Assessing misperception of rotation in benign paroxysmal positional vertigo with static and dynamic visual images.

Background: Perception of self-motion is difficult for patients to describe. In addition, the relationship between perceived rotation and eye movements is poorly understood, because most studies of patients have investigated only static orientation.

Objective: First, to determine whether patients with benign paroxysmal positional vertigo (BPPV) can use visual images to report perceived rotation elicited by the Dix-Hallpike maneuver. Second, to determine if the direction of patients' perceptions align with data on classical nystagmus direction.

Methods: After the Dix-Hallpike maneuver, BPPV patients viewed images - sketches or video animations - representing possible perceived motions. They selected one or more images representing perception.

Results: All subjects could select images. The directions of the videos were most often backward pitch and/ or ipsilateral roll and yaw relative to body orientation in the supine Dix-Hallpike position, generally consistent with the canal stimulus. Perceived direction of rotation was statistically significantly different from the direction of eye movements as published previously, suggesting a difference in mechanisms for perception and eye movements.

Conclusion: Patients can easily learn to use a video language to describe their experiences. Perception is generally aligned with canal stimulus and nystagmus, but not exactly.