Detecting clinical change with the CDR-FTLD: differences between FTLD and AD dementia

Objective: To investigate the psychometric properties of the Clinical Dementia Scale—frontotemporal lobar degeneration (CDR-FTLD) psychometric properties using Rasch analysis and its sensitivity distinguishing disease progression between FTLD and Alzheimer's disease (AD). 
Methods: Of 603 consecutive patients from the National Alzheimer Coordinating Center dataset (FTLD = 350; AD = 253), 120 FTLDs were included in a Rasch analysis to verify CDR-FTLD psychometric properties; 483 (FTLD = 230; AD = 253) were included to analyse disease progression, with 195 (FTLD = 82; AD = 113) followed-up (24 months). 
Results: The CDR-FTLD demonstrated good consistency, construct and concurrent validity and correlated well with mini-mental state examination (MMSE) and disease duration (ps < 0.05). At baseline, FTLD showed greater dementia severity than AD after matched for MMSE and disease duration (p < 0.001). Independent Rasch analyses demonstrated different patterns of progression for FTLD and AD in terms of the domains initially and then subsequently affected with disease progression. At follow-up, although MMSE showed significant changes (p < 0.05), these were greater on the CDR-FTLD (p < 0.001). 
Conclusion: The CDR-FTLD satisfactorily measures dementia severity and change in FTLD, distinguishing disease progression between FTLD and AD, with clear implications for care, prognosis and future clinical trials. © 2016 The Authors. International Journal of Geriatric Psychiatry published by John Wiley & Sons, Ltd.