Structural Elements In The Concept Of Motion Sickness

A slow rotation room in a laboratory environment provides an excellent instrument for the study of motion sickness because the experimenter can control not only the stressful Coriolis accelerations, but also other important procedural and environmental variables. By exploiting this control, combined with the judicious selection of experimental subjects, it was possible to confirm many previous findings and demonstrate that manifestations of disturbances in the vestibular system fall into two distinct categories. In the first category are reflex phenomena evoked by Coriolis accelerations when the head is rotated out of the plane of the room's rotation, and revealed through systems which, under natural stimulus conditions, have functional articulations with vestibular receiving areas. The symptomatology in the second category comprises an epiphenomenon superimposed on any manifestation of the first, when the unusual vestibular activity, presumably through facilitory-inhibitory processes, irradiates to cells or cell assemblies not normally stimulated. Selected experimental findings are used in defining the characteristics of manifestations in the two categories and in demonstrating the nature of the facultative linkage between the otherwise independent systems underlying manifestations in the two categories.

This compendium, written by active researchers in the field, encompasses topics ranging from anatomical and physiological subjects, through analyses of stimulus characteristics, prediction of sickness, and consideration of human factors, to pharmacological and behavioral therapeutic measures for terrestrial as well as microgravity travelers. Material often found scattered in diverse journals, paper-bound proceedings of symposia, difficult-to-find laboratory reports, or included with other topics in collections having a diffuse focus, are presented here in one volume dedicated to a single theme. The critical up-to-date- reviews are a first source for researchers and research program managers as well as an essential information source for engineers and practitioners.

A standard method developed for quantifying Coriolis (motion) sickness susceptibility was evaluated in 250 normal and three labyrinthine-defective subjects. The procedure required the subject to execute standard head movements (plus or minus 90 degrees in the frontal and sagittal planes) while seated in a chair device that was rotated at one of several constant velocities. The proper test velocity was predicted in the majority of cases with the Motion Experience Questionnaire. Three of the normal and all of the labyrinthine-defective subjects were found to be unsusceptible to these test conditions. Coriolis Sickness Susceptibility Index, CSSI, was determined for each subject by multiplying the appropriate E factor, the average stress effect of each head movement for the rpm used in the test, by the number of head movements required to provoke severe malaise (M III). The resultant CSSI values for the 250 subjects ranged from 0.4 to 100, but the distribution was markedly rigt skewed. The procedure yielded a high test-retest reliability (p = .89) in terms of CSSI scores and pattern of symptomatology. In reaching the Malaise III level, the nausea syndrome was manifested in most cases, but a significant percentage (9.6%) of the subjects remained free of any epigastric disturbance or nausea. (Author).

A Complete Toolbox of Theories and TechniquesThe second edition of a bestseller, Handbook of Virtual Environments: Design, Implementation, and Applications presents systematic and extensive coverage of the primary areas of research and development within VE technology. It brings together a comprehensive set of contributed articles that address the

This book is based on the proceedings of the Ergonomics Society's 1992 Annual Conference Birmingham, England, 7-10 April 1992. It contains papers, covering environmental studies, musculoskeletal studies, working postures and anthropometry, safety, and military ergonomics.