Dizziness and imbalance
Dizziness is broken down into 4 main subtypes:
- Vertigo (~50%),
- Disequilibrium (less than ~15%),
- Presyncope (less than ~15%)
- Lightheadedness (~10%).
Vertigo is a symptom where a person feels as if they or the objects around them are moving when they are not. Often it feels like a spinning or swaying movement. This may be associated with nausea, vomiting, sweating, or difficulties walking. It is typically worse when the head is moved. Vertigo is the most common type of dizziness.
The most common diseases that result in vertigo are benign paroxysmal positional vertigo (BPPV), Ménière’s disease, and labyrinthitis. Less common causes include stroke, brain tumors, brain injury, multiple sclerosis, migraines, trauma, and uneven pressures between the middle ears.
When the sense of balance is interrupted it causes dizziness, disorientation and nausea. Balance can be upset by Ménière’s disease, superior canal dehiscence syndrome, an inner ear infection, by a bad common cold affecting the head or a number of other medical conditions including but not limited to vertigo. It can also be temporarily disturbed by quick or prolonged acceleration, for example riding on a merry-go-round. Blows can also affect equilibrioreception, especially those to the side of the head or directly to the ear.
Presyncope / Lightheadedness
Lightheadedness is a common and typically unpleasant sensation of dizziness or a feeling that one may faint. The sensation of lightheadedness can be short-lived, prolonged, or, rarely, recurring. In addition to dizziness, the individual may feel as though his or her head is weightless. The individual may also feel as though the room is “spinning” or moving (vertigo) associated with lightheadedness. Most causes of lightheadedness are not serious and either cure themselves quickly, or are easily treated.
Keeping a sense of balance requires the brain to process a variety of information received from the eyes, the nervous system, and the inner ears. If the brain is unable to process these signals, such as when the messages are contradictory, or if the sensory systems are improperly functioning, an individual may experience lightheadedness or dizziness.
Lightheadedness can also be called presyncope, in contrast with syncope (fainting), particularly in cases of temporary visual field loss (i.e. vision getting “dark” or “closing in”).