Auditory Evoked Potentials in Cats with Neonatal High Frequency Hearing Loss: Evidence of Abnormal Frequency Representation in the Midbrain

OBJECT Microvascular decompression is a safe and effective procedure to treat hemifacial spasm, but the operation poses some risk to the patient’s hearing. While severe sensorineural hearing loss across all frequencies occurs at a low rate in experienced hands, a recent study suggests that as many as one-half of patients who undergo this procedure may experience ipsilateral high-frequency hearing loss (HFHL), and as many as one-quarter may experience contralateral HFHL. While it has been suggested that drill-related noise may account for this finding, this study was designed to examine the effect of a number of techniques designed to protect the vestibulocochlear nerve from operative manipulation on the incidence of HFHL. METHODS Pure-tone audiometry was performed both preoperatively and postoperatively on 67 patients who underwent microvascular decompression for hemifacial spasm during the study period. A change of greater than 10 dB at either 4 kHz or 8 kHz was considered to be HFHL. Additionally, the authors analyzed intraoperative brainstem auditory evoked potentials from this patient cohort. RESULTS The incidence of ipsilateral HFHL in this cohort was 7.4%, while the incidence of contralateral HFHL was 4.5%. One patient (1.5%; also included in the HFHL group) experienced an ipsilateral nonserviceable hearing loss. CONCLUSIONS The reduced incidence of HFHL in this study suggests that technical modifications including performing the procedure without the use of fixed retraction may greatly reduce, but not eliminate, the occurrence of HFHL following microvascular decompression for hemifacial spasm.

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Modified Earpieces and CROS for High Frequency Hearing Losses

Journal of Speech and Hearing Research ◽

10.1044/jshr.1101.204 ◽

1968 ◽

Vol 11 (1) ◽

pp. 204-218 ◽

Cited By ~ 9

Author(s):

Elizabeth Dodds ◽

Earl Harford

Keyword(s):

Hearing Loss ◽

Hearing Aids ◽

High Frequency ◽

Hearing Aid ◽

Sound Field ◽

Intensity Level ◽

Test Results ◽

High Frequency Hearing Loss ◽

Increased Sensitivity ◽

Difficult Cases

Persons with a high frequency hearing loss are difficult cases for whom to find suitable amplification. We have experienced some success with this problem in our Hearing Clinics using a specially designed earmold with a hearing aid. Thirty-five cases with high frequency hearing losses were selected from our clinical files for analysis of test results using standard, vented, and open earpieces. A statistical analysis of test results revealed that PB scores in sound field, using an average conversational intensity level (70 dB SPL), were enhanced when utilizing any one of the three earmolds. This result was due undoubtedly to increased sensitivity provided by the hearing aid. Only the open earmold used with a CROS hearing aid resulted in a significant improvement in discrimination when compared with the group’s unaided PB score under earphones or when comparing inter-earmold scores. These findings suggest that the inclusion of the open earmold with a CROS aid in the audiologist’s armamentarium should increase his flexibility in selecting hearing aids for persons with a high frequency hearing loss.

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Length of Time of iPod Use, Not Volume, is Related to High Frequency Hearing Loss

PsycEXTRA Dataset ◽

10.1037/e741342011-100 ◽

2009 ◽

Author(s):

M. Todd Allen ◽

Cynthia L. Clark

Keyword(s):

Hearing Loss ◽

High Frequency ◽

High Frequency Hearing Loss

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Evaluating the Effectiveness of Earplugs in Preventing Noise-Induced Hearing Loss in an Auto Parts Factory in China

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18137190 ◽

2021 ◽

Vol 18 (13) ◽

pp. 7190

Author(s):

Wei Gong ◽

Liangliang Zhao ◽

Ling Li ◽

Thais C. Morata ◽

Wei Qiu ◽

...

Keyword(s):

Hearing Loss ◽

High Frequency ◽

Health And Safety ◽

Health Department ◽

Detectable Effect ◽

High Frequency Hearing Loss ◽

Mandatory Requirement ◽

Exposed Workers ◽

Fit Testing ◽

Auto Parts

A survey was administered to 385 noise-exposed workers from an auto parts factory and 1268 non-noise-exposed health department employees in China. Individual 8 h A-weighted equivalent sound levels (LAeq,8h), earplug personal attenuation ratings (PARs), and pure-tone audiometric tests were performed. The average LAeq,8h of noise-exposed workers was 87 dB (A) with a mean PAR of 7 dB. The prevalence of high-frequency hearing loss was 65% for noise-exposed workers and 33% for the non-noise-exposed employees. The use of earplugs had no observable effect on the prevalence of high-frequency hearing loss of the study participants (OR 0.964, 95% CI 0.925–1.005, p = 0.085). No significant relationship between the effectiveness offered by earplug use and high-frequency hearing thresholds at 3, 4, and 6 kHz was found (t = −1.54, p = 0.125). The mandatory requirement of earplug use without individualized training on how to wear HPDs correctly had no detectable effect on the prevention of hearing loss at the auto parts factory. The hearing conservation program at the surveyed factory was not effective. Periodic hearing tests, earplug fit testing, expanding the offer of different types of hearing protection, and employee education about the importance of protecting their hearing were recommended to the occupational health and safety program.

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Caudal Pontine Reticular Formation of C57BL/6J Mice: Responses to Startle Stimuli, Inhibition by Tones, and Plasticity

Journal of Neurophysiology ◽

10.1152/jn.1998.79.5.2603 ◽

1998 ◽

Vol 79 (5) ◽

pp. 2603-2614 ◽

Cited By ~ 49

Author(s):

Stephanie Carlson ◽

James F. Willott

Keyword(s):

Hearing Loss ◽

Reticular Formation ◽

Auditory System ◽

Neural Plasticity ◽

High Frequency ◽

Acoustic Startle ◽

Acoustic Startle Response ◽

Pontine Reticular Formation ◽

High Frequency Hearing Loss ◽

Old Mice

Carlson, Stephanie and James F. Willott. Caudal pontine reticular formation of C57BL/6J mice: responses to startle stimuli, inhibition by tones, and plasticity. J. Neurophysiol. 79: 2603–2614, 1998. C57BL/6J (C57) mice were used to examine relationships between the behavioral acoustic startle response (ASR) and the responses of neurons in the caudal pontine reticular formation (PnC) in three contexts: 1) responses evoked by basic startle stimuli; 2) the prepulse inhibition (PPI) paradigm; and 3) the effects of high-frequency hearing loss and concomitant neural plasticity that occurs in middle-aged C57 mice. 1) Responses (evoked action potentials) of PnC neurons closely paralleled the ASR with respect to latency, threshold, and responses to rapidly presented stimuli. 2) “Neural PPI” (inhibition of responses evoked by a startle stimulus when preceded by a tone prepulse) was observed in all PnC neurons studied. 3) In PnC neurons of 6-mo-old mice with high-frequency (>20 kHz) hearing loss, neural PPI was enhanced with 12- and 4-kHz prepulses, as it is behaviorally. These are frequencies that have become “overrepresented” in the central auditory system of 6-mo-old C57 mice. Thus neural plasticity in the auditory system, induced by high-frequency hearing loss, is correlated with increased salience of the inhibiting tones in both behavioral and neural PPI paradigms.

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