Mild High-frequency Hearing Loss Research Articles

Audiometric characteristics of hyperacusis patients.

Hyperacusis is a frequent auditory disorder where sounds of normal volume are perceived as too loud or even painfully loud. There is a high degree of co-morbidity between hyperacusis and tinnitus, most hyperacusis patients also have tinnitus, but only about 30–40% of tinnitus patients also show symptoms of hyperacusis. In order to elucidate the mechanisms of hyperacusis, detailed measurements of loudness discomfort levels (LDLs) across the hearing range would be desirable. However, previous studies have only reported LDLs for a restricted frequency range, e.g., from 0.5 to 4 kHz or from 1 to 8 kHz. We have measured audiograms and LDLs in 381 patients with a primary complaint of hyperacusis for the full standard audiometric frequency range from 0.125 to 8 kHz. On average, patients had mild high-frequency hearing loss, but more than a third of the tested ears had normal hearing thresholds (HTs), i.e., ≤20 dB HL. LDLs were found to be significantly decreased compared to a normal-hearing reference group, with average values around 85 dB HL across the frequency range. However, receiver operating characteristic analysis showed that LDL measurements are neither sensitive nor specific enough to serve as a single test for hyperacusis. There was a moderate positive correlation between HTs and LDLs (r = 0.36), i.e., LDLs tended to be higher at frequencies where hearing loss was present, suggesting that hyperacusis is unlikely to be caused by HT increase, in contrast to tinnitus for which hearing loss is a main trigger. Moreover, our finding that LDLs are decreased across the full range of audiometric frequencies, regardless of the pattern or degree of hearing loss, indicates that hyperacusis might be due to a generalized increase in auditory gain. Tinnitus on the other hand is thought to be caused by neuroplastic changes in a restricted frequency range, suggesting that tinnitus and hyperacusis might not share a common mechanism.

Effect of Intratympanic Steroid Administration on Sensorineural Hearing Loss Associated with Acute Otitis Media

Objectives: Sensorineural hearing loss associated with acute otitis media (acute infective sensorineural hearing loss [AISNHL]) is a well-recognized but rare phenomenon with no accepted treatment pathway. Our objectives were to (1) evaluate the effects of intratympanic steroid (ITS) administration on AISNHL and (2) analyze factors which may be associated with a favorable outcome following ITS. Methods: A retrospective case note review of 7 consecutive patients (5 men, 2 women) seen between November 2006 and October 2013 and diagnosed with AISNHL was performed. Patients were prescribed 7 days of oral antibiotics and prednisolone and offered ITS thereafter if there was no improvement. Up to 3 intratympanic injections of methylprednisolone (40 mg/mL) were administered. Results: Patients were considered to have a significant improvement in their hearing if average change in threshold was equal to or greater than 10 dB following ITS. This was the case in 57% (4/7) of patients. The mean improvement in threshold was 24 dB (range 10-52 dB) in these responders. Three-fourths of responders had a mild high frequency hearing loss. Responders had a smaller sensorineural loss at presentation (responders mean 39 dB pre-ITS,15 dB post-ITS; nonresponders mean 65 dB pre-ITS, 83 dB post-ITS), presented earlier (4 days, range 3-6 days versus 12 days, range 2-21 days) and received their first ITS earlier (24 days, range 13-37 days versus 35 days, range 24-42 days) than nonresponders. Conclusions: ITS may provide a valuable contribution to the treatment of SNHL in acute otitis media. A larger study looking at timing of intratympanic administration after antibiotics and/or oral steroid treatment would be beneficial.

