Age-related changes of auditory sensitivity across the life span of CBA/CaJ mice

The inbred mouse strain CBA/CaJ is a frequently used animal model of age-related hearing loss in humans. These mice display significant hearing loss at a relatively advanced age, similar to most humans, with progressive loss of hearing as the mouse continues to age. While important descriptions of hearing loss in this mouse strain at multiple ages have previously been published, shortcomings persist in the data for hearing over the lifespan of the mouse. Therefore, we analyzed auditory brainstem response threshold data from records maintained by our research group to yield an extensive database of thresholds over nearly the entire life span of the CBA/CaJ mouse (from 79 to 1085 days). Data was collected from in-house bred mice of CBA/CaJ stock, initially from The Jackson Laboratory. Data was collected using BiosigRZ software and TDT System III hardware. Thresholds were routinely measured in conjunction with behavioral and electrophysiological experiments; only responses from baseline or experimentally naïve animals were analyzed. The resulting data set comprised 376 female mice and 441 males. At the lowest and highest frequencies (8 & 32 kHz), initial thresholds were just under 30 dB SPL and increased slowly until they were significantly different at 16-18 months compared to 1-3 months age, with the difference increasing over subsequent ages. At the middle frequencies (12 & 16 kHz), initial thresholds were just under 20 dB SPL and increased until they became different from initial at 16-18 months. At 24 kHz, initial thresholds were just above 20 dB and became different from initial at 13-16 months of age. The rate of change of thresholds with age were similar for all frequencies until about 30 months of age, when 32 kHz threshold changes lagged behind other frequencies. Generally, CBA/CaJ mice in our colony display relatively low thresholds until approximately 16 months of age, depending on frequency. After 16-18 months, thresholds become significantly worse. After approximately 20-22 months thresholds increase linearly with age.

Unilateral crosstalk cancellation via bone conduction: Methods and evaluation

Bone conduction hearing aids (BCHAs) offer an alternative solution for individuals with outer or middle ear issues who cannot benefit from traditional air conduction hearing aids. However, the phenomenon of "crosstalk," where sound intended for one ear is mistakenly transmitted to the other ear through bone conduction, presents a challenge. This unintended transmission may limit the benefits of binaural hearing that can be achieved using two BCHAs, such as accurately detecting a sound source's direction. In this article, we present a method to suppress "crosstalk" within the human head using an adaptive algorithm to control two audiometric bone transducers. •Our method involves positioning an error sensor at a location considered close to the cochlea, such as the ear canal or the mastoid, and utilizing an adaptive algorithm to estimate the crosstalk compensation filter. This filter generates an anti-signal, which is then transmitted to one of the two transducers, effectively cancelling the crosstalk.•To verify whether the crosstalk cancellation reaches the cochlea in the inner ear, we provide a procedure for measuring hearing thresholds with and without crosstalk cancellation. This acts as a subjective measure of the efficacy of our crosstalk cancellation method. By leveraging an adaptive algorithm, this approach provides personalized cancellation and has the potential to enhance the performance of binaural BCHAs.

Association between sleep duration and hearing threshold shifts of adults in the United States: National Health and Nutrition Examination Survey, 2015-2016

BACKGROUND

Obstructive sleep apnea (OSA) is linked to hearing loss (HL). Another sleep characteristics, sleep duration might also be associated with HL, but prior evidence is limited. This study is aimed to investigate the association between sleep duration and hearing level in the adult US population.

METHODS

In total, a sample of 2777 individuals aged 20-69 years from the 2015-2016 National Health and Nutrition Examination Survey cycle (NHANES, 2015-2016) were investigated in this study. Self-reported sleep duration data was classified into the short-sleep (< 7 h), normal-sleep (7-9 h), and long-sleep (> 9 h) group. Multivariable linear regression models between sleep duration and hearing threshold shifts were estimated. Interactions between sleep duration and age, gender, race, OSA were also considered, and the study population was stratified by age, gender, race, and OSA to analyze the potential disparities among adults in different subgroups.

RESULTS

Long-sleep duration was positively associated with speech- and high-frequency pure-tone average (PTA) thresholds with statistical significance (β = 1.31, 95%CI: 0.10, 2.53, P = 0.0347, and β = 2.71, 95%CI: 0.69, 4.74, P = 0.0087, respectively). When stratified by age, short sleep duration was positively associated with low-, and speech-frequency PTAs (P = 0.0140 and 0.0225, respectively) for adults aged 40-59 years, and long-sleep duration was positively associated with low-, and speech-frequency PTAs (P = 0.0495 and 0.0142, respectively) for adults aged 60-69 years with statistical significance. There was statistically significant interaction between OSA and sleep duration on speech-frequency PTA, but no significant interaction between either gender or race with sleep duration on hearing thresholds among US adults.

