大多人是posterior canal BPPV, Epley manuever works. 但做的时候角度要拿准， 有小种可能ear rock （Otoconia) will enter into the horizontal canal. 左右边也要搞清楚， 不要做反了。
耳石症症状1) always movement related;2) short duration (usually less than 30 seconds); 3) syptom fatigue when test is repeated; 4) strong spinning senstation with 眼震
大多数人作对了一次就好， 有人的ear rock 也可能挤在一起， it takes time to fatigue symtpoms. If self treatment does not solve, vestibular therapist will be the best option.
