Dizziness is a disturbance that causes an individual to feel unsteady, giddy, woozy, or have a sensation of movement, spinning, or floating. Vertigo is a specific term for a hallucination of movement of either self or surroundings – it is due to vestibular system involvement. Dizziness and Vertigo can be caused by a number of systems. An organ in our inner ear, the labyrinth, is an important part of our vestibular (balance) system. The labyrinth interacts with other systems in the body, such as the visual (eyes) and skeletal (bones and joints) systems, to maintain the body's position. These systems, along with the brain and the nervous system, can be the source of balance problems.
Three structures of the labyrinth, the semicircular canals, let us know when we are in a rotary (circular) motion. The semicircular canals, the superior, posterior, and horizontal, are fluid-filled. Motion of the fluid tells us if we are moving. The semicircular canals and the visual and skeletal systems have specific functions that determine an individual's orientation. The vestibule is the region of the inner ear where the semicircular canals converge, close to the cochlea (the hearing organ). The vestibular system works with the visual system to keep objects in focus when the head is moving. Joint and muscle receptors also are important in maintaining balance. The brain receives, interprets, and processes the information from these systems that control our balance.
Movement of fluid in the semicircular canals signals the brain about the direction and speed of rotation of the head-for example, whether we are nodding our head up and down or looking from right to left. Each semicircular canal has a bulbed end, or enlarged portion, that contains hair cells. Rotation of the head causes a flow of fluid, which in turn causes displacement of the top portion of the hair cells that are embedded in the jelly-like cupula. Two other organs that are part of the vestibular system are the utricle and saccule. These are called the otolithic organs and are responsible for detecting linear acceleration, or movement in a straight line. The hair cells of the otolithic organs are blanketed with a jelly-like layer studded with tiny calcium stones called otoconia. When the head is tilted or the body position is changed with respect to gravity, the displacement of the stones causes the hair cells to bend.
Infections (viral or bacterial), head injury, disorders of blood circulation affecting the inner ear or brain, certain medications, and aging may change our balance system and result in a balance problem. Individuals who have illnesses, brain disorders, or injuries of the visual or skeletal systems, such as eye muscle imbalance and arthritis, may also experience balance difficulties. A conflict of signals to the brain about the sensation of movement can cause motion sickness (for instance, when an individual tries to read while riding in a car). Some symptoms of motion sickness are dizziness, sweating, nausea, vomiting, and generalized discomfort. Balance disorders can be due to problems in any of four areas:
|Vertigo - Illusion of movement; a sensation as if the external world were revolving around an individual (objective vertigo) or as if the individual were revolving in space (subjective vertigo).|
|Meniere's Disease Management - an inner ear fluid balance disorder that causes episodes of vertigo, fluctuating hearing loss, tinnitus (a ringing or roaring in the ears), and the sensation of fullness in the ear. The cause of Ménière's disease is unknown. It has been shown to be caused by increase in the pressure of the inner ear fluids. Treatment is aimed at reduction of inner ear pressure. This disease can become bilateral in up to 40% of patients. Laboratory testing is required.|
BPPV - Benign Paroxysmal Positional Vertigo - A brief, intense sensation of vertigo that occurs because of a specific positional change of the head. An individual may experience BPPV when rolling over to the left or right upon getting out of bed in the morning, or when looking up for an object on a high shelf. The cause of BPPV is due to free floating otoconia in the endolymph fluid of a specific semicircular canal, it may be caused by an inner ear infection, head injury, anesthetics, for no known reason or aging. BPPV can be recurrent and debilitating. Treatment is available using physical therapy exercises and surgery in selected cases.
|MdDS - Mal de Embarkment Syndome – This is a condition of the inner ear associated with a constant rocking sensation that can last for days or months or even years. It is similar to the sensation after being on a boat for a period of time. Etiology is unknown. Positional exercise is helpful for many patients and medications have provided relief. Other causes need to be excluded and laboratory testing is required.|
|Vestibular Hydrops - This is a condition of increased fluid in the semicircular canals without hearing loss. Episodes may be recurrent and these patients often go on to Meniere’s disease.|
|Delayed Endolymphatic Vertigo - This vertigo disorder is seen in individuals with a previously deafened ear. It is characterized by recurrent attacks of true vertigo, no hearing in the affected ear and imbalance. The disorder can be detected on laboratory studies and clinical history and examination.|
|Recurrent Vestibulopathy - This is a condition marked by recurrent attacks of true vertigo without hearing loss over a prolonged period of time. The condition is usually self limiting and requires medications for relief. It does not progress into Meniere’s disease. It is felt to be viral related.|
|Viral Neuronitis - Viral Neuronitis This common condition is related to a preceding viral illness with subsequent severe and debilitating vertigo without any hearing loss. These are single episodes lasting for 10 to 14 days without any other associated neurological disease.|
|Perilymph Fistula - A leakage of inner ear fluid to the middle ear. It can occur after head injury, physical exertion or, rarely, without a known cause.|
|Vestibular Migraine - This disorder has the common association of true vertigo with antecedent migraine attack related to all dizzy spells. History and physical examination are required to rule out other causes.|