Executive function in progressive and nonprogressive behavioral variant frontotemporal dementia

Background: Recent studies suggest that behavioral variant frontotemporal dementia (bv-FTD) patients differ in their prognosis with fast-progressing and very slowĝ€"progressing cases. We investigated executive and behavioral profiles of progressive and nonprogressive bv-FTD patients to establish diagnostic markers discriminating the two groups.  

Methods: A range of neuropsychological and behavioral tests were used. Mean overlap-based statistical analyses and logistic regression analyses were performed to distinguish progressive from nonprogressive bv-FTD cases.  

Results: Although progressors and nonprogressors showed similar behavioral profiles, they were distinguishable by their performance on executive tasks. The nonprogressorsg performance on all tests was with the normal range, whereas the progressors were consistently impaired on four tests: Digit Span Backward, Hayling Test of inhibitory control, Letter Fluency, and Trails B. Logistic regression showed that 86% of patients could be classified on the basis of Digit Span and Hayling subscores.  

Conclusions: Contrary to some prior reports, behavioral variant frontotemporal dementia (bv-FTD) patients who progress over time are typically impaired on executive tasks at first presentation, although an important minority of true FTD patients perform normally. Previous inconsistencies are explicable by the mixture of patients with progressing FTD and phenocopy cases.