Change In Pure-tone Thresholds Research Articles

The impact of cardiovascular diseases on hearing deterioration: a 13-year follow-up study

Objective To study the impact of cardiovascular diseases (CVDs) on hearing deterioration among ageing adults in a longitudinal setting. Furthermore, to describe the pure tone threshold changes at the 0.125–8 kHz frequency range over 13 years. Design A population-based follow-up study. Study sample A random sample of 850 adults, of whom 559 participated in the follow-up study. Otological examination, a structured interview, and pure tone audiometry were conducted. Multivariate regression models were used to estimate the effect of CVD (participants had at least one cardiovascular condition) on hearing deterioration of the better ear hearing level (BEHL), defined as a change in the pure-tone average (PTA) of the frequencies 0.5, 1, 2, and 4 kHz and separately at the lower (0.125, 0.25, and 0.5 kHz) and higher (4, 6, and 8 kHz) frequencies. Results In the multivariable-adjusted analysis, the BEHL change at 13 years was 0.7 dB greater among participants with CVD (p = 0.3). The mean BEHL change during the 13-year follow-up was 12.0 dB (95% CI 11.4–12.6) among all participants. Conclusions No significant association between CVD and hearing threshold changes was found.

Prevention of Noise-Induced Hearing Loss Using Investigational Medicines for the Inner Ear: Previous Trial Outcomes Should Inform Future Trial Design.

Significance:Noise-induced hearing loss (NIHL) is an important public health issue resulting in decreased quality of life for affected individuals, and significant costs to employers and governmental agencies.Recent Advances:Advances in the mechanistic understanding of NIHL have prompted a growing number of proposed, in-progress, and completed clinical trials for possible protections against NIHL via antioxidants and other drug agents. Thirty-one clinical trials evaluating prevention of either temporary or permanent NIHL were identified and are reviewed.Critical Issues:This review revealed little consistency in the noise-exposed populations in which drugs are evaluated or the primary outcomes used to measure NIHL prevention. Changes in pure-tone thresholds were the most common primary outcomes; specific threshold metrics included both average hearing loss and incidence of significant hearing loss. Changes in otoacoustic emission (OAE) amplitude were relatively common secondary outcomes. Extended high-frequency (EHF) hearing and speech-in-noise perception are commonly adversely affected by noise exposure but are not consistently included in clinical trials assessing prevention of NIHL.Future Directions:Multiple criteria are available for monitoring NIHL, but the specific criterion to be used to define clinically significant otoprotection remains a topic of discussion. Audiogram-based primary outcome measures can be combined with secondary outcomes, including OAE amplitude, EHF hearing, speech-in-noise testing, tinnitus surveys, and patient-reported outcomes. Standardization of test protocols for the above primary and secondary outcomes, and associated reporting criterion for each, would facilitate clinical trial design and comparison of results across investigational drug agents. Antioxid. Redox Signal. 36, 1171–1202.

Supplementary Effect of Choline Alfoscerate on Speech Recognition in Patients With Age-Related Hearing Loss: A Prospective Study in 34 Patients (57 Ears).

To investigate the effect of choline alfoscerate (CA) on hearing amplification in patients with age related hearing loss, we performed a prospective case-control observational study from March 2016 to September 2020. We assessed patients with bilateral word recognition score (WRS) <50% using monosyllabic words. The patients were 65–85 years old, without any history of dementia, Alzheimer’s disease, parkinsonism, or depression. After enrollment, all patients started using hearing aids (HA). The CA group received a daily dose of 800 mg CA for 11 months. We performed between-group comparisons of audiological data, including pure tone audiometry, WRS, HA fitting data obtained using real-ear measurement (REM), and the Abbreviated Profile of Hearing Aid benefit scores after treatment. After CA administration, the WRS improved significantly in the CA group (4.2 ± 8.3%), but deteriorated in the control group (−0.6 ± 8.1%, p = 0.035). However, there was no significant between-group difference in the change in pure tone thresholds and aided speech intelligibility index calculated from REM. These findings suggest that the difference in WRS was relevant to central speech understanding rather than peripheral audibility. Therefore, administering oral CA could effectively enrich listening comprehension in older HA users.

