling Earphones on Preferred Listening Level When Listening to Portable Music Players in Noisy Environments / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Active noise cancelling (ANC) is a technology that can reduce external noise by producing a signal that is similar to noise but different in that it has an opposite phase to noise. Nowadays ANC has become an important technology in the field of hearing aids, but many studies have not focused on the effect of ANC of earphones when listening to portable music players. In this study, we aimed to evaluate whether ANC earphones can effectively reduce external noise and lower the preferred listening level. SUBJECTS AND METHOD: Three different earphones (Ear-canal, On-the-ear, Covering-the-ear) were tested in three different noise environments. Nine participants were tested in 10 experiments. First, through the real ear measurement (REM) system, we evaluated the differences in sound pressure level when the ANC was either turned on or off. Second, we evaluated the effects of ANC on Preferred Listening Level (PLL) for participants listening to the same song with different earphones. Through the REM system, we evaluate the level of sound pressure level when participants controlled the volume and felt most comfortable with the volume level. RESULTS: All three types of earphones showed statistically significant effects on noise reduction when ANC was turned on. The noise reduction effect was most prominent with the Ear-canal earphone. All three types of earphones also showed statistically significant effect on PLL reduction. CONCLUSION: ANC earphones may be helpful in noise reduction and preventing noise induced hearing loss when listening to music in noisy environments. Among the three types of earphones, Ear-canal earphone seems to be the most effective in noise reduction.

Comparison of Inter-aural Attenuations between the TIP-300 insert Earphone and the Telephonics TDH-50P Supra-aural Earphone / 听力学及言语疾病杂志

Objective To afford a clinical reference for applications of TIP-300 insert earphone in accordance with its difference in inter-aural attenuation from the telephonics TDH-50P supra-aural earphone.Methods Detections of inter-aural attenuation for pure tone air conduction were performed on the enrolled individuals combined with unilateral anakusis and one normal ear (male and female were 13 and 22 respectively) by GSI61 audiometer?TIP-300 insert earphone or telephonics TDH-50Psupra-aural earphone.Results Inter-aural attenuation differences were significant ( P