Audiometric Measurements Research Articles

Coupling of earphones to human ears and to standard coupler

A standardized acoustical coupler should enable the calibration of audiometric earphones which ensures that the hearing thresholds determined in the audiometric measurement are independent of the earphone type. This requires that the coupler approximates the average human ear closely. Nevertheless, the differences among earphones as well as between human ears and the coupler affect the results of the audiometric measurements inducing uncertainty. As the mentioned differences are related to the coupling of different earphones to human ears and to a standardized coupler, the effects of this coupling are investigated by measuring the transfer functions from input voltage of the earphone terminals to the pressure at the ear canal entrance in two situations: open and blocked canals. Since the "ear canal entrance" is not well-defined for the coupler, transfer function measurements in the coupler were carried out in a similar way but at different depths. In order to describe and compare the earphone couplings, the pressure divisions at the entrance of the ear canal are calculated from the measured transfer functions. The results indicate that significant difference appears among sound pressures generated in different individuals' ears. Also, the earphone couplings to human ears and to the coupler differ considerably.

How we do it: Tympanoplasty: are different three‐ and four‐frequency averages comparable?

The results of tympanoplasty may be reported in a variety of ways. Pure-tone audiometry underpins reporting, yet there is no constancy in the pure-tone threshold average used. We examine the relationship between the 0.5, 1, 2 kHz, 0.5, 1, 2, 3 kHz and 0.5, 1, 2, 4 kHz pure-tone audiometry averages. Using audiometric data collected for 77 patients, we have compared hearing threshold using three different frequency averages derived from pure-tone audiometry. The 0.5, 1, 2 kHz, 0.5, 1, 2, 3 kHz and 0.5, 1, 2, 4 kHz three- and four-frequency averages are significantly different, this difference being primarily determined by the changes in the 4-kHz threshold. Using an average including 4 kHz results in 8% few patients achieving an ABG closure to within either 10 dB or 20 dB. When comparing surgical results with others, surgeons should use reports employing comparable audiometric measures of analysis.

Spoken Language Processing: A Convergent Approach to Conceptualizing (Central) Auditory Processing

Spoken Language Processing: A Convergent Approach to Conceptualizing (Central) Auditory Processing

Auditory Characteristics of Children with Autism

The objectives of this study were (1) to describe the auditory characteristics of children with autism relative to those of typically developing children and (2) to describe the test-retest reliability of behavioral auditory test measures with this population of children with autism. Audiometric data were obtained from 22 children diagnosed with autism and 22 of their typically developing peers. The audiologic test battery consisted of behavioral measures (i.e., visual reinforcement audiometry, tangible reinforcement operant conditioning audiometry, and conditioned play audiometry) and physiological measures (auditory brain stem response audiometry, distortion product otoacoustic emissions, and acoustic reflexes). Children with autism had physiologic test results equivalent to their typically developing counterparts. That is, no differences in auditory brain stem response audiometry, distortion product otoacoustic emissions, or acoustic reflex results were noted between the children with autism and typically developing children. However, behavioral measures revealed that about half of the children diagnosed with autism presented pure-tone averages outside of normal limits (i.e., >20 dB HL), although their response thresholds to speech were within normal limits. All behavioral test results were within normal limits (i.e., </=20 dB HL) for the typically developing children. In addition, test-retest variability was typically 15 dB or greater for children with autism as compared with variability of 10 dB or less for most of the typically developing children. Children with autism demonstrated essentially equivalent results on a battery of physiological auditory tests as those obtained from typically developing children. However, on average, behavioral responses of children with autism were elevated and less reliable relative to those of typically developing children. Furthermore, approximately half of the children with autism demonstrated behavioral pure-tone averages outside of the normal hearing range (i.e., >20 dB HL) despite having normal to near-normal hearing sensitivity as determined by other audiometric measures.

