Route learning impairment associated with encephalomalasia secondary to traumatic brain injury: a case report.

Topographical disorientation is marked by difficulty finding one's way in familiar or new environments. The present case study reports findings from a 30-year-old male with encephalomalasia of the left parahippocampal region secondary to brain trauma with subsequent difficulty in learning of new routes. His navigation in premorbidly known (familiar) surroundings was intact. Magnetic resonance images revealed left parahippocampal and bilateral occipital encephalomalasia. Neuropsychological screening showed impairment in structuring a representation of the spatial relationships among landmarks with relatively preserved ability to learn visual and verbal information of these landmarks. Decreased visual perception and inappropriate visual inputs due to cervical dystonia and right homonymous hemianopsia also appear to play a role in his disability. The current knowledge about the neuronal systems involved in visual cognition and topographical orientation also are addressed in this report.