What Is High-Frequency Hearing Loss
People with high-frequency hearing loss can't hear sounds in higher frequencies, such as sounds like the letters s, h and f. On an audiogram, the frequencies go from low to high frequencies. The definition of high frequency varies. Some experts consider 2000 Hertz (2kHz) to be high frequency. The high frequency ranges go from 2000 Hertz to 8000 Hertz. (1000 Hz is considered to be mid-frequency.)
What Happens in High Frequency Hearing Loss?
A high-frequency hearing loss will affect a person's ability to understand speech. This happens because the consonants (s, h, f) are high-frequency sounds that range from 1,500 to 6,000 Hertz. Losing hearing in those frequencies means that those sounds are harder to discern. For children, this can mean a negative impact on their education due to inability to understand speech in the classroom.
High Frequency Hearing Loss Seems Stable in Adults, But Increasing in Teenagers
In an effort to find out how many people have this type of hearing loss, researchers compared data from the 1959-1962 National Health Examination Study, to data from the 1999-2004 National Health and Nutrition Examination Study. Using statistical analysis, they found that from 1999 to 2004, adults heard better compared to adults in the 1959-1962 study.
In the study of teenagers, researchers compared data from the Third National Health and Nutrition Examination Survey (NHANES) for 1988-1994, to data from the 2005-2006 NHANES survey. For the earlier study, data for 2,928 participants was used; for the later study, data for 1,771 participants was used. All the participants were 12 to 19 years old.
The researchers found that from 2005 to 2006, unilateral hearing loss was more common and high-frequency hearing loss was more prevalent among the teenagers, than compared to the teens studied in the late 1980s and early 90s. (The researchers defined high frequency as 3000 to 8000 Hertz.) Specifically, from 1988-1994, the prevalence of high-frequency hearing loss was just 12.8%; but from 2005 to 2006, it was 16.4%. This was considered to be "significantly higher" by the researchers. In their analysis, the researchers did not find any difference in levels of exposure to noise between the two surveys, but pointed out that teenagers tend to underreport and underestimate their level of exposure to noise. Therefore, the jump in high frequency hearing loss among teenagers could be an indication of an increase in exposure to noise, resulting in noise-induced hearing loss.
Other Causes of High-Frequency Loss
Noise is not the only cause of high-frequency hearing loss. There are many causes. Causes include aging (presbycusis), genetics, ototoxicity (such as chemotherapy drugs), and diseases and syndromes. There are also suspected causes such as diabetes.
Preventing High-Frequency Hearing Loss
There are ways to prevent high-frequency hearing loss. People concerned about risks can consider various methods of hearing protection, such as ear plugs.
Managing High-Frequency Hearing Loss
Hearing aids can take the higher frequency sounds and lower them. There are two different ways to do this. The first way, called frequency transposition, takes the higher frequency energies and moves them to a lower frequency, which results in a mixing of the transposed (moved) sound and the non-transposed lower frequency sound. The other way, called nonlinear frequency compression, uses a compression ratio on the high frequency sound to lower it, but does not move it, thereby avoiding mixing with lower frequencies. If you believe you are experiencing hearing loss of this type, seeing an audiologist is crucial.
Treating High-Frequency Hearing Loss
High-frequency hearing loss can be managed by using hearing aids and cochlear implants. Of course, learning sign language and lipreading skills also can help.
Americans Hear as Well or Better Today Compared With 40 Years Ago: Hearing Threshold Levels in the Unscreened Adult Population of the United States, 1959-1962 and 1999-2004. Ear & Hearing. December 2010 - Volume 31 - Issue 6 - pp 725-734
Developmental Disabilities: Hearing Loss. Centers for Disease Control and Prevention. http://www.cdc.gov/ncbddd/dd/hi2.htm
Glista,Danielle MSc; Susan Scollie, PhD; Melissa Polonenko, MCISc; and Jacob Sulkers, BA. A Comparison of Performance in Children with Nonlinear Frequency Compression Systems. Hearing Review. November 2009.
Shargorodsky,Josef, Sharon G. Curhan, Gary C. Curhan, Roland Eavey. Change in Prevalence of Hearing Loss in US Adolescents JAMA. 2010;304(7):772-778.
Simpson, A. Frequency-lowering devices for managing high-frequency hearing loss: a review.Trends in Amplification. 2009 Jun;13(2):87-106.