CONCLUSION

Short/long sleep durations are associated with worse hearing level comparing to sleep 7-9 h in the American adults. Nonoptimal sleep duration may be a potential risk factor for HL.

Generation of distortion product otoacoustic emissions in infants with a combined air and bone conduction stimulus

OBJECTIVES

Evaluation of Distortion Product Otoacoustic Emissions (DPOAEs) by combining Air Conduction (AC) and Bone Conduction (BC) stimuli in infants.

METHODS

Measurements were performed in 19 normal hearing infants, and in 23 adults serving as a control group. The stimulus consisted either of two AC tones, or of combined AC/BC tones. DPOAEs were measured for f2 at 0.7, 1, 2, 4 kHz, and a constant ratio of f2/f1 = 1.22. Sound pressure level of the primary stimulus L1 was held constant at 70 dB SPL, while the level of L2 was decreased in 10 dB steps from 70 to 40 dB SPL. A response was included for further analysis when DPOAEs reached a Signal to Noise Ratio (SNR) of ≥6 dB. Additional DPOAE responses of <6 dB SNR were included when visual inspection of the measurements indicated clear DPOAEs.

RESULTS

DPOAEs could be elicited in infants at 2 and 4 kHz for the AC/BC stimulus. DPOAE amplitudes evoked by the AC/AC stimulus were larger than those by the AC/BC stimulus, with the exception of 1 kHz. The highest amplitudes of DPOAEs were registered for a stimulation level of L1 = L2 = 70 dB, with the exception of AC/AC at 1 kHz, where the highest amplitudes were with L1-L2 = 10 dB.

CONCLUSIONS

We demonstrated that DPOAEs can be generated in infants by a combined AC/BC stimulus at 2 and 4 kHz. The high noise floor needs to be further reduced to achieve more valid measurements in frequencies <2 kHz.

Hearing threshold and physical performance in older people: a cross-sectional study from the HUNT4 cohort

PURPOSE

To evaluate the association between increased hearing loss and reduced physical performance in older people.

METHODS

Cross-sectional population-based study using data from the fourth wave of the Trøndelag Health Survey (HUNT4) in Norway. Data were obtained from the subproject HUNT4 Hearing which collected audiometric data of people > 70 years (N = 13,197). Analyses were performed on all participants who had completed audiometry and measured balance using the Short Physical Performance Battery (SPPB), which was scored from 0 (worst score) to 12. The hearing threshold was expressed as a pure tone average (PTA). Associations between the hearing threshold for the best and worst ear and physical performance were analyzed by linear regression models adjusted for age, sex, education, diabetes, and cardiovascular disease. Hearing threshold was indicated with steps of 10 dB.

RESULTS

Of 13,197 eligible participants, 4101 who completed audiometry and SPPB (52.3% women. mean age 76.3 years) were included. The analyses revealed an association between reduced SPPB and increased hearing threshold in the best ear (b = - 0.296; 95% CI - 0.343 to - 0. 249; P < 0.001) and the worst ear (b = - 0.229; 95% CI - 0.270 to - 0.189; P < 0.001).

CONCLUSIONS

In this population study, we found that the increased hearing threshold was associated to reduced physical performance as measured by SPPB. The association seemed to be strongest for the best ear. The association between hearing threshold and physical performance illustrates the importance of assessing physical performance in people with hearing loss to prevent the risk of falls and disability. The underlying causes of the associations between hearing loss and poorer physical performance are not fully understood and should be further investigated.

LEVEL OF EVIDENCE

Level 3.

Benefits of amplification for unaided speech discrimination in age-related hearing loss with flat type audiogram

OBJECTIVE

The present study aimed to investigate whether hearing aid use can induce improvement as acclimatization effect in unaided speech perception in patients with age-related hearing loss.

METHODS

Fifty ears in 41 patients (age range: 65-91 years) diagnosed as age-related hearing loss were enrolled in this study. They used hearing aids for more than 8 hours per day. Unaided speech audiometry using 67-S Japanese monosyllabic word list was performed one or two years after the commencement of hearing aid use. The changes in the unaided speech discrimination score before and after the commencement of hearing aid use were analyzed. To investigate factors for improvement, the patients' backgrounds in terms of age, sex, pure tone average, unaided maximum speech discrimination score, fitting period (one year/two years), fitting ear (bilateral/unilateral), audiogram type (flat-type/other-type), and the level of amplification were also analyzed.

