Tinnitus is a condition in which the ears detect sound when no external sound source is present. Almost everyone has had this condition at some point in life, for some it occurs randomly in the morning while for others it is sudden. Usually, it presents itself as a constant ringing that lasts for a short period after being exposed to loud music. Other people describe tinnitus as the sound of singing crickets, much like what you would hear when trying to fall asleep in a quiet room.
From the outer ear through the middle and inner ear to the brain’s auditory cortex, tinnitus can occur anywhere in the hearing canal. For some people, the noises originate in the head instead of ears. Although often described as a ringing noise, tinnitus may sound differently from one person to the next.
Many people who develop tinnitus worry that they’re going deaf, but this rarely happens. For most afflicted individuals, this condition is merely an annoyance and never develops into anything serious. In severe cases, however, tinnitus can be extremely disturbing, so much so that it reduces the quality of life.
There are two types of tinnitus, namely objective and subjective. In the latter case, only the affected patient can hear the sounds. In subjective tinnitus, a doctor can hear unwanted noises in the ears of a patient with a stethoscope when running tests.
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Tinnitus: What Causes Constant Ringing in Ears?
Tinnitus can be a symptom of an underlying medical condition. It may also signify damage that has occurred in the middle ear. The resulting damage interferes with the normal way in which ears detect sound and how the brain interprets auditory signals.
In order to understand how various factors cause tinnitus, it’s important to know about basic functions of the ears. The outer ear usually picks up sound waves and passes them on to the middle ear. In the middle ear, sound detection is done by the cochlea, a coiled spiral tube lined with numerous sensitive hair cells. The final phase of transmitting sound is left to the auditory nerve, which transfers sound signals from the cochlea to the brain for interpretation.
The cochlea fails to send information as required if any part of it is damaged. If that happens, the brain looks for sensory hair cells in the ears that still function. In the process of doing so, some of the resulting signals might be over-represented in the brain, thus causing tinnitus sounds. Another school of thought is that the brain becomes confused and starts to produce its own sounds to make up for the lack of normal sound signals that a part of the cochlear is no longer producing.
Besides chronic conditions, injuries, medications and other factors can also cause damage to the cochlea and hence cause hearing related problems such as tinnitus. Below is a categorized outline of factors that are known to cause or have a connection to tinnitus.
Common Non-Medical Related Causes of Tinnitus
- The Natural Process of Aging
For many people, their hearing becomes worse as they grow older. The reason for this is that hair cells in the cochlea tend to deteriorate with age. This natural type of hearing loss is medically known as presbycusis. It mostly starts around age 60, and can lead to tinnitus. There’s not much you can do to prevent presbycusis, but quitting smoking and/or wearing ear protection gear when around loud sources of noise can help to prevent the condition from becoming more pronounced.
- Continuous Exposure to Loud Noise
Too much noise tends to overwhelm the cilia, which are the sensory hair cells that regulate flow of sound waves in your ears. Depending on the level of exposure, loud noise can cause partial or permanent damage. A short period of noise exposure beyond safe levels usually results in temporary hearing loss accompanied with a constant ringing sound in the ears. Loud equipment like chainsaws, lawn mowers, and firearms are common causes of noise related tinnitus. Listening to loud music from portable media devices such iPods and MP3 players for long hours also increase the chances of developing chronic tinnitus.
- Earwax Blockages
Earwax plays an important role in the auditory canal. It protects your ear by slowing the growth of bacteria and trapping dirt. However, when too much wax accumulates in the ears, it can cause partial hearing loss along with a constant ringing sound in the ears. If you already have tinnitus, earwax blockage can make the condition even worse by heightening unwanted sounds.
- Injuries to the Head or Neck
It’s estimated that one out of every ten people suffering from tinnitus started with this problem after suffering a neck or head injury. Injuries to the head or neck can affect the hearing center in your brain or microscopic nerve endings in the inner ear. Therefore, such injuries may be the cause of hearing loss and tinnitus.
