The FTLD-modified Clinical Dementia Rating scale is a reliable tool for defining disease severity in Frontotemporal Lobar Degeneration: evidence from a brain SPECT study

Background: Frontotemporal Lobar Degeneration (FTLD) is a heterogeneous disorder characterized by impairment in executive functions, behavioural disturbance and language deficit. Reliable scales of global impairment are under evaluation. A consortium of Mayo Clinic and University of California FTLD Centers has recently developed the FTLD-modified Clinical Dementia Rating (CDR) scale to assess FTLD severity. Objective: To evaluate whether FTLD-modified CDR scores correlate with the pattern and degree of brain SPECT hypoperfusion in patients with FTLD. Methods: Ninety-nine patients with FTLD entered the study. Patients underwent a clinical evaluation and a wide standardized neuropsychological assessment, including mini-mental state examination (MMSE) and FTLD-modified CDR. A brain SPECT perfusion imaging study was carried out in each patient. A linear correlation analysis between frontotemporal dementia-modified CDR or neuropsychological tests scores and perfusion data was performed. Results: There was a significant relationship between higher FTLD-modified CDR score and lower global regional cerebral blood flow in the frontal and temporal lobes, bilaterally. No significant correlation between MMSE and brain frontotemporal hypoperfusion was found. The correlation between brain hypoperfusion pattern and neuropsychological test scores tapping different cognitive domains fitted with previously published data. Conclusions: The recently introduced FTLD-modified CDR scale correlates with the degree of frontotemporal hypoperfusion in patients with FTLD. This study confirms and further supports the usefulness of FTLD-modified CDR in future clinical trials to monitor disease progression.