RESULTS

Significant improvement in the unaided speech discrimination score after hearing aid use was seen only in the flat-type audiogram group. More than half of older patients in the flat-type audiogram group improved their unaided maximum speech discrimination score 10 % or more. The analysis of aided hearing thresholds revealed that the flat-type audiogram group had significantly lower thresholds of 3kHz and 4kHz than the other-type audiogram group. The age, sex, pure tone average, fitting period, fitting ear, functional gain were not influential factors for improvement. On the other hand, unaided maximum speech discrimination score before using hearing aid and aided hearing threshold at 4kHz had a negative correlation with improvement.

CONCLUSION

The findings suggested that older patients with age-related hearing loss whose audiogram is a flat type can benefit from amplification as means of improving their unaided speech perception since flat-type audiogram can be more easily adjusted to sufficiently amplify speech sound at high frequencies. It should be considered that the potential for experience-dependent plasticity is retained even in older adults.

Extended high-frequency audiometry: hearing thresholds in adults

PURPOSE

This study aimed to determine hearing thresholds in an otologically normal population without occupational noise exposure aged 18 to 64 years using extended high-frequency audiometry (EHFA).

METHODS

Individuals from the general population who have never had hearing problems and whose job was not associated with noise exposure were included in the study and classified by age into 5 categories: 18-24 and, further, by 10 years of age. Each of these groups was further divided according to gender. All subjects underwent tympanometry, conventional pure-tone audiometry within the 0.125-8 kHz range, and extended high-frequency audiometry within the 9-16 kHz range, performed according to the standards. The significance level for statistical testing was set at 5%.

RESULTS

Here, we established hearing thresholds in an otologically healthy population within the extended high-frequency (EHF) range (9-16 kHz). We found the EHFA to be a highly sensitive method for early detection of hearing loss, with hearing thresholds decreasing as soon as 35 years of age. In males, the hearing thresholds grew with age more rapidly than in women. The ability to respond at EHF gradually decreased with age and increasing frequency.

CONCLUSION

Our results can help improve the knowledge of EHF hearing thresholds for individual sexes and age groups. So far, the standard 7029:2017 is not binding and, moreover, it only reaches up to the frequency of 12.5 kHz. EHFA is a highly sensitive method for the evaluation of hearing loss depending on age and sex.

The outer ear pathway during hearing by bone conduction

There have been conflicting reports in the literature about the importance of the induced ear canal sound pressure for the perception of bone-conducted (BC) sound. Here we investigated this by comparing the ear canal sound pressure at threshold for air-conducted (AC) and BC stimulation. Twenty-one adults with subjectively normal hearing function participated. They were tested for their hearing thresholds in the frequency range 250 Hz to 12.5 kHz with AC and BC stimulation and the ear canal sound pressure within 5 mm of the eardrum was obtained with probe tube microphones. Contralateral masking used with BC stimulation shifted the hearing threshold by 5 to 10 dB due to central masking effects. When the ear canal sound pressures at threshold were investigated, the results indicate that the ear canal component for hearing BC sound is around 10 dB below other contributors at frequencies below 2 kHz and similar to other important contributors at frequencies between 2 and 4 kHz. At frequencies above 4 kHz, the contribution from the ear canal sound pressure on BC hearing declines and was around 40 dB below other contributors at 12.5 kHz. The contribution of the ear canal sound pressure in the mid-frequency region is facilitated by the ear canal resonance occurring in this frequency area. The results were similar irrespective of stimulation position. The study also revealed problems estimating the force out of BC transducers caused by a shift in resonance frequency when the artificial mastoid impedance deviates from the impedance of human mastoids. The current study indicates that model predictions have underestimated the contribution from the ear canal sound pressure on BC hearing by around 10 dB.

Extended high-frequency audiometry in healthy adults with different age groups

Background

It was well-documented that extended high-frequency (EHF, above 8 kHz) hearing test could be more sensitive comparing with the conventional measurement on frequency below 8 kHz, regarding the early prediction of auditory damage in certain population. However, hardly any age-specific thresholds of EHF in population with normal hearing ability were observed. This study aims to monitor the age-dependent hearing thresholds at EHF (from 9 to 20 kHz) in healthy hearing population.

Methods

A total of 162 healthy participants (from 21 to 70 years) with normal conventional pure tone audiograms were recruited and separated into five groups by age. Conventional pure tone average was performed with frequencies from 0.25 to 8 kHz under air conduction and from 0.25 to 4 kHz under bone conduction. EHF audiometry from 9 to 20 kHz was determined under air conduction.

