Vestibular neuronitis is disease of the vestibular nerve that causes severe episodes of vertigo. The vestibular nerve is responsible for sending messages from the inner ear to the brain. If the vestibular nerves in each ear are sending different signals, the result is an inability to feel balanced. Vestibular neuronitis is most common in adults. Symptoms can vary from mild dizzy spells to a severe swaying sensation. Other symptoms include nausea, vomiting, trouble seeing and impaired concentration.