Early hearing threshold changes and peculiarities of audiometric assessments among patients in a drug-resistant tuberculosis treatment center.

Hearing threshold changes occurred relative to baseline at both one and two weeks after onset of aminoglycoside therapy. To assess changes in audiometric hearing thresholds between pre-treatment values and two weeks into therapy. To document observed changes, and occurrence of ototoxicity within the period. Prospective analytical cohort study on drug-resistant tuberculosis patients. Basic demographic parameters were taken. Three-point audiometric assessments within two weeks into therapy were done. Percentage of patients with ototoxicity were calculated. Pure tone threshold changes between the three audiometric values were compared. Audiograms of 53 patients comprising 56.6% males; age range was 13 to 91 years. Both air and bone conduction hearing thresholds significantly worsened between baseline and one week into therapy (p=0.011, and 0.015 respectively), and between baseline and two weeks into therapy (p=0.003 and 0.042 respectively). Minimal insignificant reduction occurred between both air and bone conduction hearing values of week 1 and week 2 of therapy (p= 1.000 and 0.856 respectively). By audiometric criteria, 4 patients (7.5%) developed ototoxicity within two weeks of treatment. Audiometric assessments within two weeks into therapy with anti-tuberculous therapy may not represent baseline audiometry. 7.5% of the patients developed ototoxicity within two weeks of therapy.

Vagus nerve stimulation paired with tones for tinnitus suppression: Effects on voice and hearing.

ObjectiveIn individuals with chronic tinnitus, our interest was to determine whether daily low‐level electrical stimulation of the vagus nerve paired with tones (paired‐VNSt) for tinnitus suppression had any adverse effects on motor‐speech production and physiological acoustics of sustained vowels. Similarly, we were also interested in evaluating for changes in pure‐tone thresholds, word‐recognition performance, and minimum‐masking levels. Both voice and hearing functions were measured repeatedly over a period of 1 year.Study designLongitudinal with repeated‐measures.MethodsDigitized samples of sustained frontal, midline, and back vowels (/e/, /o/, /ah/) were analyzed with computer software to quantify the degree of jitter, shimmer, and harmonic‐to‐noise ratio contained in these waveforms. Pure‐tone thresholds, monosyllabic word‐recognition performance, and MMLs were also evaluated for VNS alterations. Linear‐regression analysis was the benchmark statistic used to document change over time in voice and hearing status from a baseline condition.ResultsMost of the regression functions for the vocal samples and audiometric variables had slope values that were not significantly different from zero. Four of the nine vocal functions showed a significant improvement over time, whereas three of the pure tone regression functions at 2‐4 kHz showed some degree of decline; all changes observed were for the left ear, all were at adjacent frequencies, and all were ipsilateral to the side of VNS. However, mean pure‐tone threshold changes did not exceed 4.29 dB from baseline and therefore, would not be considered clinically significant. In some individuals, larger threshold shifts were observed. No significant regression/slope effects were observed for word‐recognition or MMLs.ConclusionQuantitative voice analysis and assessment of audiometric variables showed minimal if any evidence of adverse effects using paired‐VNSt over a treatment period of 1 year. Therefore, we conclude that paired‐VNSt is a safe tool for tinnitus abatement in humans without significant side effects.Level of evidenceLevel IV.

Longitudinal Pure-Tone Threshold Changes in the Same Subjects: Analysis of Factors Affecting Hearing.

To investigate the change of hearing threshold over time and analyze factors that could affect hearing, this longitudinal study of pure-tone threshold changes in the same subjects at a 9-year interval was performed. Retrospective longitudinal study in a single center (n = 1,978). A total of 1,978 subjects were included; they received pure-tone audiometry at a 9-year interval. The degree of the threshold changes was examined and compared between age groups. The subjects' data, such as the level of cholesterol, were analyzed to find risk factors on hearing. The average of the threshold changes was 3.35 dB in the 20s to 30s; 4.38 dB in the 30s to 40s; 5.75 dB in the 40s to 50s; 7.21 dB in the 50s to 60s; and 10.00 dB in the 60s to 70s (all P < 0.05). If the low-density lipoprotein cholesterol (LDL-C) was maintained below 100 mg/dl, the difference in the weighted four-frequency average was 5.45 dB, whereas it was 6.15 dB in the subjects whose LDL-C was over 100 mg/dl (P = 0.032, age-adjusted). In current smokers, the thresholds increased more than in never- or ex-smokers (P = 0.026 in the weighted four-frequency average and P = 0.011 at 8,000 Hz, age-adjusted). The degree of the threshold changes exhibited an exponential increase with age. Cessation of smoking is advisable to prevent increased aggravation of hearing. Strict management of the low-density lipoprotein cholesterol may have a positive effect on hearing. 3 Laryngoscope, 129:470-476, 2019.

