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Hearing Loss
And Other Ear Disorders

It is estimated that 1 in every 10 Americans has some degree of hearing loss. That figure increases to 1 in 3 by age 65, and 1 out of every 2 persons after age 75. But age is by no means the only cause of decreased hearing ability. Problems can arise in any portion of the auditory system and can be caused by anything from a blockage in the ear canal to lesions in the brain. Hearing loss is classified in three complementary ways: type, degree and configuration.

Type of hearing impairment refers to the functional area of the hearing system that is affected.

Degree of hearing loss describes the amount of impairment, often in terms of anticipated level of difficulty hearing conversational speech.

Configuration describes the range of frequencies (pitches) at which the hearing loss has occurred. This factor influences the ability to hear and distinguish speech sounds.

Types of Hearing Disorders:
Conductive Hearing Loss - the mechanical function of the auditory system has been affected. The source of the problem may be in either the outer or middle ear, or both. Common causes of conductive hearing loss include wax blockage, ruptured eardrum, discontinuity or calcification of the middle ear bones, and fluid/infection in the middle ear space. Symptoms of conductive impairment include speaking softly, a subdued or softened quality in the sounds heard (a reduction in loudness), and good speech understanding once sound is loud enough. Medical treatment or management is often available for this type of hearing disorder.

Sensorineural Hearing Loss - the electrical transmission function and/or the neural pathways have been impaired. Some of the sensory cells of the inner ear may be damaged or missing. Neural fibers along the auditory nerve may also be affected. This type of hearing loss is considered permanent, with no medical treatment for restoration of hearing; however, the source of the impairment may have other medical implications. Common causes of sensorineural hearing loss include heredity, genetics, pre-natal and post-natal health, presbycusis (normal aging of the auditory system), noise exposure, autoimmune disease, certain illnesses, and some drugs and medications. Neural losses may occur from genetic defects, stroke, vascular disorders, or compression of the hearing nerve by a tumor or other lesion. Symptoms of sensorineural hearing loss can include loud speech, not hearing clearly (often "mishearing" words or missing much of what was said) even when speech is loud enough, loss of sensitivity for soft, high-pitch sounds while louder sounds may be uncomfortable.

Mixed Hearing Loss - as the name implies, this type of hearing impairment is characterized by problems in both the conductive (outer/middle ear) and sensory (inner ear/auditory nerve) components of the hearing system. Multiple causes and symptoms may be present simultaneously.

Degrees of Hearing Loss:
This is the most common way we describe hearing loss. Very simplistically stated, it refers to the amount of difficulty the person is likely to experience with normal volume levels of sounds, particularly speech sounds.

Mild hearing loss - The person may only have occasional hearing difficulty, particularly with softer sounds, soft conversational speech, or hearing from a distance.

Moderate hearing loss - Someone with a moderate hearing impairment may only hear adequately well when the sound source is nearby (within 3-5 feet) and the volume is a little louder than normal. Adverse listening conditions such as distance and background noise increase the hearing difficulty significantly.

Moderately-Severe hearing loss - Average level speech sounds become difficult, if not impossible, to understand even in a quiet setting. Loss of visual cues, as when the speaker's back is turned, may result in total loss of ability to track conversational speech.

Severe hearing loss - A person with a severe loss can only perceive loud sounds. Shouted speech may be heard from a close distance.
Profound hearing loss - This describes someone with no functional hearing ability, what we often refer to as "deafness".

Configuration of the Hearing Loss:
Hearing loss usually occurs to differing degrees across the range of pitches (frequencies) that contribute to our perception of sound. Configuration describes the pattern or range of pitches at which the loss has occurred. Common hearing loss configurations include:

Flat - the amount of hearing loss is similar across the frequency range tested on the audiogram.

Sloping - the hearing levels gradually worsen from the low to the high-pitch tones.
Reverse Slope - hearing sensitivity is poorer for the low-pitch tones than the high-pitch tones.

Cookie Bite - the poorest hearing sensitivity is for the middle frequencies, with better hearing for the low and high pitches. This results in a U-shaped pattern on the audiogram resembling that left by a bite out of a cookie.

Ski Slope - the hearing levels may be normal or near normal for the lower pitches but significantly and progressively worsens for the higher pitches.

Corner - the person can perceive only louder low-pitch sounds with no hearing ability for any of the other test tones. On the audiogram, responses appear only near the bottom of the left-hand side of the graph.

It is common for someone to have a mild loss for low pitches and a severe loss for high-pitched sounds. This factor influences the ability to hear speech sounds because normal speech continuously varies in loudness and pitch, even within each word. Vowels tend to be strong, low requency sounds that are easier to hear fairly well even across distances and through background noise. Consonants, however, are weaker and higher in pitch. They tend to "fade out" at a distance and are lost in the louder background noise. Most people do not hear all frequencies equally well, which results in the common complaint, "I can hear, but I can't understand." Also common, although erroneous, is the complaint that the person with hearing loss hears selectively. Speech is a complex signal that not only must be heard across a broad range of frequencies but must also be processed, or translated, in order to be understood.

Disclaimer: The information provided on this website is for informational use only and is not intended to be used as a substitute for evaluation, consultation or diagnosis by a licensed physician or licensed audiologist. Further, it is not intended to be all-inclusive. Always consult with your audiologist and primary care physician regarding matters related to hearing.