Transient directional disorientation as a manifestation of cerebral ischemia.

The authors describe 2 patients who presented with transient directional disorientation (TDD) as a manifestation of cerebral ischemia. The patients suddenly lost sense of direction in a familiar environment despite preserved ability to recognize landmarks, and recovered within a short time. Brain MRI revealed an ischemic lesion in the right medial occipital lobe and the corpus callosum in case 1 and in the right parieto-occipital sulcus (POS) in case 2. After ictus, fMRI study of a navigation task was performed, which demonstrated the activation of the POS unilaterally in case 1 and bilaterally in case 2. We propose that TDD of our patients is related to temporary dysfunction of bilateral POS.