Objective: To determine the pattern of executive dysfunction in frontotemporal dementia (FTD) and corticobasal syndrome (CBS) and to determine the brain areas associated with executive dysfunction in these illnesses.
Method:We administered the Delis-Kaplan Executive Function System (D-KEFS), a collection of standardized executive function tests, to 51 patients with behavioral-variant FTD and 50 patients with CBS. We also performed a discriminant analysis on the D-KEFS to determine which executive function tests best distinguished the clinical diagnoses of FTD and CBS. Finally, we used voxel-based morphometry (VBM) to determine regional gray matter volume loss associated with executive dysfunction.
Results:Patients with FTD and patients with CBS showed executive dysfunction greater than memory dysfunction. Executive function was better preserved in the patients with CBS than the patients with FTD with the exception of tests that required motor, visuospatial ability, or both. In patients with CBS, dorsal frontal and parietal and temporal-parietal cortex was associated with executive function. In FTD, tests with a language component (Verbal Fluency) were associated with left perisylvian cortex, sorting with the left dorsolateral prefrontal cortex, and reasoning (the Twenty Questions task) with the left anterior frontal cortex. The Twenty Questions test best distinguished the clinical diagnoses of CBS and FTD. Frontotemporal dementia (FTD) is a progressive neurodegenerative disease that primarily affects the frontal and anterior temporal lobes, resulting in changes in behavior, language, and cognition.
Conclusions:1 Corticobasal syndrome (CBS) is a disorder characterized by progressive asymmetric apraxia and rigidity with other findings of cortical (e.g., alien limb, cortical sensory loss, myoclonus) and basal ganglia (e.g., bradykinesia and increased resistance to passive movement) dysfunction.2,3 Both disorders can be associated with pathologic tau aggregation.