A 5-Year Prospective Study of Diabetes and Hearing Loss in a Veteran Population

Veterans with diabetes will have significantly greater hearing loss than nondiabetic veterans. The association between diabetes and hearing loss remains unclear despite the volume of research that has been devoted to the question. Often, differences in hearing thresholds between diabetic and nondiabetic patients are confounded by age and noise exposure. In this 5-year prospective study, 342 diabetic veterans and 352 nondiabetic veterans from the Portland VA Medical Center in Oregon were tested on a variety of audiometric measures, including pure-tone thresholds. Age and noise exposure were accounted for in the analyses. There was a trend toward greater hearing loss in diabetic patients 60 years of age and younger across the frequency range. These differences were statistically significant only in the highest frequencies tested (10, 12.5, 14, and 16 kHz). The effects of both diabetes and noise exposure on high-frequency hearing thresholds were dependent on age. For patients older than 60 years, the mean thresholds were not significantly different. These results suggest that diabetic patients 60 years old or younger may show early high-frequency hearing loss similar to early presbycusis. After age 60, difference in hearing loss between diabetic and nondiabetic patients was reduced.

Behavioral audiometry: Validity of audiometric measurements obtained using the “ Delaroche protocol” in babies aged 4–18 months suffering from bilateral sensorineural hearing loss

Evaluation of the validity of the audiometric measurements obtained in babies aged from 4 to 18 months suffering from bilateral sensorineural hearing loss (SNHL) using an original behavioral audiometry (BA) protocol called the "Delaroche protocol" [IJPORL 68 (2004) 1233-1243]. (1) We compared the auditory brainstem (ABR) threshold in the better ear with the mean of the BA thresholds obtained, bilaterally, at 2000 and 4000 Hz, both measurements being performed in the diagnostic phase. (2) We compared the BA thresholds obtained prior to the age of 18 months, bilaterally, at the frequencies of 500,1000, 2000 and 4000 Hz, with the thresholds of the better ear obtained at the same frequencies at the age of 3--4 years by BA. (1) Cross- sectional study (78 children). When there was no ABR at 100 db, there was no BA response at 100 dB in 84.2% of cases, resulting in a kappa coefficient of 0.72. When there were ABR, the difference between the ABR and the BA thresholds was equal to or less than 10 dB in 67% of cases and equal to or less than 20 dB in 95% of cases. (2) Longitudinal study (50 children). The difference between the behavioral thresholds obtained within 4 and 18 months (median age=12 months) and those obtained at 3 or 4 years old in the same children (median age=39 months) was equal to or less than 10 dB in 94% of cases at the frequencies of 1000, 2000 and 4000 Hz and in 78% of cases at 500 Hz. The two analysis evidence the validity of the behavioral measurements obtained at an early age using the protocol described.

Evaluation of the relation between audiometric and psychometric measures of hearing after tympanoplasty

The objective of this prospective study was to evaluate the relation between audiometric and psychometric measures after tympanoplasty from the perspective of preoperative selection of patients and postoperative assessment of the results of reconstructive middle ear surgery. Hearing (dis)ability was measured by means of pure-tone audiometry and a validated self-assessment questionnaire: the (modified) Amsterdam Inventory of Auditory Disability and Handicap (m)AIAD. Average hearing thresholds and (m)AIAD scores were evaluated for 80 patients, pre- and 12 months postoperatively. The average improvement of the air conduction threshold in the operated ear was 5.4 (+/-14.3) dB; the average improvement in the (m)AIAD score was 2.9 points (+/-12.1). Although not very strong, the audiometric improvement and increase in (m)AIAD score are significantly related. After the calculation of postoperatively measured mean scores on the (m)AIAD for different 10-dB intervals of postoperative hearing loss averaged over both ears, an interesting relation between the (m)AIAD score and hearing losses emerges. The (m)AIAD score is almost independent of hearing loss for postoperative hearing levels between 25 and 40 dB. Residual hearing loss has to become less than 25 dB before a smaller hearing loss corresponds with a higher (better) (m)AIAD score. For losses larger than 40 dB the (m)AIAD score clearly decreases with increasing hearing loss. Finally, even small residual hearing losses lead, on average, to (m)AIAD scores that are substantially lower than the score for normally hearing subjects. In general, the patient benefit seems related to the magnitude of improvement in the air-conduction thresholds, rather than to the achievement of a certain threshold level. In addition, even small residual hearing losses (less than 25 dB HL) still lead, on average, to (m)AIAD scores that are substantially lower than the scores for normally hearing subjects.

