The Difference Between Sensorineural and Conductive Hearing Loss
The human ear is made up of many different parts, and just like with any piece of fine machinery, if one or more of these parts stops working, it can lead to big problems.
The parts of the ear fit neatly into four general areas:
- The outer ear
- The middle ear
- The inner ear
- The central auditory pathways
As sound waves enter the outer ear, they can be interrupted at any point on their way to the brain. This results in different types of hearing loss, depending on where the sound waves are interrupted, and why. In other words, each type of hearing loss relates to specific parts of the ear.
The two main types of hearing loss are sensorineural hearing loss and conductive hearing loss. Each of these types of hearing loss can exist on their own (more common), or exist concurrently (less common). When sensorineural hearing loss and conductive hearing loss occur at the same time, this is called mixed hearing loss.
These three types of hearing loss should not be confused with temporary hearing loss, which generally clears up on its own within a couple of weeks.
The type of hearing loss you are experiencing will dictate the type of treatment you will require moving forward. It’s not always as complicated or hopeless as it might seem! To figure out the type of hearing loss you or a loved one is experiencing, a better understanding of the two most common types will help. Let’s start by looking at the more common of the two: sensorineural hearing loss.
Sensorineural Hearing Loss
Most of the aging population experiencing hearing loss have age-related sensorineural hearing loss. But what does that mean, exactly?
Also known as nerve-related hearing loss, as the name suggests, sensorineural hearing loss refers to hearing loss that is the result of nerve damage. It takes place in the inner ear (the cochlea), or anywhere along the nerve pathways that connect the inner ear to the brain. In other words, your outer and middle ear are functioning properly, but some sounds aren’t being interpreted properly and may not be reaching the brain at all.
If you’re having trouble hearing soft or faint sounds, especially in noisy crowds, and are above the age of 55, your hearing loss is most likely sensorineural. You may feel like you’re picking up some sounds around you, but it’s not all crystal clear.
There are several causes of sensorineural hearing loss:
- Symptoms of illness or disease
- Side effects of medication
- Loud noises (frequent exposure)
- Head trauma (mild or severe)
Conductive Hearing Loss
Conductive hearing loss affects the opposite end of the hearing highway: the outer ear. It happens when sound waves are not traveling efficiently from the outside world through to the outer or middle ear.
The trouble can occur anywhere in the outer ear, the ear canal or the middle ear. Simply put, the sound signals hit a roadblock and have trouble making it to the nerve center where they are processed by the brain.
Conductive hearing loss occurs when something is preventing the sound from entering the outer ear or reaching all the way to the inner ear. It can be temporary with medical intervention, and if it is not temporary, can also be treatable. Causes of Conductive hearing loss include:
- Ear infections in the outer ear (for instance swimmer's ear)
- Typical common head colds that can cause fluid buildups in the middle ear
- Ear wax that can block the outer ear canal
- Presence of a foreign objects that can block the outer ear canal
- Perforated eardrum
- Tumors and other growths in the outer and middle ear
- Malformation of one or more of the bones of the middle ear
For some individuals, a genetic condition called otosclerosis could be to blame. Otosclerosis is a stiffening in the joints of the bones in the middle ear over time. This stiffening causes some of the sounds to be left behind when heading towards the inner ear. Often this condition can be improved with an operation but hearing aids are also a great solution if surgery is not a desirable option.