All balance-related components of the inner ear are part of the vestibular system, which controls our sense of balance, position, spatial orientation, movement and other activities, and ensures that surrounding objects are in visual focus when the body is moving. The vestibular system works with other sensory systems in the body such as the eyes, bones and joints to maintain the body’s position at rest and during movement. Balance dysfunction is a feeling of instability or vertigo when moving, rotating, or even standing or lying flat, which may be due to a disease, medication, or inner ear/brain lesion. So why do balance disorders develop and what are their common causes? Let’s start with the vestibular system and the inner ear vagus. Balance perception is primarily controlled by a labyrinth-like structure in the inner ear called the inner ear labyrinth, which is composed of bone and soft tissue. The hemimelia and otoliths in the labyrinth help us maintain balance, and the cochlea allows us to hear sounds. Common symptoms Balance dysfunction can last for a long or short time. Common symptoms include: dizziness or vertigo, feeling of falling or about to fall, light-headedness, drowsiness or floating sensation, blurred vision, impaired consciousness or disorientation, nausea and vomiting, diarrhea, changes in blood pressure and heart rate, panic, anxiety, etc. Etiology Possible causes of balance dysfunction include viral or bacterial infections of the inner ear, head injury, or circulatory disorders affecting the inner ear and head. People of all ages have experienced balance dysfunction problems. Balance disorders and dizziness can also be the result of certain medications; neurological and circulatory disorders can cause certain postural and balance disorders; orthopedic or ocular disorders such as arthritis and ocular spasm can also cause balance disorders; and it is important to note that many balance dysfunctions occur suddenly with no apparent trigger. There are many different types of balance dysfunction, the most common of which include: vertigo, benign paroxysmal positional vertigo (BPPV), inner ear vaginitis, Meniere’s syndrome, vestibular neuronitis, external ear lymphatic fistula, motion sickness, and Mal de debarquement syndrome (also known as seasickness syndrome). Vertigo is an abnormal sensation of rotation of oneself or of surrounding objects and may be accompanied by severe nausea and vomiting. It may be associated with a loss of balance, leading to unstable walking and falls. Vertigo itself is a symptom or cue for underlying balance dysfunction disorders, inner ear vagal disease and cerebellar pathology. Benign paroxysmal positional vertigo (BPPV) is a brief, intense episode of vertigo, usually triggered by a specific change in head position. Many people experience BPPV when they turn over, and sometimes its onset is due to a head injury or advanced age. Inner ear vaginitis is an infection or inflammation of the inner ear that can lead to vertigo and balance dysfunction, usually associated with an upper respiratory tract infection. Meniere’s syndrome is associated with changes in the volume of lymphatic fluid in parts of the vagus of the inner ear and can lead to episodes of vertigo, irregular hearing loss, tinnitus and a feeling of fullness in the ear; the etiology is unclear. Vestibular neuronitis is an inflammatory disease of the vestibular nerve, possibly due to a virus, that presents as paroxysmal, intense vertigo attacks; it can affect young to middle-aged and elderly populations and usually occurs after a nonspecific upper respiratory tract infection. External ear lymphatic fistula is caused by leakage of lymphatic fluid from the inner ear into the middle ear; it can occur in response to cranial trauma, higher atmospheric pressure differences (e.g., diving), ear surgery, or chronic infectious ear disease. In addition to vertigo and nausea, the most typical symptom is a sense of imbalance when walking or standing that is aggravated by activity and relieved by rest. External ear lymphatic fistulas can occur at birth in some infants and are associated with hearing loss at birth. Motion sickness, commonly known as seasickness or motion sickness, is the most common type of inner ear disorder. It can be caused by repetitive motion such as sea bumps, running cars or airplane flights when the air is turbulent. Symptoms usually include: nausea, vomiting, dizziness, sweating and a feeling of discomfort. These symptoms all originate from a balance disorder caused by the inner ear. Mal de debarquement syndrome (MdDS) is a balance disorder in which the sensation of constant swaying or oscillation usually occurs after an ocean cruise or sea trip and resolves within hours or days after disembarkation, although in severe cases it may last for months or even years. Treatment The first step is to determine if the balance dysfunction is due to a disease or medication, and if so, to manage the disease or adjust the medication. Treatment measures vary depending on the type of balance dysfunction. Common treatment options include: medications, balance rehabilitation therapy, head/body/eye exercises, etc. For patients with Ménière’s syndrome, it is recommended to reduce the intake of salt, alcoholic and coffee drinks and to stop smoking. Other treatments such as injection of gentamicin and steroids into the inner ear behind the eardrum may have some effect on vertigo. However, gentamicin can destroy the auditory cells in the cochlea and lead to permanent hearing loss; patients with severe Meniere’s syndrome may consider surgery; 4. .