The effect of drinking water fluoridation on the natural course of hearing in patients with otosclerosis

The effect of drinking water fluoridation on the course of hearing of non-operated otosclerotic ears was assessed in an area where the natural waters have a very low fluoride content. The study population consisted of 150 patients with surgically proven otosclerosis. Patients having an additional known cause of hearing loss were excluded from the study. Every patient had a follow-up of at least 5 years, the mean follow-up period being 8.8 years. At last follow-up examination, air conduction thresholds of patients drinking fluoridated tap water were found to be significantly better than those of patients drinking fluoride-poor water, likewise there were significant differences in bone conduction thresholds at 1, 2, and 4 kHz. It was concluded that drinking water fluoridation has a beneficial effect on hearing levels of non-operated otosclerotic ears.     

Effects of the severity and duration of lesions on the primary and anamnestic humoral responses of sheep to Dichelobacter nodosus and observations of natural resistance to footrot

Choice of outcome measure in reporting hearing results following otologic surgery, including the frequencies used and use of pre- or postoperative bone thresholds, varies from author to author. In this study, data from 550 ossicular reconstruction and pediatric tympanoplasty surgery patients were used to generate a variety of outcome measures, including pure-tone thresholds for frequencies from 0.5 kHz to 8 kHz and different frequency combination pure-tone averages (PTAs) and air-bone gaps. There were no significant differences between mean pre- and postoperative bone conduction thresholds for any of the frequencies from 0.5 to 4 kHz nor for a PTA of 1, 2, and 4 kHz. Mean postoperative air-bone gap differed by no more than 2 dB across six different frequency combination PTAs. If "success" is defined as a postoperative air-bone gap of less than 20 dB, the largest difference in success rate across the six frequency combinations was 5%. There was also little difference in mean postoperative air conduction PTAs for any of the combinations that include frequencies through 4 kHz. Choice of a more conservative or more liberal definition of success was more important than whether air-bone gap or air conduction PTA was used. The authors recommend that a standard reporting procedure be adopted that ensures presentation of the results in a format such that more direct comparisons can be made within the published literature.     

Distortion product otoacoustic emissions for the assessment of auditory sensitivity

Distortion product otoacoustic emissions (DPOAEs) were evaluated in 494 normal and 506 cochlear-impaired human ears, to determine whether DPOAEs depend on factors such as background noise, the shape of the pure tone audiogram, sex and aging, and whether a DPOAE test can perform well in distinguishing normal-hearing from hearing-impaired ears. The amplitudes of DPOAEs were measured at the frequency of 2f1-f2 (f1 < f2, f2/f1 = 1.22, f2 at 1, 2 and 4 kHz) using as stimuli two pure tones at level of 70 dB from an ILO92 Otoacoustic Emission Analyzer. The correlation coefficients between the DPOAE level and the auditory threshold decreased as the background noise levels at 1 kHz and 2 kHz increased. Therefore, it appeared that ears with large background noise levels would be inadequate for the study of DPOAEs predicting the hearing state. The sensitivity (normal-hearing ears identified as normal hearing) and the specificity (hearing-impaired ears identified as hearing impaired) at the equal-sensitivity-specificity condition were 80.7-86.7% at 1, 2 and 4 kHz, and the areas under the receiver operating characteristic (ROC) curves, which were used to estimate the test performance, were 0.88 for 1 kHz, 0.91 for 2 kHz and 0.92 for 4 kHz. Since these results suggest that a DPOAE can be used as a reliable technique for objective auditory tests, it is thought that actual values (DPOAE level: 4.3 dB at 1 kHz, 5.0 dB at 2 kHz and 2.9 dB at 4 kHz) of false-positive (hearing-impaired ears identified as normal hearing) rates corresponding to 5% can be used in clinical evaluation to separate normal hearing from hearing-impaired ears. There was, however, a significant age effect at 4 kHz on DPOAEs in the ears with the same pure tone hearing thresholds, and the areas of the ROC curves in subjects ranging from 10 to 29 years old were larger than in subjects over 50 years (1 kHz: 0.88 to 0.94 versus 0.83 to 0.84, 2 kHz: 0.95 versus 0.89, 4 kHz: 0.95 to 0.96 versus 0.88 to 0.89). Therefore, it is thought that age-adjusted norms may be necessary for the accurate interpretation of DPOAE results.     

