Spatial disorientation in Alzheimer's disease: the remembrance of things passed.

BACKGROUND Patients with Alzheimer's disease (AD) and many older adults become lost even in familiar surroundings. This is commonly attributed to memory impairment, but it may reflect impaired spatial cognition. METHODS The authors examined the role of memory, perceptual, and cognitive mechanisms in spatial disorientation by comparing the performance of normal young (YN), middle-aged (MA), older adult (OA), and AD subjects on neuropsychological and spatial orientation tests. RESULTS The tendency to become lost is shared by almost all patients with AD (93%) and some OA subjects (38%). This impairment is not related to memory impairment. Instead, it reflects an inability to link recognized scenes with locations in the environment. CONCLUSIONS Spatial disorientation reflects the impaired linking of landmarks and routes that should be assessed in conjunction with routine memory testing in elderly patients.