The menopause triggers hearing decline in healthy women.

BACKGROUND: Epidemiological studies have shown that women have better high-frequency thresholds than men in virtually all age groups, and that age-related hearing decline starts after 30 in men but not until after the age of 50 in women. This coincides with the menopausal transition in most women, thus leading us to hypothesize that the menopause triggers auditory deterioration, possibly due to reduced levels of endogenous estrogens, which are known to have protective effects on the auditory system. METHODS: 104 women with a mean age 51.2 at baseline, were tested with pure tone audiometry twice with an average interval of 7.5 years. The age at the final menstrual period (FMP) was reported by all women. Hearing decline at individual frequencies was calculated. RESULTS: Women with a FMP 0-4 years ago, had a rate of high frequency hearing decline of 0.9-1.5dB/year in the left ear, those with 5-7 years since the FMP had a corresponding rate of 1.1-1.5dB/year in the right ear, and 8-13 years after the FMP the decline was more subtle, 0.7-1.1dB/year in both ears. CONCLUSION: The menopause appears to act as a trigger of a relatively rapid age-related hearing decline in healthy women, starting in the left ear.

The influence of ageing on noise-induced hearing loss.

A lifetime of exposure to noise is likely to have negative effects on the hearing, but the interaction between noise-induced hearing loss (NIHL) and age-related hearing loss is difficult to determine. The most commonly accepted assumption is a simple accumulating effects of noise and ageing on the hearing. However, both a less than additive effect as well as a supraadditive effect has been proposed. Recently an interesting interaction between NIHL and age-related hearing loss has been reported (Gates et al., 2000). NIHL before old age reduces the effects of ageing at noise-associated frequencies, but accelerates the deterioration of hearing in adjacent frequencies. Findings from the longitudinal and cross-sectional gerontological and geriatric population study of 70-year-olds in Gothenburg, Sweden supports these observations. The incidence of tinnitus increases in old age, but not at the same high rate as presbyacusis. According to the gerontological and geriatric population study in Gothenburg tinnitus in old age is related more to hearing loss than to ageing. There are no simple correlations between exposure to noise during the active years and tinnitus in old age.

Horizontal localization and speech intelligibility with bilateral and unilateral hearing aid amplification.

Speech intelligibility and horizontal localization of 19 subjects with mild-to-moderate hearing loss were studied in order to evaluate the advantages and disadvantages of bilateral and unilateral hearing aid (HA) fittings. Eight loudspeakers were arranged in a circular array covering the horizontal plane around the subjects. Speech signals of a sentence test were delivered by one, randomly chosen, loudspeaker. At the same time, the other seven loudspeakers emitted noise with the same long-term average spectrum as the speech signals. The subjects were asked to repeat the speech signal and to point out the corresponding loudspeaker. Speech intelligibility was significantly improved by HAs, bilateral amplification being superior to unilateral. Horizontal localization could not be improved by HA amplification. However, bilateral HAs preserved the subjects' horizontal localization, whereas unilateral amplification decreased their horizontal localization abilities. Front-back confusions were common in the horizontal localization test. The results indicate that bilateral HA amplification has advantages compared with unilateral amplification.

Provision of hearing aid services: a comparison between the Nordic countries and the United Kingdom.

About one in five adults has some form of hearing impairment. This paper reports on a survey which found significant variation in the provision of hearing aid services across Denmark, Finland, Norway, Sweden and the United Kingdom. Per capita expenditure levels were estimated to vary from under 3 euros in the UK to nearly 10 in Denmark and Norway. Annual figures for the number of people receiving at least one aid varied from around eight per 1,000 in the UK and Denmark to 2.2 in Finland. Over 50% of hearing aid users in Norway and Denmark are estimated to have bilateral aids, compared to under 15% in the UK. Estimates of the number of people who have a hearing aid in these countries are considerably lower than the number who have a hearing impairment. More research is needed to verify the true extent of these differences and their cause.

Hearing impairment among adults--extent of the problem and scientific evidence on the outcome of hearing aid rehabilitation.

