circular head-shaking nystagmus

OBJECTIVE: To analyze the false-negative proportion and reasons of positioning test in benign paroxysmal positional vertigo (BPPV). METHOD: Sixty-eight cases were reviewed and analyzed during February to April 2009. All patients had typical clinical history of BPPV and diagnosed by positioning test,and all were treated with PRM successfully. If positioning test at the first time were negative, examinations repeated after either head shaking or return visits. RESULT: Thirteen patients (19...

We recorded three-dimensional eye and head movements during circular, horizontal, vertical, and torsional head shaking in six human subjects with normal vestibular function. With circular head shaking, the stimulation of the canals by the termination of the head movement is similar to that following a step in velocity about the naso-occipital axis. A large torsional nystagmus with slow phase eye velocity of about 20 degrees/s was observed upon cessation of circular head shaking. The three-dimensional eye movements expected from stimulation of the semicircular canals by the head-shaking maneuvers were calculated...