The acceptable noise level (ANL) test is a method for quantifying the amount of background noise that subjects accept when listening to speech. Large variations in ANL have been seen between normal-hearing subjects and between studies of normal-hearing subjects, but few explanatory variables have been identified.
To explore a possible relationship between a Swedish version of the ANL test, working memory capacity (WMC), and auditory evoked potentials (AEPs).
ANL, WMC, and AEP were tested in a counterbalanced order across subjects.
Twenty-one normal-hearing subjects participated in the study (14 females and 7 males; aged 20-39 yr with an average of 25.7 yr).
Reported data consists of age, pure-tone average (PTA), most comfortable level (MCL), background noise level (BNL), ANL (i.e., MCL - BNL), AEP latencies, AEP amplitudes, and WMC. Spearman's rank correlation coefficient was calculated between the collected variables to investigate associations. A principal component analysis (PCA) with Varimax rotation was conducted on the collected variables to explore underlying factors and estimate interactions between the tested variables. Subjects were also pooled into two groups depending on their results on the WMC test, one group with a score lower than the average and one with a score higher than the average. Comparisons between these two groups were made using the Mann-Whitney U-test with Bonferroni correction for multiple comparisons.
A negative association was found between ANL and WMC but not between AEP and ANL or WMC. Furthermore, ANL is derived from MCL and BNL, and a significant positive association was found between BNL and WMC. However, no significant associations were seen between AEP latencies and amplitudes and the demographic variables, MCL, and BNL. The PCA identified two underlying factors: One that contained MCL, BNL, ANL, and WMC and another that contained latency for wave Na and amplitudes for waves V and Na-Pa. Using the variables in the first factor, the findings were further explored by pooling the subjects into two groups according to their WMC (WMClow and WMChigh). It was found that the WMClow had significantly poorer BNL than the WMChigh.
The findings suggest that there is a strong relationship between BNL and WMC, while the association between MCL, ANL, and WMC seems less clear-cut.
PURPOSE: Patients with insulin-dependent diabetes mellitus (IDDM) are especially susceptible to microangiopathic complications such as nephropathy, retinopathy, and neuropathy. Microangiopathic changes are also the most important findings in histopathologic studies of the inner ear and central nervous systems in diabetic subjects. No previous studies have measured acoustic-reflex latencies (ARL) or amplitudes (ARA) in patients with IDDM. ARL and ARA reflect the function of the acoustic-reflex arch. Furthermore, possible changes in the tympanic membrane, ossicular chain, and stapedius muscle may affect the shape of acoustic-reflex. SUBJECTS AND METHODS: Acoustic-reflex thresholds, latencies, and amplitudes were studied in 53 patients with IDDM and 42 randomly selected nondiabetic control subjects, aged between 20 and 40 years, using the Madsen Model ZO 73 Impedance Bridge (Madsen Electronics, Copenhagen, Denmark). Subjects with an abnormal tympanic membrane, conductive hearing loss, and known cause for hearing impairment eg, noise damage, were excluded from the study. RESULTS: There were no differences between control and diabetic subjects in the contralateral acoustic-reflex thresholds. In contrast, patients with IDDM had longer ARLs and decreased ARAs compared with those of control subjects. ARA amplitude had linear correlation with the amplitude of tympanogram, whereas ARL had no linear correlation with auditory brainstem latencies in the same study subjects. Acoustic-reflex responses in insulin-dependent diabetic patients were not associated with the duration of diabetes, metabolic control, microangiopathy, or neuropathy. CONCLUSIONS: Prolonged ARLs and decreased ARAs in patients with insulin-dependent diabetes are probably caused more by the stiff middle ear system than disturbances in the brainstem.
The study compares the audiological profile of a group of first-time applicants for hearing aids, a group of re-applicants and a group of non-complainers, aged 70-75 years (n = 71). In spite of overlap in range, a significant difference in thresholds and discrimination was found. The lip-reading capacity was well preserved in the elderly, but showed a significant correlation to the general health condition. The audiological benefit of hearing-aids did not increase with early fitting. General satisfaction with life was independent of satisfaction with hearing; two thirds of the patients were satisfied with their aids and used them regularly. The rest were dissatisfied and used them less than once a week. The aids were most systematically used to watch TV. Pure-tone average and handicap scaling were compared as guidelines for hearing-aid fitting. The most powerful tool to identify those in need of hearing-aids was handicap scaling based on interviews concerning self-assessed hearing difficulties.
Testing the hearing abilities of marine mammals under water is a challenging task. Sample sizes are usually low, thus limiting the ability to generalize findings of susceptibility towards noise influences. A method to measure harbor porpoise hearing thresholds in situ in outdoor conditions using auditory steady state responses of the brainstem was developed and tested. The method was used on 15 live-stranded animals from the North Sea during rehabilitation, shortly before release into the wild, and on 12 wild animals incidentally caught in pound nets in Denmark (inner Danish waters). Results indicated that although the variability between individuals is wide, the shape of the hearing curve is generally similar to previously published results from behavioral trials. Using 10-kHz frequency intervals between 10 and 160 kHz, best hearing was found between 120 and 130?kHz. Additional testing using one-third octave frequency intervals (from 16 to 160?kHz) allowed for a much faster hearing assessment, but eliminated the fine scale threshold characteristics. For further investigations, the method will be used to better understand the factors influencing sensitivity differences across individuals and to establish population-level parameters describing hearing abilities of harbor porpoises.
