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 defic its that contribute to TD in AD patients are not well understood. Method: T his study examined 19 healthy older individuals (controls) and 16 AD patien ts who were administered a comprehensive neuropsychological battery along w ith a novel Route Learning Test (RLT). Areas assessed included incidental l earning, spatial relations, recall of the walking route, and recognition of landmarks. Results: Despite comparable performance on basic visuospatial a bility 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 pr edictor of RLT performance in AD patients. Among RLT subtests, AD patients performed best on recognition of landmarks compared with recognition and re call of spatial layout or recognition of incidental items in the environmen t. Conclusions: Our findings suggest that poor performance on the RLT in AD patients is characteristic of poor spatial orientation or spatial reasonin g. Therefore, episodes of TD in AD patients may occur secondary to poor spa tial orientation.