Pure-tone Hearing Thresholds Research Articles

Sensory-neural hearing loss in pseudoexfoliation syndrome.

To evaluate relationship between ocular pseudoexfoliation syndrome(PXF) and sensory-neural hearing loss (SNHL). This prospective case-control study was designed on patients who referred to a general ophthalmic clinic at Imam Khomeini Medical Center, Urmia, Iran (March 2010 through November 2010). On routine ophthalmic examination, patients diagnosed with ocular PXF were referred to the ENT department and, selected cases (after evaluating inclusion and exclusion criteria) were referred to Audiometric Department. Pure tone hearing threshold level(HTL) was measured at 1, 2, 3 kHz for each ear and was compared with International Standard (ISO 7029) median age associated hearing loss at 1, 2, 3 kHz (AAHL). Overall 21 of 50 patients (42.0%) had a higher HTL than the ISO 7029 median AAHL at 1, 2 and 3kHz, which included 14 ears of 23 patients in the male group (30.4%) and 21 ears of 27 patients in the female group (38.8%). Approximately 12.0% of patients had glaucoma at the same time, however; no significant correlation was found in SNHL prevalence and severity between PXF patient and patients with simultaneous glaucoma. SNHL was more common in patients with ocular PXF compared to their age- sex matched controls (P <0.05). Most of patients with ocular PXF had SNHL compared to their age-sex matched controls, which could be due to PXF fibrils in the inner ear. These findings suggest PXF could be a systemic disease.

Cognitive, Health, and Sociodemographic Predictors of Longitudinal Decline in Hearing Acuity Among Older Adults

We aimed to investigate predictors of change in pure-tone hearing thresholds in older adults. Data were drawn from a pooled sample from the Dynamic Analyses to Optimise Ageing (DYNOPTA) project (N = 4,221, mean age = 73.6, range: 50-103 years). Pure-tone hearing thresholds were tested for frequencies between 0.5 and 8 kHz, on up to four occasions over a period of 11 years. Linear mixed models tested for predictors of change in hearing. Hearing loss for high-range frequencies preceded decline in low-range frequencies. Men had higher baseline hearing thresholds, but women experienced faster rates of decline in hearing for mid- to high-range frequencies. The estimated rate of change for a 75-year-old adult was 0.91 decibel hearing level (dB HL) per year for pure-tone thresholds averaged over frequencies ranging between 0.5 and 4 kHz in the better ear. Baseline age (β = 0.03, p < .01), hypertension (β = 0.15, p < .01), and probable cognitive impairment (β = 0.40, p = .01) were independent predictors of annual rate of change in hearing thresholds. Incidence of probable cognitive impairment was also associated with higher hearing thresholds. Other known correlates for prevalence of hearing impairment, including low education, noise damage, diabetes, and history of stroke were independently associated with baseline levels of hearing but were not predictive of change in hearing thresholds. Faster rates of decline in hearing are predicted by probable cognitive impairment and hypertension.

Roles of spectral cues in Mandarin tone perception for sensorineural hearing-impaired patients

This study aimed to evaluate the role of spectral fine structure and envelope information in Mandarin tone perception for sensorineural hearing-impaired patients. The linear predictive coding technique was applied to synthesize 128 tokens having spectral fine structure from one tone of a monosyllabic word and spectral envelope from other tones with the same syllable. There after, the tone response performance was assessed using these 128 speech materials for 20 normal-hearing and 48 sensorineural hearing-impaired patients, including 20 with moderate, 20 with moderate to severe, and 8 with severe hearing loss. 99.7%, 97.7%, 96.3% and 83.0% of the mean tone responses were consistent with spectral fine structure for the normal hearing, moderate, moderate to severe, and severely hearing-impaired groups, respectively. No tone recognition responses were observed in consistent with spectral envelope cues. There was a significant difference in tone recognition among the normal hearing group and three hearing impaired groups (χ(2) = 59.2, P < 0.001). The negative correlation between the averages for pure-tone hearing thresholds at frequencies of 500, 1000, and 2000 Hz and tone responses that were in consistent with spectral fine structure for the hearing-impaired subjects (r = -0.643, P < 0.001). For both normal-hearing and hearing-impaired subjects, spectral fine structure plays an important role in tone recognition, and the impact of changing spectral envelope cues on tone recognition is negligible, when spectral fine structure cues are present. Sensorineural hearing impaired patients showed a progressive decrease in the recognition of lexical tones based on spectral fine structure cues, as their hearing loss becomes more severe.

