External Ear Resonance Research Articles

외이도-유양동-귀뒤바퀴피부 누공환자에서 수술 전, 후의 외이도 공명의 변화

외이도-유양동-귀뒤바퀴피부 누공환자에서 수술 전, 후의 외이도 공명의 변화

Correlation between the characteristics of resonance and aging of the external ear.

Aging causes changes in the external ear as a collapse of the external auditory canal and tympanic membrane senile. Knowing them is appropriate for the diagnosis of hearing loss and selection of hearing aids. For this reason, the study aimed to verify the influence of the anatomical changes of the external ear resonance in the auditory canal in the elderly. The sample consisted of objective measures of the external ear of elderly with collapse (group A), senile tympanic membrane (group B) and without changing the external auditory canal or tympanic membrane (group C) and adults without changing the external ear (group D). In the retrospective/clinical study were performed comparisons of measures of individuals with and without alteration of the external ear through the gain and response external ear resonant frequency and the primary peak to the right ear. In groups A, B and C was no statistically significant difference between Real Ear Unaided Response (REUR) and Real Ear Unaided Gain (REUG), but not for the peak frequency. For groups A and B were shown significant differences in REUR and REUG. Between the C and D groups were significant statistics to the REUR and REUG, but not for the frequency of the primary peak. Changes influence the external ear resonance, decreasing its amplitude. However, the frequency of the primary peak is not affected.

Real ear unaided gain and its relation with the equivalent volume of the external and middle ear

Summary Introduction: Old age is associated with changes in the characteristics of the middle ear transmission system and in external ear resonance, and these carry implications for the hearing aid (HA) verification process for which targets and measures of the real ear insertion gain (REIG) are used. Aim: To compare the real ear unaided gain (REUG) and the equivalent volumes of the external ear (VeqEE) and the middle ear (VeqME) between elderly and adult patients. Methods: This is a retrospective study in which the medical records of 28 elderly patients (aged between 61 and 102 years, average hearing thresholds between 38.75 and 85 dB HL) and 23 adult patients (aged 20–59, mean hearing thresholds between 31.25 and 116.25 dB HL) with bilateral sensorineural hearing loss and no history of middle ear abnormalities were analyzed. Immittance measurements (VeqEE, VeqME, and pressure of the peak of maximum compliance) and the REUG (frequency and amplitude of the primary peak) were recovered for a total of 40 ears. These data were compared between elderly and adults as well as between men and women, using Student's t test. Correlations (Pearson) between immittance and REUG data were also verified. Results: No statistically significant differences (p < 0.01) were found for immittance and REUG data between elderly and adults, or between men and women. A negative and weak but significant correlation was observed between the REUG primary peak and VeqEE. Conclusion: Hearing aid verification can be performed with target and measures of the REIG in the elderly population.

The effect external and middle ears have in otoacoustic emissions

SummaryCharacteristics of how external and middle ear resonance frequency can impact the capture of otoacoustic emissions. Aim: to study the impact of external and middle ear resonance frequency in otoacoustic emissions. Study Design: Prospective, clinical, series study. Materials and Methods: Microphone-probe measurements were made in the external ear, together with multifrequency timpanometry distortion product transient otoacoustic emissions in 19 right and 20 left ears from male individuals and 23 right and 23 left ears from female individuals with 17 to 30 years of age. The 85 ears were audiologically normal. Results: We did not observe statistically significant associations between the best otoacoustic emission best frequencies and the occluded external and middle ear resonance frequencies. Conclusion: Response levels for both transient and distortion product otoacoustic emissions are not influenced by the external and middle ear resonances alone.

Changes in external ear resonance after 3 types of surgery in the patients with chronic otitis media

