I find my way in a maze but not in my own territory! Navigational processing in developmental topographical disorientation.

OBJECTIVE: Developmental Topographical Disorientation (DTD) is a selective difficulty in way-finding showed by individuals with normal intellectual ability. We aimed to clarify whether getting lost even in familiar contexts could be because of a variety of developmental deficits that may affect the acquisition of one or more navigational competencies.

METHOD: Two DTD individuals were submitted to neuropsychological assessment and MRI exam, to verify the absence of further cognitive deficits and brain abnormalities; navigational and visuospatial tasks, and Radial Arm Maze (RAM) paradigms to assess spatial competencies; and switching paradigms to assess backward inhibition processes in spatial- and no-spatial contexts. DTD performances were compared with those of controls matched for gender, age, and education.

RESULTS: DTD participants were not able to retrace a previously showed route, but they could recognize previously seen landmarks. They performed RAM paradigms without significant differences from controls and adopted complex navigational strategies as the cognitive mapping. It is interesting that DTD participants exhibited a peculiar alteration of Backward Inhibition, a mechanism that allows flexibly adapting to continuously changing environments.

CONCLUSIONS: These findings demonstrate that getting lost for DTD participants did not imply the lack of basic navigational strategies and was not related to visuospatial or spatial memory deficits. We discuss the hypothesis that Backward Inhibition might play a role in updating environment representation during navigation.