A Case of Probable Dementia with Lewy Bodies Presenting with Geographic Mislocation and Nurturing Syndrome

A 83-year-old right handed man developed nurturing syndrome and geographical mislocation (misidentification of places) as a result of dementia with Lewy bodies. He showed parkinsonism, fluctuating cognition, repeated falls, systematic delusions (delusional jealousy with vivid feeling of witness), rapid eye movement sleep behavior disorder, and mild dementia. His brain MRI showed atrophy of bilateral temporal tips and amygdala. A FDG-PET showed decrease of glucose metabolism in right frontal lobe and left temporo-parietal areas. He showed constructional disability, frontal lobe dysfunction, mild deterioration of immediate memory, mild anterograde amnesia, and retrograde amnesia for recent events. Aphasia, apraxia, agnosia, confabulation, or deterioration of facial perception was not noted. He could state the genealogy, ages and recent whereabouts of his relatives, and could state the locations and geographical relationships of his neighboring buildings. He insisted that his father's existence, who had died 52 years ago, although he talked about the episode of his death just before. One month after having a dream that his sick-room was in a fictitious branch of our hospital which located in his neighboring temple, he developed a delusion that his ward was actually in the temple. The former disorder seems to correspond to the nurturing syndrome described by Venneri et al. (2000), and the latter one suggested us that his dream was causally involved in the formation of geographical mis-localization. After Ramachandran's explanation for Capgras' syndrome, we hypothesized that mis-arousal of familiarity evoked by visual perception or memory was attributable to the dysfunction of amygdala, and failure of consistency-checking was caused by the dysfunction of the right frontal lobe.