Hyperbaric Oxygen Therapy for Sudden Sensorineural Hearing Loss: A Prospective Trial of Patients Failing Steroid and Antiviral Treatment

To investigate the safety and efficacy of hyperbaric oxygen therapy (HBOT) in adult patients with sudden sensorineural hearing loss (SSNHL) who fail standard of care steroid and antiviral therapy. Prospective cohort study. An urban tertiary referral center. Nine adult patients presenting with SSNHL from December 2002 through February 2004. Patients with acute onset SSNHL of greater than 30 dB in three contiguous frequencies who failed to show audiometric improvement after 2 weeks of systemic steroids and antivirals were enrolled. Study patients received HBOT at 2.0 atmospheric pressure for 90 minutes while breathing 100% oxygen under a clear plastic hood in the chamber. Treatments were administered daily for 10 days over a 2-week period. Pre-and postHBOT mean hearing gains measured in decibels for pure-tone audiometry at 0.5, 1, 2, 3, and 4 KHz for bone and additional 8 KHz for air; pure-tone averages for air and bone; speech reception thresholds; and speech discrimination levels. Patient-reported subjective recovery rates (completely, substantially, partially, not improved) were also recorded. Overall, two patients had a dramatic improvement, and one patient had a dramatic improvement in his speech discrimination without improvement in other audiometric measures. Six patients had no demonstrable hearing gains. Two patients had complications of serous otitis media requiring myringotomy and pressure equalizing tube placement. No other complications were observed. Secondary HBOT after failure of systemic steroid and antiviral therapy may be associated with hearing gains in some patients with SSNHL.

Bone-Anchored Hearing Aids in Unilateral Inner Ear Deafness: An Evaluation of Audiometric and Patient Outcome Measurements

To evaluate the benefit of a bone-anchored hearing aid contralateral routing of sound hearing aid (BAHA CROS hearing aid) in 29 patients with unilateral inner ear deafness. Prospective clinical follow-up study. Tertiary referral center. Thirty patients were recruited. There were 19 patients with a history of acoustic neuroma surgery and 11 patients with unilateral inner ear deafness due to other causes; 1 patient was excluded. The first 21 patients had also participated in a previous evaluation. Audiometric measurements were taken before intervention, when fitted with a conventional CROS, and after BAHA implementation. Patients' subjective benefit was quantified with four different hearing aid-specific instruments: the Abbreviated Profile of Hearing Aid Benefit, the Glasgow Hearing Aid Benefit Profile, the International Outcome Inventory for Hearing Aids, and the Single-Sided Deafness questionnaire. The same instruments were used at a mean long-term follow-up of 1 year after BAHA implantation. Sound localization in an audiologic test setting was no different from chance level. The main effect of the BAHA CROS that was found was the "lift the head shadow" effect in the speech-in-noise measurements. All instruments also showed positive results in favor of the BAHA CROS at long-term follow-up. The poor sound-localization results in an audiologic test setting illustrated the inability of patients with unilateral inner ear deafness to localize sounds. The speech-in-noise measurements demonstrated the efficacy of the BAHA CROS to lift the head shadow. Patients were still satisfied at 1-year follow-up, according to the four instruments.

Decline of speech understanding and auditory thresholds in the elderly

A group of 29 elderly subjects between 60.0 and 83.7 years of age at the beginning of the study, and whose hearing loss was not greater than moderate, was tested twice, an average of 5.27 years apart. The tests measured pure-tone thresholds, word recognition in quiet, and understanding of speech with various types of distortion (low-pass filtering, time compression) or interference (single speaker, babble noise, reverberation). Performance declined consistently and significantly between the two testing phases. In addition, the variability of speech understanding measures increased significantly between testing phases, though the variability of audiometric measurements did not. A right-ear superiority was observed but this lateral asymmetry did not increase between testing phases. Comparison of the elderly subjects with a group of young subjects with normal hearing shows that the decline of speech understanding measures accelerated significantly relative to the decline in audiometric measures in the seventh to ninth decades of life. On the assumption that speech understanding depends linearly on age and audiometric variables, there is evidence that this linear relationship changes with age, suggesting that not only the accuracy but also the nature of speech understanding evolves with age.