Results

The effects of aging on hearing were evident at frequencies above 4 kHz. The hearing thresholds of EHF were less than 26 dB HL before 30 years-olds. Hearing abilities in EHF were deteriorated starting from the 31 ~ 40 group and were most obvious in the 51 ~ 60 group and the 61 ~ 70 group with the maximum thresholds of 75 dB HL. Sensitivity of EHF was inversely proportional to the frequency within each age group, and to age among groups. Subjects under 30 years old were totally responsive up to 16 kHz, and 52.2% could respond to 20 kHz. Meanwhile, no responsiveness was recorded to 20 kHz in the 51 ~ 60 group and even to 18 kHz in the 61 ~ 70 group. No gender differences in hearing threshold was observed within each age group, except an obvious decline at frequencies of 4, 6, 8, and 9 kHz in male participants of the 41 ~ 50 group.

Conclusions

Hearing thresholds at EHF from 9 to 20 kHz were more sensitive than at frequencies below 8 kHz for hearing measurement, and aging inversely affected hearing ability at EHF in healthy population. Hearing thresholds at EHF deteriorated with age and raising frequency, while the upper frequency limit decreased with aging.

Graphical abstract

[Does sealing the oval window in addition to the round window bring an advantage in reserve therapy of acute idiopathic deafness?]

BACKGROUND

Following sudden unilateral deafness or severe sensorineural hearing loss, patients with unsuccessful intravenous steroid therapy can be treated with explorative tympanotomy with sealing of the round (RW) and/or oval window (OW), due to suspected rupture of the RW with perilymph fistula (PLF) or a fissula ante fenestram (FAF). This study investigated whether additional sealing of the oval window (RW+OW) achieved an improved hearing benefit as compared to sealing of the round window only (RW) .

METHODS

This retrospective study investigated 54 patients with acute profound hearing loss who underwent tympanoscopy. Audiometric examinations were performed preoperatively and at two postoperative intervals (1 month and 3-6 months after surgery). In 28 patients, the OW was sealed in addition to the RW.

RESULTS

No intraoperatively visible PLF or FAF were reported. Hearing thresholds were significantly reduced in the early postoperative follow-up period and further improvement was observed 3-6 months later. No significant differences between the RW and RW+OW subgroups were seen at either follow-up timepoint. In 65% (Kanzaki criteria) and 74% (Siegel criteria) of patients, partial or complete postoperative hearing improvement was observed. Upon comparing the groups of patients with and without hearing improvement, no statistical significance was found in terms of gender, age, secondary diagnoses, or latency period between symptom onset and surgery.

CONCLUSION

Additional sealing of the OW did not lead to significantly better postoperative hearing thresholds. In general, postoperative hearing improvement corresponds to published spontaneous remission rates.

How Long Is Otosclerosis Surgery Effective? Hearing Results after a 22-Year Follow-Up

INTRODUCTION

Stapes surgery is a safe procedure, with favourable hearing outcome. The objective of the study is to assess the long-term hearing results, addressing the bone conduction (BC) decay and the need for hearing aids in otosclerosis patients.

METHODS

We enrolled patients who underwent stapes surgery by means of stapedectomy or stapedotomy between 1991 and 2001. All enrolled patients underwent pure-tone audiometry (PTA) between September 2017 and June 2018. A set of questions was administered to record the prevalence of subjective symptoms and the need for hearing aids.

RESULTS

Seventy patients were enrolled for a long-term evaluation; 37 patients underwent bilateral surgery; therefore, 107 ears were included in the analysis. The average follow-up period was 22 years. No statistically significant difference was found between early and late post-operative air conduction (AC) PTA (41 vs. 49 dB; p > 0.05) nor between early and late post-operative BC-PTA (29 vs. 37 dB; p > 0.05). A significant difference was observed for AC at 8 kHz (65 vs. 78 dB; p < 0.05) and BC at 2 and 4 kHz (28 vs. 40 dB and 45 vs. 58 dB, respectively; p < 0.05).

CONCLUSIONS

This is, to our knowledge, the longest mean follow-up time in the literature. A mild decrease in both AC and BC threshold can be expected and the sensorineural decay is more pronounced on the high frequencies. The subjective hearing symptoms and overall sound perception are satisfactory.

