Hearing loss typically occurs gradually over a long span of time. Because the loss is not sudden, the effects may be difficult to recognize. The same is often true of failing eyesight, when signs are not as clear and reading small print becomes difficult. With hearing loss, we begin to adjust to hearing changes and forget the clarity of sound we enjoyed with normal hearing.
Because early diagnosis and treatment is important, the first step is recognizing the most common signs of hearing loss. It may be time to visit a hearing healthcare provider, if you experience some of the following:
Conductive Hearing Loss – Originates from the outer or middle ear. Many conductive hearing loss sufferers are children, although it can affect adults. Causes may include middle ear infection, otosclerosis, cerumen (ear wax) blockage, outer ear deformity, punctured ear drum, or damaged middle ear bones. In most instances, this type of hearing loss can be treated medically or surgically.
Sensorineural Hearing Loss – The most common type of hearing loss is sometimes described as Nerve-related Deafness. The loss originates from nerve damage in the inner ear and reduces the quality and intensity of sound perception. Causes range from aging, heredity and infections to exposure to loud noise or abnormal fluid volume. While this hearing loss is permanent, effective treatment with a hearing instrument amplifies sound and increases hearing sensitivity.
Mixed Hearing Loss –This type of hearing loss originates in both the outer or middle ear and the inner ear (mixed/combination of conductive and sensorineural hearing loss) and can include surgical and hearing instrument treatment options.
Central Hearing Loss – This type of hearing loss originates from damage or impairment to the nerves of the central nervous system (CNS), either in the pathways to the brain or in the brain itself.
A hearing evaluation is a series of quick and easy tests to determine an individual’s ability to hear. A hearing evaluation may include:
Patient History – Reviews of your medical and hearing history.
Otoscopy – Your ears are visible examined using a lighted magnifier to determine the condition of the ear canals and ear drums.
Tympanometry – A simple pressure test to assess middle ear function.
Audiometry – Testing performed with headphones or insert earphones to find the softest levels of sound you can hear. Tones or beeps as well as speech may be used. The results are then graphed on an audiogram, which shows if there is hearing loss as well as the type and configuration of the hearing loss.
During a hearing evaluation, you will hear a series of tones or “beeps” in one ear at a time. The tones will get softer and softer. You will be asked to respond by either raising your hand or pressing a button whenever you hear the sound. The hearing healthcare professional will find the point at which you can just barely hear the sound for several different frequencies. These points are referred to as your thresholds. Note: Frequencies correspond to the perception of pitch, such as a fog horn (low frequency sound) or a flute (high frequency sound).
The results of the hearing evaluation are recorded on a special graph called an audiogram. The audiogram shows your hearing ability across a range of frequencies. Typical low frequencies sounds include men’s voices, background noise, and vowel sounds while women’s and children’s voices and soft consonant sounds are usually higher in frequency.
The vertical lines (top to bottom) on the audiogram represent the different frequencies from the low to high pitch. Moving left to right on the audiogram would be comparable to moving from left to right on a piano keyboard. Although the human ear can hear frequencies from 20 – 20,000 Hz, the frequencies most crucial for understanding speech are between 500 to 4000 Hz.
The horizontal lines (side to side) on the audiogram represent the level of loudness or intensity of a sound. The 0 decibel (dB) line near the top of the audiogram represents an extremely soft sound. Each horizontal line located below the 0 line represents a louder sound. Moving from top to bottom is similar to increasing the volume control on a radio or television.
Each point located on the audiogram represents the individual’s threshold for a particular frequency, which is at a certain level of loudness. The red Os represent the thresholds for the right ear and the blue Xs represent the thresholds for the left ear.
Thresholds of 0-15dB for children and 0-25 dB for adults are considered, medically to be within normal limits. The audiogram depicted here demonstrates the different degrees of hearing loss.
The hearing healthcare professional may conduct two or more speech tests. The most common two are described here:
The hearing professional uses speech tests to determine how well you are able to differentiate between speech sounds. In other words, how well you understand speech without context and facial cues.
The hearing healthcare professional will discuss the results of your tests and make any necessary recommendations.