Medical Conditions that Cause Tinnitus
- Tumors In the Neck and Head
Vascular neoplasm is a condition in which tumors arise from the endothelial cells that line the wall of blood and lymphatic vessels. When these tumors form on blood vessels of the neck and head, they can cause tinnitus.
- Acoustic Neuroma
Also known as vestibular schwannoma, acoustic neuroma is a benign and usually slow growing tumor that forms on the cranial nerves connecting the brain and inner ear. Since the cranial nerves are partly responsible for relaying information related to sound, acoustic neuroma may cause ringing in the ears or hearing loss. In most cases, this non-cancerous condition causes tinnitus in one ear.
- TMJ (Temperomandibular Joint) Disorder
The temperomandibular joint connects the jaw and temporal bones of the skull. Two muscles on this joint called the tensor tympani and tensor veli-palantini connect masticating (or eating) muscles with the ear. The temperomandibular joint forms a disorder when these muscles shorten due to chewing, teeth grinding, eating, and talking. Such jaw movements put a constant pull or pressure on the auricular cavity, hence causing a sensation of fullness in the ears, tinnitus and sometimes, hearing loss.
- AVM (Arteriovenous Malformation)
Arteriovenous malformation is an entanglement of abnormal blood vessels that occurs in the coverings of the brain. Although quite rare, people who have this condition also tend to develop pulsatile tinnitus.
- Meniere’s Disease
When endolymph (inner ear fluid) builds up to excessive levels, this causes what’s called Meniere’s disease. Meniere’s disease is characterized by a collection of symptoms such as head-spinning episodes, fullness in the ear, hearing loss, and tinnitus.
Atherosclerosis is another condition that causes pulsatile tinnitus. The condition is caused by weakened blood vessels due to aging. This in turn allows you to hear your own pulse in blood vessels located close to the ears.
Hypertension increases pressure on the walls of blood vessels that transport blood to the auditory cells and tissues. If you have tinnitus, increased blood flow can make it more noticeable. Most hypertensive individuals with tinnitus report of a pulsating sound, which corresponds to the rhythmic throbbing of arteries in the head as blood is propelled through them.
- Turbulent Blood Flow
Tinnitus can also be a symptom of a narrowed carotid artery or vein. When this blood vessel in the neck narrows, it causes turbulent blood flow that’s sometimes associated with a ringing sound in the ears.
Otosclerosis is a hereditary disorder that causes progressive loss of hearing due to an overgrowth of bone inside the inner ear. Since this condition affects hearing, it may also contribute to tinnitus.
Tinnitus or ringing in the ears may be a sign of anemia. It’s not known why this symptom is associated with anemia, but research has found a link between the two disorders.
- Thyroid Dysfunction
Thyroid dysfunction causes a variety of symptoms, one of which is tinnitus. The tinnitus brought on by hyperthyroidism (an over reactive thyroid gland) is normally linked to the heart and hence pulsatile in nature. With an under reactive thyroid (hypothyroidism), tinnitus is usually present as a constant sound.
- Paget’s Disease
Paget’s disease is a condition characterized with deterioration of bone tissue. It mostly affects older people. When bone tissue in the skull begins to deteriorate, it can lead to hearing loss with tinnitus as an accompanying symptom.
Medications Linked to Tinnitus
Some treatment drugs can cause ear poisoning, or what is medically known as ototoxicity. There are more than 200 prescription and over-the-counter ototoxic medications on the market today. These drugs can cause balance disorders, unwanted noises in the ears, or hearing loss.
If a patient is exposed to loud music when on ototoxic drugs, it can amplify the damaging effects of these medications. Fortunately, the negative effects of ototoxicity are usually reversed when the drug therapy is discontinued. In other cases, however, the damage can be permanent.
Drugs known to cause permanent hearing damage include certain chemotherapy medications such as cisplatin and carboplatin, as well as a few aminoglycoside antibiotics like gentamicin.