Objective: This study was designed to identify the external ear resonance characteristics of patients with tympanic membrane perforation and to investigate subsequent changes in external ear resonance, depending on the length of the postoperative period and which of 3 different types of operation was performed: tympanoplasty with canal wall-up mastoidectomy, epitympanoplasty, and canal wall-down mastoidectomy. Study design and setting: A total of 227 ears of 188 patients and 96 control ears comprised the study. We measured the gain and frequency of the first peak of external ear resonance with a real ear analyzer. Results: Gain and frequency of the first peak recorded in the preoperative group did not differ from those of the control group. However, negative peaks appeared around 1 to 1.5 kHz in half of these ears. The gain increased markedly in all 3 postoperative groups. The canal wall-down mastoidectomy and epitympanoplasty groups showed significantly lower frequencies compared with the tympanoplasty with canal wall-up mastoidectomy and control groups, but there was no difference between them. The increased gain diminished over time, but the peak gain did not equalize with that of the controls, even after 15 months. Conclusions: Additional gain should be considered of around 1 to 1.5 kHz for hearing aid users with tympanic membrane perforation. Postoperative changes in external ear resonance should be expected in patients with chronic otitis media, suggesting that fine readjustments of the hearing aid may be necessary. (Otolaryngol Head Neck Surg 2001;125:364-9.)

Changes in external ear resonance after ventilation tube (Grommet) insertion in children with otitis media with effusion

Objective: As otitis media with effusion is common in children, the effects of a ventilation tube should be taken into account in the prescription of hearing aids for children. In ears with a ventilation tube, the external auditory canal communicates directly with the middle ear space, and so the impedance of the middle ear may change. Consequently, this will affect external-ear resonance. The aim of this study is to observe the effects of the tympanic membrane perforations caused by the ventilation tube on external-ear resonance. We selected 30 ears with otitis media with effusion to measure external-ear resonance before and after ventilation tube insertion. We compared the external-ear resonance of a control group with that of the otitis media with the effusion group and two types of ventilation-tube groups, respectively. In the subjects who have otitis media with effusion, the average gain of the peak resonance was larger than that in the control group. After ventilation-tube insertion, the amplitude of the gain decreased to the same level as the control group, but a characteristic negative gain appeared around 1000 Hz in about half of all cases. This negative gain was observed more frequently in the ventilation tube with a larger diameter. The raised peak resonance gain in the otitis media with effusion group decreased to a level roughly the same as that of the control group after ventilation-tube insertion. Provision of an additional gain in the low frequencies around 1000 Hz should be considered for patients with a ventilation tube when prescribing hearing aids.

Aging and External Ear Resonance: Envejecimiento y la resonancia del conducto auditivo externo

External ear resonance was measured in elderly people using a probetube microphone system. Resonance frequency, amplitude, and bandwidth as well as ear canal volume were compared across age groups and genders. No significant age group trends were observed in external ear resonant frequency. Also, the amplitude and bandwidth of the resonance peaks across ages were not significantly different. For the gender effect, the mean external ear resonant frequencies are generally higher for females than for males in all age groups, but the differences are not statistically significant. The mean amplitudes of the resonant frequency are larger for men than for women. But the difference is also small. For the ear canal volume, no significant age trend was found. However, the mean ear canal volume was significantly larger for males than for females.

Changes in external ear resonance after ventilation tube insertion

Changes in external ear resonance after ventilation tube insertion

External ear resonance in patients with tympanic membrane perforations.

This study investigated the effects of a tympanic membrane perforation on the external ear resonance. Measurements of external ear resonance using a probe-tube microphone system were performed in 14 patients who had medium to large unilateral tympanic membrane perforations. The contralateral normal ears of these 14 patients served as control. The results showed that there were no significant differences in the peak frequency, peak amplitude and peak sharpness between perforated and normal ears. However, intersubject variability in the resonant frequency was greater in the perforated group. In addition, the resonance curves of these two groups were substantially different. In 10 out of the 14 patients in the perforated group, the resonance curves showed 2-3 prominent peaks separated by valleys of about 10 dB reduced gain. In addition, in 11 out of 14 perforated ears, reduced responses (3.8 dB in average) occurred consistently in the lower frequency region (0.3-2 kHz). Clinically, the abnormal external ear resonance and the larger intersubject variation must be taken into consideration in fitting hearing aids for this group of patients.

External ear resonance as a screening technique in children with otitis media with effusion

External ear resonance can be quickly and accurately measured using real ear insertion gain equipment. It has been previously shown that external ear resonance characteristics are often altered by the presence of middle ear fluid. The external ear resonance characteristics of 84 children with a history of chronic middle ear disorder were determined. Results were compared to other audiological data and otological findings recorded during surgery. External ear resonance peak amplitude was significantly correlated with the presence or absence of middle ear fluid. It was found that peak amplitude of ⩾ 24 dB was associated with only 15% of dry ears and peak amplitude of ⩽ 22 dB associated with 79% of ears without fluid. The use of external ear resonance measures as a potential screening procedure is discussed.

