Ears are amazing organs that connect you to other people and your environment. Most people in Spokane take their sense of hearing for granted—until it starts to fade. Hearing loss is typically a very gradual, painless process, so patients often aren’t aware that their hearing is impaired until the condition becomes severe enough to seriously impact their lifestyle and relationships.
Anatomy of the Ear
Your hearing organ can be divided into three segments: the outer ear, middle ear and inner ear. The complete auditory system also includes the auditory nerves and the brain’s hearing center. Here’s a closer look at your auditory system:
- The outer ear consists of the pinna or auricle, ear canal and eardrum. The pinna helps gather and intensify sound, directing it down the ear canal. The traveling sound next hits the eardrum and the formerly acoustic sound waves are converted to mechanical sound waves, being intensified once again in the process.
- The middle ear begins at the eardrum and is the air-filled space behind it. Connected to the inside of the eardrum is a tiny bone called the malleus, which in turn is connected to the incus, which in turn is connected to the stapes. These three bones are known collectively as the ossicles and are the smallest bones in our bodies. The sound wave, (now a vibration) is transmitted along this ossicular chain until the stapes makes contact to the fluid-filled cochlea of the inner ear.
- The inner ear begins with a thin membrane-covered opening to the cochlea called the oval window. The cochlea contains the hair cells or nerves vital to hearing. As the vibrating stapes “pushes” into the cochlea, it disturbs the fluid, causing a wave. This wave moves the hair cells (envision a kelp bed swaying as ocean waves pass through it) causing a signal to be sent along the auditory nerve. Humans have both inner and outer hair cells. The outer hair cells work to amplify and fine-tune incoming sound, while the inner hair cells send the information to the brain for interpretation.
- The hearing center in the brain translates these signals into what you perceive as sound while also sending information back to the cochlea. Audiologists are still working to gain a full understanding of the biochemistry of the cochlea, auditory nerve and hearing center. We know that while information is traveling up to the brain, the brain is sending information back to the cochlea, telling it which sounds to amplify and pay attention to and which ones to ignore.
Anything that impedes the transmission of sound along the auditory pathway causes hearing loss. There are many potential problems, including wax in the ear canal that blocks the incoming sound, a disconnected ossicular chain, noise-damaged outer hair cells and injury resulting in trauma to the hearing center or auditory cortex of the brain.
Many hearing losses can be corrected through medical or surgical intervention. Some, however, are permanent in nature and need to be remediated with hearing instruments. These latter cases are our focus at Columbia Hearing Centers.
To develop a successful long-term treatment plan for your individual needs, first we need to know the type, severity and frequency of your hearing impairment. We determine this through a complete hearing evaluation. The results of each patient’s hearing tests are charted on an audiogram, which is a graphic representation of hearing that helps reveal how your hearing loss impacts your daily communication abilities.
Hearing tests also reveal what areas of speech are impacted by your hearing loss. Low-frequency hearing loss means you have trouble hearing vowel sounds, while high-pitched impairments will cause you to lose consonants. When you don’t hear all sounds at a comfortable volume, speech sounds soft and distorted. This can make you think that others are mumbling or cause you to identify speech sounds without understanding what’s being said. These are common signs of hearing loss.
Hearing Loss in the Outer or Middle Ear
Typical problems with the outer ear include earwax buildups and infections of the auditory canal. Treating these problems is usually easy and effective, but it’s important to act quickly in order to avoid hearing damage. Outer or middle ear impairments are called conductive hearing loss.
Inflammation, fluid behind the eardrum, perforations of the eardrum and otosclerosis (a stiffening of the bones in the middle ear) are the most common problems to interfere with middle ear function. Most outer and middle ear problems can be addressed effectively with medication or surgery. If this is not possible or the hearing loss is permanent, you’ll probably be treated with hearing aids.
Hearing Loss in the Inner Ear
The majority of hearing issues concern the inner ear. This is called sensorineural hearing loss. The most common cause is the natural aging process, but loud noise, ototoxic medications or injuries also frequently result in sensorineural hearing loss. Inner ear damage affects the fine hair cells of the cochlea and the transmission of signals along the auditory nerves. Inner ear hearing loss can’t typically be addressed with medication or surgery and is usually corrected with hearing aids or occasionally cochlear implants.