A three-paradigm treatment model using soft tissue mobilization and guided movement-awareness techniques for a patient with chronic low back pain: a case study

The benefits of active noise reduction (ANR) hearing protectors were assessed in two groups of normal-hearing subjects, under and over the age of 40 years, and one group with bilateral high-tone hearing loss. Subjects were tested with the ears unoccluded and fitted with conventional sound attenuating E-A-R foam plugs, E-A-R HI-FI plugs, and Bilsom Viking muffs; and one ANR muff, the Peltor 7004. Within each ear condition, measurements were made in quiet of hearing thresholds for frequencies between 0.25 kHz and 8 kHz, duration and frequency difference limens, and word recognition. Hearing thresholds and word recognition were also measured in a background of impulsive cable swager noise. The E-A-R foam plug provided the highest and the E-A-R HI-FI plug, the lowest attenuation. The Bilsom Viking and Peltor muffs were virtually identical and midway between. An additional 10 dB of sound reduction was realized at 0.25 kHz with ANR. The masking effect of the noise on hearing threshold decreased with an increase in attenuation. None of the devices compromised either duration or frequency discrimination. Word recognition in noise improved in normal listeners when protectors were worn. For the impaired subjects, word recognition with poor contextual cues decreased with an increase in sound attenuation, in both quiet and noise. Like older normal listeners, their scores were relatively higher with ANR.     

Kleine-Levin syndrome in a female patient

The concept of bone conduction hearing is old. By the 16th century the conduction of sound by a rod or the staff of a spear was reported by a number of writers; however, these writers considered these phenomena as a curiosity rather than having practical value. In the 17th century, John Bulwer and George Sibscota, both interested in the deaf and their education, applied the bone conduction phenomenon as an aid to defective hearing. Soon, independent reports from Germany, France, and Italy also described bone conduction rod devices as aids to impaired hearing. In 1879, the Audiphone, a hearing fan that operated by bone conduction, was patented. The invention of the Audiphone triggered the development and sale of a number of similar devices that had considerable popularity until the invention of the carbon-electric hearing aid in the early 1900s.     

Bone conduction speech audiometry in normal subjects

The present study was designed to investigate: (1) the relationship among bone conduction (BC) pure tone averages, BC speech reception thresholds (SRTs), and BC speech detection thresholds for normal subjects; (2) short term reliability of BC SRTs; and (3) characteristics of the articulation functions for spondees obtained by bone conduction. Twenty-five normal-hearing young adults participated. The data revealed that BC SRT-pure tone average and SRT-speech detection threshold relationships are essentially the same as for air conduction. A comparison of the articulation functions for air conduction and BC revealed no practical difference between the two modes of stimulus presentation.     

The effects of coenzyme Q10 treatment on maternally inherited diabetes mellitus and deafness, and mitochondrial DNA 3243 (A to G) mutation

Little is known about cisplatin ototoxicity in pediatric patients. Measurement of otoacoustic emissions is a rapid, reproducible, objective method of evaluating hearing. We examined whether transient-evoked otoacoustic emissions in pediatric patients exposed to cisplatin in the past correlated with audiographic findings. Twelve patients were entered into the study (mean age at treatment 7.8 years, mean cumulative dose 442.5 mg/mm2, mean 7.1 doses). Hearing at 3000 Hz was preserved in 82.6% of patients. In the higher frequencies significant sensorineural hearing loss was noted: 43.5% at 4 kHz; 81.0% at 6 kHz; and 90.5% at 8 kHz. Transient-evoked otoacoustic emissions were measurable in 11 of 12 patients. Middle ear disease accounted for abnormal otoacoustic emission seen in three patients (1 with effusion, 2 with significant negative middle ear pressure). When the middle ear was normal, a statistically significant correlation was seen between the transient-evoked otoacoustic emissions reproducibility and pure-tone threshold (correlation coefficient = -0.69, p = 0.008). Increased hearing loss was also associated with young age at first dose of cisplatin (p = 0.044), high number of chemotherapy cycles (p = 0.042), and high cumulative dose (p = 0.042).     

