Papers by Charles M. Oman
Acta Oto-laryngologica, 1986
This study provides measurements in individual specimens of the sizes, cross-sectional shapes and... more This study provides measurements in individual specimens of the sizes, cross-sectional shapes and areas all around the path of fluid flow through the human horizontal semicircular duct, ampulla and utricle. These data were obtained from multiple measurements on individual specimens which had been fixed by immersion in Karnovsky's fixative and microdis-sected. The results are compared with similar measurements in the rat and guinea pig.
Journal of vestibular research, Jul 3, 2008
We demonstrate a new method for measuring the time constant of head-movement-contingent oscillops... more We demonstrate a new method for measuring the time constant of head-movement-contingent oscillopsia (HMCO) produced by vestibular Coriolis stimulation. Subjects briskly rotated their heads around pitch or roll axes whilst seated on a platform rotating at constant velocity. This induced a cross-coupled vestibular Coriolis illusion. Simultaneous with the head movement, a visual display consisting of either a moving field of white dots on a black background or superimposed on a subject-stationary horizon, or a complete virtual room with conventional furnishings appeared. The scene's motion was driven by a simplified computer model of the Coriolis illusion. Subjects either nulled (if visual motion was against the illusory body rotation) or matched (if motion was in the same direction as the illusory motion) the sensation with the exponentially slowing scene motion, by indicating whether its decline was too fast or too slow. The model time constant was approximated using a staircase technique. Time constants comparable to that of the Coriolis vestibular ocular reflex were obtained. Time constants could be significantly reduced by adding subject-stationary visual elements. This technique for measuring oscillopsia might be used to quantify adaptation to artificial gravity environments. In principle more complex models can be used, and applied to other types of oscillopsia such as are experienced by BPPV patients or by astronauts returning to Earth.
Journal of vestibular research, Feb 1, 1998
In a study of 18 human subjects, we applied a new technique, estimation of the transfer function ... more In a study of 18 human subjects, we applied a new technique, estimation of the transfer function between instantaneous lung volume (IL V) and instantaneous heart rate (HR), to assess autonomic activity during motion sickness. Two control recordings of IL V and electrocardiogram (ECG) were made prior to the development of motion sickness. During the first, subjects were seated motionless, and during the second they were seated rotating sinusoidally about an earth vertical axis. Subjects then wore prism goggles that reverse the left-right visual field and performed manual tasks until they developed moderate motion sickness. Finally, ILV and ECG were recorded while subjects maintained a relatively constant level of sickness by intermittent eye closure during rotation with the goggles. Based on analyses of IL V to HR transfer functions from the three conditions, we were unable to demonstrate a changt• in autonomic colltrol of hear! rate due tn rotatinl1 alolle or dut' to motinJl sicknes!o. Thesl finding!. d(o !lot suppo,; tht• lIotion tha. moden lte moti nH sici,;n •.•s~ is manifested a~ a g~'ne:-alize(' :Jl1. Wnomit' respnnse.
CRC Press eBooks, Jun 4, 1991
2017FUNDING NUMBERS: DTFR53-11-C-00016; SPONSORING/MONITORING AGENCY REPORT NUMBER: DOT/FRA/ORD-1... more 2017FUNDING NUMBERS: DTFR53-11-C-00016; SPONSORING/MONITORING AGENCY REPORT NUMBER: DOT/FRA/ORD-17/24PDFTech ReportHead up displaysPrototypesRailroad commuter serviceRailroad safetyReal time informationHybrid Cognitive Task Analysismoving mapiPadheads-up displaysafetyhuman-in-the-loop testingpassenger rail serviceBoston (Massachusetts)United StatesUnited States. Federal Railroad Administration. Office of Research, Development, and TechnologyUnited States. Federal Railroad Administration. Office of Research and DevelopmentLiu, AndrewOman, Charles M.Voelbel, KathleenMassachusetts Institute of TechnologyUnited States. Federal Railroad Administration. Office of Railroad Policy and DevelopmentUnited States. Federal Railroad Administration. Office of Research, Development, and TechnologyJones, MichaelNTL-RAIL TRANSPORTATION-Rail SafetyUS Transportation CollectionThis report describes the development and evaluation of a prototype real-time moving map display to support engineer situation awareness and safety performance for future U.S. high-speed rail applications. The development started with a hybrid Cognitive Task Analysis to develop Information and Functional Requirements for the display. Using basic design principles, the initial layout for an iPad-based display was created. The design was evaluated by 10 experienced engineers in a formal cognitive walk-through. After a brief training session, they answered questions about the display and performed typical actions such as entering track warrant information. Subjects completed most of these tasks successfully and provided feedback which was used to improve the display. The revised iPad display was then evaluated in a human-in-the-loop experiment. Eight experienced commuter rail engineers drove twice a 38-mile trip both with and without the display. The engineers demonstrated similar train handling performance and rule adherence in both operating conditions. They generally took 30 to 60 seconds more to enter track warrant information compared to using paper forms. Finally, the engineers thought that a similar display would be helpful for conductors and could replace paper rule books
