Positional veigo/ BPPV: It is characterized by veigo when the head is placed in a ceain critical position. There is no hearing loss or other neurologic symptoms. Positional testing establishes the diagnosis and helps to differentiate it from positional veigo of central origin. Disease caused by a disorder of posterior semicircular canal though many patients have history of head trauma and ear infection. It has been demonstrated that otoconial debris, consisting of crystals and calcium carbonate, is released from the degeneration macula of the utricle and floats freely in the endolymph. When it settles on the cupula of posterior semicircular canal in a critical head position, it causes displacement of the cupula and veigo. The veigo is fatigable on assuming the same position repeatedly due to dispersal of the otoconia but can be induced again after a period of rest. Thus, typical history and Hallpike maneuver establishes the diagnosis. The condition can be treated by performing Epley's maneuver. The principle of this maneuver is to reposition the otoconial debris from the posterior semicircular canal back into the utricle. The doctor stands behind the patient and the assistant on the side. The patient is made to sit on the table so that when he is made to lie down, his head is beyond the edge of the table as is done in Dix-Hallpike maneuver. His face is turned 450 to the affected side. The maneuver consists of five positions * Position 1. With the head turned 450, the patient is made to lie down in head-hanging position (Dix-Hallpike). It will cause veigo and nystagmus. Wait till veigo and nystagmus subside. * Position 2. Head is now turned so that affected ear is facing up at a 900 rotation. * Position 3. The whole body and head are now rotated away from the affected ear to a lateral recumbent position in a 900 -rotation face-down position. * Position 4. Patient is now brought to a sitting position with head still turned to the unaffected side by 450. * Position 5. The head is now turned forward and chin brought down 200. There should be a pause at each position till there is no nystagmus or there is slowing of nystagmus, before changing to the next position. After maneuver is complete, patient should maintain an upright posture for 48 h. Eighty percent of the patients will be cured by a single maneuver. If the patients remain symptomatic, the maneuver can be repeated. A bone vibrator placed on the mastoid bone helps to loosen the debris. - Meniere's disease: Has an episodic veigo and it lasts for >20 minutes. - Vestibular neuronitis: Veigo lasts for many days. - Labyrinthitis: There is a history of fever and trauma, and the veigo lasts for days.