n. a particle derived from *otoliths in the *utricle of the inner ear, displaced from its normal site and located within the canal portion of one of the semicircular canals. Canaliths are implicated in *benign paroxysmal positional vertigo.
(BPPV) a common cause of vertigo in which the patient complains of brief episodes of rotatory vertigo precipitated by sudden head movements. It is thought to be due to microscopic debris derived from the *otoliths of the utricle and displaced into one of the semicircular canals, most commonly the posterior semicircular canal. The debris is most commonly thought to be free in the canal (canalithiasis; see canalith) but can be attached to the *cupula (cupulolithiasis; see cupulolith). Diagnosis is by performing a *Dix–Hallpike test. Treatment is with a predetermined set of head movements to move the debris from the semicircular canal (see Epley particle repositioning manoeuvre; Semont liberatory manoeuvre; Brandt-Daroff exercises). Surgery is occasionally used to occlude the relevant semicircular canal, cut the *singular nerve or vestibular nerves, or perform a *labyrinthectomy. Drugs are generally ineffective in the treatment of this condition.... benign paroxysmal positional vertigo
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