Triagem auditiva em idosos: comparação entre auto-relato e audiometria

Apesar da alta prevalência entre idosos, a perda auditiva é pouco investigada. A audiometria é o teste padrão ouro para avaliação de perda auditiva, mas sua realização em larga escala traz dificuldades operacionais. O auto-relato pode ser uma alternativa. OBJETIVO: Determinar se uma única questão genérica tem validade para ser utilizada em pesquisas epidemiológicas. FORMA DE ESTUDO:Revisão sistemática. MATERIAL E MÉTODO: Foi realizada uma pesquisa da literatura médica nas bases de dados MEDLINE e LILACS, no período de 1990 a 2004. Foram analisados também artigos citados nas referências dos artigos identificados na busca eletrônica. Foram selecionados os artigos que compararam os resultados obtidos através de auto-relato, por meio de uma questão única genérica, e da audiometria tonal. Foram extraídos os dados de prevalência da perda auditiva, e de sensibilidade, especificidade e valores preditivos. RESULTADO: Foram incluídos dez estudos transversais. A questão única genérica parece ser um indicador aceitável de perda auditiva, sensível e razoavelmente específico, principalmente quando a perda é identificada como sendo a média tonal que inclua freqüências até 2 ou 4 kHz, a um nível de 40 dBNA, na melhor orelha. CONCLUSÃO: Uma questão única genérica tem uma boa performance em identificar idosos com perda auditiva e pode, portanto, ser recomendada para um estudo epidemiológico que não possa realizar medidas audiométricas.

Signal to noise ratio loss and consonant confusions

Previous SNR loss (also called speech loss) studies showed that (1) SNR loss cannot be predicted from audiometric measures, (2) 40% of hearing aids wearers have 5 dB SNR loss or greater, and (3) SNR loss influences speech intelligibility significantly. These showed SNR loss to be important in speech recognition, but they do little, or no to illuminate the nature of consonant confusion, resulting from SNR loss. Thus, the goal of the current study was to investigate the effect of SNR loss on 16 consonants recognition in hearing impairment as a function of SNR. Confusion matrix data were collect and analyzed, and Fletcher’s AI was calculated from the SNR. These two measures were utilized (1) to determine how SNR loss was related to the event loss, (2) to test whether clustering of syllables in terms of consonant confusions was complied with SNR loss, and (3) to compare PI functions obtained from subjects and AI model. The results show that the degree of consonant confusion varies, but members of consonants confused with target sound above chance level are similar, as a function of SNR loss and SNR. It suggests that SNR loss limits recognition for specific consonants, even in noise.

Auditory screening in the elderly: comparison between self-report and audiometry

SummaryDespite its high prevalence in the aged, hearing loss has been poorly investigated. Audiometry is the gold standard for evaluation of hearing loss, but large-scale use of the procedure involves operational difficulties. Thus, self-report may be an alternative.AimTo determine if a single global question is valid for use in epidemiologic research.Study designSystematic review.Material and MethodA search of the medical literature from 1990 to 2004 was performed using MEDLINE and LILACS. The references of the articles identified in the electronic search were also reviewed. Study Selection and Data Extraction: The articles that compared the results obtained with self-report to a single global question with those obtained by pure tone audiometry were selected. Data about the prevalence of hearing loss, and sensitivity, specificity and predictive values were extracted. Data Synthesis: Ten longitudinal studies were included. A single global question seems to be an acceptable indicator of hearing loss, sensitive and reasonably specific, mainly if the hearing loss is identified as the tone average that includes frequencies up to 2 or 4 kHz, at 40 dBHL level, in the best ear.ConclusionA single global question shows good performance in identifying older persons with hearing loss and can be recommended for an epidemiologic study if audiometric measurements cannot be performed.