The objective of this study was to evaluate the influence of atherogenic risk factors on hearing thresholds. In a cross-sectional study we analyzed data from a Danish survey in 2009-2010 on physical and psychological working conditions. The study included 576 white- and blue-collar workers from children's day care units, financial services and 10 manufacturing trades. Associations between atherogenic risk factors (blood lipids, glycosylated hemoglobin, smoking habits, body mass index (BMI), and ambulatory blood pressure) and hearing thresholds were analyzed using multiple linear regression models. Adjusted results suggested associations between smoking, high BMI and triglyceride level and low high-density lipoprotein level and increased low-frequency hearing thresholds (average of pure-tone hearing thresholds at 0.25, 0.5 and 1 kHz). Furthermore, an increasing load of atherogenic risk factors seemed associated with increased low-frequency hearing thresholds, but only at a borderline level of statistical significance. Associations were generally strongest with hearing levels of the worst hearing ear. We found no statistically significant associations between atherogenic risk factors and high-frequency hearing thresholds (average of pure-tone hearing thresholds at 4, 6 and 8 kHz).
Previously, unilateral hearing impairment (UHI) has been considered of little consequence. However, a recent meta-analysis of children with UHI displayed educational and behavioural problems and possible delays of speech and language development. Further, patients with UHI consequently report hearing difficulties. Our study investigated hearing function, possible inner ear protection, and self-assessed hearing problems in 57 subjects aged between 3-80 years with single-sided congenital ear malformations and conductive UHI. Pure-tone thresholds and speech recognition (quiet, noise) were measured, and all patients completed a self-assessment questionnaire. Pure-tone thresholds corresponding to sensorineural function did not significantly differ between the normal (air conduction) and affected ear (bone conduction). However, speech recognition in both quiet and in noise was normal on the non-affected side but significantly worse on the malformed side. A moderate to high degree of self-assessed hearing problems were reported. In conclusion, hearing function in the affected ear was found to be subnormal in terms of supra threshold signal processing. Furthermore, a high degree of hearing difficulty was reported. Therefore, active treatment, surgery, or hearing amplification, might be considered.
A total of 237 students, 10 to 17 years of age, from 14 schools underwent hearing evaluations. Otoscopic examination, tympanometry and air-conduction pure tone audiometry was conducted at low (0.5, 1, 2 kHz) and high (4 and 8 kHz) frequencies. In all schools, hearing thresholds were measured with headphones in a portable audiometric booth. Socio-demographic information from students and their parents were collected using questionnaires. Overall, the prevalence of any hearing loss greater than 15 dB was 22.3% for low or high frequency pure tone averages. Self-reported symptoms of hearing loss, such as tinnitus, difficulty following a conversation with background noise, and having to turn up the TV/radio more than in the past, were associated with audiometric thresholds, most notably at 4 kHz. These study findings are among the first to provide a detailed characterization of hearing status in a sample of youth in a Canadian demographic.
The most common complaint among individuals with hearing impairment is the inability to follow a conversation when several people are talking simultaneously, a noisy listening situation which is completely different from the quiet surrounding of the conventional pure tone audiometry used as basis for the hearing aid settings. The purpose of this report was to present important characteristics of the BeneFit Method (BFM), a procedure that fits the hearing aid under simulated conditions of competing speech and also a clinical pilot evaluation study comparing the BFM to the NAL-R recommendations and also to the Logic procedure, a GN resound proprietary fitting algorithm representing a modern digital hearing aid fitting procedure. Speech recognition scores in noise (SRSN) using monosyllabic words presented under different background noise levels were evaluated on 21 randomly selected subjects with hearing impairment. The subjects were fitted with the same type of hearing aid Danalogic 163D according to the BFM procedure as well as the logic procedure, the latter developed and recommended by the manufacturer. A comparison of the SRSN when using the subjects' current hearing aid fitted according to the NAL-R procedure was also made. Only the BFM procedure provided a significant SRSN improvement compared to the unaided condition (P
There are few published reports providing quantitative information of clinical feasibility for tone-evoked auditory brainstem response (ABR) protocols. In this study, the authors reviewed charts of 188 ABR assessments during a 20-mo period: 116 sedated (median age, 23 mos) and 72 nonsedated (median age, 4 mos). Fifty-one percent of infants had normal thresholds. The average amount of sleep time was 58 mins for sedated assessments, during which an average of 7.6 measures were obtained; nonsedated assessments averaged 49 mins with 6.2 measures obtained. Thus, a substantial amount of both test time and information about hearing can be obtained within one ABR appointment.
Effect of high speed turbine dental drill noise (DDN) on dentists' hearing at present and during the era of noisier drills was investigated. Hearing of two generations of dentists, power spectral density (PSD) functions of DDN from various drills and the equivalent level (LAeq) of a modern dental operatory were studied. The LAeq was 65 dB with 1 and 50% probability distribution levels of 74 and 57 dB, respectively. DDN was tonal with the spectrum peak always above 6 kHz, containing within 128 Hz frequency band 28-85% of the total noise energy in the PSD function. A cartridge type ball bearing drill from early 1960's was found noisier than an air bearing drill or a modern sealed head ball bearing drill by 8.5 and 5 dB, respectively. Sound pressure levels of DDN ranged from 68 to 79 dBA, being within safe limits. The high values earlier reported for cartridge type or worn drills could not be verified. Hearing of dentists free from clear ear pathology was found good and very similar to the reference, representing a population with no exposure to noise. There was no difference in hearing of 46 dentists 33-42 years of age, examined in 1973 and among whom there had been exposure to early and noisier drill, as compared to hearing of 56 dentists of similar age and years in dentistry, examined in 1988 and who had only been exposed to quieter drills of the 1970's. Noise dose and audiometric measurements were in agreement and indicated that DDN is not and has never been a risk to dentists' hearing.