Efficient Hearing Screening in Noise-Exposed Listeners Using the Digit Triplet Test

Hearing screening in occupational medicine is generally based on pure-tone threshold audiometry. However, reliable and valid thresholds can only be obtained in a sound-proof room, using a high-quality, well-calibrated audiometer, and by a well-trained administrator. Thresholds also need to be determined for several audiometric frequencies. This makes the test time-consuming and expensive, which is not ideal for the screening of large populations. A Speech-In-Noise test (SPIN), by contrast, does not have the abovementioned requirements. Because it can be implemented as a quick automated self-test, possibly over the Internet, a SPIN test is highly advantageous for screening purposes. However, its sensitivity for (isolated) high-frequency hearing loss, as typically seen in noise-exposed listeners, was unclear up to present. In this study, the authors investigated the sensitivity and specificity of the Digit Triplet SPIN test for detecting and monitoring (early-stage) high-frequency hearing loss, and its similarity across two different language versions. One-hundred eighteen noise-exposed workers, representing a wide range from no to severe high-frequency hearing loss, completed the French or Dutch version of the broadband Digit Triplet self-test in an office-like room. Pure-tone thresholds, collected by a professional audiologist in favorable settings, served as the reference. The 84 Dutch-speaking participants showed a very strong linear relation between the reference and the Digit Triplet test, with the pure-tone average at 2, 3, 4, and 6 kHz as a strong predictor (R = 0.86) for the speech-reception threshold. The sensitivity and specificity to detect mild high-frequency hearing loss were 92% (61 of 66) and 89% (16 of 18), respectively. The area under the receiver operating characteristic (ROC) curve was very high (≥0.91) for several degrees of high-frequency hearing loss. With a within-subject standard deviation of only 0.8 dB, the Digit Triplet test also had a low measurement error. The results of the 34 French-speaking subjects showed a highly similar trend. The Digit Triplet test proves to have a high sensitivity and specificity for detecting different degrees of high-frequency hearing loss. Given its ease of use, this test is very suitable for screening purposes in occupational medicine, and potentially for the screening of adolescents at risk of recreational noise-induced hearing loss.

Reversible Induction of Phantom Auditory Sensations through Simulated Unilateral Hearing Loss

Tinnitus, a phantom auditory sensation, is associated with hearing loss in most cases, but it is unclear if hearing loss causes tinnitus. Phantom auditory sensations can be induced in normal hearing listeners when they experience severe auditory deprivation such as confinement in an anechoic chamber, which can be regarded as somewhat analogous to a profound bilateral hearing loss. As this condition is relatively uncommon among tinnitus patients, induction of phantom sounds by a lesser degree of auditory deprivation could advance our understanding of the mechanisms of tinnitus. In this study, we therefore investigated the reporting of phantom sounds after continuous use of an earplug. 18 healthy volunteers with normal hearing wore a silicone earplug continuously in one ear for 7 days. The attenuation provided by the earplugs simulated a mild high-frequency hearing loss, mean attenuation increased from <10 dB at 0.25 kHz to >30 dB at 3 and 4 kHz. 14 out of 18 participants reported phantom sounds during earplug use. 11 participants presented with stable phantom sounds on day 7 and underwent tinnitus spectrum characterization with the earplug still in place. The spectra showed that the phantom sounds were perceived predominantly as high-pitched, corresponding to the frequency range most affected by the earplug. In all cases, the auditory phantom disappeared when the earplug was removed, indicating a causal relation between auditory deprivation and phantom sounds. This relation matches the predictions of our computational model of tinnitus development, which proposes a possible mechanism by which a stabilization of neuronal activity through homeostatic plasticity in the central auditory system could lead to the development of a neuronal correlate of tinnitus when auditory nerve activity is reduced due to the earplug.

Outcome of bone-anchored hearing aids for single-sided deafness: A prospective study

Conclusion: The bone-anchored hearing aid (BAHA) system can offer significant benefits to patients with single-sided deafness (SSD), primarily by lifting the head shadow effect. Objective: To evaluate the efficacy of BAHA for SSD by comparing pre- and postoperative speech, spatial and qualities of hearing scale (SSQ) scores. Methods: This was a prospective study conducted within a tertiary auditory implant department. The inclusion criteria were unilateral profound hearing loss with normal or mild high frequency hearing loss in the hearing ear (pure tone average better than or equal to 25 dBHL measured at 0.5, 1, 2 and 3 kHz) and subjective benefits reported by patients following a home trial with a BAHA Softband. Patients who met the above criteria and opted for surgery were asked to complete the SSQ questionnaire. The postoperative SSQ response was collected after at least 6 months of consistent BAHA usage. Results: This study included 25 adult patients (mean age at implantation 57.5 years). There was a statistically significant improvement in the average SSQ score in all three sections of the questionnaire with the use of the BAHA. Our patients experienced most marked benefits in speech hearing in challenging listening situations. All patients remain consistent users and there has been no explantation to date.