The goal of this project is to better understand the process of spatial orientation and navigatio... more The goal of this project is to better understand the process of spatial orientation and navigation in unfamiliar gravito-inertial environments, and ultimately to use this new information to develop effective countermeasures against the orientation and navigation problems experienced by astronauts. How do we know our location, orientation, and motion of our body with respect to the external environment ? On earth, gravity provides a convenient "down" cue. Large body rotations normally occur only in a horizontal plane. In space, the gravitational down cue is absent. When astronauts roll or pitch upside down, they must recognize where things are around them by a process of mental rotation which involves three dimensions, rather than just one. While working in unfamiliar situations they occasionally misinterpret visual cues and experience striking "visual reorientation illusions" (VRIs), in which the walls, ceiling, and floors of the spacecraft exchange subjective identities. VRIs cause disorientation, reaching errors, trigger attacks of space motion sickness, and potentially complicate emergency escape. MIR crewmembers report that 3D relationships between modules - particularly those with different visual verticals - are difficult to visualize, and so navigating through the node that connects them is not instinctive. Crew members learn routes, but their apparent lack of survey knowledge is a concern should fire, power loss, or depressurization limit visibility. Anecdotally, experience in mockups, parabolic flight, neutral buoyancy and virtual reality (VR) simulators helps. However, no techniques have been developed to quantify individual differences in orientation and navigation abilities, or the effectiveness of preflight visual. orientation training. Our understanding of the underlying physiology - for example how our sense of place and orientation is neurally coded in three dimensions in the limbic system of the brain - is incomplete. During the 16 months that this human and animal research project has been underway, we have obtained several results that are not only of basic research interest, but which have practical implications for the architecture and layout of spacecraft interiors and for the development of astronaut spatial orientation training countermeasures.
Journal of the Acoustical Society of America, Jul 1, 1973
MEETING ß ACOUSTICAL SOCIETY OF AMERICA weight of the incus appears to be independent of body wei... more MEETING ß ACOUSTICAL SOCIETY OF AMERICA weight of the incus appears to be independent of body weight. These results are important for establishing the values of parameters used in mathematical models of the middle ear. They are also relevant to theoretical considerations of the significance of middle-ear resonances. [Supported by the Medical Research Council of Canada.] P2. Successful Conditioning of the Stapedius Muscle. A.
Planetary landing requires the selection of a suitable landing zone followed by a stable, control... more Planetary landing requires the selection of a suitable landing zone followed by a stable, controlled descent to the surface. In crewed landings, astronauts are expected to play an active role in hazard identification, landing point selection, vehicle navigation, and supervision of automated systems. However, astronauts will have experienced sensorimotor adaptation during their microgravity exposure and may face unique landing conditions which could lead to inaccurate perceptions of vehicle orientation. A quantitative model of visual-vestibular integration was used to predict astronaut perceptions of vehicle orientation during various planetary landing trajectories, including altered gravity levels. The model predicted the potential for disorientation during specific portions of the landing trajectories when visual cues were not available. Astronaut spatial disorientation is also a concern for commercial crew, particularly as the number of landings increases. Our methodology allows for the early identification of trajectories or motions which may result in disorientation.
Seeing and Perceiving, 2010
Visual and balance cues concerning the relative orientation of ourselves and our environment comb... more Visual and balance cues concerning the relative orientation of ourselves and our environment combine to direct our steps to select a secure footing. How are visual cues used to select the best support surface? Here we show that, when exposed to tilted, rectangular rooms of various aspect ratios, subjects do not necessarily choose the surface with its normal oriented closest to the gravity-defined vertical. Rather their decision is also strongly biased by the visual area subtended by each candidate surface.