Scientific surveys on current and estimated prevalence of hearing impairment (HI) in adult populations (> or = 18 years of age) in Denmark, Finland, Norway, Sweden and the United Kingdom, and scientific reports on the outcome of hearing aid (HA) rehabilitation worldwide were reviewed. Only a few of the studies meet strict scientific criteria, and many locally clinically relevant studies cannot be generalized to larger populations. Population-based studies indicate an increase in prevalence of HI with age, but because of differences in study populations and available national population statistics, the studies do not allow reliable comparisons between countries or estimation of future prevalence of HI. Studies on HA prescription or outcomes do not provide uniform data in favour of non-linear amplification, but they do show some subject preference for the newer technology. No conclusions can be drawn regarding the degree of HI and the effects of amplification. The literature review alone gives only limited information regarding the extent of the problem of HI in adult populations in the target countries. Similarly, only a few studies on HA outcome meet strict scientific criteria and even fewer studies correlate rehabilitation outcome with the degree of HI, disability or handicap.

[Presbyacusis--hearing loss in old age]. / Presbyacusis--hörselnedsättning på äldre dar.

Presbyacusis is a very common type of hearing loss, often having profound effects on the quality of life in old age. Since the number of elderly persons is increasing, the incidence of presbyacusis is also expected to increase in the future. Presbyacusis is caused by cochlear degeneration, most pronounced in the basal cochlear coil. The most common audiometric configuration is a gently sloping audiogram, above all affecting the high frequencies. Efforts to improve auditory communication in old age are important, and can be expected to result in improved quality of life for elderly persons and in more efficient use of public resources. The alleviation of age-related hearing handicap includes aural rehabilitation with hearing aid fitting and training programs, specially designed for elderly people. Hearing loss is often combined with other handicaps, such as dementia, immobility and poor vision. The synergistic effects of multiple handicaps can be extensive. Prevention is an issue which is both challenging and problematic. The most important preventive measure is noise reduction, which must start early in life and not shortly before retirement. Inner ear treatment programs, currently under development, might possibly be suitable for treatment of inner ear disorders in the future. Considerable gains can be achieved with respect to resources both human and economical through rehabilitation and suitable preventive measures.

Directional sensitivity of the human macula utriculi based on morphological characteristics.

A morphometric analysis of 43 human maculae utriculi is presented. Individual data on the shape, total area and relative area of the pars interna are given. In addition, the sensitivity of the entire macula to shear stimuli in different directions was estimated. The mean area of 39 maculae from adults and children was 4.30 +/- 0.30 (SD) mm(2). The pars interna was slightly but significantly smaller than the pars externa. The interindividual variability was larger for the shape of the macula than for the total area and the percentage of the pars interna. The estimated responsiveness of the macula was largest for shear directed anteromedially and smallest for shear directed posteriorly. The data are discussed taking into consideration clinical findings on patients with unilateral loss of otolith function.

Bilateral hearing aids--effects and consequences from a user perspective.

The present study assesses the experiences with bilateral amplification in a group of 144 people provided with two hearing aids between May 1994 and July 1997. Two-thirds of the participants preferred to use both prescribed hearing aids. The participants reported that they used their hearing aids frequently. Bilateral amplification was appreciated especially for recognizing speech, for sound localization and for superior sound quality. Situations in which the subjects showed the highest appreciation of two hearing aids were when attending lectures and theatre performances and for communication in noisy background situations. There were statistically significant differences between users of bilateral and unilateral hearing aids regarding judgement of sound quality of hearing aid processed signals and localization ability in favour of bilateral hearing aid amplification. The self-assessed advantages of bilateral amplification demonstrated in this study should motivate a generous prescription strategy of two hearing aids.

Vision and hearing in old age.

The concomitant occurrence of hearing and visual impairment was investigated as part of an epidemiological longitudinal study of elderly people. An age cohort. originally consisting of 973 elderly people, was examined with visual and hearing tests three times at ages 70, 81-82 and 88. The best-corrected visual acuity was assessed. The hearing was measured by pure-tone audiometry and whispered and spoken voice (WSV). At age 70 there was no co-existence of visual and hearing impairments, and about 70% had normal vision and hearing. At 81-82 years 3-6% (WSV and audiometry. respectively) had low vision (VA < or = 0.3) and moderate to severe hearing loss, and more than one-tenth had normal vision and hearing. At 88 years 8-13% had low vision and moderate to severe hearing loss, and none of the men and less than one-tenth of the women had normal vision and hearing. At age 88 three times as many women as men had the combination of low vision and normal hearing. Normal vision with the combination of moderate to severe hearing loss was more often found in 88-year-old men. Mild impairments of the two senses were found in 0.5% at age 70 in 22%, 11% (WSV, audiometry) at age 81-82 and in 23%, 9% at age 88 years. At age 70 there was a statistical correlation between visual acuity and hearing measured with pure-tone audiometry in the male group. Those men with better hearing had slightly better visual capacity than those with hearing loss. No correlations were found for women at age 70 nor for women and men at ages 81-82 and 88. Ophthalmologists and audiology physicians should cooperate closely in the rehabilitation process to reduce disability and improve function and wellbeing among the oldest old.