Audiological changes over time in adolescents and young adults with auditory neuropathy spectrum disorder.

Auditory neuropathy spectrum disorder (ANSD) describes a condition in which a patient's otoacoustic emissions (OAE) are (or were at one time) present and auditory brainstem responses (ABR) are abnormal or absent. ANSD is also diagnosed based on the presence of cochlear microphonics and abnormal or absent ABRs with or without abnormalities of OAE. We noted the changes in audiological characteristics over time with respect to pure tone thresholds, OAEs and Speech Identification Scores (SIS) in seven individuals with ANSD. The results indicated that all the individuals with ANSD had decreased SIS over time, whereas there was subsequent reduction in pure tone thresholds only in nine out of fourteen ears. There was absence of OAEs for two individuals in both ears during the follow-up evaluations. There was no regular pattern of changes in pure tone thresholds or SIS across all individuals. This indicates that there may be gradual worsening of hearing abilities in individuals with ANSD. Thus, regular follow-up and monitoring of audiological changes are necessary for individuals with ANSD. Also, longitudinal studies need to be done to further add evidence to the audiological changes over time in individuals with ANSD.

Short-term music-induced hearing loss after sound exposure to discotheque music: The effectiveness of a break in reducing temporary threshold shift

Objective: To investigate the effect of a break in music exposure on temporary threshold shifts. Design: A cross-over design where subjects are exposed to dance music for either two hours consecutively, or exposed to two hours of dance music with a one-hour break in between. Outcome measure was the change in hearing threshold, measured in 1-dB steps at different time points after ending the music. Study sample: Eighteen normal-hearing subjects participated in this study. Results: Changes in pure-tone threshold were observed in both conditions and were similar, regardless of the break. Threshold shifts could be averaged for 1000, 2000, and 4000 Hz. The shift immediately after the ending of the music was 1.7 dB for right ears, and 3.4 dB for left ears. The difference between left and right ears was significant. One hour after the exposure, right ears were recovered to baseline conditions whereas left ears showed a small but clinically irrelevant remaining shift of approximately 1 dB. Conclusions: The advice to use chill-out zones is still valid, because this helps to reduce the duration to the exposure. This study does not provide evidence that a rest period gives an additional reduction of temporary threshold shifts.

Effects of ear-canal static pressure on pure-tone thresholds and wideband acoustic immittance.

Wideband acoustic immittance (WAI) measures provide information about middle-ear function across the traditional audiometric frequency range from 0.25 to 8.0 kHz. Recent studies have found that WAI is effective in predicting the presence of conductive hearing loss (CHL). It is not known whether WAI can accurately estimate the degree of threshold shift caused by CHL. The purpose of the present study was to evaluate the relationship between changes in pure-tone threshold and changes in wideband absorbance and acoustic conductance levels induced by positive and negative ear-canal static pressure. Twenty young adult subjects with normal hearing and a negative history of middle-ear disorders participated in the study. Experimental pure-tone thresholds at 0.5 and 2.0 kHz were estimated by using a three-interval, three-alternative forced-choice adaptive psychometric procedure under three conditions: ambient ear-canal pressure, +200 daPa static pressure, and -200 daPa static pressure. Wideband absorbance and conductance were obtained in the same subjects by using a Welch Allyn prototype diagnostic middle ear analyzer. Changes in pure-tone threshold from the ambient pressure condition to the static pressure condition were evaluated by using a paired-samples t test and Pearson product-moment correlation. Wideband middle-ear absorbance and conductance at ambient pressure in this study were consistent with published data in adults with normal hearing. The mean change in threshold at 0.5 and 2.0 kHz with +200 daPa or -200 daPa ear-canal static pressure was similar to the mean change in absorbance and conductance levels in the same conditions. However, there was one statistically significant difference between the shift in pure-tone threshold and the change in conductance level for the +200 daPa pressure condition for 2.0 kHz, with the change in threshold being 1.5 dB greater than the change in conductance level (t = 2.39, p = 0.03). In contrast to the good performance of WAI measures in predicting mean threshold shifts caused by ear-canal pressure, the shifts in WAI were not correlated with threshold shifts. Thus WAI was not well suited to predict individual threshold changes caused by ear-canal static pressure. For the conditions of this study, results suggest that mean change in absorbance or conductance level caused by ear-canal static pressure of +200 daPa or -200 daPa provides a good estimate of the change in pure-tone threshold in the same conditions. However, individual threshold change was not accurately predicted by the change in absorbance or conductance level.