Estimation of the benefit of bone-anchored hearing aids

Implantable bone conduction hearing aids are a valuable alternative to conventional aids for those who cannot use a conventional air conduction aid or find it difficult to use because of an aural discharge, most commonly due to chronic otitis media. Previously reported series of the use of a bone-anchored hearing aid (BAHA) come from the originators of this device, and an independent report of their benefit and use, especially in previous air conduction aid users, would be of value. Twenty-three patients were evaluated at least 6 months after implantation of a BAHA. All 7 previous bone conduction aid users were delighted with their BAHA, reporting increased comfort and hearing benefit that was backed by audiometric evidence. Of the 16 individuals who previously used an air conduction aid, 11 (69%) were delighted users of their BAHA. Unfortunately, the other 5 (31%) reverted to solely using their air conduction aid. There was no obvious predictor as to how these individuals might have been identified prior to implantation. In particular, their pure tone thresholds, especially the bone conduction thresholds, were no different from those of the 11 BAHA users. However, in free field audiometry, the users gained superior benefit from their BAHA compared to their air conduction aid, whereas the nonusers did not. In conclusion, in all series to date, previous users of a conventional bone conduction aid have been delighted users of a BAHA and have gained superior audiometric benefit. This is not necessarily the case with previous air conduction aid users.(ABSTRACT TRUNCATED AT 250 WORDS)     

The electrophysiological indices of the state of the different sections of the auditory analyzer in persons with a normal voice and with functional voice disorders]

Individuals with normal voice and patients with voice functional impairments undergone electrophysiological investigation of various parts of the hearing system, using tone audiometry, including the extended frequency band (10, 12, 14 and 16 kHz), as well as short- and long-latency acoustic evoked potentials (SLAEP and LLAEP). It was found out, that individuals with voice functional impairments had all of their hearing system's parts impaired to various extent, with more marked impairments in the central, rather than in the peripheral part of the hearing system. It was shown, that hearing at 4-8 kHz, as well as with the extended frequency band, especially at 14-16 kHz, time patterns of acoustic evoked potentials (latencies of waves III and V of SLAEP, the interpeak interval I-V, as well as the latency periods of the LLAEP components P2 and N2) could be useful in professional selection of individuals of voice and speech professions and for solving labor expertise matters. Of those individuals with normal voice but systematic vocal stress, 17.5% had impaired hearing at 14 and 16 kHz, as well as significant latency prolongation of the LLAEP wave N2 with tone stimulation at 1 and 4 kHz. Apparently, individuals of voice and speech professions should be referred to as the "risk" group. It may well be, that extended band audiometry and acoustic evoked potentials time patterns could be useful in determining the thresholds between the normality and pathology in voice dysfunctions.     

Blood pressure measurement. Criteria employed in scientific articles published in Brazilian journals]

OBJECT: To investigate whether hand-arm vibration and noise have a combined effect on temporary threshold shift (TTS) of hearing among healthy subjects. METHOD AND DESIGN: Nineteen healthy subjects with an average age of 25.7 (SD 7.7) years were exposed to vibration (30 m/s2, 60 Hz), noise [90 dB(A)] and both, respectively. The subject's right hand was placed on the plate of a vibrator and the right ear exposed to noise via headphones. Subjects were exposed to vibration and/or noise for 3 min and after a 1-min pause the exposure was repeated five times. Hearing thresholds at 1, 4 and 6 kHz were measured during the time periods before, between (during pauses) and after exposure. RESULTS: Exposure to vibration alone caused almost no hearing threshold changes at every frequency tested. But exposure to noise or a combination of vibration and noise caused a significant increase in TTSs at 4 and 6 kHz. Moreover, exposure to a combination of vibration and noise caused significantly higher TTSs than exposure to noise at 4 and 6 kHz. CONCLUSION: The present results demonstrate the combined effects of hand-arm vibration and noise can enhance exposure to hand-arm vibration and noise can enhance the TTS of hearing more than noise exposure, though hand-arm vibration alone may hardly affect TTS.     