Tympanoplasty with Island Cartilage or Temporalis Fascia: A Comparative Study

Purpose: To compare clinical and audiological outcomes of the type 1 tympanoplasties where conchal cartilage (island graft) and temporalis fascia were used as the graft material. Procedures: In this retrospective study, the results of type 1 tympanoplasty operations (n = 50) in which cartilage and temporalis fascia were used for graft material were compared. Results: Pre- and postoperative otoscopic findings of both groups were similar (p > 0.05). Preoperatively, the pure tone averages (PTAs) and hearing thresholds of the fascia and cartilage groups were similar (p > 0.05). However, postoperatively, the PTAs and air-bone gap closure were better with temporalis fascia compared to cartilage grafting (p < 0.05). On frequency-specific comparisons, the pure tone thresholds at the frequencies of 0.5, 1 and 2 kHz recovered better with temporalis fascia compared to cartilage (p < 0.05). Although the pure tone recovery was better at 4 kHz with temporalis fascia, the difference between the groups were not significantly different (p > 0.05). Conclusion and Message: In conclusion, in contrast to many reports in the literature, temporalis fascia grafting seems better in our study than grafting with conchal cartilage.

Analysis of hearing improvement in patients with severe to profound sudden sensorineural hearing loss according to the level of pure tone hearing threshold

Patients with profound sudden sensorineural hearing loss (SSNHL) have a poor prognosis regardless of the type of treatment they receive. However, there is evidence that a proportion of patients with profound hearing loss may exhibit variable degrees of recovery, and this has yet to be specifically investigated. Here, we report a comparison of levels of hearing improvement in patients stratified according to their level of hearing threshold before treatment. We divided patients with severe to profound SSNHL into three groups: patients with an initial hearing threshold of 80-89 dB (n = 18), 90-99 dB (n = 16), and ≥100 dB (n = 34). We compared improvements in hearing threshold at different frequencies and recovery rates between the three groups. No significant differences were observed in hearing threshold improvements at different frequencies in the three groups after treatment. However, in the group with an initial hearing threshold of ≥100 dB, significantly less complete and partial recoveries occurred compared to those in the 80-89 or 90-99 dB groups. Our results suggest that initial hearing threshold in excess of 100 dB alters the likelihood of satisfactory recovery in patients with severe to profound SSNHL.

Audiometric Records Analysis in a Clinical Population in China

Objective:The objective of this study was to characterize the typical hearing loss presenting at a clinical audiology center.Methods: Audiometric records for 8,032 cases were obtained from the database at Beijing Tongren Hospital, Capital Medical University. Based on this information, age distribution, audiometric configuration, type, degree and asymmetry of hearing loss were characterized. Results: Results showed that 48.4% of all cases of hearing loss occurred from 31 to 60 years of age, sloping hearing loss was the most common audiometric configuration, and sensorineural hearing loss dominated the type of hearing loss for both males and females. Mean pure-tone hearing thresholds revealed significant differences between genders, that is, thresholds for females were poorer than those for males from 250 to 1,000 Hz, whereas thresholds for males were poorer than those for females from 2,000 to 8,000 Hz. Analysis showed that 57.3% of audiograms showed some degree of asymmetry. No significant difference was found between genders for the average asymmetric thresholds. Conclusion: This study provides the characteristics of age distribution, audiometric configuration, type, degree and asymmetry of hearing loss from a representative clinical audiology center. These data are useful for public policy efforts involving hearing loss prevention and rehabilitative program development.

