Occlusion Of External Ear Canal Research Articles

Contralateral occlusion test: The effect of external ear canal occlusion on predicting conductive hearing loss

Introduction and objectivesThe contralateral occlusion test (COT) has the potential to allow the quantitative evaluation of unilateral conductive hearing loss. The purpose of this study was to determine the accuracy of the test in predicting the degree of hearing loss. Materials and methodsFifty-three subjects with unilateral conductive hearing loss were recruited from an otolaryngology department of a tertiary hospital. The COT was performed using 128, 256, 512, 1024 and 2048Hz tuning forks with the non-affected ear canal totally occluded to determine lateralization. Pure-tone audiometry was performed to establish the presence and degree of the air-bone gap (ABG) and the pure-tone average (PTA). The tuning fork responses were correlated with the ABG and the PTA to determine their accuracy. ResultsThe COT showed a better association between hearing loss and the lateralization response using the 512Hz tuning fork (p=0.001). The sensitivity of the 512Hz fork in detecting a PTA of at least 35.6dB was 94.6% and the specificity was 75.0% for a positive predictive value of 89.7% and a negative predictive value of 85.7%, assuming a pretest prevalence of 69.8%. ConclusionsThe overall accuracy of the COT in predicting the degree of unilateral conductive hearing loss was significant. The COT had significant power in one direction: if lateralization to the affected ear occurred, it was almost certain evidence of a moderate or severe conductive hearing loss.

Contralateral occlusion test: The effect of external ear canal occlusion on predicting conductive hearing loss

Introduction and objectivesThe contralateral occlusion test (COT) has the potential to allow the quantitative evaluation of unilateral conductive hearing loss. The purpose of this study was to determine the accuracy of the test in predicting the degree of hearing loss. Materials and methodsFifty-three subjects with unilateral conductive hearing loss were recruited from an otolaryngology department of a tertiary hospital. The COT was performed using 128, 256, 512, 1024 and 2048Hz tuning forks with the non-affected ear canal totally occluded to determine lateralization. Pure-tone audiometry was performed to establish the presence and degree of the air-bone gap (ABG) and the pure-tone average (PTA). The tuning fork responses were correlated with the ABG and the PTA to determine their accuracy. ResultsThe COT showed a better association between hearing loss and the lateralization response using the 512Hz tuning fork (p=0.001). The sensitivity of the 512Hz fork in detecting a PTA of at least 35.6dB was 94.6% and the specificity was 75.0% for a positive predictive value of 89.7% and a negative predictive value of 85.7%, assuming a pretest prevalence of 69.8%. ConclusionsThe overall accuracy of the COT in predicting the degree of unilateral conductive hearing loss was significant. The COT had significant power in one direction: if lateralization to the affected ear occurred, it was almost certain evidence of a moderate or severe conductive hearing loss.

Contralateral Occlusion Test (COT): the effect of external ear canal occlusion with aging.

This study aimed to evaluate the effects of complete external ear canal occlusion on hearing thresholds with aging. The goal was to decide which tuning fork is more appropriate to use for the contralateral occlusion test (COT), in individuals of different ages. Forty-two normal hearing subjects between 21 and 67 years were divided into three age groups (20-30 years, 40-50 years, and 60-70 years). Participants underwent sound field audiometry tests with warble tones, with and without ear canal occlusion. Each ear was tested with the standard frequencies (250, 500, 1000, and 2000 Hz). The contralateral ear was suppressed by masking. Hearing thresholds showed an increase as the frequency increased from 20.85 dB (250 Hz, 20-30 years group) to 48 dB (2000 Hz, 60-70 years group). The threshold differences between occlusion and no occlusion conditions were statistically significant and increased ranging from 11.1 dB (250 Hz, 20-30 years group) to 32 dB (2000 Hz, 20-30 years group). We found statistically significant differences for the three age groups and for all evaluations except to 500 Hz difference and average difference. The mean hearing loss produced by occlusion at 500 Hz was approximately 19 dB. We found no statistically significant differences between right and left ears and gender for all measurements. We conclude that the use of the 512 Hz tuning fork is the most suitable for COT, and its use may allow clinicians to distinguish mild from moderate unilateral conductive hearing loss.

Contralateral Occlusion Test: The effect of external ear canal occlusion on hearing thresholds

Introduction and goalsBedside testing with tuning forks may decrease turnaround time and improve decision making for a quick qualitative assessment of hearing loss. The purpose of this study was to quantify the effects of ear canal occlusion on hearing, in order to decide which tuning fork frequency is more appropriate to use for quantifying hearing loss with the Contralateral Occlusion Test. MethodsTwenty normal-hearing adults (forty ears) underwent sound field pure tone audiometry with and without ear canal occlusion. Each ear was tested with the standard frequencies. The contralateral ear was suppressed with by masking. Ear occlusion was performed by two examiners. ResultsParticipants aged between 21 and 30 years (25.6±3.03 years) showed an increase in hearing thresholds with increasing frequencies from 19.94dB (250Hz) to 39.25dB (2000Hz). The threshold difference between occluded and unoccluded conditions was statistically significant and increased from 10.69dB (250Hz) to 32.12dB (2000Hz). There were no statistically significant differences according to gender or between the examiners. ConclusionThe occlusion effect increased the hearing thresholds and became more evident with higher frequencies. The occlusion method as performed demonstrated reproducibility. In the Contralateral Occlusion Test, 256Hz or 512Hz tuning forks should be used for diagnosis of mild hearing loss, and a 2048Hz tuning fork should be used for moderate hearing loss.

