Abstract
Four cases with similar symptoms of fits consisting of vertigo, headache, disturbance of consciousness, and spasm, are presented. Two of them were confirmed by operation to have haemoatoma in vermis of cerebellum.
1) "The acute vermis syndrome", is defined and characterized in order to facilitate diagnosis in the future.
2) The characteristic nystagmus observed in these cases, are named "the irregular burst of spontaneous horizontal nystagmus". It is presumed that said nystagmus might be caused by disturbance in an intermediate part of vermis of cerebellum, particularly fastigial nuclei of both sides.
3) It is presumed that "vertical positioning nystagmus with vertigeous sensation" seen in the four cases might be caused by lack of vestibular repression due to the disturbance in the lower vermis.