Secondhand Smoke and Sensorineural Hearing Loss in Adolescents

To investigate the hypothesis that second-hand smoke (SHS) exposure is associated with sensorineural hearing loss (SNHL) in adolescents. A complex, multistage, stratified geographic area design for collecting representative data from the noninstitutionalized US population. Cross-sectional data from National Health and Nutrition Examination Survey (2005-2006) were available for 1533 participants 12 to 19 years of age who underwent audiometric testing, had serum cotinine levels available, and were not actively smoking. SNHL was defined as an average pure-tone level greater than 15 dB for 0.5, 1, and 2 kHz (low frequency) and 3, 4, 6, and 8 kHz (high frequency). Secondhand smoke exposure, as assessed by serum cotinine levels, was associated with elevated pure-tone hearing thresholds at 2, 3, and 4 kHz, a higher rate of unilateral low-frequency SNHL (11.8% vs 7.5%; P < .04), and a 1.83-fold increased risk of unilateral low-frequency SNHL in multivariate analyses (95% confidence interval, 1.08-3.41). The prevalence of SNHL was directly related to level of SHS exposure as reflected by serum cotinine levels. In addition, nearly 82% of adolescents with SNHL did not recognize hearing difficulties. Secondhand smoke is associated with elevated pure-tone thresholds and an increased prevalence of low-frequency SNHL that is directly related to level of exposure, and most affected individuals are unaware of the hearing loss. Thus, adolescents exposed to SHS may need to be closely monitored for early hearing loss with periodic audiologic testing.

Distributions of pure-tone hearing threshold levels among adolescents and adults in the United States by gender, ethnicity, and age: Results from the US National Health and Nutrition Examination Survey

Cumulative distributions of audiometric pure-tone thresholds for a non-occupationally noise-exposed population vary with demographic characteristics (e.g. gender, ethnicity, age), tested ear, and stimulus frequency. However, commonly-used audiometric databases either do not take these differences into account, or account for them using data not easily generalized to the US population. The objective of this study was to obtain distributions that are generalizable to the US population without significant history of exposure to occupational noise. Cumulative pure tone threshold distributions from the National Health and Nutrition Examination Survey (NHANES) III and the 1999–2004 data from the continuous NHANES were fitted with an asymmetric sigmoid function with reverse asymmetry, by gender, ethnicity, age, ear, and the stimulus frequency. Results indicated that conditional distributions based on these factors are warranted. Percentiles on the cumulative distribution functions can be transformed into standard normal variates (i.e. z-scores) to facilitate combination of results over time or across individuals with different demographic characteristics. However, combinations across frequency could obscure meaningful differences between the reference group and the hearing test results under analysis.SumarioLas distribuciones acumuladas de umbrales de tonos puros audiométrios en una población expuesta a ruido no laboral varía con las características demográficas (p.e., género, raza, edad), el oído evaluado, y la frecuencia del estímulo. Sin embargo, bases audiométricas de datos comúnmente utilizadas, o no toman estas diferencias en consideración o las reconocen utilizando datos que no son fácilmente generalizables para la población de los EEUU. El objetivo de este estudio fue obtener distribuciones que fueran generalizables para la población de los EEUU, que no tenía una historia significativa de exposición a ruido laboral. Las distribuciones acumuladas de umbrales de tonos puros de la III Encuesta sobre el Examen Nacional de Salud y Nutrición (NHANES) y de los datos de 1999-2004 de la NHANES continuo fueron ordenadas con una función sigmoidea asimétrica con asimetría reversa, por género, raza, edad, oído y frecuencia del estímulo. Los resultados indicaron que se garantizaban las distribuciones condicionales basadas en estos factores. Los percentiles de las funciones de distribución acumulada pueden transformarse en una variante estándar normal (p.e., puntajes z) para facilitar la combinación de resultados en el tiempo y entre individuos con características demográficas diferentes. Sin embargo, las combinaciones entre las frecuencias pueden ocultar diferencias significativas entre el grupo de referencia y los resultados de la prueba auditiva bajo análisis.

