You probably already know that strokes can lead to trouble speaking, paralysis, difficult swallowing, loss of motor skills, and more. However, many people don’t realize that a stroke can also cause “invisible” problems which can have a major impact on rehabilitation and recovery – hearing loss.
What is a Stroke?
A stroke is – at its most basic – brain damage caused by a lack of oxygen. Like the rest of the human body, the brain needs oxygen and nutrients to function properly. In a healthy body, blood vessels transport this oxygen and these nutrients to the brain.
If one of these key blood vessels becomes clogged (often with plaque, cholesterol, or a blood clot from another part of the body), the brain cells begin to die. All of this can happen in an instant – within 60 seconds! The longer the stroke victim’s brain goes without oxygen, the more brain damage can be expected.
Many stroke victims must re-learn to perform simple tasks such as speaking and walking. This is because the brain cells where that information was stored died from a lack of oxygenated blood.
Types of Strokes
There are three main types of strokes – ischemic, hemorrhagic, and transient ischemic attacks (TIAs).
Ischemic strokes occur when a blood clot or other substance blocks a blood vessel, thereby depriving parts of the brain of oxygen. About 85% of strokes are ischemic strokes.
Hemorrhagic strokes happen when an artery inside or on the surface of the brain bursts and bleeds, killing brain cells in that area.
TIAs, also known as mini-strokes, occur when something temporarily blocks an artery of the brain, but the blood supply is restored before the brain is permanently damaged. TIAs often cause temporary stroke-like symptoms which usually last 24 hours or less.
The impact of a stroke on a person’s hearing doesn’t necessarily depend on the type of stroke, rather the part of the brain that was damaged by the stroke. A stroke that affects the region of the temporal lobe (the orange area in the diagram to the left) will usually result in a mild hearing loss if the damage is confined to only one temporal lobe. Although rare, a stroke may affect both temporal lobes, resulting in complete hearing loss, or deafness.
Types of Hearing Problems Related to Strokes
Depending on the area that was damaged during the stroke, a patient may experience different types of hearing loss. Unfortunately, other symptoms such as difficulty speaking may affect the patient’s ability to communicate their symptoms with their doctor.
Auditory agnosia is the inability to recognize or differentiate sounds, as they occur in complex conversations, musical tones, and songs.
Auditory verbal agnosia, also called pure tone word deafness, is the inability to comprehend speech. It is a rare type of aphasia that results from damage to language-specific auditory areas of the brain. People with this disorder feel as though they can’t hear when someone else is speaking, even if the person is speaking loudly or shouting.
Auditory illusions involve hearing a different or mangled version of the actual sound. People with this disorder often perceive normal sounds as unusual, strange, repeated, or loud.
Auditory hallucinations are hallucinations of sounds, or the perception of hearing sounds that are not actually there.
Sensorineural Hearing Loss (SNHL) is the loss of hearing due to the pathology of the inner ear, auditory nerve, or cochlear nuclei. It is unclear whether the link between SNHL and strokes is due to factors such as age (individuals over the age of 60 are at a greater risk for both strokes and SNHL), or if the hearing pathways are directly affected by the stroke.
Sudden Sensorineural Hearing Loss (SSNHL) is the sudden onset of hearing loss, which is often temporary. Studies have shown a link between SSNHL and strokes, although the stroke may not be the cause of SSNHL. Rather, SSNHL may indicate a higher risk of a future stroke. According to a 2008 study in Taiwan, individuals who reported SSNHL were more than 150% more likely to experience a stroke within two years of the hearing loss.
Regaining Hearing After a Stroke
Unfortunately, health care providers do not routinely assess hearing loss after a stroke, perhaps because of its “invisible” nature. Furthermore, the patient may not even be aware of their hearing loss at the time of the stroke due to other severe symptoms.
Hearing is an important part of rehabilitation and recovery. An undiagnosed hearing loss after a stroke can hinder communication between the patient, their family, and their healthcare provider. Sadly, this prevents the patient from being able to fully participate in rehabilitation and regain their independence.
Despite this, it is possible for stroke survivors to recover and live happy, healthy lives. If your stroke caused hearing loss, Whisper Hearing Centers can help. Our compassionate, experienced audiologists are eager to help you improve your quality of life by regaining your hearing. Visit one of our 13 central Indiana locations, send us a message, or give us a call today.