Planning ability impairments in probable Alzheimer's disease patients: Evidence from the Tower of London test

ABSTRACT Alzheimer's disease (AD) is associated with progressive impairment of higher-level cognitive abilities. Previous research suggests that early impairment of executive functions occurs during the course of the disease, but few studies have specifically investigated planning ability in an AD population. Objective: The purpose of the current study was to examine whether AD patients retain the ability to plan ahead, by analyzing specificities of their behavior in successfully achieving a pre-established goal. Methods: Twenty-one AD patients and thirty-three elderly controls underwent a problem-solving assessment using the Tower of London (TOL) test. Results: AD patients were less accurate and less efficient than controls. AD patients also committed more mistakes. This indicates a decline in working memory and inhibitory deficits, resulting in impulsive and inappropriate behaviors. Conclusion: These results are in agreement with previous studies, showing executive function problems in patients with AD. Specifically, this study demonstrates the presence of planning ability deficits in AD, considering both qualitative and quantitative approaches. The wide range of analysis presented in this study can aid clinicians in identifying the nature of the poor performance of AD patients during a planning task.