Contralateral Occlusion Test: The effect of external ear canal occlusion on hearing thresholds

Introduction and goalsBedside testing with tuning forks may decrease turnaround time and improve decision making for a quick qualitative assessment of hearing loss. The purpose of this study was to quantify the effects of ear canal occlusion on hearing, in order to decide which tuning fork frequency is more appropriate to use for quantifying hearing loss with the Contralateral Occlusion Test. MethodsTwenty normal-hearing adults (forty ears) underwent sound field pure tone audiometry with and without ear canal occlusion. Each ear was tested with the standard frequencies. The contralateral ear was suppressed with by masking. Ear occlusion was performed by two examiners. ResultsParticipants aged between 21 and 30 years (25.6±3.03 years) showed an increase in hearing thresholds with increasing frequencies from 19.94dB (250Hz) to 39.25dB (2000Hz). The threshold difference between occluded and unoccluded conditions was statistically significant and increased from 10.69dB (250Hz) to 32.12dB (2000Hz). There were no statistically significant differences according to gender or between the examiners. ConclusionThe occlusion effect increased the hearing thresholds and became more evident with higher frequencies. The occlusion method as performed demonstrated reproducibility. In the Contralateral Occlusion Test, 256Hz or 512Hz tuning forks should be used for diagnosis of mild hearing loss, and a 2048Hz tuning fork should be used for moderate hearing loss.

Frequency of Profound Congenital Hearing Loss in Healthy Newborn Infants in Fars Province

Introduction Deafness is one of the most important sensory disturbances at birth. Hearing loss can affect the development of speaking and learning during life. Early diagnosis and intervention improve language outcome. The current study aimed to determine the frequency of profound congenital hearing loss in healthy newborn infants in Fars province. Methods In a multicenter prospective study, from August 2010 to August 2011, 12573 newborns were screened for hearing loss prior to discharge from the wellborn nursery at nine teaching and private hospitals in Fars province. A three-stage hearing screening protocol using transient evoked otoacoustic emissions (TEOAE) screening with referral for diagnostic second TEOAE and auditory brainstem evoked response (ABER) assessment was employed. All neonates with abnormal initial TEOAE screening, followed with phone call for language outcome after one year. Newborns with hospital admission or drug administration excluded from the study.Results The overall pass rate in the initial screening was 91.8%, thus 1019(8.1/1000) neonates referred for diagnostic audiological assessments. Out of 1019 infants scheduled for follow-up study, only 619 neonates returned. Using follow-up letters and phone calls, it was managed to improve the response rate for language outcome after one year. Two infants were identified with profound bilateral congenital hearing impairment. These infants were immediately referred for cochlear implantation.Conclusion Findings of the current study showed that the frequency of profound congenital hearing loss is 0.159/1000 normal newborn infants in Fars province. The initial TEOAE has high false positive that may be due to occlusion of external ear canal by vernix in the early postnatal period.

일측 외이도 폐쇄시의 전정기능의 변화

Background & Objectives: The mechanism for maintaining balance in human is dependent on visual, vestibular, proprioceptive and superficial sensory information. We supposed that another information, auditory stimulation, may affect the balance system and cause dizziness in patient with conductive hearing loss. The purpose of this study is to know whether the exclusion of sound influences the balance system. Materials & Methods: Ten otologically healthy young person were tested before and after the occlusion of right external auditory canal. Computerized dynamic posturography (CDP), electronystagmography (ENG), and rotation chair test (RCT) were done. Results: The composite score of CDP after occlusion was 78.7, which was slightly decreased comprare to before the occlusion (82.1). The phase of SHA test showed phase lead after occlusion compare to pre-occlusion. Symmetry showed asymmetric change to opposite side of occluded ear compare to pre-occlusion. Conclusions: Though statistically not verified, occlusion of external ear canal might influence the balance system. Further studies will be needed to evaluate the relationship between conductive hearing loss and balance system. (J Clinical Otolaryngol 2005;16:124–127)

Acquired resistance to acoustic trauma by sound conditioning is primarily mediated by changes restricted to the cochlea, not by systemic responses

Hearing loss caused by intense sound exposure can be significantly reduced by pre-exposing subjects to moderate-level acoustic stimuli. This phenomenon occurs in a variety of mammals. We investigated whether sound conditioning provides acquired resistance to acoustic trauma through local mechanisms selectively in the conditioned ears or if systemic mechanisms are involved that would yield contralateral protection in unconditioned ears. Guinea pigs (group I) in which one external ear canal was occluded were exposed to conditioning sound (2–20 kHz, 85 dB SPL, 5 h/day, 10 days). After removing the occlusion, the animals were then subjected bilaterally to intense noise (2–20 kHz, 110 dB SPL, 5 h) 5 days after the last conditioning exposure. Animals without ear canal occlusion were also exposed to the intense sound without conditioning (group II) or following the same conditioning exposure (group III). Intense sound exposure caused significantly greater permanent ABR threshold shifts at all frequencies tested (4, 8, 12, 16 and 20 kHz) in group II than in group III. In group I, the occluded ears showed significantly greater threshold shifts at all frequencies compared to the unoccluded ears. The threshold shifts in the occluded ears in group I were identical to those observed in group II; and the shifts in unoccluded ears in group I were identical to those in group III. Protective effects provided by sound conditioning were almost the same in group III and in the unoccluded ears in group I. The extent of hair cell damage supported the physiological findings. These results indicate that acquired resistance to acoustic trauma provided by sound conditioning is restricted to the cochlea exposed to conditioning sound, suggesting that conditioning protection is mediated primarily by the changes that occur locally within the conditioned cochlea. This animal model, with unilateral external ear canal occlusion during sound conditioning, is useful for studies of the mechanisms of conditioning protection.