Vertigo is the feeling of spinning or falling through space when there is no motion. Sensations associated with vertigo include a sense of spinning, tumbling, falling forward or backward, or the ground rolling beneath one's feet. It may be difficult to focus visually; many people find it uncomfortable to keep their eyes open during vertigo spells. Sweating, nausea, and vomiting are also common. Depending on the cause, vertigo can last from a few minutes to days.
Vertigo is not a disease, but a symptom of a broad range of disorders, diseases, and conditions, including:
- Diseases or disorders of the inner ear (such as motion sickness; the formation of “sludge” in the inner ear, which causes the inner ear to send a confusing motion signal to the brain; or tumors in the inner ear)
- Injuries or other damage to the inner ear (for example, from drugs such as aspirin and some diuretics, chemotherapeutics, and antibiotics)
- Diseases or disorders of the brain (such as tumors, migraine, transient ischemic attack or stroke, or a psychiatric disease or disorder)
- Disorders affecting the acoustic nerve, which connects the inner ear to the brain
- Ménière’s disease or Ménière’s syndrome
- Viral and bacterial infections
- Multiple sclerosis
- Damage to the nerves in the neck that help the brain monitor the relative position of the neck and trunk (this form of vertigo, called cervical vertigo, often occurs after an injury such as a whiplash injury but may be associated with arthritis in the neck or degenerative cervical spine disease)
- Low blood pressure
Under normal circumstances, the brain relies on 3 sensory systems to maintain spatial orientation: the vestibular system (inner ear), visual system (eyes), and somatosensory system (conveys information from the skin, joint, and muscle receptors). These three systems overlap, allowing the brain to assemble an accurate sense of spatial orientation. However, a compromised system or conflicting signals can cause vertigo.
The vestibular system is most often involved with vertigo. The sensory organs for the vestibular system are located in the bony labyrinths of the inner ear. They include 3 semicircular canals and an otolithic apparatus on each side. The otolithic apparatus consists of tiny particles of calcium carbonate suspended in a gelatinous matrix in 2 structures called the utricle and saccule. These particles shift in response to movement in a straight line, stimulating cilia (hair-like fibers) that are embedded in the gel. Movement at an angle is detected by the semicircular canals. These components work together to provide a sense of spatial orientation.
Broadly classified, vertigo is usually either physiologic or pathologic. Physiologic vertigo is normal and occurs when there is a conflict between the signals sent to the brain by the vestibular system and by the other balance-sensing systems of the body. It can also occur when the head is subjected to unfamiliar movements, such as the rolling motion associated with seasickness, spinning for an extended period, or when the head is held in an unusual position (eg, head and neck are tilted back for an extended period). Physiologic vertigo is usually easily corrected, either by moving the head and neck into a more normal position or focusing on an external reference point to give the vestibular system an opportunity to stabilize. This is why a person with motion sickness is advised to look into the distance and focus on some faraway point, such as the horizon.
Pathologic vertigo occurs because of lesions or disorders in any of the 3 sensory systems (usually the vestibular system). Pathologic vertigo is further broken down into the following:
- Labyrinthine dysfunction—Labyrinthine dysfunction can occur as a result of any disease or condition that affects the ability of the vestibular organs (the labyrinths) to communicate with the brain.
- Vertigo of the vestibular nerve—Diseases of the eighth (vestibular) cranial nerve cause vertigo of the vestibular nerve.
- Central vertigo—Lesions on the brainstem or cerebellum (parts of the nervous system in which information from the vestibular system is integrated with information from the eyes and musculoskeletal position sensors, or proprioceptors) can cause central vertigo.
- Psychogenic vertigo—Psychogenic vertigo usually occurs with panic attacks or agoraphobia (fear of open spaces).
No matter what the cause, vertigo is common, affecting millions of people annually. Episodes of vertigo increase with age, accounting for more than 61% of all cases of dizziness by age 65 years (Oghalai 2000). The overall incidence of dizziness, vertigo, and imbalance is 5 to 10% of the overall population and 40% in patients older than 40 years.