<unk>  was first dicribed by Adler and Barany, who described it as a problem in the otolith organs. In 1952, Margaret Dix and Charles Hallpike named it positional nystagmus of the<unk>  positional type and noticed nystagmus and<unk>  with different headmovements. It is understood that<unk>  is the result of free floating calcium carbonate crystal formation (canalolithiasis) inside the semicircular canals and Movement of these otoconia with head movement will result in inappropriate stimulation of hair cells following movement of the endolymph. According to which semicircular canal the otoconia have migrated to into 3 subtypes including posterior semicircular canal<unk> , lateral semicircular canal<unk> , and superior (anterior) semicircular canal<unk> .  Common causes of<unk>  may include age related degeneration of the vestibular system, and head trauma.  The diagnostic study of choice for<unk>  is patient history and observing nystagmus on Dix-Hall pike maneuver and in most of the cases treatment is Epley maneuver.
Benign paroxysmal positional vertigo
Benign positional vertigo 
Labyrinthitis
Psychogenic dizziness
Retinal migraine
Thunderclap headache
Cluster headache
Open-angle glaucoma