Otoacoustic emissions in ears with hearing loss

Fifty ears of 37 patients demonstrating several common types of hearing impairment were examined for the presence of spontaneous and evoked otoacoustic emissions to investigate the relationship of acoustic emissions to hearing pathology. Of the 50 ears, 44 exhibited various degrees of sensorineural hearing loss. Evoked otoacoustic emissions to clicks were detected in 34 of 35 sensorineural hearing loss ears with a subjective click threshold less than 55 dB SPL (25 dB nHL). None of nine ears with sensorineural hearing impairment and a subjective click threshold greater than 55 dB SPL demonstrated click-evoked emissions. Spectral analyses revealed that the constituent frequency components of evoked emissions were always within the frequency range where audiometric thresholds were less than 35 dB HL, and in the majority (94%) of cases, thresholds were less than 25 dB HL. In ears with relatively well-preserved hearing within the frequency range of click or 1.5-kHz toneburst stimuli, the basic features of evoked emissions were similar to those described for normal ears. Similarly, for ears demonstrating spontaneous otoacoustic emissions, estimated audiometric thresholds at the emitted frequencies were always less than 20 dB HL. The influence of the type of otologic pathology on acoustic emissions was studied in a subset of ears exhibiting typical high-frequency hearing losses. Ears with a noise-induced impairment showed a significant reduction in the incidence of both spontaneous emissions and spectral peaks in evoked emissions that was not evident in ears with similar patterns of hearing loss caused by other factors.     

Click- and tone-burst-evoked otoacoustic emissions in normally hearing ears and in ears with high-frequency sensorineural hearing loss

Summary Otoacoustic emissions (OAEs) evoked by clicks and tone bursts (TBs) were measured using a minor modification of the 1987 Bray and Kemp system in normal and hearing-impaired ears with high-frequency sensorineural hearing loss. Sixty ears of 60 subjects were tested. The average behavioral hearing threshold of 20 normally hearing ears was measured for the different nonlinear stimulus groups and defined as 0 dBnHL. Emissions were recorded in another 20 normally hearing ears and in 20 ears with steep high-frequency sensorineural hearing loss above 2 kHz. An unfiltered click of 80 s duration and TBs at frequencies of 0.5, 1, 2, 3, 4, 5, and 6 kHz served as stimuli. The ears with high-frequency hearing loss were clearly distinguished from the normal ears in that emission energy decreased with higher frequency stimuli above 2 kHz. The mean slopes of the response-growth functions were significantly higher at lower audiometric thresholds. The normal ears showed a slope of 0.21–0.35dB/dBnHL above 2kHz while the slope of the pathological ears was 0.04–0.13 dB/dBnHL. These differences in TBOAEs could possibly be used clinically to carry out hearing tests that are more frequency-specific than those measuring solely click-evoked OAEs. Pathological ears had emissions in the lower frequency range, where they had a normal audiometric threshold. However, these emissions had significantly far lower amplitudes at frequencies around 0.5 and 1 kHz when compared to normal ears. This reduced emission energy may indicate a cochlear impairment of the pathological ears in frequency ranges where they still had normal audiometric thresholds.Portions of this report were presented at the ADANO (Arbeitsgemeinschaft Deutscher Audiologen und Neurotologen) Meeting in Flims, Switzerland, March 29–31, 1990 Offprint requests to: R. Hauser     

Influence of well-known risk factors for hearing loss in a longitudinal twin study

Abstract

Objective: The aim was to investigate the influence of environmental exposures on hearing loss in a twin cohort. Study sample: Male twins born 1914–1958, representing an unscreened population, were tested for hearing loss at two occasions, 18 years apart. Design: Clinical audiometry and a questionnaire were performed at both time points in this longitudinal study. Noise and solvent exposure were assessed using occupational work codes and a job exposure matrix. Hearing impairment was investigated using two different pure tone averages: PTA4 (0.5, 1, 2, and 4?kHz) and HPTA4 (3, 4, 6, and 8?kHz). Results: Age affected all outcome measures. Noise exposure between time point one and two affected the threshold shifts of PTA4 and HPTA4 more in participants with a pre-existing hearing loss at time point one. Lifetime occupational noise exposure was a risk factor especially for the low-frequency hearing threshold PTA4. Firearm use was a statistically significant risk factor for all outcome measures. Conclusions: Pre-existing hearing loss can increase the risk of hearing impairment due to occupational noise exposure. An increased risk for NIHL was also seen in the group with exposures below 85?dB(A), a result that indicates awareness of NIHL should be raised even for those working in environments where sound levels are below 85?dB(A).     