Occupational safety: effects of workplace radiofrequencies on hearing function

The effects of radio frequency (RF) and microwave radiation on humans have been the subject of continuous investigation. Clinical investigations related to occupational RF/microwave exposure have been reported by investigators (1). Since one of the major groups occupationally exposed to RF and microwave radiation includes those working in radio broadcasting and TV transmitter stations, this study investigates whether RF affects auditory systems of people exposed to RF. The study is carried out with people working in radio broadcasting stations and living in employee residential houses close to the broadcasting stations. All subjects in the control group were similar in age, work regime, socioeconomic status, and lack of experience in working with RF sources. Brainstem Evoked Response Audiometer (BERA) and Pure Tone Audiometry (PTA) were used to measure the effects of RF under investigation on hearing functions of the subjects. In BERA measurements, I-III, III-V and I-V interpeak latencies were evaluated. In pure tone audiometric measurements, 250 Hz, 500 Hz, 1000 Hz, 2000 Hz, 4000 Hz and 8000 Hz frequencies of hearing threshold were measured in subjects of experimental and control groups. Interpeak latencies and bone conduction hearing thresholds of subjects in the experimental group were compared with those of the control group. BERA results showed that I-III, I-V and III-V interpeak latencies of people occupationally exposed to RF were not higher than subjects in control groups (p>0.05). Results of BERA indicated no statistically significant differences between exposure and control subjects. In audiometric evaluation, hearing threshold of people occupationally exposed to RF were found higher than the control group subjects for frequencies of 4000 Hz and 8000 Hz in terms of bone and air conduction of right and left ear (p < 0.01). The results of traditional audiometer indicated that RF promotes sensorineural hearing loss and affects cochlea parts related to 4000 Hz and 8000 Hz. These findings may have immediate implications and considerations for workplace safety in order to provide an occupationally safe environment to employees working in such settings.

An objective method for measuring the attenuation of hearing protection devices using otoacoustic emissions

An objective human subject test technique for measuring the attenuation performance of hearing protection devices is presented. The technique is similar to the real-ear attenuation at threshold (REAT) technique, except distortion product otoacoustic emission (DPOAE) measurements in the ear canal replace the standard audiometric threshold measurements. The primary advantages of the new technique are that the measurement is objective, relatively fast, and can be applied at supra-threshold sound levels. Microphone in real ear (MIRE) data is also available from the DPOAE probe in the ear canal. Disadvantages are the restricted frequency range in which DPOAE signals may be reliably recorded (2–5 kHz) and the need for an in-ear probe. Attenuation data for a set of earmuffs was measured on a pool of seven subjects using DPOAE, MIRE, and threshold methods. The DPOAE and threshold measurements were in agreement, validating the DPOAE method. The MIRE data were significantly higher than the DPOAE or threshold data. The difference in the attenuation levels represents sound reaching the cochlea that is bypassing the ear canal. This difference was smaller for measurements of the attenuation performance of a helmet, which provides increased shielding from bypass transmission paths through the head.

Bone-Anchored Hearing Aid in Unilateral Inner Ear Deafness: A Study of 20 Patients

Objective: To evaluate the benefit of a bone-anchored hearing aid (BAHA) contralateral routing of sound (CROS) in 20 patients with unilateral inner ear deafness. Subjects: 21 patients were recruited; 15 had undergone acoustic neuroma surgery and 6 patients had unilateral profound hearing loss due to other causes; 1 patient was excluded. Only patients with thresholds of better than 25 dB HL (500–2000 Hz) and an air-bone gap of less than 10 dB in the best ear were included. Methods: Evaluation involved audiometric measurements before intervention, when fitted with a conventional CROS and after implementation and quantification of the patients’ subjective benefit with a hearing aid-specific instrument: the Abbreviated Profile of Hearing Aid Benefit (APHAB). Results: Lateralization scores were not significantly different from chance (50%) in any of the three conditions. Measurements of speech perception in noise showed an increase in the signal to noise ratio (S/N ratio) with the conventional CROS (p = 0.001) and with the BAHA CROS compared to the unaided condition when speech was presented at the front with noise on the poor hearing side. On the other hand, a lower S/N ratio was seen with the BAHA CROS (p = 0.003) compared to the unaided situation when noise was presented at the front with speech on the poor hearing side. The patient outcome measure (APHAB) showed improvement, particularly with the BAHA CROS. Conclusions: The poor sound localization results illustrate the inability of patients with unilateral inner ear deafness to localize sounds. The speech-in-noise measurements reflect the benefit of a BAHA CROS in lifting the head shadow while avoiding some of the disadvantages of a conventional CROS. The benefit of the BAHA CROS was most clearly reflected in the patients’ opinion measured with the APHAB.

Predicting Success with Hearing Aids in Everyday Living

Persons with impaired hearing who are candidates for amplification are not all equally successful with hearing aids in daily living. Having the ability to predict success with amplification in everyday life from measures that can be obtained during an initial evaluation of the patient's candidacy would result in greater patient satisfaction with hearing aids and more efficient use of clinical resources. This study investigated the relationship between various demographic and audiometric measures, and two measures of hearing aid success in 50 hearing aid wearers. Audiometric predictors included measures of audibility and suprathreshold distortion. The unaided and aided signal-to-noise ratio (SNR) loss on the QuickSIN test provided the best predictors of hearing aid success in daily living. However, much of this predictive relationship appeared attributable to the patient's age.