Is the ‘‘4-kHz notch’’ in the noise-induced-hearing-loss audiogram due to a tectorial membrane resonance at 2.8 kHz (the frequency of the maximum external ear resonance)?

If Allen is right, and the apparent transmission zero located one-half octave below the best frequency of a nerve fiber is due to the resonance of the tectorial membrane mass on its connecting stiffness, then perhaps an explanation for the half-octave shift in TTS and PTS above the stimulating frequency is available (the tectorial membrane agitation breaks off the hairs). Along the same vein, the typical diplacusis that accompanies a Meniere’s attack can perhaps be explained by the conflicting periodicity pitch cues (unchanged) and place cues (shifted due to the stiffened basilar membrane). The disappearance of diplacusis over time may be an indication of the plasticity of the tonitopic organization of the brain.

External ear resonance in children with otitis media with effusion

A middle ear effusion has been shown, in KEMAR, to increase the height of the resonant peak of the external auditory canal by 6 dB SPL. It has also been shown that the hearing impairment due to otitis media with effusion is related to the volume of middle ear fluid. Therefore, it was hypothesized that measurement of the height of the resonant peak of the external auditory canal could be used as a method of assessing the magnitude of any hearing impairment due to otitis media with effusion. 182 ears from 182 children aged 3-12 (mean 6.3) years were studied. Pure-tone audiometry and impedance tympanometry were performed, and the acoustics of the external auditory canal were measured using the Rastronics CC1-10 frequency response analyser. The mean height of the resonant peak (17.9 dB SPL) of children with a type A tympanogram was significantly different from the mean value (23.6 dB SPL) of those with a type B tympanogram. There was a significant correlation between the height of the resonant peak and the speech frequency average of the pure-tone thresholds. The sensitivity and specificity of using the height of the resonant peak to detect hearing impairments in different age groups were calculated and compared with the sensitivity and specificity of tympanometry. The test did not provide the same degree of sensitivity as tympanometry but was more specific. The additional advantages of the test are that it is quick, taking less than 1 min per ear, and is well tolerated by children in whom there was a 99% compliance.(ABSTRACT TRUNCATED AT 250 WORDS)

External Ear Resonance Characteristics in Children

External ear resonance characteristics were determined for 78 children ages 3-13 using an ear canal probe tube microphone system. The average peak resonant frequency was 2848 Hz (range: 1774-4039), and the average measured gain at the eardrum was 18.9 dB (range: 11.5-26.7). Correlations of average peak resonant frequency and peak resonant amplitudes with age, height, weight, head circumference, and/or canal opening area were poor. These values are very similar to the adult data reported by Shaw (1974). Slight deviations can be attributed, in part, to the different sound field calibration methods used.

An update on the external ear resonance in infants and young children.

The diffuse field to ear canal sound pressure transformations determined for 26 children (34 ears) from birth to 3 years old, confirm the earlier findings [Kruger B. Ruben RJ. Acta Otolaryngol (Stockh) 1987; 103:578-85] that the external ear fundamental resonance frequency is significantly higher at birth (about 6 kHz), and decreases with age to adult values (2.7 kHz) by the second year. The transformations were measured with either single or double probe tubes (coupled to miniature microphones) that were placed in the ear canal of sleeping infants. The accuracy of the magnitude of the transformations is discussed. Previously reported implications for hearing aid selection are supported.

Revised estimate of minimum audible pressure: where is the "missing 6 dB"?

Eardrum pressures at hearing threshold have been calculated from both earphone data (ISO R389-1964 and ANSI S3.6-1969) and free-field data (ISO R226-1961). When head diffraction, external-ear resonance, and an apparent flaw in ISO R226 are accounted for in the free-field data, and real-ear versus coupler differences and physiological noise are accounted for in the earphone data, the agreement between the two derivations is good. At the audiometric frequencies of 125, 250, 500, 1000, 2000, 4000, and 8000 Hz, the estimated eardrum pressures at absolute threshold are 30, 19, 12, 9, 15, 13, and 14 dB SPL, respectively. Except for the effects of physiological noise at low frequencies, no evidence of the "missing 6 dB" is seen, an observation consistent with the experimental results of several recent studies.