Evidence of hearing loss in a ‘normally-hearing’ college-student population

We report pure-tone hearing threshold findings in 56 college students. All subjects reported normal hearing during telephone interviews, yet not all subjects had normal sensitivity as defined by well-accepted criteria. At one or more test frequencies (0.25–8 kHz), 7% of ears had thresholds ≥25 dB HL and 12% had thresholds ≥20 dB HL. The proportion of ears with abnormal findings decreased when three-frequency pure-tone-averages were used. Low-frequency PTA hearing loss was detected in 2.7% of ears and high-frequency PTA hearing loss was detected in 7.1% of ears; however, there was little evidence for ‘notched’ audiograms. There was a statistically reliable relationship in which personal music player use was correlated with decreased hearing status in male subjects. Routine screening and education regarding hearing loss risk factors are critical as college students do not always self-identify early changes in hearing. Large-scale systematic investigations of college students’ hearing status appear to be warranted; the current sample size was not adequate to precisely measure potential contributions of different sound sources to the elevated thresholds measured in some subjects.SumarioReportamos los hallazgos de umbrales auditivos con tonos puros en 56 estudiantes universitarios. Todos los sujetos reportaron audición normal durante entrevistas telefónicas, aunque no todos tenían sensibilidad auditiva normal, conforme se define por criterios bien aceptados. En una o más de las frecuencias evaluadas (0.25-8 kHz), el 7% de los oídos tuvieron umbrales >25 dB HL y el 12% tuvieron umbrales >20 dB HL. La proporción de oídos con hallazgos anormales disminuyó cuando se usaron promedios tonales puros de tres frecuencias. Se detectaron hipoacusias con PTA en las frecuencias bajas en 2.7% de los oídos, e hipoacusias con PTA en altas frecuencias fueron detectadas en un 7.1% de los oídos; sin embargo, hubo poca evidencia de audiogramas con “muescas”. Existió una relación estadísticamente confiable en la que el uso de dispositivos para escuchar música se correlacionó con una disminución en la condición auditiva de sujetos varones. El tamiz de rutina y la educación en relación con los factores de riesgo para la hipoacusia se vuelven críticos, dado que los estudiantes universitarios no siempre auto-identifican cambios en su audición. Parecen justificadas las investigaciones sistemáticas a gran escala en estudiantes universitarios sobre su condición auditiva; el tamaño actual de la muestra no fue adecuado para medir con precisión las contribuciones potenciales de diferentes fuentes de sonido en la elevación de los umbrales medidos.

Factors Associated with the Occurrence of Hearing Loss after Pneumococcal Meningitis

On the basis of a nationwide registration during a 5-year period (1999-2003), the frequency and severity of hearing loss was investigated retrospectively in 343 consecutive Danish patients who survived pneumococcal meningitis, to identify important risk factors (including the pneumococcal serotype) for development of hearing loss. Results of blood and cerebrospinal fluid (CSF) biochemistry, bacterial serotyping, follow-up audiological examinations, and medical records were collected, and disease-related risk factors for hearing loss were identified. The mean pure-tone hearing threshold levels were compared with normative data. Of 240 patients examined by use of audiometry, 129 (54%) had a hearing deficit, and 50 (39%) of these 129 patients were not suspected of hearing loss at discharge from hospital. Of the 240 patients, 16 (7%) had profound unilateral hearing loss, and another 16 (7%) had bilateral profound hearing loss. Significant risk factors for hearing loss were advanced age, the presence of comorbidity, severity of meningitis, a low CSF glucose level, a high CSF protein level, and a certain pneumococcal serotype (P < .05). By applying multivariate logistic regression analysis, we found that advanced age, female sex, and a certain serotype were significant risk factors, because fewer patients with serotype 6B had hearing loss than did patients with serotype 12F (P = .03), which was the most commonly occurring serotype. Hearing loss is common after pneumococcal meningitis, and audiometry should be performed on all those who survive pneumococcal meningitis. Important risk factors for hearing loss are advanced age, female sex, severity of meningitis, and bacterial serotype.

Single-shot, low-dose intratympanic gentamicin in Ménière disease: role of vestibular-evoked myogenic potentials and caloric test in the prediction of outcome

Objective The aim of this study was to assess the efficacy and safety of single and low-dose intratympanic gentamicin therapy in patients with Ménière disease and who were monitored both with caloric tests and vestibular-evoked myogenic potentials (VEMPs) to see if VEMPs have an additional role in predicting the efficacy of the drug. Study design This is a prospective cohort study. Setting Tertiary referral center is the study setting. Patients Twenty-five intractable Ménière disease patients were included as the study group. Intervention(s) Low-dose (16 mg/mL), single-shot intratympanic gentamicin was applied. VEMP and caloric test were applied 2 weeks after the application. Main outcome measure(s) Safety and efficacy of protocol were evaluated at the sixth month postoperatively with tonal audiogram and visual analog scale, respectively. Results Mean average pure-tone hearing threshold at 0.5, 1, 2, 4, and 8 kHz was 49.6 and 51.0 dB before and after the application, respectively ( P > .05). Mean pretreatment and posttreatment visual analog scale scores of patients were 17.6 mm (10–30 mm) and 74.6 mm (41–100 mm), respectively ( P < .01). Posttreatment VEMPs were absent in 17, deteriorated in 2, and not changed in 6 patients. VEMP was a significant predictor of posttreatment visual analog scale score, whereas caloric test was not ( P < .01). Conclusions Low-dose, single-shot intratympanic gentamicin treatment proved to be effective and safe among intractable Ménière patients. VEMPs obtained at posttreatment second week were significant predictors of patients posttreatment sixth-month dizziness status and vertigo control.

