How we hear
To understand hearing loss, it helps to understand how hearing works. Your ear is an amazing organ that can perceive sounds from barely audible to very loud and can pinpoint the direction of a sound source to an amazing degree of accuracy
The human ear consists of three parts:
The outer ear
includes the visible part of the ear (pinna) and the ear canal. Sound waves in the air, collected by the pinna travel down the ear
canal to the eardrum (tympanic membrane). The sound waves set the eardrum into vibration.
The middle ear
is an air-filled cavity separated from the outer ear by the eardrum. The middle ear contains the three smallest bones in the
human body, the ossicles. These bones vibrate along with the eardrum and convert sound waves into mechanical energy.
The inner ear
contains the cochlea, which is a snaillike organ filled with fluid and contains thousands of tiny nerve fibers. The mechanical action of theossicles creates movement in the fluid and stimulates the nerve fibers.
The nerve fibers then send electrical impulses along the auditory nerve to the brain, which interprets these impulses as sound.
Types of hearing loss
Conductive hearing loss results from diseases or disorders that limit the transmission of sound through the outer or middle ear. This hearing
loss can often be treated medically or surgically. In some cases, a hearing instrument can provide sufficient hearing improvement.
Sensorineural hearing loss affects the inner ear or neural pathways. In this case, sound is transmitted through the outer and middle ear, but the inner ear is less efficient in transmitting the sound, usually due to damages to the fine haircells inside the cochlea. This leads to reduced perception of sound intensity and quality. This type of hearing loss is usually compensated with a hearing instrument that amplifies sound to overcome the decrease in hearing sensitivity
• Long-term exposure to noise; • Heredity; • Illness; • Reactions to medications; • Injury; • Ear wax; • Aging
Degree of hearing loss Different levels of hearing loss are referred to as degrees, depending on the severity of impairment.
Hearing loss affects a great number of people around the world. And it affects them in a variety of ways. Over time, hearing loss can lead to anxiety, depression, isolation, and loneliness. So by leaving hearing impairment untreated, a physical condition may also become a psychological one. This is why it is so important to seek a solution at an early stage.
None 0 – 25 dB No perceptible difficulty.
Mild 26 – 40 dB Difficulties with hearing soft speech and conversations, but can understand in quiet environments.
Moderate 41 – 55 dB Difficulties with understanding speech, especially in the presence of background noise. Higher volume levels are
needed for hearing TV or radio.
Moderateto severe 56 – 70 dB Clarity of speech is considerably affected. Speech must be loud. Possible difficulties in group conversations.
Severe 71 – 90 dB Normal speech is inaudible; therefore comprehension is only possible through extremely loud or amplified speech.
Profound 91+ dB Even amplified speech is unclear and even inaudible.