Journal of vestibular research, Aug 1, 2003
This double issue of the Journal of Vestibular Research contains eight vestibular research papers... more This double issue of the Journal of Vestibular Research contains eight vestibular research papers from the National Space Biomedical Research Institute (NSBRI). NASA established the NSBRI in 1997 through a nationwide competition. Research teams of scientists were formed in several disciplines of physiology related to long duration spaceflight, including the neurovestibular function. During the first five years of NSBRI research, each team’s goal has been to define the biomedical problems associated with long duration spaceflight, to understand the basic mechanisms, and publish findings in peer-reviewed journals. The teams also have the important additional goal of defining, developing, and validating scientifically based countermeasures. In the neurovestibular domain, the most serious risks of spaceflight include motion sickness, particularly while wearing a space suit; disorientation caused by weightlessness or by the Coriolis cross-coupling effects of artificial gravity; disabling vertigo during re-entry and landing; and an inability to stand or walk upon return to Earth. Potential countermeasures include new methods for preventing, treating, and monitoring space motion sickness, sensory-motor training to facilitate adaptive responses to gravity transitions, the use of
PubMed, Apr 1, 2006
Background: Astronauts floating inside a spacecraft must be able to recall the direction to surro... more Background: Astronauts floating inside a spacecraft must be able to recall the direction to surrounding visual landmarks, regardless of their viewing perspective. If 3D orientation skills are taught preflight, should perspective sequences be blocked or randomized? Can standard spatial skill tests predict performance? Methods: Undergraduates (40 men and 40 women; ages 19-24) learned 3D spatial relationships among landmark pictures in a cubic chamber simulating a space station node. Subjects learned to predict picture directions when told one picture's direction (the one behind them) and the subject's simulated roll orientation, which was changed between trials by rotating pictures. The dependent variable was the proportion of correct predictions. A between group (n=40 per group) independent variable was training type (random vs. blocked sequencing of perspectives). Experiment phase (familiarization, training, transfer, and 2 retention phases) was a within group variable. Subjects also took three standard spatial skill tests: Card Rotation, Cube Comparison, and Group Imbedded Figures. Results: As hypothesized, during training, performance for the random group (0.56) was worse than the blocked group (0.83); during transfer, the random group (0.75) was better than the blocked group (0.56); during retention-i, the random group (0.70) was better than the blocked group (0.55); and during retention-2, the random group (0.76) was better than the blocked group (0.65). Spatial skill tests correlated differently across the two groups, indicating that random sequencing elicits different skills. Conclusion: Random presentation enhances 3D spatial skill transfer and retention. Standard spatial tests can predict performance and have the potential to customize training.
SAE technical paper series, Jul 19, 2004
Guidelines for designing you-are-here (YAH) maps aboard International Space Station (ISS) are pro... more Guidelines for designing you-are-here (YAH) maps aboard International Space Station (ISS) are proposed, based on results from previous 3D spatial navigation studies conducted by our research group and colleagues. This paper reviews terrestrial YAH maps, the common errors associated with them, and how to appropriately implement what is known from terrestrial to micro-gravity YAH maps. We conclude with a creative example of an ISS YAH map that utilizes given guidelines and information visualization techniques.
PubMed, May 1, 1988
The effects of two drugs used to prevent symptoms of motion sickness in the operational environme... more The effects of two drugs used to prevent symptoms of motion sickness in the operational environment were examined in this study of human performance as measured by computer-based tests of cognitive and psychomotor skills. Each subject was exposed repetitively to five tests: Symbol-Digit Substitution, Simple Reaction Time, Pattern Recognition, Digit Span Memory, and Pattern Memory. Although there have been previous reports of decreases in human performance in similar testing with higher dosages of scopolamine or dextroamphetamine, no significant decrements were observed with the operational-level combined dose used in this study (0.4 mg oral scopolamine and 5.0 mg oral dextroamphetamine.) The controversy over the use of combination drug therapy in this environment is discussed along with the indications for further research based on the findings.
SAE technical paper series, Feb 1, 1982
Approximately 43 percent of Apollo, Skylab, Soyuz/Salyut and Shuttle crewmen have experienced sym... more Approximately 43 percent of Apollo, Skylab, Soyuz/Salyut and Shuttle crewmen have experienced symptoms resembling motion sickness during their first several days in space. This paper reviews the space sickness problem in both an operational and physiological context, and describes experiments planned by a team of vestibular researchers from the USA and Canada to study space sickness and associated sensory-motor adaptation to weightlessness during Spacelab missions 1 and 4, and the German Spacelab mission D-1.