Transient evoked otoacoustic emissions in patients with normal hearing and in patients with hearing loss

OBJECTIVES: 1) To evaluate transient evoked otoacoustic emission (TEOAE) test performance when measurements are made under routine clinical conditions. 2) To evaluate TEOAE test performance as a function of frequency and as a function of the magnitude of hearing loss. 3) To compare test performance using univariate and multivariate approaches to data analyses. 4) To provide a means of interpreting clinical TEOAE measurements. DESIGN: TEOAEs were measured in 452 ears of 246 patients. All measurements were made after acoustic immittance assessments, which were used to demonstrate that middle-ear function was normal at the time of the TEOAE test. TEOAE amplitudes and signal to noise ratios (SNRs), analyzed into octave bands centered at 1, 2, and 4 kHz, were compared with the pure-tone threshold at the same frequencies. Data were analyzed with clinical decision theory, cumulative distributions, discriminant analyses, and logistic regressions. RESULTS: Using univariate analysis techniques, TEOAEs accurately identified auditory status at 2 and 4 kHz but were less accurate at 1 kHz. Test performance was best when audiometric thresholds between 20 and 30 dB HL were used as the criteria for normal hearing. TEOAE SNR resulted in better test performance than did TEOAE amplitude alone; this effect decreased as frequency increased. Multivariate analysis methods resulted in better separation between normal and impaired ears than did univariate approaches, which relied on only TEOAE amplitude or SNR when test frequency band and audiometric frequency were the same. This improvement in test performance was greatest at 1 kHz, decreased as frequency increased, and was negligible at 4 kHz. CONCLUSIONS: TEOAEs can be used to identify hearing loss in children under routine clinical conditions. Univariate tests accurately identified auditory status at mid and high frequencies but performed more poorly at lower frequencies. The decrease in performance as frequency decreases may be a result of increased noise at lower frequencies but also may be due to properties of the measurement paradigm ("QuickScreen," high-pass filter at 0.8 kHz), which would not be ideal for recording energy around 1 kHz. The improvement in test performance when SNR was used and the interaction of this effect with frequency, however, would be consistent with the view that test performance in lower frequencies is at least partially influenced by the level of background noise. Multivariate analysis techniques improved test performance compared with the more traditional univariate approaches to data analysis. An approach is provided that allows one to assign measured TEOAE amplitudes, SNRs, or outputs from multivariate analyses to one of three categories: response properties consistent with normal hearing; results consistent with hearing loss; hearing status undetermined.     

Prognostic factors for hearing preservation following observation-only versus stereotactic irradiation (STI) in patients with acoustic neuroma

Prognostic factors for hearing preservation following observation-only versus STI were compared in patients with acoustic neuroma. There were 48 patients with acoustic neuroma treated by fractionated STI. Between 1991 and 1997, patients were given 36 Gy in 20 fractions over 5 weeks (36 Gy/20 Fr/5 wks) to 44 Gy/22 Fr/6 wks followed by a 4 Gy boost. A linear accelerator was used for irradiation. Twenty-three patients with acoustic neuroma who were followed without any treatment (observation-only group) were selected as matched controls. The largest hearing loss was observed at the frequency of 2 kHz in the observation-only group and at 1-2 kHz in the STI group. Hearing loss at 1 kHz was more frequent in the STI group (p < 0.01). There were no significant prognostic factors which predicted hearing preservation in the observation-only group. Stereotactic irradiation has been suggested to damage to cochlear nerve function in patients whose cochlear nerve had been impaired already. Tumor control rate of STI appeared to be as good as single fraction radiosurgery rates in the literature and better than in the observation-only group. Hearing preservation rate in the STI group was as good as in the observation-only group and appeared to be better than single fraction radiosurgery. In conclusion, because there were no factors predictive of hearing preservation in the observation-only group, it is difficult to select patients for observation only. Fractionated STI is potentially the treatment of choice, resulting in the same hearing preservation rate as achieved with observation only, although longer follow-up periods are needed.     

Hearing and vocalizations of wild-caught Australian budgerigars (Melopsittacus undulatus).

This study examined the hearing and contact calls of wild-caught Australian budgerigars (Melopsittacus undulatus) and compared these data to hearing and vocalizations in the much more extensively studied domesticated budgerigar. The spectral energy in the contact calls of both wild-caught and domesticated budgerigars falls almost exclusively in the frequency of 2–4 kHz. Absolute and masked thresholds were similar in both groups of birds. Similar to the results found in domesticated birds, critical ratio functions for the wild-caught budgerigars decreased at frequencies of 1.0 kHz–2.86 kHz and then increased again dramatically at frequencies above 2.86 kHz. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hearing in a megachiropteran fruit bat (Rousettus aegyptiacus).