Tympanic Membrane Perforation and Hearing Loss From Blast Overpressure in Operation Enduring Freedom and Operation Iraqi Freedom Wounded

Tympanic membrane perforation is the most common primary blast injury in the current conflicts and occurs in approximately one tenth of service members wounded by combat explosions. We wanted to determine the severity of perforation and its effect on hearing and combat readiness. This analysis is a retrospective study of US service members injured in combat explosions in Afghanistan or Iraq and treated at our institution between March 2003 and July 2006. Data captured included location and grade of perforation, symptoms, healing rates, audiogram results, need for hearing aids, and loss of eligibility for military service. Of 436 explosion-wounded patients admitted to our facility, 65 (15%) patients had tympanic membrane perforation diagnosed by the otolaryngology service. A total of 97 tympanic membrane perforations occurred among 65 patients. The average surface area involved was 41% +/- 32% (right) and 35% +/- 34% (left). More than one third of perforations were grade 4. The most common locations were central and anterior-inferior. Most (83%) patients reported symptoms, most commonly diminished hearing (77%) and tinnitus (50%). Outcome data were available for 77% of perforations. Spontaneous healing occurred in 48%. The remainder (52%) had surgical intervention. The most common audiogram abnormality was mild high frequency hearing loss. Ultimately, three patients (5%) required hearing aids and one discharge from military service. Tympanic membrane perforation occurs in 16% of explosion-injured patients. Most patients are symptomatic and many have large perforations requiring operative intervention. Long-term hearing loss is uncommon but does impact ability to continue military service.

Word recognition in competing babble and the effects of age, temporal processing, and absolute sensitivity.

This study was designed to clarify whether speech understanding in a fluctuating background is related to temporal processing as measured by the detection of gaps in noise bursts. Fifty adults with normal hearing or mild high-frequency hearing loss served as subjects. Gap detection thresholds were obtained using a three-interval, forced-choice paradigm. A 150-ms noise burst was used as the gap carrier with the gap placed close to carrier onset. A high-frequency masker without a temporal gap was gated on and off with the noise bursts. A continuous white-noise floor was present in the background. Word scores for the subjects were obtained at a presentation level of 55 dB HL in competing babble levels of 50, 55, and 60 dB HL. A repeated measures analysis of covariance of the word scores examined the effects of age, absolute sensitivity, and temporal sensitivity. The results of the analysis indicated that word scores in competing babble decreased significantly with increases in babble level, age, and gap detection thresholds. The effects of absolute sensitivity on word scores in competing babble were not significant. These results suggest that age and temporal processing influence speech understanding in fluctuating backgrounds in adults with normal hearing or mild high-frequency hearing loss.

Effects of a 2- to 4-week course of repetitive transcranial magnetic stimulation (rTMS) on neuropsychologic functioning, electroencephalogram, and auditory threshold in depressed patients

Background: The safety of repetitive transcranial magnetic stimulation (rTMS) has only previously been formally studied in volunteers receiving a single session of stimulation or in a small number of depressed subjects receiving a 2-week treatment course. This study examined safety issues in depressed subjects receiving up to 4 weeks of rTMS. Efficacy results from this study have been previously reported. Methods: Eighteen subjects with DSM-IV major depression participated in a 2-week, parallel, double-blind, sham-controlled study of rTMS treatment. Twelve subjects then went on to receive 4 weeks active rTMS in an open follow-up. We examined the effects of rTMS on neuropsychologic function (up to 4 weeks), auditory threshold (up to 6 weeks exposure to rTMS noise), and an electroencephalogram (after 2 weeks). Data were analyzed by repeated measures analysis. Results: There were trends for improvement in neuropsychologic performance, probably due to practice effects. No mean changes in auditory threshold occurred, but two patients showed mild high-frequency hearing loss after several weeks of rTMS. Electroencephalograms in two patients, one of whom had sham stimulation, showed minor abnormality. Conclusions: No significant mean deficits were demonstrated in this cohort. Overall, rTMS for up to 4 weeks is safe, but individual results suggest caution and the need for further investigation of the safety of several weeks of rTMS.

