Executive function and activities of daily living in Alzheimer's disease: a correlational meta-analysis.

BACKGROUND The assessment of executive function (EF) and activities of daily living (ADL) are important elements in the diagnosis of Alzheimer's disease. METHODS Following a comprehensive search in three databases, a random-effects meta-analysis was used to investigate the association between ADL ability and seventeen tests of EF, three tests of attention and working memory and the Mini-Mental State Examination. The association between EF and ADL ability was further investigated in relation to four different methods of assessing ADL, and one specific ADL, driving. RESULTS Forty-nine studies met the inclusion criteria, and a total of 3,663 participants were included, the majority of whom were diagnosed with Alzheimer's disease. Most of the individual tests, including commonly used tests of EF such as the Clock Drawing Test, Letter Fluency and the Trail Making Test Part B, showed a significant moderate association with ADL. Associations between EF and ADL ability were similar for all four methods of assessing ADL ability. Driving ability was also moderately associated with EF. CONCLUSION The meta-analysis suggests a consistent moderate association between ADL and EF, supporting the growing evidence for a link between ADL and executive dysfunction in early dementia.