Hearing Loss and Assessment

There Are Three Main Types of Hearing Loss:

  1. SENSORINEURAL - This loss occurs when there is damage to the inner ear mechanism (cochlea, vestibular system or auditory nerve). This is typically a permanent, non-medical type of hearing loss, and usually helped by amplification.
  2. CONDUCTIVE - This loss occurs when there is a problem with the outer or middle ear and sounds are not transmitted properly. This type of hearing loss is usually treatable through medical intervention. If not, then a hearing aid is the second choice of treatment.
  3. MIXED - This loss occurs with a combination of sensorineural and conductive components.

Figure 1: Photo of an ear and parts

Attributed to the American Academy of Audiology

Identifying Factors of a Hearing Loss:

  • Do you have difficulty conversing in a noisy environment?
  • Do you feel that people do not speak clearly or loud enough?
  • Do you miss parts of a conversation?
  • Do you ever answer a question incorrectly because you misheard it?
  • Do you hear better when you watch the speaker's face?
  • Do you ever have difficulty hearing what is said on the TV, or over the telephone?
  • Do you ever feel frustrated or isolated if you are unable to follow a conversation.

Statistics

The most recent statistics compiled from the National Institute on Deafness and Other Communication Disorders (NIDCD):

  • Approximately 36 million Americans have a hearing impairment
  • Hearing loss affects approximately 17 in 1,000 children under age 18.
  • Approximately 314 in 1,000 people over the age 64 have hearing loss, and 40 to 50 percent of people 75 years and older have hearing loss.
  • Ten million Americans have suffered irreversible noise induced hearing loss, and 30 million more are exposed to dangerous noise levels each day.
  • Only 1 out of 5 people who could benefit from using a hearing aid actually wears one.

Hearing Loss Assessment:

Hearing loss is measured using a machine called an audiometer. Pure tone sounds are emitted at various pitches and loudness levels to which threshold responses are reported and plotted on a graph called an audiogram.

Frequency in Hertz

Attributed to the American Academy of Audiology

The audiogram is based on a logarithmic scale reported as a function of frequency (pitch) and decibels (loudness). Thereby hearing loss is described in terms of degree. Thresholds that fall in the yellow shaded area of the graph between 0dB - 25dB reflect normal hearing acuity. Thresholds within the blue shaded area of 26dB - 40dB reflect a mild loss. Thresholds within the pink shaded area of 41dB- 70B reflect a moderate to moderately-severe loss. Thresholds within the purple shaded area of 71dB - 90dB reflect a severe loss. And thresholds within the green shaded area of 91dB or greater reflect a profound loss.

Additional diagnostic measures include discrimination testing to assess speech audibility and understanding and middle ear function testing to help differentiate between a middle ear vs inner ear pathology.