Dissociating Frontotemporal Dementia and Alzheimer's Disease Using Measures of Executive Functions - A Meta-Analysis

Abstract

Diagnosis of Alzheimer’s disease (AD) and frontotemporal dementia (FTD) currently relies mostly upon clinical symptoms rather than histopathologic and genetic factors. This yields a problem as clinical symptoms of both diseases are difficult to distinguish. A possible solution lies in impairments in cognitive domains that are closely related to frontal cortical functioning such as executive functions, as FTD shows more focal bilateral frontal atrophy while atrophy in AD generally shows a more posterior pattern. In this meta-analytic review selective attention, concept shifting, divided attention, fluency, response control and planning were analysed for their capacity to dissociate between FTD and AD. With data from 24 included studies, effect sizes were calculated for each cognitive domain. The resulting effect sizes indicated that patient groups were quite easy to dissociate from controls, while distinguishing patient groups based on performances on different executive functions remained problematic. Thus, this series of executive tests cannot be used to reliably differentiate between FTD and AD in clinical practice. In prospect, the limited potential of executive measures to dissociate between FTD and AD found in this study should be considered in research as well as in clinical practice. A new direction in achieving improved differential diagnosis of FTD and AD may be provided by exploring social cognitive measures.