Rotation test

The rotation test is an experiment to check whether the vestibular function is normal. It is the basic principle of semicircular canal function to make semicircular canal fluid flow to stimulate ampulla and induce vestibular response. The characteristics of induced nystagmus are generally used as the criterion for judgment. The relationship between endolymph fluid flow and evoked nystagmus can be inferred according to the following laws: 1. Flouren's law The plane of nystagmus motion is the same as the plane of the stimulated semicircular canal. 2. When Ewald's first law of the external semicircular canal is stimulated, if the endolymphatic fluid flows from the tube to the ampulla, a strong stimulus will be generated, and the flow from the ampulla to the tube will produce a weaker stimulus. When the upper semi-regular and second semi-regular are stimulated, the situation is opposite. The ratio of strong and weak stimuli is 2: 1 or 3: 2. 3. Ewald's second law nystagmus is fast toward the semicircular canal on the stronger side, while slow phase is towards the semicircular canal on the weaker side.