Coupling of earphones to human ear and to coupler

The use of a standardized acoustical coupler should enable a calibration of audiometric earphones which ensures that the thresholds determined in the audiometry will be independent of the earphone type. This requires that the coupler approximates the average human ear closely. Nevertheless, the differences among earphones as well as between human ears and the coupler affect the results of audiometric measurements inducing uncertainty. The influence of these differences is examined by investigating the coupling of different earphones to human ears and to the standardized coupler. This is done by measurement of the transfer functions from input voltage of the earphone terminals to the entrance of the ear canal in two situations: (1) open, and (2) blocked. Similar measurements were carried out with the coupler, but since the ‘‘ear-canal entrance’’ is not well-defined for the coupler, the mentioned measurements were done at different depths in the coupler. The earphone’s coupling to (i) human ears and to (ii) the coupler, described in terms of the pressure division at the entrance of the ear canal, were compared. The results indicate that the coupling to the human ear and the coupling to the standardized coupler differ.

Possible new assessment of patulous eustachian tube function: audiometry for tones presented in the nasal cavity

ObjectiveTo assess the acoustic transfer function of the Eustachian tube by means of audiometric measurements in order to evaluate the severity of the patulous condition. Material and MethodsDetection thresholds for tones presented in the nasal cavity (at the nostril) were measured in subjects with a patulous Eustachian tube (PET) and in normal subjects. ResultsIn typical cases, these thresholds were lower in the subjects with PET and were markedly elevated to the same level as those of normal subjects by the insufflation of Lugol's solution (iodine solution). The pre- versus post-insufflation threshold differences seemed to reflect the effects of a patulous tube on the acoustic characteristics via the Eustachian tube. Based on the obtained results, sound patency via a patulous tube appeared to be dominant in lower frequency tones. Conclusion The present method seems to be another easy way to assess PET.

Meniere’s disease in Finland. An epidemiological and clinical study on occurrence, clinical picture and policy

Objectives: The symptom complex originating from the inner ear, known as Meniere’s disease, was studied especially from the epidemiologic point of view. Study design: A total of 442 patients’ charts were retrospectively analysed in several hospital districts of Finland. The period of 1992–1996 was covered. The main focus was on the epidemiological assessment of the disease in Finland. To clarify the epidemiological figures, the validity of the diagnostic assessment was examined using the latest guidelines (1995) of the Committee on Hearing and Equilibrium of the American Academy of Oto-Laryngology - Head and Neck Surgery (AAO-HNS) as a gold standard. Methods: The diagnostic tools used in the different hospitals were documented and evaluated, and diagnostic accuracy at the different levels of the health care system was evaluated. The clinical picture of Meniere’s disease was characterised, and the therapeutic modalities employed were evaluated. The audiometric configurations were classified according to two principles. The prognosis of hearing impairment was specified by creating a multi-variable model. Results: Half of the patients (N=221) fulfilled the AAO-HNS criteria for definite disease. The prevalence and incidence of definite cases of Meniere’s disease appeared to be lower in Finland than could be expected based on previous international studies. A prevalence of at least 43 per 100,000 and an average annual incidence of 4.3 per 100,000 were obtained. The prevalence rates in the catchment areas of the university and central hospitals did not differ statistically, but a significant (p < 0.001) difference was found between the average prevalences in the northern and southern Finnish hospital districts. Fluctuation of hearing in repeated audiometric measurements appeared to be a highly sensitive (94 %) diagnostic test to detect definite Meniere’s disease. According to the multivariable model created in this study, the hearing impairment in Meniere’s disease affects males and females equally, and the deterioration is about 1 dB per year due to the duration of the disease and 0.5 dB per year due to aging. The disease was controlled conservatively in 69 % of the cases. A gently sloping, high-frequency audiometric pattern was most prevalent according to the EU Work Group classification, and a flat pattern according to the mid-frequency-based classification. Conclusions: The variability of diagnostic criteria, diagnostic tools and therapeutic modalities shows an evident need for up-to-date therapy recommendations for Meniere’s disease in Finland.