This is performed by placing the head of the patient in the dix hallpike position that evokes the vertigo. The posterior canal on the affected side is in the earth vertical plane when the head is in this position. after the cessation of initial nystagmus, the head is rolled through 180 degrees, (this is done in two 90 degree increments, stopping in each position until the nystagmus resolves) to the postion in which the offending ear is up. The patient is then brought to the upright sitting postion. This procedure is likely to be successful when nystagmus of the same direction ccontinues to be elicited in each of the new position (as the debris continues to move away from the cupula). This manuver is repeated until no nystagmus is elicited. This is successful in 90 % of cases. Posterior canal BPPV can be converted to lateral canal bppv during epley manuver. The lateral canal bppv resolves in several days. Drugs are usually not prescribed, but low dose meclizine or calmpose CCAN be given 1 hour before the procedure if the patient is anxious or prone to vomiting.