Autism and hearing loss.

A group of 199 children and adolescents (153 boys, 46 girls) with autistic disorder was audiologically evaluated. Mild to moderate hearing loss was diagnosed in 7.9% and unilateral hearing loss in 1.6% of those who could be tested appropriately. Pronounced to profound bilateral hearing loss or deafness was diagnosed in 3.5% of all cases, representing a prevalence considerably above that in the general population and comparable to the prevalence found in populations with mental retardation. Hearing deficits in autism occurred at similar rates at all levels of intellectual functioning, so it does not appear that the covariation with intellectual impairment per se can account for all of the variance of hearing deficit in autism. Hyperacusis was common, affecting 18.0% of the autism group and 0% in an age-matched nonautism comparison group. In addition, the rate of serous otitis media (23.5%) and related conductive hearing loss (18.3%) appeared to be increased in autistic disorder. The study emphasizes the need for auditory evaluation of individuals with autism in order to refer those with pronounced to profound hearing loss for aural habilitation and to follow those with mild to moderate hearing loss because of the risk of deterioration.

Self-assessed hearing problems in Sweden: a demographic study.

A study of self-assessed hearing problems was performed comprising 48,680 Swedish inhabitants aged 16-84 years. The participants of the survey responded to personal interviews during the period 1986-1993. One of the questions in the interview concerned difficulties of hearing in background noise. The total prevalence of the reported hearing problems was 10.7 per cent, varying from 2.4 per cent in the youngest age group to 30 per cent in the oldest. Men reported difficulties in hearing more often than women, except in the youngest age group. Hearing problems were more often reported by manual workers, unemployed and by those who had taken early retirement, than by non-manual employees and the self-employed. Regional differences regarding hearing problems were observed. The prevalence of self-reported problems was lowest in metropolitan Stockholm (7.9 per cent) and increased in the following order: other major cities (9.4 per cent), other cities (10.5 per cent), small population centres (12.5 per cent), agricultural areas (13.5 per cent) and sparsely populated forest areas (15 per cent). In summary, a number of factors related to ageing, socioeconomic status and domicile were related to self-assessed difficulties hearing a conversation. These factors obviously include determinants such as genetics, health status, gender-related differences, exposure to noise and possible conditioning effects of low-level noise exposure.

Auditory function in whiplash-associated disorders.

This was a consecutive, prospective clinical study on 153 ambulatory patients in a tertiary referral center (i.e., a county hospital). All patients had whiplash-associated disorders (WAD) of at least grade II, according to the Quebec classification. All patients underwent pure-tone audiometry, and their audiograms were compared with ISO standards. Fourteen percent of patients with WAD had a hearing impairment exceeding the 90th percentile of the ISO standards. However, in most cases the hearing was not associated with whiplash injury. A subgroup (33 patients)--with normal hearing or slight hearing impairment according to the audiogram--was selected from the total group of patients with WAD. The 33 selected patients and 33 matched controls were tested with the speech-in-noise test (SRN test). However, 40% of this subgroup of patients with WAD reported hearing problems. As many as 30% of the patients with WAD had an abnormal SRN test result, as against 5% of the controls. Significant relations were found between the SRN test and self-assessed hearing loss, but not between the SRN test and tinnitus.

Hearing in patients operated unilaterally for otosclerosis. Self-assessment of hearing and audiometric results.