Migraine increases the proportion of sudden sensorineural hearing loss: A longitudinal follow-up study

Objective

The aim of the present study was to investigate the proportion of sudden sensorineural hearing loss (SSNHL) patients in a representative population cohort with migraine.

Hearing loss in school children. A longitudinal study of sensorineural hearing impairment

In a longitudinal study, 2325 children were hearing tested at age 7, 10 and 13 with screening audiometry. The screening level was 20 dB HL. Approximately 75% of the children passed the screening level at all ages. Hearing loss was more frequent in boys than in girls at age 13 (16%:9%). The left ear was more commonly affected than the right ear. High frequency dips increased for boys with age, but not for girls. The increasing incidence of hearing loss for boys with age is probably due to noisy leisure time activities.     

Distortion-product emissions and auditory sensitivity in human ears with normal hearing and cochlear hearing loss.

Distortion product emissions (DPEs) at 2f1-f2 frequencies were measured in 53 human ears; 21 of them exhibited cochlear hearing loss. DPEs were obtained as a function of stimulus level (DPE growth curves) at seven frequency regions between 707 Hz and 5656 Hz. Several distinctly different shapes or patterns of DPE growth curves were observed. These included single-segment monotonic growth curves with and without saturation at moderate and high stimulus levels, diphasic growth curves with nulls at moderate stimulus levels, and non-monotonic growth curves with negative slopes at high stimulus levels. Low-level, irregularly shaped segments were more frequent in normal-hearing ears, suggestive of normal low-level active nonlinearities from the outer-hair-cell subsystem. High-level, steeply sloped segments were frequent in hearing-impaired ears, suggestive of residual nonlinearities from a cochlear partition without functional outer hair cells. The stimulus level at which the DPE could just be distinguished from the noise floor, the DPE detection threshold, demonstrated moderate positive correlations (r's from 0.50 to 0.81) with auditory thresholds when all ears, both normal and impaired, were considered together. Those correlations were not strong enough to quantitatively predict auditory thresholds with any great accuracy. However, DPE thresholds were able to predict abnormal auditory sensitivity with some precision. DPE thresholds correctly predicted abnormal auditory sensitivity 79% of the time in the present study, and up to 96% of the time in previous studies. These results suggest that DPE thresholds may prove useful for hearing screening in cases where cooperation from the subject is limited or where corroboration of cochlear hearing loss is required. Different patterns of DPE growth curves suggest underlying micro-mechanical differences between ears, but the differential diagnostic value of those patterns remains to be determined.     

Autoimmune sensorineural hearing loss: a preliminary experimental study

The aim of this study was to compare cochlear alterations produced by induction of anti-type II collagen antibodies with alterations produced by passive transfer of anticochlear antibodies. Guinea pigs (GP) were used. The anticochlear antibodies were obtained by injecting GP membranous cochlea plus Freund's adjuvant into rabbits. After partial purification of the immunoglobulins, the antibodies (20 mg) were injected intramuscularly into 10 normal GP. A second group of 10 normal GP received intramuscular injections of purified chicken type II collagen (1 mg) plus Freund's adjuvant. A control group of 10 normal GP was studied under the same conditions without any stimulus. The cochlea function was analysed with brainstem evoked audiometry (BERA). The structural study was carried out by immunofluorescent and hematoxylin preparations. The results showed structural alterations in both experimental groups (loss of nucleus in the spiral ganglion); however, significant changes in the BERA were not found. Only increase of the latency of wave I could be seen. These preliminary results support the hypothesis that antibodies to collagen type II may play an important role in human autoimmune sensorineural hearing loss, but the possible existence of other cochlear antigens is discussed.     

Otosclerosis and sensorineural hearing loss: a histopathologic study

The precise role and mechanism whereby otosclerosis is associated with sensorineural hearing loss remains unclear. Previous histopathologic reports are inconsistent with regard to the location of the otosclerotic focus, invasion of the otic capsule, and the number of remaining peripheral sensorineural elements. From the combined temporal bone collections of the University of Chicago and the Mayo Clinic, we identified a group of 125 ears from 80 patients, all with confirmed otosclerosis. Six of these ears were associated clinically with sensorineural hearing loss without stapes fixation. The histopathology of the otosclerotic focus was reviewed in terms of its location and depth of invasion. The cochlea and spiral ganglion were reconstructed, and the state of the organ of Corti and the presence or absence of peripheral cochlear nerve fibers were noted. Correlations with ganglion cell counts were made. The present study showed that the pattern of degeneration of peripheral sensory and neural elements in the cases presented is very similar to that found in cases of age-related processes such as presbycusis.     

