The benefit of hearing aids: influence of hearing loss and age

The relation between accessible benefit and hearing loss in combination with age of the patient is analysed. The degree of hearing loss and improvement derived by hearing aid use as found in this work is based on the individually determined speech reception threshold (SRT) for the condition with and without hearing aid in a noiseless environment. It was found that a significant correlation exists between hearing loss and SRT gain by the hearing aid (difference between unaided and aided speech reception threshold) for a pure-tone hearing loss of less than 40 dB at 500 Hz, irrespective of age, whereas for a hearing impairment of 40-60 dB, the gain by using the hearing aid is dependent on the age of the patient. A multiple regression analysis was performed to study the relation between benefit and hearing loss for the two groups of hearing impairment and different age groups.     

Glucocorticoid influence on prognosis of idiopathic sudden sensorineural hearing loss

IntroductionIdiopathic Sudden Sensorineural Hearing Loss (ISSHL) is defined when a loss of at least 30 dB occurs in over 3 continuous frequencies, in up to 72 hours, of which etiology is not established, despite adequate investigation. Different types of treatment regimens have been proposed, but only glucocorticoids have shown some evidence of benefit in the literature.ObjectiveTo analyze whether the type of treatment or time of treatment with glucocorticoids have any influence on hearing recovery in ISSHL.MethodsObservational retrospective cohort study. One hundred twenty-seven patients with ISSHL, treated at outpatient clinics between the years 2000 and 2010, were studied. We evaluated the prognostic correlation of the type of treatment and time to treatment with glucocorticoids and ISSHL.ResultsThe absolute hearing gain and the relative hearing gain was as follows: 23.6 dB and 37.2%. Complete recovery was observed in 15.7% of patients, significant recovery in 27.6% and recovery in 57.5%.ConclusionIn this study, there was no difference between the use and nonuse of glucocorticoids in hearing improvement. However, when started within seven days after onset, the use of glucocorticoids was a factor of better prognosis.     

The influence of conductive hearing loss on DPOAE-threshold. The effect of an individually optimized stimulation

BACKGROUND: The DPOAE-threshold, estimated from extrapolated I/O functions, allows an objective assessment of the mechanical sensitivity of the inner ear. In children, the specificity of this diagnostic tool is impaired by conductive hearing loss. METHODS: In this study, we propose an individual optimization of the primary tone level ratio. This procedure allows the detection of a conductive hearing loss that can be accounted for when estimating the DPOAE-threshold. By means of a simulation using DPOAE-data from 22 normally hearing subjects, the effects of this procedure on the estimation of the DPOAE-threshold are examined. RESULTS: An individually optimized DPOAE stimulation distinctly improves the signal-to-noise ratio of the DPOAE which enables an estimation of the DPOAE-threshold for sound conductive losses up to 15 dB. The DPOAE-threshold only worsens in individual cases. CONCLUSIONS: An individually optimized stimulation paradigm may improve the specificity of inner ear diagnostics with the DPOAE-threshold. A clinical evaluation of the method in children, however, is necessary.     

The effect of type of hearing loss on hearing aid use

This study examined the effect of type of loss and reduced PB discrimination on hours of daily hearing aid wear. Patient data were entered in one of four matrices designed to permit examination of one variable while balancing the effects of other variables. When the influences of amount of hearing loss, age, hearing aid experience, and employment status were balanced, no evidence was found that type or shape of loss influenced the number of hours of daily hearing aid use. When the data for each type/shape of loss were pooled without regard to amount of loss, age, aid experience, and employment status, hours of reported wear were least for those with normal hearing in the better ear (8 hours) and most for those with conductive components (15.8 hours). Since patients with conductive components had the largest hearing losses, it was concluded that hours of wear are influenced primarily by amount, not type of loss. Discrimination scores were examined within the same balanced design. Although PB max scores for patients with conductive components were systematically higher than scores for patients with sensorineural losses, the reported wear times were essentially the same. Previous findings that sensorineural hearing loss and reduced speech discrimination adversely influenced hearing aid wear were attributed to differences in amount of loss and other intervening psycho-socio-vocational variables.     

Intermittent noise-induced hearing loss and the influence of carbon monoxide

Intermittent noise causes less hearing loss than continuous noise of equal intensity. The reduction in damage observed with intermittent noise may be explained by the fact that the auditory system has time to recover between the noise phases. Simultaneous carbon monoxide (CO) exposure produces greater noise-induced hearing loss than does noise alone (Chen and Fechter, 1999). In the present study, intermittent noise (octave-band with a center frequency of 13.6 kHz, 100 dB) of a 2 h total duration but with a different duty cycle (% of noise during exposure) was used. The intermittent exposure that had a shorter noise duty cycle induced a less permanent threshold shift (PTS) than those that had a longer noise duty cycle (or less rest periods). This relation between the loss in compound action potential (CAP) sensitivity and the noise duty cycle (or rest period) was abolished by the presence of CO. The cochlear microphonic (CM) amplitude revealed similar results to those seen using the CAP. While intermittent noise that had a short noise duty cycle did not cause hair cell loss by itself, the combined exposure to noise and CO (1200 ppm) caused remarkable OHC loss in the basal turn.     