Equivalent threshold sound pressure levels (ETSPL) for Interacoustics DD 45 supra-aural audiometric earphones

This paper describes the determination and results of pure-tone equivalent threshold sound pressure levels for the Interacoustics DD 45 audiometric earphone equipped with standard Model 51 cushions. The size and shape of the DD 45 transducer resembles the classic Telephonics TDH 39 earphone. Pure-tone hearing threshold measurements were performed for both ears of 29 test subjects. All audiometric frequencies from 125 to 8000 Hz were used. The data are intended for inclusion in future standardized reference equivalent threshold sound pressure levels. The results show that the DD 45 may be a good substitute for the THD 39 without the traditional 5-dB problem at 6000 Hz.SumarioEste trabajo describe la determinación y los resultados de los niveles de presión sonora para umbrales equivalente de tonos puros, con auriculares audiométricos Interacoustics DD 45 equipados con amortiguadores estándar Modelo 51. El tamaño y la forma de los transductores DD 45 se parecen al auricular clásico Telephonics TDH 39. Se realizaron mediciones de umbrales auditivos con tonos puros en ambos oídos de 29 sujetos de estudio. Se usaron todas las frecuencias audiométricas desde 125 a 8000 Hz. Los datos serán incluidos en referencias futuras de estandarización de presión sonora para umbrales equivalentes. Los resultados muestran que los DD 45 pueden ser un buen sustituto para los TDH 39 sin el problema tradicional de 5-dB en 6000 Hz.

Judgement of disproportionate loss between Mandarin monosyllable discrimination and pure tone hearing thresholds

To establish the criteria of the disproportionate loss of Mandarin monosyllable discriminative abilities to pure tone hearing thresholds. Total of 165 patients with varying degrees of sensorineural hearing loss were recruited for routine audiological evaluations. The speech discrimination scores were obtained by Mandarin phonemic-balanced monosyllable lists via self-made speech audiometric software. The Performance-Intensity (P-I) function for individual ear was obtained by the same list which was administrated in ascending intensities, with 25 monosyllables presenting randomly. The lowest intensity was determined by the lowest pure tone threshold among all audiometric frequencies minus 5 dB. The intensities were increased in 5 dB step until the score was 100% or the intensity was reached to the patient's uncomfortable level. The PB(max) was obtained from the P-I plot. Three parameters about pure tone average hearing thresholds, including PTA(1) (average of 0.5, 1 and 2 kHz), PTA(2) (average of 1, 2 and 4 kHz) and PTA(3) (average of 0.5, 1, 2 and 4 kHz), as well as three parameters about audiogram slope, including Slope(0.5) (4 kHz minus 0.5 kHz), Slope(1) (4 kHz minus 1 kHz) and Slope(2) (4 kHz minus 2 kHz), were calculated respectively. The correlations between PB(max) and above parameters were analyzed by SPSS10.0 statistical software. The audiogram slopes were not shown any correlation with PB(max), while the pure tone average thresholds, especially PTA(3) (r = -0.595, P = 0.000) were confirmed to correlate with PB(max). In the scatter plot based on PB(max) and PTA(3), a linear boundary was constructed encompassing approximately 99% of observed data collected from the sensorineural hearing-impaired. Any PB(max) score falling below the boundary should be considered with high possibility and disproportionately poor comparison with pure tone hearing thresholds.