The Egyptian fruit bat (Rousettus aegyptiacus) is one of the few megachiropteran bats capable of echolocation. However, it uses rudimentary tongue clicks rather than laryngeally produced echo calls. We determined the audiogram of 2 bats using a conditioned avoidance procedure with fruit puree reward. At an intensity of 60 dB sound pressure level, the bats' hearing extended from 2.25 kHz to 64 kHz, with a region of good sensitivity between 8 kHz and 45 kHz. A dip in sensitivity at 32 kHz appears to be due to pinna directionality. The hearing of Egyptian fruit bats is typical for a mammal of that size and is not as limited as previously reported. Methodological issues, specifically training an animal to listen for low-intensity signals and imposing a significant cost for failing to report signals (i.e., misses), are discussed as the basis for the discrepancy between our results and earlier reports. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cost of illness: an inextricable maze or an aid in decision making? The case of schizophrenia

Distortion-product otoacoustic emissions (DPOAEs) are still undergoing evaluation for clinical use. Although the effects of ageing on otoacoustic emissions have been studied quite extensively in the past, DPOAE response-growth or input-output (I-O) measures, which are well suited as an objective method for monitoring cochlear function at specific frequencies, have been less thoroughly examined. The aim of the present study was to assess the 2f1-f2 DPOAEs in a clinical setting in order to examine the response of 20 normally hearing middle-aged adults and to compare the results with those of 20 people of the same age with ears of sensorineural high-frequency hearing loss (HL). The experiment consisted of two stages. First, the DPOAE-gram was recorded in 1-4-octave steps at a stimulus level of 70 dB SPL over a frequency range of the f2 primary tone which extended from 1.001 to 6.299 kHz. Secondly, in order to elicit DPOAE I-O functions, the two primary stimuli were presented at equilevel intensities ranging from 20 to 71 dB SPL. The stimulus-level step size was 3 dB. The I-O functions were recorded at five separate DPOAE frequencies, with the f2 frequency most closely related to the clinical audiogram (f2 = 1.0, 1.5, 2.0, 4.0 and 6.0 kHz). Two clearly separated portions in the form of the I-O function for normally hearing ears were found. The first portion, in response to primary levels of 60 dB SPL and below, showed a plateau (saturating) behaviour. If primary levels exceeded 60 dB SPL, I-O functions became more linear. The attenuation of the saturation portion of the I-O function in ears with high-frequency HL across the frequency-test range is difficult to explain because elevated behavioural thresholds were observed only for frequencies > 1.5 kHz. Thus, the more linear I-Os associated with the hearing-loss frequencies may indicate deficiencies in the active properties of outer hair cells (OHCs), whereas those for I-Os < 1.5 kHz, where hearing was normal, may indicate a beginning of damage to active OHC micromechanical processes prior to their clinical manifestation. DPOAE recordings from people with high-frequency HL, possibly age-related, supplement recordings of TEOAEs and give complementary information on degenerative changes in the outer hair-cells. DPOAE I-O functions may reveal discrete pathological alterations both in the active cochlear signal processing and in the passive mechanisms of the cochlea prior to their detection by clinical audiometric tests.     

Are aminoglycoside antibiotics excitotoxic?

Guinea pigs received gentamicin to induce a profound hearing loss (61 dB auditory threshold shift at 18 kHz). Concomitant administration of maleic or tartaric acid dissolved in dimethyl sulfoxide (DMSO) significantly reduced the threshold shift to < 40 dB. The results have several important implications. First, they support the hypothesis of a free-radical mechanism of gentamicin toxicity since the protective compounds are metal chelators and scavengers. Second, they caution against these and similar chemicals, commonly found in drug preparations, as vehicles in tests of aminoglycoside toxicity. For example, a recent study by others describing attenuation of aminoglycoside ototoxicity by NMDA antagonists may have been influenced by the presence of maleate, tartrate and DMSO. Third, they suggest simple antioxidants as a potentially efficient and inexpensive clinical prophylaxis of aminoglycoside-induced hearing loss.     

