What is dizziness?
Dizziness is one of the most common reasons for a visit to a Primary Care Physician. Dizziness is not a very descriptive term; it is one of the vestibular disorders that encompasses lightheadedness, heavyheadedness, faintness or about to pass out, disorientation, distortion of position in three-dimensional space, turning sensation, spinning sensation, or rocking sensation. To some it may seem that they are moving, to others it may seem the world is moving. Sometimes it is a sensation related to imbalance or a sense of an impending fall. Although vertigo has long been used by doctors as a more specific term to describe an inner ear condition, frequently such a distinction can be misleading.
What causes dizziness?
The most common cause of dizziness is the side effect to a medication. The chemical nature of many medications interferes with the neurotransmission in the brain or may drop the blood flow to the brain to critically low levels (hypotension). However, whenever dizziness is followed by a complete loss of consciousness, serious concerns regarding health of the heart or cardiovascular system need prompt medical attention. As the ears share the same blood supply as the brain, conditions that restrict blood flow to the brain can lead to dizziness.
Whenever dizziness is accompanied by other neurological symptoms such as weakness of an arm or leg, double vision, slurred speech, clumsiness of just one arm or leg, facial numbness or facial weakness, serious concerns regarding stroke need prompt medical attention.
These are important instances when dizziness heralds a life-threatening medical problem, and such concerns should be addressed without delay at a local Emergency Room. More commonly, dizziness is simply a sign of something wrong somewhere in the vastly complex vestibular system. Another common cause of dizziness is anxiety, usually closely coupled with other symptoms of fright or panic.
What is the vestibular system?
A complex system composed of sensors in the inner ear (vestibular labyrinth), upper neck (cervical proprioception), eyes (visual motion and tree dimensional orientation), and body (somatic proprioception) analyzed in several areas of the brain (brainstem, cerebellum, parietal and temporal cortex) affecting eyes (vestibulo-ocular reflexes), neck (vestibulo-collic reflexes), and balance (vestibulo-spinal reflexes) and at the same time keeping us apprised of where were are and how were moving through the world (visuospatial orientation). A system this complex deserves to be called a sense, like our sense of hearing, sight, etc. Its complexity befuddles doctors and patients alike.
What are vestibular tests?
A set of laboratory tests done in hospital or clinic that measure the function of various parts of the system individually. Called electronystagmography (ENG) in the past, today advanced technology allows for more comprehensive testing of vestibular disorders.
Videonystagmography (VNG) is a technique to measure the way eyes move in darkness (without the use of electrodes) using video cameras that see in the dark. Positional testing, including the Dix-Hallpike positioning test, can determine the presence of a common vestibular problem, benign paroxysmal positional vertigo (BPPV).
Caloric testing is a way to compare the response of each ear to warming or cooling stimulation. The damaged ear will respond less vigorously or not at all. Rotational chair (SVAR) testing measures the vestibulo-ocular reflex (VOR), providing information on how the brain is responding to the condition of the vestibular labyrinth, how the brain can suppress stimulation of the vestibular labyrinth, and how well the brain senses visual motion with or without stimulation of the vestibular labyrinth. Computerized dynamic platform posturography (CDPP) testing can assess postural stability.
What is vestibular rehabilitation?
Physical therapy that promotes neurological adaptation required to restore the vestibular sense. A vestibular rehabilitation therapist assesses specific lost abilities and vestibular disorders, then teaches exercises to be done on a daily basis to recover those lost abilities, without the use of medications.
During 6-8 weekly therapy sessions, new exercises are assigned to reach increasingly complex levels of vestibular function. A similar process is used by dancers, skaters, gymnasts, and fighter pilots to maintain a higher level of vestibular fitness necessary for their daily activities. A vestibular rehabilitation therapist is the coach necessary to complete the process in patients with vestibular disorders.