L-N-Acetylcysteine treatment is associated with improved hearing outcome in sudden idiopathic sensorineural hearing loss

Conclusion: Combination therapy corticosteroids plus an oral antioxidant L-N-acetylcysteine (LNAC) was associated with improved hearing over corticosteroids alone, particularly at the 6-month follow-up and at high frequencies (i.e. 4000 Hz). This is the first report of a beneficial effect of LNAC in sudden idiopathic sensorineural hearing loss (SISNHL). Objective: To determine the association between antioxidant treatment and functional outcomes in SISNHL. Methods: This was a case-control study of adult patients with SISNHL, treated with oral prednisone plus intratympanic dexamethasone either alone or in combination with LNAC. The outcome measure was change in pure-tone thresholds at 500–4000 Hz. Hearing recovery was also recorded as the percentage of subjects with final pure-tone threshold average (PTA) within 50% of the difference between the initial value of the affected ear and the value of the unaffected ear. Comparisons were made between combination (corticosteroids plus LNAC) and single (no LNAC use) therapy groups. Results: At 6 months, the mean PTA improvements were 26.1 dB and 15.1 dB for the combination and single therapy groups, respectively (p = 0.046). Higher gains at 4000 Hz were noted with LNAC use. The percentage of patients with at least 50% recovery was 63% and 35% for the combination and single therapy groups, respectively (p = 0.0319).

Sex Differences in a Cross Sectional Study of Age-related Hearing Loss in Korean

ObjectivesThe purpose of this study was to obtain sex- and age-specific reference level for hearing threshold of normal aging in Korean and to determine if the rate of change in pure-tone hearing thresholds differed by sex.MethodsSubjects were clients who visited the Health Promotion Center, Daegu Fatima Hospital, Daegu, Korea, from January 2004 to September 2005. Pure-tone audiometric measures were obtained from 3,470 subjects who also completed a hearing questionnaire. The slope of a linear regression was used to estimate the rate of change in pure-tone thresholds at 0.25 to 8 kHz for each ear in 214 men and 902 women without past history of otorrhea, usage of ototoxic drugs, head injury, job in noisy environment, and military service.ResultsHearing thresholds were elevated with age in all test frequencies. Significant sex differences were found in pure-tone thresholds at 4 and 8 kHz after adjusting for age using analysis of covariance. In those high frequencies, hearing was worse in men than in women. The average rate of change in threshold was 0.28 and 0.24 dB per year at 0.25 kHz, increasing gradually to 1.27 and 1.05 dB per year at 8 kHz for men and women, respectively. Men had significantly faster rates of threshold increase at 4 and 8 kHz than women.ConclusionThese cross-sectional measures of hearing levels and rate of threshold increases at 4 and 8 kHz showed significant sex differences in Korean men and women with little evidence of noise-induced hearing loss.

