Background and Aim: acceptable noise level (ANL) is the loudest level of background noise that human can tolerate while listening a running speech. ANL test is used for the prediction that whether a hearing aid (HA) candidate can use HA successfully by determining how well the individual tolerates background noise while listening to speech. In the current review, we reviewed the basis and theories of the ANL test and the factors that identified from the studies that have conducted on ANL and the influence of this test in increasing the quality of life of hearing aid users along with a discussion of its application in clinical audiology.Recent Findings: Research showed that subjects with a higher tolerance for background noise are most probable to be the successful hearing aid users. Clinical trials demonstrated that ANL test provides reliable results and can predict HA successful use with 85% accuracy.Conclusion: acceptable noise level is a reliable and valid test that can be used as a predictive index for the successful application of HA, and it is applicable in before/after HA fitting assessments.Thus, it is suggested that ANL can be implemented in the fitting and counseling process of HAs prescription. Further studies are required to resolve biases over the employment of this test in bilinguals.

Background and Aim: acceptable noise level (ANL) measures the amount of accepted background noise while listening to the story. In the current study, ANL was carried out in children with learning disability (LD) and compared with the results of normal children by using examiner- and self-adjusted methods.Methods: Forty seven (25 male, 22 female) normal children with good and better educational background and 46 (27 male, 19 female) LD children ranging in age from 7-12 years old were participated. ANL was assessed using an ear-level loudspeaker in front of children. The differences of ANL, most comfortable level (MCL), and background noise level (BNL) between groups and their relationship between examiner- and self-adjusted procedures were investigated.Results: Mean ANLs of LD children either in examiner- or self-adjusted methods (8.91±4.66 and 11.00±5.38, respectively) were worse than those of normal children (7.19±3.63 and 9.61±3.41, respectively). The difference between mean ANL of normal and LD children was statistically significant only for examiner-adjusted method (p=0.05). There were also significant differences in BNL between groups for examiner- and self-adjusted method (p< 0.05). A strong positive correlation was found between examiner- and self-adjusted conditions for ANL, MCL, and BNL among groups (p<0.001).Conclusion: ANL is clinically applicable in LD children. Moreover, LD children accept lower background noise; therefore modification of their listening environment is recommended. Because of a strong positive relationship between ANL in examiner- and self-adjusted procedures, both methods can be implemented in different situations.

Background and Aim: The acceptable noise level (ANL) assesses the noise that a person can tolerate during a running speech. Although it is a strong test, it has not yet become popular in clinical practice. One of the reasons is its contradictory results. Since it is a psychoacoustic test, psychological factors can affect its output. Investigation of these factors can provide more accurate results. This study aims to investigate the effects of noise and work-related fatigue on the ANL in normal-hearing people. Methods: Participants were the male workers in the administration (n = 26) and production (n = 26) departments of an automotive manufacturing industry in Iran. They were evaluated before and after leaving the workplace in order to determine the effects of noise exposure, fatigue as well as their simultaneous effects on the ANL. Results: In both groups, the ANL showed a significant increase after work compared to its level before work, and the background noise level (BNL) was significantly decreased. There was no significant difference in the BNL between administration and production groups before work. The most comfortable level (MCL) showed no significant increase. Moreover, the MCL changes were not significantly different in the production group compared to administration group, but the BNL and ANL changes were significantly higher. Conclusion: noise exposure and work-related fatigue affect the ANL. During the ANL test, earlier exposure to noise and the amount of fatigue should be controlled.

Background and Aim: The acceptable noise level (ANL), which is an effective clinical tool for quantitative assessment of noise tolerance, is affected by some known variables related to both subject and testing materials. The present study examined how the characteristics of different babble noises may affect the ANL results in normal adult listeners. Methods: Forty Persian listeners with normal hearing participated. In addition to typical ANL testing with 12-talker noise, the ANL was obtained in 8 different conditions varying in number of talkers from 2 to 10 in the babble noises presenting forward and backward. Results: There was a significantly lower ANL for 2-talker babble compared to 4, 8, 10, and 12-talker babble in both forward and backward noise conditions. With the increase in talkers in noise, the ANL becomes worse but reaches almost a plateau with more than 4 talkers in babble noise. There was a statistically significant difference between 2-talker forward and 2-talker backward noises, with no difference for the other conditions. Conclusion: This finding that the ANL is affected by the number of talkers in babble noise and by the forward and backward background noise suggests that informational masking and listening in dip mechanisms are involved in ANL for normal hearing people at least.