Delayed and Progressive Hearing Loss after Microvascular Decompression of Cranial Nerves

An unusual case of unilateral delayed and progressive hearing loss following a microvascular decompression operation on cranial nerves V, VII, and VIII on the left side is reported. Preoperative and postoperative audiologic evaluation revealed a mild high-frequency hearing loss for both ears, normal thresholds for the acoustic middle ear reflex response, and normal brain stem auditory evoked potentials. Three years after this microvascular decompression procedure, the patient noticed slowly decreasing hearing in her left ear, and subsequent serial audiograms revealed a progressive sensorineural hearing loss and a decrease in her speech discrimination score. Brain stem auditory evoked potentials showed progressive changes. Because of the patient's increasing symptoms of vertigo and tinnitus in the left ear, reexploration of the eighth cranial nerve was performed 5 1/2 years after the initial procedure. This second operation revealed reactive tissue around the eighth cranial nerve that was atrophic and yellow. We interpret the delayed and progressive hearing loss to be a result of reactive scar tissue and progressive atrophy of the auditory nerve.

The spectral center of gravity effect and auditory filter bandwidth

The spectral center of gravity refers to a listener’s averaging of frequency and intensity components when formant peaks in a speechlike signal are separated by 3.5 Bark units or less. In this paper a total of 18 synthetic vowels whose spectra approximated /ae/ or /inverted vee/ were generated digitally; each stimulus contained the first 40 harmonics of a 100-Hz fundamental. Nine spectra contained three formants, while the balance contained only two. Subjects with normal hearing and mild high-frequency hearing loss above 3000 Hz were instructed to identify synthetic vowels as either /ae/ or /inverted vee/ as F2 frequency was varied between nine different values in 100-Hz steps for both the two-formant and three-formant stimuli. Probit analysis indicated that the normal-hearing subjects identified stimuli more consistently than the mildly hearing-impaired listeners across F2 frequencies for three-formant than for two-formant spectra. The F2 frequency corresponding to the perceived increase in vowel frontness occurred at a lower frequency for normal-hearing listeners. Auditory filter bandwidth was negatively correlated with the F3−F2 Bark difference. Results suggest that spectral averaging may help listeners disambiguate confusing speech signals.

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805 AMIKACIN (AM) AND TICARCILLIN (TI) AS EMPIRIC THERAPY IN FEBRILE NEOTROPENIC CHILDREN WITH CANCER

Efficacy and toxicity of Am (600 mg/M2/d IV) and Ti (12 gm/M2/d IV) as empiric therapy were evaluated in 46 febrile neutropenic (≤1000 PMNs/mm3) children with cancer. Documented infection (DI), clinically apparent infection (CA), possible infection (PI) and doubtful infections (DOI) were evaluated as follows: Bacterial pathogens identified were E. coli-5, P. aeurginosa-2, Klebsiella sp.-2, Serratia sp-1, Staph. sp.-5 and Strep. sp.-1. The 4 non-responders did not have documented infections. Blood urea nitrogen, creatinine, creatinine clearance, potassium and urine analysis obtained before and after antibiotic therapy showed no significant differences. Comparisons of mean peak/trough serum levels of Am obtained on day 2 (23.9/< 2μg/ml) and day 5 (24.2/< 2μg/ml) showed no accumulation. Two of 23 paired audiograms obtained early in the course of and after Am therapy showed transient mild high frequency hearing loss. Am and Ti have low toxicity, are well tolerated and are adequate empiric therapy for the febrile neutropenic child.