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1.
Audiol Neurotol Extra ; 6(2): 20-39, 2016.
Article in English | MEDLINE | ID: mdl-27990155

ABSTRACT

This study examined potential prevention of music-induced temporary threshold shift (TTS) in normal-hearing participants. A dietary supplement composed of ß-carotene, vitamins C and E, and magnesium was assessed using a randomized, placebo-controlled, double-blind study design. Dosing began 3 days prior to the music exposure with the final dose consumed approximately 30-min pre-exposure. There were no group differences in post-exposure TTS or music-induced decreases in distortion product otoacoustic emission (DPOAE) amplitude. Transient tinnitus was more likely to be reported by the treatment group, but there were no group differences in perceived loudness or bothersomeness. All subjects were monitored until auditory function returned to pre-exposure levels. Taken together, this supplement had no effect on noise-induced changes in hearing. Recommendations for future clinical trials are discussed.

2.
Noise Health ; 13(55): 432-43, 2011.
Article in English | MEDLINE | ID: mdl-22122960

ABSTRACT

Noise-induced hearing loss (NIHL) is a significant clinical, social, and economic issue. The development of novel therapeutic agents to reduce NIHL will potentially benefit multiple very large noise-exposed populations. Oxidative stress has been identified as a significant contributor to noise-induced sensory cell death and NIHL, and several antioxidant strategies have now been suggested for potential translation to human subjects. One such strategy is a combination of beta-carotene, vitamins C and E, and magnesium, which has shown promise for protection against NIHL in rodent models, and is being evaluated in a series of international human clinical trials using temporary (military gunfire, audio player use) and permanent (stamping factory, military airbase) threshold shift models (NCT00808470). The noise exposures used in the recently completed Swedish military gunfire study described in this report did not, on average, result in measurable changes in auditory function using conventional pure-tone thresholds and distortion product otoacoustic emission (DPOAE) amplitudes as metrics. However, analysis of the plasma samples confirmed significant elevations in the bloodstream 2 hours after oral consumption of active clinical supplies, indicating the dose is realistic. The plasma outcomes are encouraging, but clinical acceptance of any novel therapeutic critically depends on demonstration that the agent reduces noise-induced threshold shift in randomized, placebo-controlled, prospective human clinical trials. Although this noise insult did not induce hearing loss, the trial design and study protocol can be applied to other populations exposed to different noise insults.


Subject(s)
Hearing Loss, Noise-Induced/prevention & control , Micronutrients/administration & dosage , Military Personnel , Oxidative Stress/drug effects , Adult , Ascorbic Acid/administration & dosage , Ascorbic Acid/blood , Ascorbic Acid/physiology , Audiometry, Pure-Tone , Cross-Over Studies , Female , Hearing Loss, Noise-Induced/blood , Hearing Loss, Noise-Induced/physiopathology , Humans , Magnesium/administration & dosage , Magnesium/blood , Magnesium/physiology , Male , Micronutrients/blood , Micronutrients/physiology , Otoacoustic Emissions, Spontaneous/drug effects , Otoacoustic Emissions, Spontaneous/physiology , Oxidative Stress/physiology , Sweden , Vitamin E/administration & dosage , Vitamin E/blood , Vitamin E/physiology , Young Adult , beta Carotene/administration & dosage , beta Carotene/blood , beta Carotene/physiology
3.
Int J Audiol ; 50 Suppl 1: S21-31, 2011 Mar.
Article in English | MEDLINE | ID: mdl-21288064

ABSTRACT

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.


Subject(s)
Hearing Loss/epidemiology , Students/statistics & numerical data , Universities/statistics & numerical data , Acoustic Stimulation , Adolescent , Adult , Analysis of Variance , Audiometry, Pure-Tone , Auditory Threshold , Chi-Square Distribution , Female , Hearing Loss/diagnosis , Hearing Loss/physiopathology , Humans , MP3-Player , Male , Music , Prevalence , Risk Assessment , Risk Factors , Self Report , Sex Factors , Young Adult
4.
Am J Med Genet ; 108(4): 295-303, 2002 Apr 01.
Article in English | MEDLINE | ID: mdl-11920834

ABSTRACT

Charcot-Marie-Tooth disease (CMT) is a clinically and genetically heterogeneous group of polyneuropathies characterized by degeneration of peripheral nerves, resulting in distal muscle atrophy, sensory loss, and deformities of hands and feet. We have studied 34 individuals in a large 84-member four-generation central Illinois family with autosomal dominant Charcot-Marie-Tooth and deafness. Nerve conduction velocities are consistent with type 1 CMT. Audiological evaluation revealed both auditory neuropathy and cochlear involvement in affected individuals. There is increasing clinical severity and younger age of onset of CMT and deafness with each progressive generation, suggestive of anticipation (P < 0.05). The proband, a female diagnosed at birth with hypotonia, bilateral vocal cord palsy, swallowing incoordination, and hearing impairment, died at age 18 months. Another individual died at the age of 3 months from hypotonia later attributed to CMT. Genetic analysis indicated that affected individuals in this family do not have the common 1.4 Mb duplication associated with type 1A CMT; however, all affected individuals have a unique G to C transversion at position 248 in coding exon 3 of the peripheral myelin PMP22 gene located on chromosome 17p11.2-p12. This mutation is predicted to cause an Ala67Pro substitution in the second transmembrane domain of PMP22, consistent with the molecular cause of the CMT phenotype. However, it does not explain the cochlear component of the deafness, the clinical observation of anticipation, and other features in this family.


Subject(s)
Charcot-Marie-Tooth Disease/pathology , Deafness/pathology , Adolescent , Adult , Charcot-Marie-Tooth Disease/genetics , Child , Child, Preschool , DNA/chemistry , DNA/genetics , DNA Mutational Analysis , Deafness/genetics , Family Health , Fatal Outcome , Female , Hearing Tests , Humans , Infant , Male , Middle Aged , Mutation , Myelin Proteins/genetics , Pedigree , Sural Nerve/pathology , Sural Nerve/ultrastructure , Trinucleotide Repeats/genetics
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