Background and Aim: It is well known that hearing aid fitting is an effective approach to improve the communication ability of hearing-impaired people. In the past, most of the hearing aids were fitted unilaterally rather than bilate-rally. Whereas the unilateral hearing aid fitting improves verbal communication partially, it causes late-onset auditory deprivation. The main aim of this study is to investigate the ANL for each ear among the users with unilateral hearing aid experience. Methods: A total of 23 participants were rec-ruited (14 females, 9 males). The mean age was 74. 65 years (ranged from 41 to 83). All subjects had bilateral symmetric sensorineural hearing loss. The most comfortable level (MCL), Back-ground noise level (BNL), and acceptable noise level (ANL) were measured for ear with ampli-fication experience and ear without experience. Results: MCL, BNL and ANL in the aided ear was 82. 22, 73. 48 and 8. 74 respectively, in addi-tion in the unaided ear the results for MCL, BNL and ANL was 81. 78, 72. 13 and 9. 65 respectively. Comparing the mean values of MCL, BNL and ANL between two ears showed no significant difference. Conclusion: There was not any difference for BNL and ANL measures.

Background and Aim: Music can be a favorite, annoying, or even a distracting noise. It is known that the processing of brain hemispheres is affected by the pleasantness/unpleasantness of music, which could be utilized as a signal or noise in auditory neuroscience. By using the acceptable noise level (ANL) test, which is the quantification of noise tolerance while listening to a running speech, we investigated whether the pleasantness/unpleasantness of music affects the ANL results under monotic-listening and dichotic-listening conditions. Methods: Based on the subjective scale scores, pleasant and unpleasant music (10 songs) were selected as alternatives to babble noise or running speech for testing 50 subjects for seven monotic and dichotic listening conditions. Results: While pleasant music changed the ANL significantly under monotic listening conditions, the higher level of babble noise was tolerated, and both characteristics of music pleasantness and unpleasantness changed ANL significantly for various dichotic conditions. The range of the ANL for dichotic conditions is wider than that for monotic conditions. Conclusion: Music can affect the ANL in terms of pleasantness and unpleasantness for both monotic and dichotic listening conditions, with a greater effect on dichotic conditions, indicating the role of hemispheric specification in emotional music processing.

Background and Aim: Difficulty in perception of speech in noise is one of the main complaints of hearing-impaired people. Due to profound hearing loss in cochlear implant (CI) users, they need higher signal-to-noise ratio for a better perception. Bimodal fitting is a preferred way for CI users because it prevents auditory nerve degeneration, is a complement of frequency range at the opposite ear, an is less invasive to provide binaural hearing. acceptable noise level (ANL), as a reliable test to assess noise tolerance, has not yet been used in comparing children with bimodal hearing and CI. This study aimed to determine whether bimodal fitting can help CI children tolerate more noise. Methods: This descriptive-analytical study was conducted on 13 children with unilateral CI and bimodal hearing. Audiometry test was performed at aided and non-aided conditions. Then, their noise tolerance was assessed by the Persian version of ANL test. Results: Bimodal hearing resulted in statistically significant increase in ANL. The mean of ANL at unilateral CI and bimodal hearing conditions were 6. 15±, 2. 90 and 4. 77±, 1. 70, respectively. Conclusion: Bimodal fitting lead to more noise tolerance in unilateral CI children due to the combination of binaural summation and binaural release from masking.

Introduction: The acceptable noise level (ANL) evaluates the willingness of a listener to hear a continuous speech in the presence of background noise. ANL is related to some variables. Although many studies were accomplished on the relationship between ANL and hearing aid satisfaction, no study was found for the usage of ANL as the predictor of initial hearing aid acquisition. Therefore, the current study aimed at determining the relationship between the initial acceptance of hearing aid and individual’s ANL. The study also aimed at quantifying human potentials for what is out of their personal control, as well as assessing their commitment in the actions that improve and enrich their quality of life.Methods: A total of 60 patients with hearing loss who were the candidate for wearing hearing aid were participated. ANLs were measured and comprehensive hearing aid counseling was given to the patients. Patients were free to accept or reject using hearing aids. The Pearson correlation was used to assess the relationships among variables, and the independent t test was used to compare data between the groupsResults: The analysis revealed a correlation between ANL and the acceptance of hearing aid. ANL means in the subjects who accept and reject hearing aid were 7.83 and 11.73, respectively.Conclusion: The results showed the correlation between lower ANLs and acceptance of hearing aid and also the correlation between higher ANLs and resistance to get hearing aid. Participants who accepted to take hearing aid had lower ANL mean and the ones who refused to take hearing aid had higher ANL mean.