The impact of intra-operative factors in otosclerosis outcomes: retrospective study in a tertiary centre

The aim of the study was to assess results from a large cohort of patients undergoing otosclerosis surgery with respect to the impact of intra-operative variables on post-operative hearing function and complications. We enrolled 384 patients affected by otosclerosis who were subjected to stapes surgery between 2004 and 2013 at a single institution. Surgery was performed in all cases under local anaesthesia, using a manual perforator and/or microdrill. Teflon-piston prosthesis was used in all patients. Audiological data obtained preoperatively and at last follow-up examination (minimum 12 months) were compared. Statistical analysis was performed using the multiple regression model. Peripheral rim otosclerosis and diffuse otosclerosis were associated with better functional results compared to the obliterative pattern (p < 0.05). Mean post-operative Air-Bone Gap was significantly higher in the 0.4 mm, compared to 0.6 mm piston group at 0.5 kHz (p < 0.001) and 1 kHz (p < 0.02); in the stapedotomy group a statistically significant difference was found between 0.4 and 0.6 mm piston groups, in favour of the latter (p < 0.05). No differences were encountered in terms of average hearing threshold and complications. Intra-operative variables cannot be fully predictable and our data could help in stratification of the results and as a landmark for the surgeon’s decisions.

Relative contributions of auditory and cognitive functions on speech recognition in quiet and in noise among older adults

Introduction

Hearing acuity, central auditory processing and cognition contribute to the speech recognition difficulty experienced by older adults. Therefore, quantifying the contribution of these factors on speech recognition problem is important in order to formulate a holistic and effective rehabilitation.

Objective

To examine the relative contributions of auditory functioning and cognition status to speech recognition in quiet and in noise.

Methods

We measured speech recognition in quiet and in composite noise using the Malay Hearing in noise test on 72 native Malay speakers (60–82 years) older adults with normal to mild hearing loss. Auditory function included pure tone audiogram, gaps-in-noise, and dichotic digit tests. Cognitive function was assessed using the Malay Montreal cognitive assessment.

Results

Linear regression analyses using backward elimination technique revealed that had the better ear four frequency average (0.5–4 kHz) (4FA), high frequency average and Malay Montreal cognitive assessment attributed to speech perception in quiet (total r² = 0.499). On the other hand, high frequency average, Malay Montreal cognitive assessment and dichotic digit tests contributed significantly to speech recognition in noise (total r² = 0.307). Whereas the better ear high frequency average primarily measured the speech recognition in quiet, the speech recognition in noise was mainly measured by cognitive function.

Conclusions

These findings highlight the fact that besides hearing sensitivity, cognition plays an important role in speech recognition ability among older adults, especially in noisy environments. Therefore, in addition to hearing aids, rehabilitation, which trains cognition, may have a role in improving speech recognition in noise ability of older adults.

Effect of loading of the central part of the tympanic membrane on pure tone audiometry

SUMMARY

This study was conducted to determine the effects of loading of the central part of the tympanic membrane by different weights on pure tone audiometry of healthy ears. Sixty patients with normal otoscopic view, normal pure tone audiometry and wide external auditory canal to allow direct and endoscopic visualization of TM, but without any history of ear surgeries, were selected and divided equally and randomly into two groups. Loading of the central part of the TM was carried out using weights ranging from [(1 λ) 13.6 mg] to [(40 λ) 544 mg]; (λ) is a symbol for the weight of 1 microliter of mercury. The study was carried out in two steps assisted by direct oto-endoscopy, and pure tone audiometry was used to measure the effects of loading on both air and bone conduction hearing. Air conduction hearing thresholds increased in a statistically significant pattern at low frequencies, 500 Hz, 1000 Hz and 2000 Hz, when the TM was loaded by 340 mg (25 λ). The maximal effect was recorded at 544 mg (40 λ), which affected air conduction hearing at all tested frequencies (500 Hz, 1000 Hz, 2000 Hz and 4000 Hz). However, no statistically significant effect was detected on bone conduction hearing thresholds throughout the study. In conclusion, loading of the tympanic membrane by different masses affects the air conduction hearing threshold by only 340 mg (25 λ), which is very large in comparison to the mass of ossicles, without any significant effects on bone conduction hearing.

Cochlear implantation outcomes in children with common cavity deformity; a retrospective study

Objective

A common cavity deformity (CCD) is a deformed inner ear in which the cochlea and vestibule are confluent forming a common rudimentary cystic cavity that results in profound hearing loss. There are few studies paying attention to common cavity. Our group is engrossed in observing the improvement of auditory and verbal abilities in children who have received cochlear implantation (CI), and comparing these targets between children with common cavity and normal inner ear structure.

Material and methods

A retrospective study was conducted in 12 patients with profound hearing loss that were divided into a common cavity group and a control group, six in each group matched in sex, age and time of implantation, based on inner ear structure. Categories of Auditory Performance (CAP) and speech intelligibility rating (SIR) scores and aided hearing thresholds were collected and compared between the two groups. All patients wore CI for more than 1 year at the Cochlear Center of Anhui Medical University from 2011 to 2015.