Symposium on hearing loss - The otolaryngologist's responsibility.: Differential diagnosis of hearing loss.

In the practice of otolaryngology, a definite diagnosis or at least a working diagnosis should be established for all cases of hearing loss and especially sensorineural hearing loss. In this study, we described a time proven method by which the otolaryngologist can meet his responsibility for this important societal problem.     

Aspirin-induced hearing loss as a model of sensorineural hearing loss

Performance in forward-masking, temporal-integration, and gap-detection tasks was measured in five normal-hearing subjects before and during a five-day period of aspirin use. The drug regimen was 3.9 g per day, taken in four equal doses at 6-h intervals. In the subjects showing substantial temporary hearing loss induced by the aspirin. (1) forward masking declined at about a normal rate as the masker-to-signal interval was increased. (2) the temporal-integration functions were flatter than normal, and (3) detection of a temporal gap was worse than normal at low sound-pressure levels (SPLs) but was essentially normal at levels above about 60 dB SPL. These aspirin-induced changes in performance are similar to the differences observed between normal listeners and listeners with mild sensorineural hearing loss. Thus, temporary, aspirin-induced hearing loss offers promise as a model condition for sensorineural hearing loss. The advantages offered by this model include all those typically attributed to within-subjects experimental designs, as well as the ability to manipulate the amount of hearing loss. Its primary disadvantages are that the hearing loss is not asymmetrically distributed toward the high-frequency region, as it typically is with sensorineural deafness, and there are large individual differences in the amount of temporary hearing loss induced by fixed doses of aspirin.     

The development of a biologically-inspired directional microphone for hearing aids

The development of novel micro-fabrication techniques for producing a directional microphone for hearing aids is here described. The mechanisms underlying both the structure and function of these unusual microphones were originally inspired by the ears of an inconspicuous insect, the parasitoid fly Ormia ochracea. The structure of Ormia's ears inspired new approaches to design directional microphones that are more sensitive and have lower thermal noise than that typical of those using traditional approaches. The mechanisms for directional hearing in this animal are discussed along with the engineering design concepts that they have inspired, because they illustrate how basic research can inspire technology development-translational research. However, to realize the potential of bio-exploitation this microphone diaphragm concept would have been very difficult to realize without the availability of new silicon micro-fabrication technologies. Thus, this report can be viewed as an example of what may be possible with the application of new fabrication methods to microphones. Challenges and opportunities provided by the use of silicon micro-fabrication technology for microphones are discussed.     

The incidence of aminoglycoside antibiotic-induced hearing loss

The definition of ototoxicity in most clinical studies of aminoglycoside antibiotics is an increase in pure-tone threshold from a baseline audiogram greater than or equal to 15 dB at two or more frequencies, or greater than or equal to 20 dB at one or more frequencies. In this study, test-retest auditory threshold differences of this magnitude were found in a group of 20 normal volunteers who were not taking any known ototoxic drugs. Depending on which of the two criteria for ototoxicity are used, these data represent a 20% or 33% incidence of ototoxicity. We believe that many of the audiometric changes reported to represent aminoglycoside antibiotic ototoxicity may actually represent the normal test-retest variability of pure-tone audiometry. If this is true, the reported incidence of hearing loss due to aminoglycoside antibiotics may be exaggerated.     

The 5-year incidence and progression of hearing loss: the epidemiology of hearing loss study

CONTEXT: Hearing impairment affects many older adults, but the incidence is unknown. OBJECTIVE: To determine the 5-year incidence and progression of hearing impairment. DESIGN: A longitudinal, population-based study of adults aged 48 to 92 years at baseline examination. Hearing sensitivity was measured twice, 5 years apart. SETTING: Testing was conducted at the Beaver Dam Community Hospital, Beaver Dam, Wis. PARTICIPANTS: A total of 1636 participants without hearing loss and 1085 participants with hearing loss at the baseline examination in 1993-1995 were reexamined in 1998-2000. MAIN OUTCOME MEASURES: The examinations included otoscopy, screening tympanometry, and tone air- and bone-conduction audiometry. Incidence of hearing impairment was defined as a pure-tone average (PTA) of thresholds at 500, 1000, 2000, and 4000 Hz (PTA 0.5, 1, 2, and 4 kHz) greater than 25 dB HL (hearing level) in either ear at follow-up among those without hearing loss at baseline. Progression was defined as a change of more than 5 dB in the PTA 0.5, 1, 2, and 4 kHz among those with hearing loss at baseline. RESULTS: The 5-year incidence of hearing impairment was 21%. More than half of those with hearing loss at baseline experienced a decline in hearing. Age was an important risk factor for both incidence and progression. Male sex, occupation, and education were associated with the incidence of hearing loss after adjusting for age. CONCLUSIONS: Older adults have a high risk of developing hearing loss. Among those with hearing loss, most experience further declines in hearing sensitivity over time. These data indicate that hearing impairment is an important public health problem and underscore the need for appropriate hearing screening and treatment.