不同听力损失耳听觉稳态诱发反应阈值与纯音听阈的比较

目的研究不同听力损失耳的听觉稳态诱发反应(auditory steady-state evoked response,ASSR)与纯音听阈的关系,为客观的听力评估提供指导。方法对67例(103耳)不同听力损失耳分别行ASSR与纯音测听检查,比较ASSR分别在0.5、1、24、kHz频率处的反应阈值与纯音听阈的相关性及差值。结果ASSR的反应阈与纯音听阈在0.5、1、24、kHz频率处的相关系数分别为0.84、0.83、0.89、0.91,呈极显著相关(P<0.01);ASSR的反应阈与纯音听阈在0.5、1、2、4 kHz频率处的差值在轻度耳聋组分别为(11.2±3.5)dBHL、(12.9±3.7)dBHL、(13.6±4.1)dBHL、(13.4±4.5)dBHL;在中度耳聋组分别为(3.4±4.6)dBHL,(4.9±4.3)dBHL,(6.8±5.7)dBHL,(7.1±5.6)dBHL;在重度耳聋组分别为(1.5±3.1)dBHL,(3.4±2.1)dBHL,(2.9±2.3)dBHL,(1.2±2.6)dBHL;其中轻度耳聋组的ASSR的反应阈与纯音听阈的平均差值与重度耳聋组的平均差值有统计学意义(P<0.01)。结论ASSR反应阈与纯音听阈有显著相关性,随着听力损失的加重,ASSR反应阈愈接近纯音听阈,ASSR可作为不同听力损失者客观的听力评估。     

Neural hearing loss in a child with poliomyelitis: a histopathological study

The temporal bones of a 26-month-old white female with a paralytic syndrome clinically and pathologically identical to poliomyelitis were examined. The aetiological agent was unknown although a non-poliomyelitis enterovirus infection seemed likely. There was a complete absence of the cochlear neurons and substantially reduced peripheral and central axons with loss of some inner hair cells but preservation of outer hair cells. Scarpa's ganglion, and the geniculate ganglion were partially atrophied. The saccule and utricle were mildly dilated and Reissner's membrane of the apical turn was bulging. In two previous audiological studies a 10--20 dB bilateral sensorineural hearing loss was found in poliomyelitis patients and a neuronal lesion was postulated which is now supported by our findings. This is a rare example of an almost pure neural hearing loss.     

Risk factors for hearing loss in neonates: a prospective study

OBJECTIVES: To identify potential risk factors for neonatal hearing loss that are not included in the current variables recognized by the Joint Committee on Infant Hearing (JCIH). METHODS: A series of consecutively born neonates with risk factors for hearing loss based on the 1994 JCIH registry were screened prospectively. There were 110 subjects with hearing loss and 636 subjects without hearing loss. Data collected as potential risk factors for infant hearing loss included not only those on the JCIH list but also others that we believed to be possibly significant. The infant hearing screening was performed on each subject using auditory brain stem testing. Statistical analysis of data was performed using the chi-square test. RESULTS: In addition to the variables listed by the JCIH, we identified 11 additional risk factors that were associated with hearing loss in our neonatal population. These are: length of stay in the intensive care unit, respiratory distress syndrome, retrolental fibroplasia, asphyxia, meconium aspiration, neurodegenerative disorders, chromosomal abnormalities, drug and alcohol abuse by the mother, maternal diabetes, multiple births, and lack of prenatal care. CONCLUSION: This study identifies 11 risk factors in addition to those currently on the high-risk registry published by the JCIH for neonatal hearing loss. The inclusion of these additional risk factors in neonatal screening programs may improve the detection rate of neonates with hearing loss. Further study will be needed to determine whether inclusion of these additional risk factors in a hearing screening program can provide an efficacious alternative to the use of universal infant screening.     

High-frequency audiometry: hearing thresholds in normal ears

High tone audiometry is an audiometric test serviceable in order to discover with precocity conditions affecting first the basal cochlear turn, as in ototoxicity occurs. Despite its increasing diffusion there are not fixed values allowing the use of a HL decibels scale generally introduced, like the adopted for low tone frequencies. This is partly due to difficulties for gauging several devices employed. Besides the age has an important influence in hearing of high tones and as a result the valutations given by distinct AA., disagree among them and each laboratory must establish their normal values grouped according to ages. However the knowledge of these figures is useful because they get a referent when one looks through the literature. This paper reflect our experience with normal population after being realized a brief medical history including an otoscopy and a diagnostic audiometry with the aim to eliminate possible otological pathology undiagnosed. Our results are compared with those of other authors.     