Exfoliation syndrome related to sensorineural hearing loss

To investigate the relationship between exfoliation syndrome and sensorineural hearing loss. A prospective study was designed. Patients with evidence of ocular exfoliation syndrome (study group) and individuals without any clinical signs of exfoliation syndrome (control group) were selected. Cases and controls were chosen to have similar demographic characteristics. Study and control group subjects with a history of conditions affecting hearing function were excluded. Pure-tone audiometry was performed in all participants in both groups and hearing thresholds were measured at frequencies of 0.25, 0.5, 1, 2, 4 and 8 kHz (kilohertz) for each ear. A total of 69 subjects participated in the study. The study group included 47 subjects and the control group 22. There was no significant difference in mean age (P = 0.985) and gender (P = 0.378) between groups. Mean pure-tone hearing thresholds were significantly higher in study group at frequencies of 4 kHz (P = 0.004) and 8 kHz (P = 0.001), but not at frequencies of 0.25, 0.5, 1 and 2 kHz. The greatest difference in the comparison of mean hearing thresholds between study and control group was noted at 8 kHz. The above results are in accordance with previous studies and provide additional evidence of the association between exfoliation syndrome and sensorineural hearing loss at high frequencies. Particular effect was shown on the highest frequency of 8 kHz. These findings may support the systemic nature of exfoliation syndrome.

Laterality of Exostosis in Surfers Due to Evaporative Cooling Effect

1. To correlate exostosis severity with ear canal evaporative cooling. 2. To assess hearing and complications after canalplasty. Retrospective chart review. A retrospective chart review from 1990 to 2007 at a university tertiary referral center. Surfers from the west coast of the United States were twice as likely to have severe exostoses in the right ear compared with the left. Evaporative cooling from a predominant northerly wind direction during the coldest water temperature months in this region may contribute to this lateral bias because surfers on this coast spend most of their time facing west. Few postoperative complications were identified. No cases of facial nerve injury or entry into the temporomandibular joint occurred. Differences in preoperative versus postoperative pure-tone hearing thresholds were not significant. Exostosis severity seems to correspond to the ear that is more exposed to the predominant coastal wind. We propose that evaporative cooling in a cold water environment contributes to greater progression of exostoses in the ear with more exposure to the predominant wind. Exostosis removal using the postauricular approach carries a low complication rate.

Perceptibility of environmental sounds by earphone wearers listening to pop and rock music

To examine how the perceptibility of environmental sounds is affected by listening to music through earphones, the hearing thresholds for pure tones presented through a loudspeaker were measured. Under the condition that the listener wore canalphones, thresholds were considerably higher than those under the condition that the listener’s ears were open. When pseudo-music signals were presented through the canalphones at the A-weighted sound pressure level of 70 dB, the hearing threshold at 2 kHz was almost 70 dB higher than the absolute threshold. How environmental noise affects the listener’s comfortable level of music played on portable audio devices was also examined. The mean comfortable listening levels (A-weighted) under a quiet condition were between 65 dB and 69 dB and those under a noisy condition ranged between 73 dB and 76 dB. It was indicated that when listening to music through canalphones at a comfortable level on a busy street, many environmental sounds would be inaudible.

Maternal infection with toxoplasma gondii in pregnancy and the risk of hearing loss in the offspring

The aim of this study was to investigate the association between maternal infection with Toxoplasma gondii (T. gondii) in pregnancy and subsequent risk of hearing loss in the offspring. The study included 27 727 children born in Norway 1992–1994. Maternal toxoplasma infection during pregnancy was ascertained by serological examination and fetal infection was ascertained by parasite detection in amniotic fluid and/or postnatal serological examination. Hearing loss was defined as mean hearing loss >35 dB HL in the better ear averaged over the pure-tone hearing thresholds at 500, 1000, and 2000 Hz, and the children were identified through linkage to the Norwegian Registry of Hearing Loss in Children. Twenty-two of the 27 727 children (0.08%) were diagnosed with hearing loss. Forty women had primary T. gondii infection in pregnancy. None of their offspring had hearing loss. There was also no association between T. gondii infection prior to pregnancy and hearing loss in the offspring. Hence, we did not find any association between T. gondii infection in pregnancy and hearing loss in the offspring.SumarioEl propósito de este estudio fue investigar la asociación entre la infección materna con Toxoplasma gondii (T. Gondii) en el embarazo y el riesgo subsiguiente de pérdida auditiva en el bebé. El estudio incluyó 27.727 niños nacidos en Noruega entre 1992 y 1994. La infección materna por toxoplasma durante el embarazo fue evaluada por examen serológico y la infección fetal fue evaluada por detección del parásito en el líquido amniótico y/o por examen serológico post-natal. La pérdida auditiva fue definida como una hipoacusia media de > 35 dB en el mejor oído, promediado con base en los umbrales auditivos de tonos puros en 500, 1000 y 2000 Hz, y los niños fueron identificados a través de contacto con el Registro Noruego de Hipoacusia en Niños. Veintidós de los 27.727 niños (0.08%) se diagnosticaron con una pérdida auditiva. Cuarenta mujeres tuvi-eron infección primaria por T. Gondii durante el embarazo. Ninguno de sus hijos exhibieron una pérdida auditiva. No existió asociación entre la infección por T. Gondii antes del embarazo y la hipoacusia en el producto. Por tanto, no encontramos ninguna asociación entre la infección por T. Gondii en el embarazo y la aparición de una pérdida auditiva en el producto.