Otoacoustic emissions in a hearing conservation program: General applicability in longitudinal monitoring and the relation to changes in pure-tone thresholds

The hearing status of workers (N = 233) in a printing office was assessed twice within seventeen months by pure-tone audiometry and otoacoustic emissions (OAEs). One of the questions was how a quality criterion of OAE-measurements based on a minimum signal-to-noise-ratio (SNR) would affect the applicability on the entire population. Secondly, effects of noise exposure were investigated in overall changes in audiogram and OAE-measurements. For TEOAEs (transient evoked OAEs) in the frequency band of 4 kHz, only 55% of the data points meet the SNR-inclusion criterion. For DPOAEs (distortion product OAEs) around 6 kHz approximately 80% of the data points satisfy the criterion. Thus OAEs have a limited applicability for monitoring the hearing status of this entire population. Audiometry shows significant deteriorations at 6 and 8 kHz. TEOAEs show a significant decline at all frequency bands (1–4 kHz), DPOAEs between 4 and 8 kHz and less pronounced between 1 and 2 kHz. On group level, OAEs show a decline in a larger frequency region than the audiogram, suggesting an increased sensitivity of OAEs compared to audiometry.SumarioLa condición auditiva de trabajadores (N = 233) en una imprenta fue evaluada en un período de diez y siete meses con audiometría tonal y emisiones otoacústicas (OAEs). Una de las inquietudes fue cómo un criterio de calidad de las mediciones de las OAE que se basa en una relación señal/ruido mínima (SNR) puede afectar la aplicabilidad a toda la población. Secundariamente, se investigaron los efectos de la exposición a ruido en los cambios globales en el audiograma y las mediciones de las EOA. Con TEOAEs (OAE evocadas por transitorios), en la banda de frecuencia de 4 kHz, solo el 55% de los datos parecen coincidir con el criterio de inclusión de la SNR. Con DPOAEs (OAEs por productos de distorsión) alrededor de 6 kHz, aproximadamente el 80% de los datos parece satisfacer el criterio. Por esto, las OAEs tienen una aplicabilidad limitada para monitorear el estado auditivo de la población general. La audiometría muestra deterioro significativo en 8 y 9 kHz. Las TEOAEs muestran una declinación significativa en todas las bandas de frecuencia (1-4 kHz) y las DPOAEs, entre 4 y 8 kHz, aunque menos pronunciadamente entre 1 y 2 kHz. A nivel grupal, las OAEs muestran declinación en una región frecuencial más ancha que en el audiograma, sugiriendo una sensibilidad incrementada de las OAEs en comparación con la audiometría.

Factors Affecting Sensitivity of Distortion-Product Otoacoustic Emissions to Ototoxic Hearing Loss

(1) To determine the ototoxicity detection rate (sensitivity) for distortion-product otoacoustic emissions (DPOAEs) testing in adults who received ototoxic medications and experienced pure-tone threshold changes during the course of treatment; (2) to determine the extent to which DPOAE sensitivity to ototoxicity depends on the type of drug administered (platinum or antibiotic), magnitude of ototoxic threshold shifts, pre-exposure pure-tone threshold, and DPOAE data; and (3) to build a model to predict DPOAE sensitivity. DPOAE and audiometric data were obtained as part of a prospective Veterans Affairs study investigating methods of ototoxicity monitoring. Data were analyzed from 90 ears of 53 subjects receiving ototoxic medications and showing significant hearing changes in at least one ear. Pure-tone threshold data were obtained at frequencies from 0.5 to 20 kHz, using 1/6-octave precision near the upper frequency limit of hearing. DPOAE data are reported for f2's from 0.8 to 8.0 kHz in 1/6-octave increments using primary levels (L1/L2) of 65/59 dB SPL and a primary frequency ratio (f2/f1) of 1.2. Test results were evaluated at various times during drug treatment to determine whether DPOAE level changes were associated with behavioral hearing changes. Univariate and multivariate analysis techniques were used to determine factors that affected DPOAE sensitivity to ototoxic damage. Of the 90 ears examined, 82 (91%) had DPOAEs that could be monitored for changes. Sixty-four of these 82 ears (78%) had DPOAEs that were reduced or absent following drug treatment. DPOAE sensitivity to ototoxicity was unrelated to the type of ototoxic drug administered. Rather, DPOAE sensitivity depended on the magnitude of postexposure hearing changes and on variables related to pre-exposure audiogram and DPOAE measurements. Behavioral hearing changes not detected by DPOAEs were small on average (<7 dB). DPOAE sensitivity was reduced in ears with poorer pre-exposure hearing, and in ears with measurable DPOAE frequencies limited to f2's below 2.5 kHz or more than one octave from the frequency region where hearing change occurred. Results of logistic regression modeling showed that DPOAEs present at f2's greater than 2.5 kHz were associated with the eventual success of ototoxicity monitoring with DPOAEs. However, independent variables examined could not explain differences in the relative timing of behavioral and DPOAE changes. A roughly equivalent proportion of ears experienced DPOAE changes before, during, or after behavioral hearing changes. DPOAEs are a useful screening tool for ototoxicity in adults with pre-exposure hearing loss, but are less sensitive compared with a behavioral test method that targets thresholds near the upper limit of a subject's audible frequency range. Ears successfully monitored for ototoxicity with DPOAEs are those with better pre-exposure hearing, greater postexposure hearing changes, and baseline DPOAEs near the highest behavioral test frequencies and present at high f2's. Results suggest that successful monitoring of ototoxicity with DPOAEs may be predicted clinically by assessing the measurable DPOAE f2 frequency range and its relation to the highest behavioral test frequencies.

