Route learning performance in Alzheimer disease patients.

OBJECTIVE: To examine performance on an objective measure of route learning in Alzheimer disease (AD) patients.
BACKGROUND: Topographic disorientation (TD) is a common problem among AD patients. The underlying cognitive deficits that contribute to TD in AD patients are not well understood.
METHOD: This study examined 19 healthy older individuals (controls) and 16 AD patients who were administered a comprehensive neuropsychological battery along with a novel Route Learning Test (RLT). Areas assessed included incidental learning, spatial relations. recall of the walking route, and recognition of landmarks.
RESULTS: Despite comparable performance on basic visuospatial ability measures, AD patients performed significantly worse than controls on the RLT and evidenced poor incidental learning for environmental details. A measure of egocentric and allocentric orientation ability was the best predictor of RLT performance in AD patients. Among RLT subtests, AD patients performed best on recognition of landmarks compared with recognition and recall of spatial layout or recognition of incidental items in the environment.
CONCLUSIONS: Our findings suggest that poor performance on the RLT in AD patients is characteristic of poor spatial orientation or spatial reasoning. Therefore, episodes of TD in AD patients may occur secondary to poor spatial orientation.