Results

Postoperative CAP and SIR scores were higher than before operation in both groups (p < 0.05), although the scores were lower in the CCD group than in the control group (p < 0.05). The aided threshold was also lower in the control group than in the CCD group (p < 0.05).

Conclusion

Even though audiological improvement in children with CCD was not as good as in those without CCD, CI provides benefits in auditory perception and communication skills in these children.

Mode of recording and modulation frequency effects of auditory steady state response thresholds

INTRODUCTION

The performance of auditory steady state response (ASSR) in threshold testing when recorded ipsilaterally and contralaterally, as well as at low and high modulation frequencies (MFs), has not been systematically studied.

OBJECTIVE

To verify the influences of mode of recording (ipsilateral vs. contralateral) and modulation frequency (40Hz vs. 90Hz) on ASSR thresholds.

METHODS

Fifteen female and 14 male subjects (aged 18-30 years) with normal hearing bilaterally were studied. Narrow-band CE-chirp^® stimuli (centerd at 500, 1000, 2000, and 4000Hz) modulated at 40 and 90Hz MFs were presented to the participants' right ear. The ASSR thresholds were then recorded at each test frequency in both ipsilateral and contralateral channels.

RESULTS

Due to pronounced interaction effects between mode of recording and MF (p<0.05 by two-way repeated measures ANOVA), mean ASSR thresholds were then compared among four conditions (ipsi-40Hz, ipsi-90Hz, contra-40Hz, and contra-90Hz) using one-way repeated measures ANOVA. At the 500 and 1000Hz test frequencies, contra-40Hz condition produced the lowest mean ASSR thresholds. In contrast, at high frequencies (2000 and 4000Hz), ipsi-90Hz condition revealed the lowest mean ASSR thresholds. At most test frequencies, contra-90Hz produced the highest mean ASSR thresholds.

CONCLUSIONS

Based on the findings, the present study recommends two different protocols for an optimum threshold testing with ASSR, at least when testing young adults. This includes the use of contra-40Hz recording mode due to its promising performance in hearing threshold estimation.

Can the learning curve in stapes surgery predict future functional outcome?

Over the last 20 years, the number of stapes operations performed has decreased steadily. This inadequate exposure to stapes surgery poses problems for both trainees and trainers. We retrospectively reviewed the outcomes of stapedotomy performed by a young physician at the ENT Clinic of the "A. Gemelli" Hospital of Rome. We used the technique of "one-shot" CO₂ Laser stapedotomy using a titanium-Teflon piston. For data analysis, we considered the audiograms obtained 24 hours preoperatively and at the last follow-up examination (mean 45 months). Air conduction (AC) and bone conduction (BC) PTA were calculated for 0.25, 0.5, 1, 2 and 4 kHz thresholds. Air bone gap (ABG) were obtained from ACPTA and BCPTA. Postoperative hearing gain was calculated from the ABG before the operation minus the ABG at late follow-up examination. Analysis of outcomes did not show a clear endpoint for the learning curve; complete closure of the ABG was obtained in a large number of patients at the beginning followed by patients who showed a higher ABG. Fortunately, we did not observed any "dead ear". The study supports a learning curve in stapes surgery, but the results can vary widely among surgeries with excellent results followed by others that are not fully satisfactory. Stapes surgery should not be one of the first ear surgeries performed by a young otologist due to the functional outcome expected by patients and the lack of necessary surgical skills.

Clinical observation on hearing conditions of centenarians in northern district of China

CONCLUSION

The hearing conditions of the centenarians were quite poor as regards hearing thresholds and speech detection ability.

OBJECTIVE

To investigate hearing conditions of centenarians.

METHODS

A total of 54 centenarians in Rizhao and Linyi Districts in Shandong Province were investigated to assess hearing conditions of centenerians comprehensively by questionnaire investigation, pure-tone audiometry, acoustic immitance, intelligence evaluation, and speech detection scores. Also, 135 individuals were recruited as controls and divided into four groups according to their age: 45-59 years, 60-69 years, 70-79 years, and 80-89 years.

RESULTS

The hearing thresholds of the centenarians were dramatically higher than those of the control group (p < 0.05) and all centenarians suffered moderate to profound hearing loss according to the World Health Organization (WHO) criteria. Few centenarians had normal level of speech detection scores. All centenarians showed descending hearing curve, and the hearing threshold of the male centenarians at 8000 Hz was higher than that of the females (p = 0.047). There was a significant air-bone conduction gap in the centenarians (p < 0.05).