Longitudinal changes in speech recognition in older persons

Recognition of isolated monosyllabic words in quiet and recognition of key words in low- and high-context sentences in babble were measured in a large sample of older persons enrolled in a longitudinal study of age-related hearing loss. Repeated measures were obtained yearly or every 2 to 3 years. To control for concurrent changes in pure-tone thresholds and speech levels, speech-recognition scores were adjusted using an importance-weighted speech-audibility metric (AI). Linear-regression slope estimated the rate of change in adjusted speech-recognition scores. Recognition of words in quiet declined significantly faster with age than predicted by declines in speech audibility. As subjects aged, observed scores deviated increasingly from AI-predicted scores, but this effect did not accelerate with age. Rate of decline in word recognition was significantly faster for females than males and for females with high serum progesterone levels, whereas noise history had no effect. Rate of decline did not accelerate with age but increased with degree of hearing loss, suggesting that with more severe injury to the auditory system, impairments to auditory function other than reduced audibility resulted in faster declines in word recognition as subjects aged. Recognition of key words in low- and high-context sentences in babble did not decline significantly with age.

The Outcomes of Bone Anchored Hearing Aid (BAHA) Fitting in a Paediatric Cohort

The aim of this study was to examine the pattern of changes in distortion product otoacoustic emissions (DPOAEs) in children with ototoxic hearing loss during chemotherapy. The participants included a control group of 15 normal hearing children (3-12 years) and an experimental group of 7 paediatric oncology patients (1-13 years). Participants were tested using pure tone audiometry (PTA), tympanometry, and DPOAEs (primaries 65/55 dB SPL). The results revealed no perfect match between PTA and DPOAE results with respect to frequency and pattern of decrease/increase of DPOAE amplitudes. Further analysis of DPOAEs in the experimental group revealed three main patterns of change: (1) Concurrent decreases in DPOAEs that matched pure tone threshold (PTT) changes at approximately the same frequencies; (2) DPOAE changes prior to PTT change, suggesting possible predictive power in DPOAE testing and (3) DPOAE and PTT changes not related in terms of test frequency and direction of change, noted in a patient with a high cumulative carboplatin dose.

Magnetic Resonance Imaging Compatibility and Safety of the SOUNDTEC Direct System

