Acoustics. Statistical distribution of hearing thresholds of otologically normal persons in the age range from 18 years to 25 years under free-field listening conditions

Introduction Treatment of cholesteatoma consists of either excision or exteriorisation of disease. Approaches have traditionally included a radical or modified radical mastoidectomy and combined approach tympanoplasty. Hearing thresholds following a modified radical mastoidectomy alone have been reported as poor. We assessed hearing outcomes in patients undergoing a primary malleostapedial reconstruction combined with their open cavity surgery. Methods All patients undergoing open cavity mastoidectomy with primary malleostapedial rotation ossiculoplasty between 2009 and 2013 were identified. Case notes were reviewed, and demographic data, recurrence rate and audiometry were recorded. Results Twenty-one patients were identified. The age range was 10–65 years. There was no evidence of recurrence of cholesteatoma. The mean postoperative air-bone gap was 20dBHL, 23dBHL, 10dBHL and 27dBHL at 0.5kHz, 1kHz, 2kHz and 4kHz respectively. Excluding cases consistent with a postoperative ossicular discontinuity (n=3), the mean postoperative air-bone gap was 15dBHL, 19dBHL, 8dBHL and 26dBHL at 0.5kHz, 1kHz, 2kHz and 4kHz respectively. Conclusions The improvement in hearing thresholds demonstrated in this cohort of patients supports the use of this form of ossiculoplasty in those undergoing open cavity procedures. This would also suggest that the subsequent use of hearing aids in these patients would require less amplification and therefore provide superior hearing outcomes. As hearing loss remains a significant concern following modified radical mastoidectomy, we suggest an open cavity with primary malleostapedial rotation ossiculoplasty as a viable alternative to modified radical mastoidectomy alone, in selected cases.

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The comparison of changes in hearing thresholds and insertion losses due to occlusion induced by ear impression in sound field assessment

Auditory and Vestibular Research ◽

10.18502/avr.v29i2.2788 ◽

2020 ◽

Author(s):

Seyyed Hossein Hosseini ◽

Nariman Rahbar ◽

Seyyed Jalal Sameni

Keyword(s):

Insertion Loss ◽

Behavioral Assessment ◽

Sound Field ◽

Threshold Condition ◽

Behavioral Threshold ◽

Hearing Thresholds ◽

Field Assessment ◽

The Difference ◽

Age Range ◽

Insertion Losses

Background and Aim: The methods of determining the amount of sound attenuation by ear mold, earplug or any other foreign body that placed in or out of the ear canal, is divided in subjective and objective. Due to the contradictory results in the studies in this field, this study aimed to use more audiometric frequencies considering the strengths and weaknesses of previous studies. Methods: This study was conducted on 30 individuals with normal hearing in the age range of 21-26-year-old. First the impression mold was prepared from both ears. The evaluating real ear unaided response and the real ear occluded response. In the next step, hearing thresholds were assessed by sound field with a precision of 1 dB, once in both open ear and once in both closed ears. Finally, the insertion loss due to mold placement at each frequency was compared with the amount of behavioral threshold changes at the same frequency. Results: By using paired t-test at frequencies of 400, 500, 800, 1000, 1500, 1600, 2000, 2500, 3000, 4000, 5000, 6000, 6300 and 8000 Hz, the difference in behavioral hearing thresholds with and without molding was greater than the amount of the insertion loss (p < 0.001). Conclusion: The insertion loss due to impression for behavioral assessment at all of the tested frequencies were more than the attenuation in real ear evaluation (p < 0.001). In this regard, consequently the standard deviation of insertion loss due to impression in behavioral threshold condition was more than real ear measurement. Keywords: Sound field assessment; insertion loss; real ear occluded response; ear impression; probe microphone measurement; real ear measurement

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The Effect of the XM45 Gas Mask and Hood on Directional Hearing

Proceedings of the Human Factors and Ergonomics Society Annual Meeting ◽

10.1177/107118139704100229 ◽

1997 ◽

Vol 41 (2) ◽

pp. 864-867

Author(s):

T. R. Letowski ◽

G. L. Ricard ◽

J. E. Greives

Keyword(s):

Speech Intelligibility ◽

Free Field ◽

Directional Hearing ◽

Directional Sensitivity ◽

Protective Equipment ◽

Spatial Awareness ◽

Hearing Thresholds ◽

Gas Mask ◽

Modified Rhyme Test ◽

Narrow Bands

We measured listeners' directional sensitivity for narrow bands of noise and for speech recognition while they were wearing the XM45 gas mask and hood and compared it to normal free-field listening. Bekesy tracking was used to measure absolute hearing thresholds for 1/3 octave bands of noise centered at 0.125, 0.25, 0.5, 1, 2, 3, 4, 6, and 8 kHz. and masked intelligibility thresholds for speech were measured using the Modified Rhyme Test. Both the noise and speech signals were presented from loudspeakers located at azimuths of 0°, 45°, 90°, 135°, and 180°. The mask and hood significantly elevated noise-band thresholds for those bands centered at 1.0 kHz and above. Sensitivity to masked speech was increased by over 12 dB by lateral loudspeaker placement, and wearing a gas mask and hood reduced this gain by 80 percent. These results document a loss of auditory spatial awareness that has not been apparent from previous studies of speech intelligibility while wearing chemical protective equipment.

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