Auditory brainstem responses to clicks and tone bursts in C57 BL/6J mice

In auditory research, hearing function of mouse mutants is assessed in vivo by evoked potential recording. Evaluation of the response parameters should be performed with reference to the evoked responses recorded from wild-type mice. This study reports normative data calculated on auditory brainstem responses (ABRs) obtained from 20 wild-type C57 BL/6J mice at a postnatal age between 21 and 45 days. Acoustic stimuli consisted tone bursts at 8, 14, 20, 26, 32 kHz, and clicks. Each stimulus was delivered in free field at stimulation intensity starting from a maximum of 100 dB peak equivalent SPL (dB peSPL) at decreasing steps of 10 dB with a repetition rate of 13/sec. Evoked responses were recorded by needle electrodes inserted subcutaneously. At high intensity stimulation, five response waveforms, each consisting of a positive peak and a subsequent negative valley, were identified within 7 msec, and were labelled with sequential capital Roman numerals from I to V. Peak IV was the most robust and stable at low intensities for both tone burst and click stimuli, and was therefore utilized to estimate hearing thresholds. Both latencies and amplitudes of ABR peaks showed good reproducibility with acceptable standard deviations. Mean wave IV thresholds measured across all animals ranged from a maximum of 23 dB peSPL for clicks to a minimum of 7 dB peSPL for 20 kHz-tone burst stimuli. Statistical analysis of the distribution of latencies and amplitudes of peaks from I to V performed for each stimulus type yielded a normative data set which was utilised to obtain the most consistent fitting-curve model. This could serve as a reference for further studies on murine models of hearing loss.

Measurement of implant stability and auditory pure-tone thresholds of Baha patients comparing osteosysthesis and osseointegrated systems

With bone-anchored hearing systems the implant-bone junction is critical for the transmission of mechanical vibrations to the skull. The implant stability might differ between available and widely applied implants and can be estimated by resonance frequency analysis. The implant stability and the audiological performance of ten adult long-time users where a bone-anchored hearing system was connected by an Baha osseointegrated implant (Cochlear Ltd, Mölnlycke, Sweden) were compared with the implant stability of fourteen adult patients provided with a Ti-epiplating osteosysthesis system (Medicon, Tuttlingen, Germany). The acute implant stability was compared between these two implants with one cadaveric skull. The results show higher resonance frequencies and thus higher implant stability for the osseointegrating system of both, measuring acute and after long-time use of the implants. The audiological outcomes show frequency dependent differences between both systems as determined by comparing pure-tone bone-conduction audiometry. However, measuring thresholds by a direct stimulation of the implant reveals better hearing with low frequencies for the osseointegrated system and for high frequencies with the osteosysthesis system. At all, the implant selection has an impact on the implant stability and on the pure-tone hearing.

Dealing with paediatric cholesteatoma: how we changed our management

We reviewed our series of surgeries for paediatric cholesteatoma to assess outcomes and functional results considering the extension of disease and surgical techniques. Between January 2003 and December 2009, 36 patients (range 6-14 years) were operated on for cholesteatoma. We considered the sites involved by the cholesteatoma (mastoid, antrum, attic, middle ear, Eustachian tube), surgical techniques used (intact canal wall, canal wall down) and how our habits changed over the years; moreover, we evaluated ossicular chain conditions and how we managed the ossiculoplasty. As outcomes, we considered the percentage of residual and recurrent cholesteatoma for each technique and hearing function (air bone gap closure, high frequencies bone conduction hearing loss) at follow-up. Intact canal wall was performed in 20 patients and canal wall down in 13 patients, in 9 as first surgery. In both groups, we observed improvement of the air bone gap; in the intact canal wall group, a residual cholesteatoma was observed in 6 patients whereas, during follow-up, 2 patients who underwent a canal wall down showed a recurrent cholesteatoma that was treated in an outpatient setting. Eradication of cholesteatoma and restoration of hearing function in paediatric patients present unique surgical challenges. Our experience shows an increased choice of intact canal wall over the years. Therefore, it is important for the surgeon to counsel parents about the probable need for multiple surgeries, especially if an intact canal wall mastoidectomy is performed.

Establishment of Normative data for Monaural Recordings of Auditory Brainstem Response and its Application in Screening Patients with Hearing Loss: A Cohort Study

OBJECTIVES

To establish normative data required for recording Auditory Brainstem Response (ABR) using monaural stimulations in children with normal hearing.

METHODS

This study was conducted on 40 apparently healthy children. Database was collected after assessing with otological questionnaire, otoscopic examination and audiometric evaluation. Brainstem Evoked Response Audiometry (BERA) was used as a tool for establishment of normative data. ABR recordings by monaural presentation were obtained by following the standard test protocol given by Hall.