The objective of this study was to examine the outcome of unilateral stapes surgery in one patient group with bilateral hearing loss and one group with unilateral hearing loss. The patients' own estimations of improvement in hearing ability and the occurrence of other ear-related symptoms were examined retrospectively and in a follow-up study. Ninety-five of 123 patients operated for otosclerosis in only one ear between 1987 and 1992 responded to a follow-up examination. Observed audiometric findings and changes thereof, along with the patients' own estimations of their hearing handicap pre- and postoperatively, and the occurrence of other ear-related symptoms were studied. Despite good surgical results (closure of air-bone gap within 20 dB in 94%), 33% of the patients had severe hearing disabilities postoperatively, and many of these patients needed further amplification with a hearing aid. Mild dizziness occurred in 33% of the patients postoperatively and did not decrease over time. Discomfort in the operated ear due to strong sounds was reported in 20%. Change in sound quality occurred in 80% of the operated ears, but tended to disappear over time. From the results of this study it may be concluded that surgery in one ear only, leaving the other ear with poor hearing, is not an optimal hearing rehabilitation of patients with otosclerosis. It is important endevour to achieve bilateral hearing in order to give the patient good social hearing. Postoperative dizziness and unpleasant hearing quality do occur frequently, and the patients need to be informed about these problems preoperatively.

Measures of the binaural interaction component in human auditory brainstem response using objective detection criteria.

The occurrence of binaural interaction in humans has been demonstrated using auditory brainstem response (ABR). A distinctly binaural potential, beta, is derived by subtracting the ABR recording evoked by binaural clicks from the monaural aggregate, i.e., the sum of the two corresponding ABR recordings evoked by monaural clicks. However, few clinical data are available, possibly because the beta-wave is considered an elusive response due to a low signal-to-noise-ratio. In the present study, beta-wave latency, amplitude and area were evaluated for 10 subjects with normal hearing using automatic analysis and averaging based on a large number of stimulations. The efficacy of the beta-wave measures was assessed using different stimulus rates, as binaural interaction is known to decrease with increasing stimulus rate. It was found that the beta-wave given by automatic analysis demonstrated known characteristics of binaural interaction in human ABR, i.e. the absence of binaural interaction during wave III, significant binaural interaction during wave V and a significant decrease in binaural interaction when the stimulus rate was increased. These findings suggest that a beta-wave in the binaural difference waveform can be detected and quantified using automatic analysis, thus it is suitable for clinical studies, at least for patients with normal hearing thresholds.

The binaural interaction component in human ABR is stable within the 0- to 1-ms range of interaural time differences.

The effect of unilaterally delayed acoustic stimuli on binaural interaction was studied in 12 subjects with normal hearing. Auditory brainstem response (ABR) was obtained in the midline between the forehead and the neck, and click stimuli were unilaterally delayed at 0.2-ms intervals in the 0- to 1-ms range. Binaural interaction was evaluated by measuring the beta wave in the binaural difference waveform, i.e. the remainder after subtracting the binaurally evoked registration from the sum of the two monaural registrations. Computation of the binaural difference waveform showed the beta wave amplitude to be relatively stable throughout the 0- to 1-ms range of interaural time differences. This finding suggests stable binaural interaction within the range of interaural time differences where binaural click stimuli induce a binaurally fused intracranial image.

Aural rehabilitation in the elderly: supply of hearing aids related to measured need and self-assessed hearing problems.

Three age cohorts of elderly persons in Göteborg (70, 75 and 88 years of age) were studied regarding hearing aid (HA) rehabilitation, on the one hand, and measured and self-assessed hearing, on the other. The participants, 615 in number, were representative of their ages and were selected from a geriatric population study. At age 70, 12% of the participants had been equipped with HAs. At age 75, the corresponding figure was 14% and at age 88, 32%. The correlations between self-assessed and audiometrically measured hearing were reasonably high (r = 0.5-0.7). According to the result for the self-assessed measure, we estimate that elderly persons with pure-tone averages (PTAs) at 30 dB HL (0.5-4 kHz, better ear) are in need of aural rehabilitation. Nevertheless, few subjects with PTAs between 30 and 49 dB HL have been equipped with HAs. At age 88, almost 20% of those with pronounced problems had no HA. Very few participants with no documented hearing problems for aural rehabilitation had been equipped with HAs.

Hearing in advanced age. A study of presbyacusis in 85-, 88- and 90-year-old people.