PubMed, Aug 1, 2007
Background: Astronauts have reported spatial disorientation and navigation problems inside spacec... more Background: Astronauts have reported spatial disorientation and navigation problems inside spacecraft whose interior visual vertical direction varies from module to module. If they had relevant preflight practice they might orient better. This experiment examined the influence of relative body orientation and individual spatial skills during VR training on a simulated emergency egress task. Method: During training, 36 subjects were each led on 12 tours through a space station by a virtual tour guide. Subjects wore a head-mounted display and controlled their motion with a game-pad. Each tour traversed multiple modules and involved up to three changes in visual vertical direction. Each subject was assigned to one of three groups that maintained different postures: visually upright relative to the "local" module; constant orientation relative to the "station" irrespective of local visual vertical; and "mixed" (local, followed by station orientation). Groups were balanced on the basis of mental rotation and perspective-taking test scores. Subjects then performed 24 emergency egress testing trials without the tour guide. Smoke reduced visibility during the last 12 trials. Egress time, sense of direction (by pointing to origin and destination) and configuration knowledge were measured. Results: Both individual 3D spatial abilities and orientation during training influence emergency egress performance, pointing, and configuration knowledge. Local training facilitates landmark and route learning, but station training enhances sense of direction relative to station, and, therefore, performance in low visibility. Conclusions: We recommend a sequence of local, followed by station, and then randomized orientation training, preferably customized to a trainee's 3D spatial ability.
Journal of vestibular research, Aug 1, 2003
Human orientation requires one to remember and visualize spatial arrangements of landmarks from d... more Human orientation requires one to remember and visualize spatial arrangements of landmarks from different perspectives. Astronauts have reported difficulties remembering relationships between environmental landmarks when imagined in arbitrary 3D orientations. The present study investigated the effects of strategy training on humans' 1) ability to infer their orientation from landmarks presented ahead and below, 2) performance when subsequently learning a different array, and 3) retention of configurational knowledge over time. On the first experiment day, 24 subjects were tested in a virtual cubic chamber in which a picture of an animal was drawn on each wall. Through trial-by-trial exposures, they had to memorize the spatial relationships among the six pictures around them and learn to predict the direction to a specific picture when facing any view direction, and in any roll orientation. Half of the subjects ("strategy group") were taught methods for remembering picture groupings, while the remainder received no such training ("control group"). After learning one picture array, the procedure was repeated in a second. Accuracy (% correct) and response time learning curves were measured. Performance for the second array and configurational memory of both arrays were also retested 1, 7, and 30 days later. Results showed that subjects "learned how to learn" this generic 3D spatial memory task regardless of their relative orientation to the environment, that ability and configurational knowledge was retained for at least a month, that figure rotation ability and field independence correlate with performance, and that teaching subjects specific strategies in advance significantly improves performance. Training astronauts to perform a similar generic 3D spatial memory task, and suggesting strategies in advance, may help them orient in three dimensions.
PubMed, Aug 1, 1982
Eight subjects, wearing left-right vision reversing goggles, executed sequences of controlled act... more Eight subjects, wearing left-right vision reversing goggles, executed sequences of controlled active head movements to provoke motion sickness. Head movement sequences were interspaced with periods of eye closure and no head movement to permit partial remission of symptoms between sequences. Subjects reported the level of discomfort experienced by using a magnitude estimation technique derived from Stevens' (1957) ratio scaling method. Using this approach, we demonstrated that the time course of subjective discomfort exhibits a profile, similar in all our subjects, characterized by both fast and slow response components. The potential usefulness of magnitude estimation for research on the dynamic properties of the mechanism generating motion sickness symptoms is discussed.
Human Factors, Sep 27, 2016
This article describes a closed-loop, integrated human-vehicle model designed to help understand ... more This article describes a closed-loop, integrated human-vehicle model designed to help understand the underlying cognitive processes that influenced changes in subject visual attention, mental workload, and situation awareness across control mode transitions in a simulated human-in-the-loop lunar landing experiment. Control mode transitions from autopilot to manual flight may cause total attentional demands to exceed operator capacity. Attentional resources must be reallocated and reprioritized, which can increase the average uncertainty in the operator's estimates of low-priority system states. We define this increase in uncertainty as a reduction in situation awareness. We present a model built upon the optimal control model for state estimation, the crossover model for manual control, and the SEEV (salience, effort, expectancy, value) model for visual attention. We modify the SEEV attention executive to direct visual attention based, in part, on the uncertainty in the operator's estimates of system states. The model was validated using the simulated lunar landing experimental data, demonstrating an average difference in the percentage of attention ≤3.6% for all simulator instruments. The model's predictions of mental workload and situation awareness, measured by task performance and system state uncertainty, also mimicked the experimental data. Our model supports the hypothesis that visual attention is influenced by the uncertainty in system state estimates. Conceptualizing situation awareness around the metric of system state uncertainty is a valuable way for system designers to understand and predict how reallocations in the operator's visual attention during control mode transitions can produce reallocations in situation awareness of certain states.
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Papers by Charles M. Oman