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The Effect of Sound Stimulation on Pure-tone Hearing Threshold

This study has been completed.
Information provided by (Responsible Party):
Earlogic Korea, Inc. Identifier:
First received: August 16, 2010
Last updated: September 7, 2011
Last verified: September 2011

The purpose of this study is to investigate if sound stimulation could improve pure-tone hearing threshold.

In the late 1990s, researchers discovered that acoustic stimuli slow progressive sensorineural hearing loss and exposure to a moderately augmented acoustic environment can delay the loss of auditory function. In addition, prolonged exposure to an augmented acoustic environment could improve age-related auditory changes. These ameliorative effects were shown in several types of mouse strains, as long as the acoustic environment was provided prior to the occurrence of severe hearing loss.

In addition to delaying progressive hearing loss, acoustic stimuli could also protect hearing ability against damage by traumatic noise. In particular, a method called forward sound conditioning (i.e., prior exposure to moderate levels of sound) has been shown to reduce noise-induced hearing impairment in a number of mammalian species, including humans.

Interestingly, recent report has suggested that low-level sound conditioning also reduces free radical-induced damage to hair cells, increases antioxidant enzyme activity, and reduces Cox-2 expression in cochlea, and can enhance cochlear sensitivity. Specifically, increased cochlear sensitivity was observed when distortion product otoacoustic emissions (DPOAEs) and compound action potentials (CAPs) were measured.

In addition to forward sound conditioning, backward sound conditioning (i.e., the use of acoustic stimuli after exposure to a traumatic noise) has been shown to protect hearing ability against acoustic trauma and to prevent the cortical map reorganization induced by traumatic noise.

Based on the results of animal studies, the investigators conducted a human study in 2007 and observed that sound stimulation could improve hearing ability. On average, the pure-tone hearing threshold decreased by 8.91 dB after sound stimulation for 2 weeks. In that study, however, the investigators observed only the hearing threshold changes by sound stimulation.

To verify the previous ameliorative effect of sound stimulation, the investigators included a control period in this study.

Condition Intervention
Sensorineural Hearing Loss Behavioral: Sound stimulation

Study Type: Interventional
Study Design: Allocation: Non-Randomized
Intervention Model: Single Group Assignment
Masking: Open Label
Primary Purpose: Treatment
Official Title: The Effect of Sound Stimulation on Pure-tone Hearing Threshold

Resource links provided by NLM:

Further study details as provided by Earlogic Korea, Inc.:

Primary Outcome Measures:
  • Changes of pure-tone hearing thresholds after sound stimulation [ Time Frame: 4-6 weeks ]

Estimated Enrollment: 30
Study Start Date: May 2010
Study Completion Date: January 2011
Primary Completion Date: December 2010 (Final data collection date for primary outcome measure)
Intervention Details:
    Behavioral: Sound stimulation
    Listening to sound stimuli at the lowest audible level.

Ages Eligible for Study:   18 Years to 70 Years   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • You are a male or female aged between 18 and 70 years
  • You have 25~70 dB HL hearing loss at any frequency above 1.5 kHz
  • You are able to use an mp3 player
  • You are able to read English

Exclusion Criteria:

  • Under the medications that could cause hearing loss (such as gentamicin, aspirin, ibuprofen, or acetaminophen)
  • Chronic disease that could affect hearing (such as diabetes or high blood pressure)
  • Temporal hearing loss
  • Hearing loss more than 75 dB HL at any frequency
  • Ear infections, chronic middle ear disease or any abnormality of the ear canal or ear drum
  • Hearing aid user
  • Pregnant females
  Contacts and Locations
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Please refer to this study by its identifier: NCT01184248

United States, California
Earlogic Corporation
Los Angeles, California, United States, 90005
Sponsors and Collaborators
Earlogic Korea, Inc.
Principal Investigator: Eunyee Kwak, Ph.D. Earlogic Auditory Research Institute