Abstract
Purpose : When vision is impaired or lost, the ability to develop precise spatial memory representations (supramodal cognitive maps) for guidance of spatiomotor control, such as manual operation or non-visual navigation, becomes crucially important but is neglected in current rehabilitation approaches. The Cognitive-Kinesthetic (C-K) rehabilitation training based on memory-guided drawing (Likova, 2012), rapidly improves spatial memory for cognitive mapping, in particular for manual spatiomotor performance in the blind and low vision, and drives brain plasticity in respective cortical networks. The present purpose was to translate this approach from the manual to the navigation domain.
Methods : The C-K navigation training consisted of 2 hrs/day for 5 days of non-visual navigational decision-making solely based on cognitive maps formed non-visually in memory through haptic exploration of raised-line maps. This process was interleaved with a precise spatiomotor externalization of the planned route or the full map through blind memory-guided drawing. Training improvement was assessed before and after the training by a Computerized Similarity Index (CSI); transfer-of-training to core spatio-cognitive performance was assessed by the standardized Cognitive Test for the Blind (CTB); and brain reorganization was assessed by whole-brain functional Magnetic Resonance Imaging (fMRI) in a 3T Siemens Prisma.
Results : Post-training, both the CSI and the CTB measures showed a highly significant enhancement of all assessed outcomes, including the ability to non-visually make and execute navigational decisions solely based on the cognitive maps formed in memory, such as selecting the best path to a target. The pre/post fMRI comparisons revealed functional reorganization in key navigation and memory brain areas, such the retrosplenial and hippocampal cortices.
Conclusions : Taken together, the behavioral and brain imaging results confirmed the hypothesis that the C-K training can be successfully translated to rapidly and profoundly enhance spatial cognition and cognitive mapping required for effective navigation in the visually deprived, and to drive brain plasticity in the respective navigation and spatial memory networks. The strong changes show that the 10-hr C-K training is a powerful investigative tool to enhance understanding of brain and behavioral reorganization mechanisms under visual deprivation.