Dizziness describes feelings of lightheadedness or unsteadiness. Vertigo describes a sensation of movement of spinning, either of self or of surrounding objects. Although patients use these terms interchangeably, dizziness and vertigo describe two different symptoms that are often linked by a common cause, according to the Vestibular Disorders Association. Disorders that affect the vestibular system—the parts of the inner ear and brain that control balance and eye movements—most commonly cause both vertigo and dizziness.
Benign Paroxysmal Positional Vertigo
Benign paroxysmal positional vertigo—BPPV—describes a disorder of the inner thought to occur due to the displacement of calcium carbonate crystals in the ear. These crystals stimulate hair cells in the inner ear creating the illusion of motion, and therefore the symptom of vertigo, as described by the Merck Manuals Online Medical Library.
BPPV causes episodes of dizziness and vertigo that last from a few seconds to several minutes. The sensation of movement may be so strong it triggers nausea and vomiting. BPPV usually subsides on its own with a few weeks; however, the condition may continue for months or even years, making treatment difficult.
Vestibular Neuritis and Labyrinthitis
Viruses and bacterial infections can cause infections of the inner ear. These infections can cause inflammation of the nerves in the ear, a condition known as vestibular neuritis. Vestibular neuritis causes mild to severe dizziness and vertigo. Violent vertigo can trigger nausea, vomiting, balance problems, difficulty with vision and impaired concentration, according to the Vestibular Disorders Association.
Inner ear infections can also cause inflammation of the labyrinth—the system of passages in the ear formed by bones and membranes. Inflammation of the labyrinth, a condition known as labyrinthitis, causes symptoms similar to vestibular neuritis but can also affect hearing by causing tinnitus which is characterized by ringing of the ears or hearing loss.
Meniere's Disease
Meniere’s disease, another disorder of the inner ear, occurs as a result of a change in fluid volume in the inner ear. The membranous labyrinth contains fluid known as the endolymph. This fluid moves as the head moves and sends signals to the brain about the motion. An increase in the endolymph sends incorrect signals to the brain resulting in the symptoms of vertigo and severe dizziness.
Although the exact cause of Meniere’s disease remains unknown, scientists continue to investigate factors such as noise pollution, viral infections and biological factors that may contribute to the onset of the disorder, according to the National Institute on Deafness and other Communication Disorders. Other symptoms of Meniere’s disease include ringing in the ears, hearing loss and feelings of pain and pressure in the ear.