Hearing in large mammals: Horses (Equus caballus) and cattle (Bos taurus).

Determined behavioral audiograms for 3 horses and 2 cows. Horses' hearing ranged from 55 Hz to 33.3 kHz, with a region of best sensitivity from 1 to 16 kHz. Cattle hearing ranged from 23 Hz to 35 kHz, with a well-defined point of best sensitivity at 8 kHz. Of the 2 species, cattle proved to have more acute hearing, with a lowest threshold of –21 db (re 20 μN/m–2) compared with the horses' lowest threshold of 7 db. Comparative analysis of the hearing abilities of these 2 species with those of other mammals provides further support for the relation between interaural distance and high-frequency hearing and between high- and low-frequency hearing. (39 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modulation of prepulse inhibition by an augmented acoustic environment in DBA/2J mice.

DBA/2J (DBA) mice exhibit progressive hearing loss, evident for high frequencies (>20 kHz) at age 3–4 weeks and severe by 12–16 weeks. From age 25 days to 12 weeks, DBA mice were exposed for 12 hr nightly to an augmented acoustic environment (AAE): moderately intense broadband noise bursts. After AAE treatment, prepulse inhibition (PPI) to tone prepulses (4–24 kHz, 70 dB SPL) was stronger, and baseline acoustic startle responses were larger, compared with results for age-matched DBA mice (testing performed with AAE off). Nightly AAE treatment was then terminated, and both AAE effects were largely gone 1 week later. Reinstatement of AAE treatment after the 4-week period had no significant effect on startle magnitude, but PPI improved significantly, with the AAE effect reacquired after 3 weeks. It is proposed that AAE modulates neural plasticity induced by high-frequency hearing loss in auditory system components of the PPI pathway. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hearing in two cricetid rodents: Wood rat (Neotoma floridana) and grasshopper mouse (Onychomys leucogaster).

Investigated the degree to which both general and specific selective pressures have played a role in the evolution of hearing in wood rats and grasshopper mice. The audiograms of 2 wood rats and 3 grasshopper mice were determined with a conditioned avoidance procedure. The wood rats were able to hear tones from 940 Hz to 56 kHz at a level of 60 db sound pressure level (SPL), with their best sensitivity of –3 db occurring at 8 kHz. The hearing of the grasshopper mice ranged from 1.85 to 69 kHz at 60 db (SPL), with their best sensitivity of 9 db also occurring at 8 kHz. Results support the relation between interaural distance and high-frequency hearing and between high- and low-frequency hearing. The inability of the grasshopper mouse and other desert rodents such as kangaroo rats and gerbils to hear low frequencies demonstrates that not all rodents in deserts have developed good low-frequency hearing. (65 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interleukin 8 can affect inner ear function

The chemokine interleukin 8 (IL-8) was instilled into the round window niche of rats through a small perforation in the tympanic membrane in order to study its effect on inner ear function by electrophysiological and morphological techniques. The frequency-specific auditory brainstem response (ABR) was recorded at the frequencies 4, 8, 10, 12, 16 and 20 kHz just before and 1, 2, 5 and 14 days after instilling IL-8 to ascertain the hearing level during each interval. Morphological examination by light microscopy was performed during the same interval following the instillation of IL-8. On day 1, the rise in ABR threshold was within 5 dB SPL (non-significant elevation). However, a significant threshold elevation (above 5 dB SPL) occurred in high-frequency areas (16 and 20 kHz) on day 2, and in middle frequency areas (10 and 12 kHz) on day 5 with sensorineural hearing loss type intensity-latency curves. By day 14, the elevated thresholds had returned to pre-instillation levels. In the lowest areas (4 and 8 kHz), no significant threshold elevation was detected at any time during the observation period. By light microscopy, on day 1, clusters of inflammatory cells (predominantly neutrophils) were observed just outside the round window membrane (RWM), while only a few neutrophils were detected in the cochlea. These cells were still present outside the RWM on day 2. The neutrophils had disappeared by day 5 and only macrophages were present on the middle ear side of the RWM. However, throughout the observation period, the organ of Corti and stria vascularis appeared to be intact. These results suggest that IL-8 in the middle ear cavity is able to influence inner ear function.