Orientation perception, motion sickness and vertigo: beyond the sensory conflict approach.

Current theoretical issues central to the understanding of pathological disorientation (vertigo) are addressed through a critical review of research into perceptual disorientation in healthy subjects (motion sickness). Investigations inspired by the 'sensory conflict' model of orientation perception typically paid insufficient attention to higher-order meaningful properties of the environment, purposive activity, and individual differences in sensorimotor experience and skill. These factors are incorporated into an alternative 'active perception' approach, which characterizes perception of orientation as arising from interactions between intra-individual variables and the perceptual properties and sensorimotor demands of the environments encountered. It follows that vertigo is a form of disability which can only be properly assessed in the broader context of a range of relevant attributes of the patient, and his or her activities and environment. Analysis of the principles governing responses to disorienting conditions identifies several factors relevant to the assessment and rehabilitation of vertiginous patients.