What is Tinnitus?
Tinnitus is commonly described as a ringing in the ears, but it also can sound like roaring, clicking, hissing, or buzzing. It may be soft or loud, high pitched or low pitched. You might hear it in either one or both ears. Roughly 10 percent of the adult population of the United States has experienced tinnitus lasting at least five minutes in the past year. This amounts to nearly 24 million Americans.
What Causes Tinnitus?
Tinnitus (pronounced tin-NY-tus or TIN-u-tus) is not a disease. It is a symptom that something is wrong in the auditory system, which includes the ear, the auditory nerve that connects the inner ear to the brain, and the parts of the brain that process sound. Tinnitus is commonly accompanied by hearing loss when there is damage to the outer hair cells in the inner ear.
Possible causes of tinnitus include:
- Damage to hearing system (often accompanied by hearing loss) from the aging process and/
or loud noise exposure (Tinnitus is often the first sign of hearing loss in adults!)
- Ear and sinus infections
- Injury to the ear or head
- Disease of the ear
- Diseases of the heart or blood vessels
- Side effect of medication (More than 200 drugs are known to cause tinnitus when you start or stop taking them)
- Emotional stress
- Hormonal changes in women
- Thyroid abnormalities
- Ear wax deep in ear canal
- Brain tumors (rare)—Pulsatile tinnitus is a rare type of tinnitus that sounds like a rhythmic pulsing in the ear, usually in time with your heartbeat. A doctor may be able to hear it by pressing a stethoscope against your neck or by placing a tiny microphone inside the ear canal. This kind of tinnitus is most often caused by problems with blood flow in the head or neck. Pulsatile tinnitus also may be caused by brain tumors or abnormalities in brain structure.
Even with all of these associated conditions and causes, some people develop tinnitus for no obvious reason. Most of the time, tinnitus isn’t a sign of a serious health problem, although if it’s loud or doesn’t go away, it can cause fatigue, depression, anxiety, and problems with memory and concentration. For some, tinnitus can be a source of real mental and emotional anguish.
Why do I have this noise in my ears?
Although we hear tinnitus in our ears, its source is really in the networks of brain cells (what scientists call neural circuits) that make sense of the sounds our ears hear. A way to think about tinnitus is that it often originates in the ear, but it continues and is perceived in the brain.
Scientists still haven’t agreed upon what happens in the brain to create the illusion of sound when there is none. Some think that tinnitus is similar to chronic pain syndrome, in which the pain persists even after an injury has healed.
Tinnitus could be the result of the brain’s neural circuits trying to adapt to the loss of sensory hair cells by increasing sensitivity to sound. This would explain why some people with tinnitus are oversensitive to loud noise (a phenomenon known as hyperacusis).
Tinnitus also could be the result of neural circuits thrown out of balance when damage in the inner ear changes signaling activity in the auditory cortex, where the brain processes sound. Another theory is it could be the result of abnormal interactions between neural circuits communicating with the limbic region, which regulates mood and emotion.