Vestibular evoked myogenic potential in noise-induced hearing loss

Noise affects one's hearing as well as balance mechanism. The hearing mechanism of the noise-exposed individuals has been extensively studied. However, in view of the poor research focus on the sacculo-collic reflexes, especially in this study area, the present study was undertaken to examine the vestibular evoked myogenic potentials (VEMP) in subjects with noise-induced hearing loss (NIHL). A total of 30 subjects (55 ears) with NIHL participated in the present study within the age range of 30-40 years. VEMP recordings were done at 99 dBnHL using IHS instrument. The results indicated that as the average pure tone hearing threshold increased, the VEMP latencies were prolonged and peak to peak amplitude was reduced in NIHL subjects. Out of the 55 ears, VEMP was absent in 16 (29.0%) ears. The latency was prolonged and the peak to peak amplitude was reduced in 19 (34.6%) ears. VEMP results were normal in 20 (36.4%) ears. Therefore, VEMP was abnormal or absent in 67% of NIHL subjects in the present study. Hence it can be concluded that the possibility of vestibular dysfunction, specially the saccular pathway, is high in individuals with NIHL. VEMP, a non-invasive and user friendly procedure, can be employed in these individuals to assess sacculo-collic reflex.

Sex Differences in a Cross Sectional Study of Age-related Hearing Loss in Korean

ObjectivesThe purpose of this study was to obtain sex- and age-specific reference level for hearing threshold of normal aging in Korean and to determine if the rate of change in pure-tone hearing thresholds differed by sex.MethodsSubjects were clients who visited the Health Promotion Center, Daegu Fatima Hospital, Daegu, Korea, from January 2004 to September 2005. Pure-tone audiometric measures were obtained from 3,470 subjects who also completed a hearing questionnaire. The slope of a linear regression was used to estimate the rate of change in pure-tone thresholds at 0.25 to 8 kHz for each ear in 214 men and 902 women without past history of otorrhea, usage of ototoxic drugs, head injury, job in noisy environment, and military service.ResultsHearing thresholds were elevated with age in all test frequencies. Significant sex differences were found in pure-tone thresholds at 4 and 8 kHz after adjusting for age using analysis of covariance. In those high frequencies, hearing was worse in men than in women. The average rate of change in threshold was 0.28 and 0.24 dB per year at 0.25 kHz, increasing gradually to 1.27 and 1.05 dB per year at 8 kHz for men and women, respectively. Men had significantly faster rates of threshold increase at 4 and 8 kHz than women.ConclusionThese cross-sectional measures of hearing levels and rate of threshold increases at 4 and 8 kHz showed significant sex differences in Korean men and women with little evidence of noise-induced hearing loss.

SLC26A4 genotype, but not cochlear radiologic structure, is correlated with hearing loss in ears with an enlarged vestibular aqueduct.

Identify correlations among SLC26A4 genotype, cochlear structural anomalies, and hearing loss associated with enlargement of the vestibular aqueduct (EVA). Prospective cohort survey, National Institutes of Health, Clinical Center, a federal biomedical research facility. Eighty-three individuals, 11 months to 59 years of age, with EVA in at least one ear were studied. Correlations among pure-tone hearing thresholds, number of mutant SLC26A4 alleles, and the presence of cochlear anomalies detected by computed tomography or magnetic resonance imaging were examined. Linear mixed-effects model indicated significantly poorer hearing in ears with EVA in individuals with two mutant alleles of SLC26A4 than in those with EVA and a single mutant allele (P = .012) or no mutant alleles (P = .007) in this gene. There was no detectable relationship between degree of hearing loss and the presence of structural cochlear anomalies. The number of mutant alleles of SLC26A4, but not the presence of cochlear anomalies, has a significant association with severity of hearing loss in ears with EVA. This information will be useful for prognostic counseling of patients and families with EVA.