Benign Positional Vertigo
Benign paroxysmal positional vertigo is a condition where a sensation of vertigo occurs when lying down with the head turned toward one side. This position is called the Hallpike position. The sensation comes on shortly after assuming this position and increases in intensity before gradually subsiding. Each time the Hallpike position is assumed, the vertigo becomes less pronounced. This is the basis for the initial treatment of this disorder.
Theories
This condition is thought to arise from one of two theories. The cupulolithiasis theory suggests that otoliths normally found in the utricular macula (one of the otolith organs) become dislodged and deform the posterior canal ampulla, when the Hallpike position is assumed. The alternative theory is the canalithiasis theory where particles form within the posterior semicircular canal. Upon assuming the Hallpike position these particles exert traction on the posterior canal ampulla and cause vertigo.
Conservative Treatment
The initial treatment of this disorder involves repeating the Hallpike positioning maneuvers until the vertigo response fatigues. Eventually the brain will compensate and adapt to the point where it will not arouse the sensation of vertigo.
Another form of treatment involves attemting to reposition these floating particles within the posterior semicircular canal into the utricle. The Epley maneuver attempts to reposition these particles. Other variant maneuvers can also be used.
There are two theories for BPV.The cupulolithiasis theory implies that otoconia from the utricle become dislodged and irritate the cupula of the posterior semicircular canal. The canalithiasis theory implies that calcified deposits are found within the posterior semicircular canal. By their motion within the canal they create a force on the cupula that leads to vertigo. Various maneuvers can be used to reposition these deposits into the utricle.
Surgical Treatment
When conservative means to treat this disorder have been exhausted, surgical options can be considered. These include surgically partitioning the posterior semicircular canal from the rest of the inner ear. Another option is to section the nerve that transmits information from the posterior semicircular canal ampulla toward the brain. This is a procedure called a posterior ampullary neurectomy or singular neurectomy.