Hearing in elderly people was investigated in an epidemiological longitudinal study (H70) encompassing a cohort representative of an urban Swedish population born in 1901-02. The participants in the study were followed audiometrically over a 20-year period from 70 to 90 years of age. This study focused on hearing and its decline during the later time span in which the participants were tested at the age of 85, 88 and 90 years. The results revealed that hearing loss in advanced age progressed only slightly in both men and women. The annual hearing threshold decline was about twice as large in the eighth decade of life as compared with the ninth. Hearing function was similar in the respondents tested at the out-patient clinic and in those tested at home. There were no consistent indications that survivors to a great age showed better hearing at entry to the study at 70 years of age. Some gender differences were found and are discussed.

Auditory function in 70- and 75-year-olds of four age cohorts. A cross-sectional and time-lag study of presbyacusis.

Within the framework of the gerontological and geriatric population studies in Göteborg, Sweden, 473 elderly persons were examined using pure-tone audiometry in two recent cohorts. The aim of this study was to present cross-sectionally acquired hearing data in these contemporary groups aged 70 and 75. Another objective was to compare hearing function at the same age over the last two decades (time-lag study) in three 70-year-old cohorts and three 75-year-old cohorts. The largest time-lags were 14 years (75-year-olds) and 21 years (70-year-olds). The most recently tested cohort of 70-year-olds, studied in 1992, demonstrated median pure-tone averages (PTA: 0.5, 1 and 2 kHz) of 20.2 dB HL in the left ear of men and 18.2 dB HL in women. The left median pure-tone thresholds at 4 kHz were 56.0 dB HL in men and 34.7 dB HL in women. Hearing acuity in 70-year-olds was not demonstrated to have changed in any consistent fashion over a 21-year time-lag. For the most recently evaluated 75-year-olds, the median PTA in the left ear was 27.3 dB HL in men and 21.6 dB in women. The left median 4 kHz threshold was 67.3 in the male group and 45.5 dB HL in the female group. Hearing in 75-year-olds over a time-lag of 14 years demonstrated somewhat better pure-tone thresholds predominantly in the men's better ear in the earliest cohort when compared to the cohort tested in 1990-91. However, there were no consistent differences of pure-tone thresholds between these age cohorts, except for the intermediate cohort 2, in which the men had generally worse hearing. Thus, there was no apparent evidence of changes of the auditory function in elderly of the same age over the last two decades. Gender-specific dissimilarities in annual pure-tone threshold deterioration between the ages of 70 and 75 were found and are discussed.

Smooth pursuit neck torsion test: a specific test for cervical dizziness.

OBJECTIVE: This study aimed to determine how the smooth pursuit neck torsion (SPNT) test is affected by various diseases associated with disturbances in balance and arising in the neck, in the posterior intracranial fossa, and in the labyrinth in patients having such conditions, and to compare the findings with those in healthy subjects. STUDY DESIGN: This study was a consecutive, prospective, double-blind clinical study. SETTING: This study was conducted with ambulatory patients in a tertiary referral center (i.e., a county hospital). PATIENTS: Studied were 75 patients with whiplash-associated disorders (WAD) of at least grade II, according to the Quebec classification, all of whom had been injured in car accidents. Of these, 50 patients reported dizziness and 25 did not. CONTROL SUBJECTS: Twenty patients had vertigo of central origin with positive central nervous system findings, 20 patients had Meniere's disease, and 30 subjects were healthy. INTERVENTION: The SPNT test is a smooth pursuit eye movement test. The subjects are placed in a neutral position, and then they turn 45 degrees to the right and to the left. The difference between the average gain in neutral and torsion positions is the test parameter. In addition to the SPNT test, the authors performed saccade tests, auditory brain stem response, and the caloric test. MAIN OUTCOME MEASURES: In the two WAD groups, neck torsion reduced the SP gain (p < 0.001), but in control patients with central and peripheral vertigo and in the healthy control subjects, it did not. RESULTS: The sensitivity of the SPNT test in the WAD group with dizziness was 90% and the specificity was 91%. The sensitivity in the WAD group without dizziness was 56%. CONCLUSION: The SPNT test seems to be useful for diagnosing cervical dizziness, at least in patients with WAD having symptoms of dizziness, because it has a high sensitivity and specificity.