The Effect of Sound Stimulation on Pure-tone Hearing Threshold

• ClinicalTrials.gov Identifier: NCT01184248
• Recruitment Status: Completed
• First Posted: August 18, 2010
• Last Update Posted: September 8, 2011
• Sponsor: Earlogic Korea, Inc.
• Information provided by (Responsible Party): Earlogic Korea, Inc.

Study Description

Brief Summary:

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 or disease	Intervention/treatment	Phase
Sensorineural Hearing Loss	Behavioral: Sound stimulation	Not Applicable

Study Design

• Study Type: Interventional (Clinical Trial)
• Estimated Enrollment: 30 participants
• Allocation: Non-Randomized
• Intervention Model: Single Group Assignment
• Masking: None (Open Label)
• Primary Purpose: Treatment
• Official Title: The Effect of Sound Stimulation on Pure-tone Hearing Threshold
• Study Start Date: May 2010
• Actual Primary Completion Date: December 2010
• Actual Study Completion Date: January 2011

Arms and Interventions

Intervention Details:

• Behavioral: Sound stimulation
  Listening to sound stimuli at the lowest audible level.

Outcome Measures

Primary Outcome Measures :

1. Changes of pure-tone hearing thresholds after sound stimulation [ Time Frame: 4-6 weeks ]

Eligibility Criteria

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

Criteria

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

Locations

United States, California

Earlogic Corporation

Los Angeles, California, United States, 90005

Sponsors and Collaborators

Earlogic Korea, Inc.

Investigators

• Principal Investigator: Eunyee Kwak, Ph.D.; Earlogic Auditory Research Institute

More Information

Publications:

Canlon B, Borg E, Flock A. Protection against noise trauma by pre-exposure to a low level acoustic stimulus. Hear Res. 1988 Jul 15;34(2):197-200. doi: 10.1016/0378-5955(88)90107-4.

Miyakita T, Hellstrom PA, Frimanson E, Axelsson A. Effect of low level acoustic stimulation on temporary threshold shift in young humans. Hear Res. 1992 Jul;60(2):149-55. doi: 10.1016/0378-5955(92)90017-h.

Harris KC, Bielefeld E, Hu BH, Henderson D. Increased resistance to free radical damage induced by low-level sound conditioning. Hear Res. 2006 Mar;213(1-2):118-29. doi: 10.1016/j.heares.2005.11.012. Epub 2006 Feb 8.

Kujawa SG, Liberman MC. Long-term sound conditioning enhances cochlear sensitivity. J Neurophysiol. 1999 Aug;82(2):863-73. doi: 10.1152/jn.1999.82.2.863.

Niu X, Tahera Y, Canlon B. Protection against acoustic trauma by forward and backward sound conditioning. Audiol Neurootol. 2004 Sep-Oct;9(5):265-73. doi: 10.1159/000080226. Epub 2004 Aug 13.

Norena AJ, Eggermont JJ. Enriched acoustic environment after noise trauma reduces hearing loss and prevents cortical map reorganization. J Neurosci. 2005 Jan 19;25(3):699-705. doi: 10.1523/JNEUROSCI.2226-04.2005.

• Responsible Party: Earlogic Korea, Inc.
• ClinicalTrials.gov Identifier: NCT01184248
• Other Study ID Numbers: IEK14152010
• First Posted: August 18, 2010
• Last Update Posted: September 8, 2011
• Last Verified: September 2011

Additional relevant MeSH terms:

Hearing Loss; Hearing Loss, Sensorineural; Hearing Disorders; Ear Diseases; Otorhinolaryngologic Diseases; Sensation Disorders; Neurologic Manifestations; Nervous System Diseases