Sensorineural hearing loss and Kawasaki disease: a prospective study

PURPOSE: Kawasaki disease (KD) is an acute, self-limited vasculitis of infants and children that is now the most common cause of acquired heart disease in the pediatric age group in the United States and Japan. Reports have documented the association of acute KD with sensorineural hearing loss. To assess the prevalence of hearing loss following acute KD in a geographically and ethnically diverse population, a prospective, multicenter study of hearing loss in patients with KD was conducted. MATERIALS AND METHODS: Patients with acute KD were enrolled in 7 clinical centers and underwent a primary audiologic evaluation within 30 days of the onset of fever. Patients were subsequently reevaluated after resolution of the acute phase of the disease. A questionnaire assessing risk factors for hearing loss was also administered. RESULTS: A total of 62 patients were evaluated during the 29-month study period. At the first audiologic evaluation, 19 patients (30.6%) had sensorineural hearing loss, 6 patients (9.7%) had conductive hearing loss, 17 patients (27.4%) had normal hearing, and 20 patients (32.3%) had inconclusive studies. Overall, 2 of 36 patients (5.5%) had sensorineural hearing loss documented on their second audiologic evaluation. No risk factors for hearing loss were identified by the questionnaire. CONCLUSIONS: Transient sensorineural hearing loss (20 to 35 dB) is a frequent complication of acute KD and may be related to salicylate toxicity in some patients. Persistent sensorineural hearing loss is uncommon. Parents and primary care providers should be made aware of the potential for persistent sensorineural hearing loss following resolution of KD, but routine audiologic screening of this patient population does not appear to be warranted.     

Functional hearing loss presenting as sudden hearing loss: a case report

A case of functional hearing loss presenting as sudden sensorineural hearing loss in the only hearing ear of a musician is presented. Pure-tone audiometric evaluation showed good intratest and intertest consistency. The pitfalls of diagnosis, ultimately made by brain stem evoked response audiometry, are discussed in light of the literature on sudden and functional hearing loss. Psychiatric evaluation revealed features consistent with hysterical conversion. It is argued that it is important to establish the exact etiologic agent of functional hearing loss despite the difficulty of diagnosis so that the patient may receive appropriate treatment.     

Epidemiological considerations in sudden hearing loss: a study of 183 cases

Summary We have studied certain epidemiological problems not often encountered in the literature, involving patients with sudden hearing loss. We performed a retrospective cross-sectional study on 183 patients at the University of Padova and found that: (a) age at the onset of the hearing loss incurred is closely associated with the presence of concomitant diseases; (b) partial or total recovery of hearing is strongly predicated by the variables of age at onset and the interval between onset of hearing loss and the beginning of treatment given. We have also used polar-coordinate diagrams to show that cases of sudden hearing loss tend to be cyclic and are more prevalent in the central months of each season.     

Epidemiological considerations in sudden hearing loss: a study of 183 cases

We have studied certain epidemiological problems not often encountered in the literature, involving patients with sudden hearing loss. We performed a retrospective cross-sectional study on 183 patients at the University of Padova and found that: age at the onset of the hearing loss incurred is closely associated with the presence of concomitant diseases; partial or total recovery of hearing is strongly predicated by the variables of age at onset and the interval between onset of hearing loss and the beginning of treatment given. We have also used polar-coordinate diagrams to show that cases of sudden hearing loss tend to be cyclic and are more prevalent in the central months of each season.     

Homograft tympanoplasty: a long-term review of 477 ears

Homograft materials have been employed to reconstruct the tympanic membrane and ossicular chain since the mid-1960s. Although the use of homograft materials remains somewhat controversial, this technique has been shown to provide excellent long-term results, both anatomically and functionally. This study reports on the long-term results of 477 ears undergoing homograft tympanoplasty and the modification of previously reported surgical techniques.     

Hearing loss in the elderly: a 17-year longitudinal study

A 5-year longitudinal study into hearing levels of 261 randomly selected elderly people was performed between 1968 and 1973. From 47 survivors, 37 subjects have been traced and their hearing retested with pure tone audiometry. The age range of those followed up was 80-85 years. The results indicate that the rate of hearing loss found after 5 years remained the same over the next 12 years. The deterioration rate is very much greater for the higher frequencies with losses of 1.89 dB annually at 6 KHz compared with 0.35 dB per annum for 1 KHz. The findings confirm that hearing loss continues steadily into the ninth decade, information previously not established.