Hearing and Balance
There are many causes of balance problems, such as medications, ear infections, a head injury, or anything else that affects the inner ear or brain. Low blood pressure can lead to dizziness when you stand up too quickly. Problems that affect the skeletal or visual systems, such as arthritis or eye muscle imbalance, can also cause balance disorders. Your risk of having balance problems increases as you get older.
Your sense of balance relies on a series of signals to the brain from several organs and structures in the body, which together are known as the vestibular system. The vestibular system begins with a maze-like structure in your inner ear called the labyrinth, which is made of bone and soft tissue. The inner ear chamber (labyrinth) is encased in bone and filled with fluid (endolymph and perilymph). This fluid bathes the delicate nerve endings of the hearing and the balance mechanism. Movement of fluid in the balance chambers (vestibule and three semicircular canals) also stimulates nerve endings, resulting in electrical impulses to the brain, where they are interpreted as motion.
The human balance system is made up of three parts: the eyes, the inner ear, and the muscles and joints of the body. All three systems work independently and yet work together to keep the body in balance.
The eyes receive visual clues that give the brain information as to the position of the body relative to its surroundings. The muscles and joints are called proprioceptors. The most important ones are in the head and neck (head position relative to the rest of the body) and the ankles and joints (body sway relative to the ground).
The inner ear balance mechanism has two main parts: the three semicircular canals and the vestibule. Together they are called the vestibular labyrinth and are filled with fluid. When the head moves, fluid within the labyrinth moves and stimulates nerve endings that send impulses along the balance nerve to the brain. Those impulses are sent to the brain in equal amounts from both the right and left inner ear. Nerve impulses may be started by the semicircular canals when turning suddenly, or the impulses may come from the vestibule, which responds to changes of position, such as lying down, turning over or getting out of bed.
When one inner ear is not functioning correctly the brain receives nerve impulses that are no longer equal, causing it to perceive this information as distorted or off balance. The brain sends messages to the eyes, causing them to move back and forth, making the surroundings appear to spin. It is this eye movement (called nystagmus) that creates a sensation of things spinning.
When the signals from any of these sensory systems malfunction, you can have problems with your sense of balance. If you have additional problems with motor control, such as weakness, slowness, tremor, or rigidity, you can lose your ability to recover properly from imbalance. This raises the risk of falling and injury.
There are more than a dozen different balance disorders. Some of the most common are:
- Benign paroxysmal positional vertigo (BPPV) or positional vertigo: A brief, intense episode of vertigo triggered by a specific change in the position of the head. You might feel as if you're spinning when you bend down to look under something, tilt your head to look up or over your shoulder, or roll over in bed. BPPV occurs when loose otoconia tumble into one of the semicircular canals and weigh on the cupula. The cupula doesn't flex properly and sends wrong information about your head’s position, causing vertigo. BPPV can result from a head injury, or can develop just from getting older.
- Labyrinthitis: An infection or inflammation of the inner ear that causes dizziness and loss of balance. It is often associated with an upper respiratory infection such as the flu.
- Meniere's disease: Episodes of vertigo, hearing loss, tinnitus , and a feeling of fullness in the ear. It may be associated with a change in fluid volume within parts of the labyrinth, but the cause or causes are still unknown.
- Vestibular neuronitis: An inflammation of the vestibular nerve that can be caused by a virus, and primarily causes vertigo.
- Perilymph fistula: A leakage of inner ear fluid into the middle ear. It causes unsteadiness that usually increases with activity, along with dizziness and nausea. Perilymph fistula can occur after a head injury, dramatic changes in air pressure (such as when scuba diving), physical exertion, ear surgery, or chronic ear infections. Some people are born with perilymph fistula.
- Mal de Debarquement syndrome (MdDS): A feeling of continuously rocking or bobbing, typically after an ocean cruise or other sea travel. Usually the symptoms go away a few hours or days after you reach land. Severe cases, however, can last months or even years, and the cause remains unknown.
To help you decide whether to seek medical help for a dizzy spell, ask yourself the following questions. If you answer “yes” to any of these questions, talk to your doctor:
- Do I feel unsteady?
- Do I feel as if the room is spinning around me?
- Do I feel as if I’m moving when I know I’m sitting or standing still?
- Do I lose my balance and fall?
- Do I feel as if I’m falling?
- Do I feel lightheaded or as if I might faint?
- Do I have blurred vision?
- Do I ever feel disoriented—losing my sense of time or location