The most frequently reported symptoms of vestibular disorders are dizziness, unsteadiness or imbalance when walking, vertigo, and nausea. These symptoms may be quite mild, lasting minutes, or quite severe, resulting in total disability. Because the vestibular system interacts with many other parts of the nervous system, symptoms may also be experienced as problems with vision, muscles, and thinking, and memory. In addition, people with vestibular disorders may suffer headache and muscular aches in the neck and back, increased tendency to suffer from motion sickness, and increased sensitivity to noise and bright lights. Patients with vestibular disorders often report fatigue and loss of stamina and an inability to concentrate. Difficulty with reading and speech may occur during times of fatigue. When these symptoms are constant and disabling, they may be accompanied by irritability, loss of self-esteem, and/or depression. Blows to the head and whiplash are a frequent cause of vestibular disorders in people under age 50. High doses or long-term use of certain antibiotics can also cause permanent damage to the inner ear.
The inner ear consists of a system of fluid-filled tubes and sacs called the labyrinth as well as the nerves that connect the labyrinth to the brain. The labyrinth, which rests inside the bone of the skull, contains both an organ devoted to hearing, called the cochlea, and other organs, called the vestibular system, which are devoted to the control of balance and eye movements.
Vestibular disorders occur frequently and can affect people of all ages and all walks of life. According to studies from the USA National Institutes of Health, 90 million Americans (42% of the population) will complain to their doctors of dizziness at least once in their lifetime. In many cases, the cause will lie in the inner ear. The cost of medical care for patients with balance disorders has been estimated to exceed $1 billion per year in the United States. Balance disorders increase in frequency in the older age groups and by age 75 become one of the most common reasons for seeking help from physicians.