The purpose of this study was to evaluate magnetic resonance imaging (MRI) compatibility and safety of an electromagnetic implanted hearing device (the SOUNDTEC Direct System; SOUNDTEC, Inc., Oklahoma City, OK) implant during a 0.3-Tesla open MRI imaging examination of the head and neck and to develop an MRI protocol that maximizes patient safety while minimizing the need for implant removal. The current literature regarding MRI compatibility of implantable hearing devices was reviewed. Linear and torsional forces, heating, and implant magnetization were evaluated in vitro. Implanted fresh-frozen human temporal bones were used to evaluate image distortion. A prospective study of 11 volunteers previously implanted with the SOUNDTEC Direct System was conducted to evaluate MRI compatibility and safety. A MEDLINE search of the literature between 1980 and July 2005 was reviewed to summarize MRI compatibility testing of implantable hearing devices. Torsional and linear forces experienced by eight implant magnets were measured using calibrated neurologic Von Frey Hairs and compared with finite element analysis predictions as well as forces required to separate the incudostapedial joints of 12 fresh-frozen human temporal bones. Implant heating was determined by measuring the temperature change of eight implant vials compared with saline controls immediately after a head MRI scan. Implant magnetization was evaluated after repeated exposure to a 0.3-Tesla magnetic field. An 11-patient prospective study was performed to evaluate MRI compatibility in a 0.3-Tesla open MRI environment using adult volunteers previously implanted with the SOUNDTEC Direct System. A modified MRI protocol was developed to maximize patient safety. Each individual underwent an audiometric and otologic examination immediately before and after MRI. Peak linear force at the MRI entry measured 0.5 g +/- 0.2 standard deviation (SD). Maximum torque occurred at isocenter and measured 11.4 g-cm +/- 1.2 SD. The mean torque required to separate the incudostapedial joint was 33.8 g-cm +/- 20.4 SD. The average increase in temperature of the eight implant vials was 0.45 degrees C +/- 0.11 SD, whereas the increase in temperature of the three saline controls measured 0.47 degrees C +/- 0.11 SD. The average change in magnetic flux density of the 14 implant magnets tested was 22.0 gauss. Maximum image distortion occurred during the gradient echo sequence and measured 8.6 cm in diameter with a volume of 5,096 mm. Eleven patients completed a total of 12 head, one shoulder, and three lumbar 0.3-Tesla open MRI scans without patient- or device-related complications other than degradation of the MR image. There was no report of discomfort, tinnitus, dizziness, change in hearing, or change in device performance. All post-MRI changes in pure-tone thresholds, speech discrimination, soundfield thresholds, and aided soundfield thresholds were within the range of test-retest variability. When considering MRI of implantable ferromagnetic hearing devices, issues related to mechanical forces, implant heating, current induction, implant demagnetization, image degradation, and acoustic trauma must be considered. The SOUNDTEC Direct System is both MRI-compatible and safe in a 0.3-Tesla open MRI environment when a modified protocol is used. Degradation of the head MRI image may impair visualization of the ipsilateral temporal bone and adjacent structures within a 2.5- to 4.3-cm radius of the implant and is minimized by using a fast spin echo sequence.

Auditory filter shapes of CBA/CaJ mice: Behavioral assessments

Auditory filter shape and frequency tuning may be derived by measuring changes in pure tone thresholds as a function of the bandwidth of notched-noise maskers. When these psychophysical methods were applied to CBA/CaJ mice, the resulting filter shapes were well fit by roex(p,r) functions originally developed for human subjects. The equivalent rectangular bandwidths (ERBs) of the filter shapes ranged from 16 to 19% of test frequencies between 8 to 16 kHz. These ERBs correspond well to the performance of humans at high frequencies and the limited number of mammalian species that have been characterized with notched-noise procedures. Frequency tuning was maintained throughout most of the adult lifespan and then showed a selective high-frequency loss at ages beyond 2 years. These results suggest that auditory filtering effects in adult CBA/CaJ mice are similar to normal processes in other mammalian species and provide an excellent model of human presbycusis when they begin to degrade in aging individuals.

Extended high‐frequency audiometry in patients with acoustic trauma

The aim of this study was to examine extended high-frequency (EHF) hearing in patients with acoustic trauma. A prospective, case-control study in a group of soldiers with acoustic trauma caused by shooting practice during basic training. Tertiary referral centre. A total of 39 young soldiers hospitalized for hearing loss and tinnitus following exposure to weapon impulse noise were studied. Conventional audiometry in the frequency range 0.25-8 kHz and EHF audiometry in the frequency range 9-20 kHz were performed, both on admittance and before discharge. Thirty healthy recruits of similar age and sex were used as controls. Pure-tone threshold changes documented by conventional and EHF audiometry. The most significant differences in pure-tone thresholds on initial testing were found in the frequency range 0.25-11.2 kHz, and especially in the 4-8 kHz region. Reduction in thresholds across most frequencies was observed after treatment, although recovery was partial in most cases. The EHF audiometry adds no significant additional information to conventional pure-tone audiometry in assessing and monitoring noise-induced hearing loss.

