The Role of "Extra-Vestibular" Inputs in Maintaining Spatial Orientation in Military Vehicles
Abstract
An individual's 5 sense of spatial orientation is commonly attributed to be derived from visual, vestibular, and proprioceptive inputs. Spatial disorientation is often ascribed to arise from a conflict between one or all of these three systems. However, relying on this well studied view of spatial perception has not totally explained motion intolerance and spatial disorientation. It is likely that more than these three systems are involved in spatial orientation. This paper examines how cues obtained from posture, respiration, and blood flow contribute to spatial orientation. Disordered regulation of any of these factors can be identified in land based tests and allows us to study pre-disposing factors to motion sickness. In addition, examining these factors in motion environments allows US to study the mechanisms involved in motion intolerance. Postural studies were obtained in a cohort of individuals experiencing motion sickness in a variety of military environments. A definite pattern of altered postural control on land was demonstrated in over seventy percent of these individuals. The predictive value of this test and refinement of the test for increased accuracy as a pre-screening method are examined in this report. A second cohort of individuals was examined while underway in a United States Navy ship. Respiratory and postural measurements were performed on 3 motion sick and three non-motion sick individuals within 24 hours of going to sea as well as 48 hours after the first measurement. Initial postural and respiratory adaptations were compared to ship motion and the strategies of individuals without motion sickness were compared to the strategies of the motion sick individuals. Adaptive patterns were examined in each group and found to be complete within 48 hours. The implications of these findings are examined in developing strategies to deal with spatial disorientation in a number of military settings.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 2003
- Accession Number
- ADP013847
Entities
People
- Michael E Hoffer
Organizations
- Naval Medical Center San Diego