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Balance disorders

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Vertigo. Not to be confused with acrophobia, an extreme or irrational fear of heights.

Vertigo

Spatial disorientation. Spatial disorientation, spatial unawareness is the inability of a person to correctly determine his body position in space.

Spatial disorientation

This phenomenon refers especially to aircraft pilots and underwater divers,[1] but can be also induced in normal conditions - chemically or physically (e.g. by blindfolding). In aviation, the term means the inability to correctly interpret aircraft attitude, altitude or airspeed, in relation to the Earth or point of reference, especially after a reference point (e.g., the horizon) has been lost. Spatial disorientation is a condition in which an aircraft pilot's perception of direction does not agree with reality. While it can be brought on by disturbances or disease within the vestibular system, it is more typically a temporary condition resulting from flight into poor weather conditions with low or no visibility. A pilot who enters such conditions will quickly lose spatial orientation if there has been no training in flying with reference to instruments.

Seasickness. Causes[edit] This condition is caused by the rocking motion of the craft.[2] Most people tend to concentrate on the inner surroundings,[clarification needed] or close the eyes and try to sleep.

Seasickness

This will cause the worst effect of the disturbance. The brain receives conflicting signals: while the eyes show a world that is still, our body, and in particular the equilibrium sensors located in our ears, send signals of a moving environment. This discordance causes the mind to send to the whole body a general alarm signal, in order to stop all activities,[clarification needed] in particular the most complex of all, the digestion process.[3] Dizziness. One can induce dizziness by engaging in disorientating activities such as spinning.

Dizziness

A stroke is the cause of isolated dizziness in 0.7% of people who present to the emergency room.[6] Differential diagnosis[edit] Many conditions are associated with dizziness. However, the most common subcategories can be broken down as follows: 40% peripheral vestibular dysfunction, 10% central nervous system lesion, 15% psychiatric disorder, 25% presyncope/dysequilibrium, and 10% nonspecific dizziness.[7] The medical conditions that often have dizziness as a symptom include:[7][8][9][10] Mechanism[edit]

Motion sickness. Motion sickness or kinetosis, also known as travel sickness, is a condition in which a disagreement exists between visually perceived movement and the vestibular system's sense of movement.

Motion sickness

Depending on the cause, it can also be referred to as seasickness, car sickness, simulation sickness or airsickness.[1] Cause[edit] The most common hypothesis for the cause of motion sickness is that it functions as a psychological defense mechanism against neurotoxins.[5] The area postrema in the brain is responsible for inducing vomiting when poisons are detected, and for resolving conflicts between vision and balance. Illusions of self-motion. Illusions of self-motion refers to a phenomenon that occurs when someone feels like their body is moving when no movement is taking place.

Illusions of self-motion

Ideomotor phenomenon. Ideomotor phenomenon is a psychological phenomenon wherein a subject makes motions unconsciously.

Ideomotor phenomenon

An example of table-turning in 19th century France. A circle of participants press their hands against a table, and the ideomotor effect causes the table to tilt in such a way as to produce a written message, in a manner similar to a ouija board. The ideomotor response (or "ideomotor reflex"), often abbreviated to IMR, is a concept in hypnosis and psychological research.[1] It is derived from the terms "ideo" (idea, or mental representation) and "motor" (muscular action). Broken escalator phenomenon. The broken escalator phenomenon also known as the "Walker Effect" is the sensation of losing balance or dizziness reported by some people when stepping onto an escalator which is not working.

Broken escalator phenomenon

It is said that there is a brief, odd sensation of imbalance, despite full awareness that the escalator is not going to move.[1][2] It has been shown that this effect causes people to step inappropriately fast onto a moving platform that is no longer moving, even when this is obvious to the participant.[2] This effect separates the declarative and procedural functions of the brain.

Balance disorder. A balance disorder is a disturbance that causes an individual to feel unsteady, for example when standing or walking.

Balance disorder

It may be accompanied by feelings of giddiness or wooziness, or having a sensation of movement, spinning, or floating. Balance is the result of several body systems working together: the visual system (eyes), vestibular system (ears) and proprioception (the body's sense of where it is in space). Degeneration or loss of function in any of these systems can lead to balance deficits.[1] Symptoms[edit] When balance is impaired, an individual has difficulty maintaining upright orientation. A sensation of dizziness or vertigo.Lightheadedness or feeling woozy.Problems reading and difficulty seeing.Disorientation. Some individuals may also experience nausea and vomiting, diarrhea, faintness, changes in heart rate and blood pressure, fear, anxiety, or panic.

Cognitive dysfunction (disorientation) may occur with vestibular disorders.