Longitudinal Study of Pure-Tone Thresholds in Older Persons

Pure-tone thresholds for conventional and extended high frequencies were analyzed for 188 older adult human subjects (91 females, 97 males). The objectives were to study longitudinal changes in thresholds as well as the effects of initial threshold levels, age, gender, and noise history on these longitudinal changes. At the time of entry into the study, subjects' ages ranged from 60 to 81 years, with a mean age of 68 years. Subjects had between 2 and 21 visits (mean = 9.81 visits) over a period of 3 to 11.5 years (mean = 6.40 years). Conventional pure-tone thresholds at 0.25 to 8 kHz were measured during most visits. Extended high-frequency (EHF) thresholds at 9 to 18 kHz were measured every 2 to 3 years. The slope of a linear regression was used to estimate the rate of change in pure-tone thresholds at 0.25 to 18 kHz for each ear. A questionnaire was used to identify those subjects with a positive noise history. The average rate of change in thresholds was 0.7 dB per year at 0.25 kHz, increasing gradually to 1.2 dB per year at 8 kHz and 1.23 dB per year at 12 kHz. The rate of change for thresholds increased significantly with age, at 0.25 to 3, 10, and 11 kHz for females and at 6 kHz for males. After adjusting for age, females had a significantly slower rate of change at 1 kHz but a significantly faster rate of change at 6 to 12 kHz than males. For 0.25 and 1 kHz, subjects with more hearing loss at higher frequencies had a faster rate of change at these frequencies, whereas for 6 and 8 kHz, subjects with more hearing loss at mid and high frequencies had a slower rate of change at these frequencies. The rates of threshold change for subjects with a positive noise history were not statistically different from those with a negative noise history. On average, hearing threshold increased approximately 1 dB per year for subjects age 60 and over. Age, gender, and initial threshold levels can affect the rate of change in thresholds. Older female subjects (> or =70 years) had faster rate of change at 0.25 to 3, 10, and 11 kHz than younger female subjects (60 to 69 years). Older male subjects had faster rate of change at 6 kHz than younger male subjects. Females had a slower rate of change at 1 kHz and a faster rate of change at 6 to 12 kHz than males. Subjects with higher initial thresholds at low and mid frequencies tended to have faster rate of threshold change at 0.25 to 2 kHz in the following years. Subjects with higher initial thresholds at mid and higher frequencies tended to have slower rate of change at 6 to 8 kHz in the following years. Noise history did not have a significant effect on the rate of threshold changes.

Changes in input/output function of distortion product otoacoustic emissions during the glycerol test in Ménière's disease

ObjectiveTo investigate the manner of change in the input/output (I/O) function of distortion product otoacoustic emissions (DPOAEs) during the glycerol test in patients with Ménière's disease.Material and MethodsThe DPOAE I/O functions at three F2 frequencies of 1001, 1501, and 2002 Hz were measured before and after the glycerol test following pure-tone audiometry for 16 ears of 16 patients with unilateral Ménière's disease. Changes in DPOAE I/O function during the glycerol test were analyzed using maximum level of DPOAEs (max. DP level) and the detection threshold of DPOAEs (DP threshold) in the I/O function as parameters.ResultsSignificant changes in I/O function during the glycerol test were observed for at least one of three F2 frequencies in all 8 ears and 6 of 8 ears with and without positive test results, respectively, regardless of change in pure-tone thresholds at 1000 and 2000 Hz. A total of 12 ears exhibited two findings of significant change in parameters indicating improvement of cochlear function, increase in max. DP level and lowering of DP threshold, and 2 ears exhibited decrease in max. DP level, a finding indicative of deterioration of cochlear function. Neither of the two parameters exhibited significant change simultaneously, except in one I/O function. Moreover, there appeared to be no clear relationship between the parameter exhibiting significant change and F2 frequencies or changes in pure-tone threshold.ConclusionSubtle changes in cochlear function during the glycerol test can be detected with higher sensitivity by measurement of the DPOAE I/O function than by conventional audiometry. However, multiple parameters should be used in analysis of change in the I/O function since it is difficult to predict how the I/O function will change prior to the glycerol test. Furthermore, the high sensitivity of DPOAEs in detecting change in cochlear function may provide useful information on inner ear status in Ménière's disease.