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  • Labyrinthitis

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    Labyrinthitis, also known as vestibular neuritis, is the inflammation of the inner ear. It results in a sensation of the world spinning and also possible hearing loss or ringing in the ears. It can occur as a single attack, a series of attacks, or a persistent condition that diminishes over three to six weeks. It may be associated with nausea, vomiting, and eye nystagmus. The cause is often not clear. It may be due to a virus, but it can also arise from bacterial infection, head injury, extreme stress, an allergy, or as a reaction to medication. 30% of affected people had a common cold prior to developing the disease. Either bacterial or viral labyrinthitis can cause a permanent hearing loss in rare cases. This appears to result from an imbalance of neuronal input between the left and right inner ears. Vestibular neuritis affects approximately 35 people per million per year. It typically occurs in those between 30 and 60 years of age. There is no significant gender difference. It derives its name from the labyrinths that house the vestibular system, which senses changes in head position.

  • Righting reflex

    serch.it?q=Righting-reflex

    The righting reflex, also known as the labyrinthine righting reflex, is a reflex that corrects the orientation of the body when it is taken out of its normal upright position. It is initiated by the vestibular system, which detects that the body is not erect and causes the head to move back into position as the rest of the body follows. The perception of head movement involves the body sensing linear acceleration or the force of gravity through the otoliths, and angular acceleration through the semicircular canals. The reflex uses a combination of visual system inputs, vestibular inputs, and somatosensory inputs to make postural adjustments when the body becomes displaced from its normal vertical position. These inputs are used to create what is called an efference copy. This means that the brain makes comparisons in the cerebellum between expected posture and perceived posture, and corrects for the difference. The reflex takes 6 or 7 weeks to perfect, but can be affected by various types of balance disorders. The righting reflex has also been studied in cats and other non-human mammals.

  • Benign paroxysmal positional vertigo

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    Benign paroxysmal positional vertigo (BPPV) is a disorder arising from a problem in the inner ear. Symptoms are repeated, brief periods of vertigo with movement, that is, of a spinning sensation upon changes in the position of the head. This can occur with turning in bed or changing position. Each episode of vertigo typically lasts less than one minute. Nausea is commonly associated. BPPV is one of the most common causes of vertigo. BPPV can result from a head injury or simply occur among those who are older. A specific cause is often not found. The underlying mechanism involves a small calcified otolith moving around loose in the inner ear. It is a type of balance disorder along with labyrinthitis and Ménière's disease. Diagnosis is typically made when the Dix–Hallpike test results in nystagmus (a specific movement pattern of the eyes) and other possible causes have been ruled out. In typical cases, medical imaging is not needed. BPPV is often treated with a number of simple movements such as the Epley maneuver or Brandt–Daroff exercises. Medications may be used to help with nausea. There is tentative evidence that betahistine may help with vertigo but its use is not generally needed. BPPV is not a serious condition. Typically it resolves in one to two weeks. It, however, may recur in some people. The first medical description of the condition occurred in 1921 by Robert Barany. About 2.4% of people are affected at some point in time. Among those who live until their 80s, 10% have been affected. BPPV affects females twice as often as males. Onset is typically in the person's 50s to 70s.

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