ИСТИНА

The development of innovative methods for testing cognitive disturbances with the use of up-to-date technologies is gaining in importance in psychological rehabilitation. An important problem is the development of methods for the diagnosis and correction of spatial cognition disorders that manifest themselves, in particular, in decreasing the accuracy of mental spatial representations (SR) of the environment. The scientific literature considers two types of spatial representations: egocentric representations (ER), encoding object locations relative to the observer and allocentric representations (AR), specifying the relative positions of the objects relative one another. The literature lacks studies of the accuracy of ER and AR processing in working memory. Objective. To study the problem, we had developed a method for evaluating the accuracy of encoding spatial information and applied it to examine the accuracy in reproducing complex three-dimensional scenes. It was supposed that the reproduction accuracy would show significant difference depending on which system (egocentric or allocentric) was involved in the mental reconstruction of the scene. Description of the experiment. Six unique virtual scenes were constructed each consisted of seven objects located in different 3D positions. Each scene was shown for 25 seconds using the CAVE virtual reality system. Thirty six participants (22F, 14M, age range 18—26) were tested. The participant’s task was to remember the scene and then to reproduce it in a virtual space using the given viewpoint: «the frontal viewpoint» (to reproduce the memorized scene from the egocentric position), «from the left» and «from the above» viewpoints (to reproduce the scene from the left or above imaginary allocentric positions, respectively). To perform the task, the participants chose objects from the library of virtual objects and placed them in virtual space using the flystick. Their coordinates in the virtual space were recorded. Next, the accuracy of ER and AR cording was calculated in terms of metrics, topology and depth parameters. The egocentric representations («the frontal viewpoint») was shown to form significantly better than the allocentric representations (from the left and from above). Whatever the aspect, the topological parameters of the space were kept in the short memory significantly better than the parameters of depth, which, in their turn, were coded better than the parameters of metrics. It was shown also that the coding accuracy of the spatial representations was different for two types of allocentric aspects: the aspect from above was reproduced significantly better than the aspect from the left. The developed method allowed us to identify the coding features of the spatial information in ER and AR blocks in terms of metrics, topology, and depth parameters. It can be used in the clinical rehabilitation for testing the defects of space perception and the defects of short memory. The obtained results enable improving the present-day models of coding spatial information.