RESULTS

ABR parameters like Absolute latencies, amplitudes, amplitude ratios, Inter- peak latencies and thresholds were assessed for their normative values which are required to establish a baseline data. The Interaural latency difference was less than 0.2 ms (milliseconds) and was found to be normal limit. Mean values of absolute latencies for left ear were1.66 ms 3.68 ms and 5.64 ms respectively and for right ear these were 1.66 ms, 3.65 ms and 5.59 ms respectively. Mean values for amplitude of wave I and V for left ear were 0.32 uV and 0.41 uV respectively. For right values were 0.31 uV and 0.36 uV respectively. Mean values of amplitude ratio (V/I) for left and right ears were 1.81 and 1.74 respectively. Mean values of interpeak latencies of wave I-III, III-V, I-V were 2.02 ms, 2.02 ms and 3.92 ms respectively for left ear and for right ear values were 2.04 ms, 1.98 ms and 4.03 ms respectively. Mean values for left and right ear hearing threshold was 25.25 dBnHL.

CONCLUSION

ABR parameters shows variation in values depending upon age, myelination process, maturation of auditory pathway, environmental factors, laboratory setup etc. Hence it is concluded that each laboratory should have its own normative data which can be used as a baseline data for screening of patients with hearing loss.

The effect of parvalbumin deficiency on the acoustic startle response and prepulse inhibition in mice

The strength of the acoustic startle response (ASR) to short bursts of broadband noise or tone pips (4, 8 and 16 kHz) and the prepulse inhibition (PPI) of the ASR elicited by prepulse tones (4, 8 and 16 kHz) were measured in parvalbumin-deficient (PV-/-) mice and in age-matched PV+/+ mice as controls. Hearing thresholds as determined from recordings of auditory brainstem responses were found to be similar in both genotypes. The ASRs to broadband noise and tones of low and middle frequencies were stronger than the ASRs in response to high-frequency tones in both groups. In PV-/- mice, we observed smaller ASR amplitudes in response to relatively weak startling stimuli (80-90 dB sound pressure level (SPL)) of either broadband noise or 8-kHz tones compared to those recorded in PV+/+ mice. For these startling stimuli, PV-/- mice had higher ASR thresholds and longer ASR latencies. PPI of the ASR in PV-/- mice was less effective than in PV+/+ mice, for all tested prepulse frequencies (4, 8 or 16 kHz) at 70 dB SPL. Our findings demonstrate no effect of PV deficiency on hearing thresholds in PV-/- mice. However, the frequency-specific differences in the ASR and the significant reduction of PPI of ASR likely reflect specific changes of neuronal circuits, mainly inhibitory, in the auditory centers in PV-deficient mice.

The Relationship between the Behavioral Hearing Thresholds and Maximum Bilirubin Levels at Birth in Children with a History of Neonatal Hyperbilirubinemia

INTRODUCTION

Neonatal hyperbilirubinemia is one of the most important factors affecting the auditory system and can cause sensorineural hearing loss. This study investigated the relationship between behavioral hearing thresholds in children with a history of jaundice and the maximum level of bilirubin concentration in the blood.

MATERIALS AND METHODS

This study was performed on 18 children with a mean age of 5.6 years and with a history of neonatal hyperbilirubinemia. Behavioral hearing thresholds, transient evoked emissions and brainstem evoked responses were evaluated in all children.

RESULTS

Six children (33.3%) had normal hearing thresholds and the remaining (66.7%) had some degree of hearing loss. There was no significant relationship (r=-0.28, P=0.09) between the mean total bilirubin levels and behavioral hearing thresholds in all samples. A transient evoked emission was seen only in children with normal hearing thresholds however in eight cases brainstem evoked responses had not detected.

CONCLUSION

Increased blood levels of bilirubin at the neonatal period were potentially one of the causes of hearing loss. There was a lack of a direct relationship between neonatal bilirubin levels and the average hearing thresholds which emphasizes on the necessity of monitoring the various amounts of bilirubin levels.

Effects of hypertension on hearing

To determine the likely association between hypertension and hearing loss. 150 cases and 124 controls, both genders, aged 45-64, included in the research after sample estimation. Hypertension was verified through blood pressure readings and was classified as grade 1, grade 2 and grade 3 hypertension or no hypertension according to the blood pressure readings. Hearing was assessed by measuring pure tone threshold at various frequencies ranging between 250 and 8,000 Hz. There is a significant association between hypertension and increase in the hearing threshold. Hearing loss in the population under study suggests that hypertension is an accelerating factor of degeneration of the hearing apparatus due to aging. Association between Increased hearing threshold and hypertension in this research, can allow for an integrated work of cardiologists, nephrologists, otorhinolaryngologists, audiologists and other health professionals concerned with alterations caused by hypertension.