Cognitive impairment by spatial disorientation.

INTRODUCTION: Maintaining spatial orientation is a biological imperative. When orientation is threatened, attention resources are diverted to regaining orientation, possibly to the detriment of attention required by concurrent tasks. Hence, a factor in aviation mishaps may be the negative impact of disorientation on concurrent performance, such as interpreting instruments. We examined how subjects learn to manage the impact of acute disorienting stimuli on concurrent spatial cognitive tasks.

METHODS: Subjects performed the Manikin (MAN) and Choice Reaction Time (CRT) tests under three disorienting experiments: i) after self-controlled head rolls, N = 16; ii) during rotation of the background field of view, N = 12; and iii) after head movements provoking Coriolis during body rotation in yaw, N = 6.

RESULTS: Number correct and reaction times on the MAN task were negatively affected by each type of disorientation only when the task was performed in the presence of disorienting motion presented early in the experimental session. Later in the session, subjects learned to attain best performance levels irrespective of disorientation. Performance on the CRT task, which has good stimulus response compatibility with little high order processing, was unaffected. The slight symptoms of malaise provoked by disorientation did not interfere with performance in experiments (i) and (ii) but more severe symptoms in (iii) correlated with loss of performance.

CONCLUSION: Our studies suggest that the ability to maintain a high level of cognitive performance is susceptible to impairment when novel circumstances of disorientation are encountered. Extensive practice on particular tasks protects against encounters with novel disorientation. Once disorientation is identified, its potential impact on multitasking may be quarantined despite disorientation symptoms. The results indicate the need for over-training on tasks and experience with a wide variety of disorientation scenarios.