Understanding the ear anatomy is crucial to learn how we hear, the ear is made up of three parts: the outer, middle, and inner ear. All three parts of the ear are important for detecting sound by working together to move sound from the outer part through the middle and into the inner part of the ear. Ears also help to maintain balance.
Sound entering the outer ear travels through the middle ear and causes the eardrum and ossicles in the middle ear to vibrate. As it travels, it amplifies (becomes louder) and changes from air to liquid.
The middle ear includes the eardrum, the cavity (also called the tympanic cavity), and the ossicles (3 tiny bones that are attached)
- Malleus (or hammer) – long handle attached to the eardrum
- Incus (or anvil) – the bridge bone between the malleus and the stapes
- Stapes (or stirrup) – the footplate; the smallest bone in the body
When the stapes moves, it pushes the oval window, which then moves the cochlea. The cochlea takes the fluid vibration of sounds from the surrounding semicircular ducts and translates them into signals that are sent to the brain by nerves like the vestibular nerve and cochlear nerve.
The Inner ear includes the oval window – connects the middle ear with the inner ear, the semicircular ducts – filled with fluid; attached to cochlea and nerves; send information on balance and head position to the brain and the cochlea – spiral-shaped organ of hearing; transforms sound into signals that get sent to the brain and the auditory tube that drains fluid from the middle ear into the throat behind the nose
An audiogram is used to record and display hearing thresholds, which are the softest levels at which a sound (or speech) is audible to the listener. The top axis depicts frequency (or what we perceive as pitch) which are most important for speech because most speech sounds fall somewhere within this frequency range, while The side axis depicts intensity (or what we perceive as loudness)
HEARING LOSS SIGNS
Hearing loss affects patients in many ways. Over time, it can lead to anxiety, depression, isolation, and loneliness. In children, it can result in behavioral problems, social problems, and academic challenges. Therefore, intervention for hearing loss must be done promptly to minimize its negative impact on patients.
If you think your hearing might be impaired, answering these questions is the right place to start:
Do others comment that the TV volume is too loud?
Can you hear the doorbell or the telephone ringing?
Do you have trouble following conversations in crowded or noisy environments?
Do people seem to mumble and not speak clearly during conversation?
Do people tell you that you speak too loudly?
Do you frequently ask people to repeat themselves?
If you answered yes to any of these questions, there is a chance that you may have some degree of hearing loss. We recommend that you have a hearing test done by an audiologist.
HEARING LOSS TYPES
There are three common types of hearing loss, based on one or more ear parts malfunctions as below:
happens when a disorder limits the transmission of sound through the outer or middle ear. This hearing loss can usually be treated medically or surgically. If the hearing problem can’t be solved medically, a hearing instrument can provide sufficient hearing improvement.
Happens when the disorder affects the sensory cells within the cochlea or the neural pathways. In this case the inner ear and/or the neural pathways are less efficient in perceiving the signal and HL is usually due to cochlea sensory cells damage or the fine endings of the auditory nerve.
Mixed hearing loss is a term used to describe the simultaneous occurrence of conductive and sensorineural hearing loss. Treatment options for this type of hearing loss can include medical procedures and the use of hearing aids.
A hearing aid is a small electronic – amplifying device that you wear in or behind your ear. It makes some sounds louder so that a person with hearing loss can listen, communicate, and participate more fully in daily activities. A hearing aid can help people hear more in both quiet and noisy situations.
Most hearing aids share several similar electronic components; a microphone, amplifier, speaker. The hearing aid receives sound through a microphone, which transfers the sound waves to electrical signals and sends them to an amplifier. The amplifier increases the power of the signals and then sends them into the ear canal through a speaker.
Hearing aids differ in design, technology used to achieve amplification & special features associated with sound quality.
The selection of hearing aids is based on the type and severity of hearing loss, listening needs, and lifestyle.