title: Measuring disease progression in frontotemporal lobar degeneration: a clinical and MRI study.
abstract: OBJECTIVE
  There is currently much interest in biomarkers of disease activity in frontotemporal lobar degeneration (FTLD). We assessed MRI and behavioral measures of progression in a longitudinal FTLD cohort.
  
  
  METHODS
  Thirty-two patients with FTLD (11 behavioral variant frontotemporal dementia [bvFTD], 11 semantic dementia [SemD], 10 progressive nonfluent aphasia [PNFA]) and 24 age-matched healthy controls were assessed using volumetric brain MRI and standard behavioral measures (Mini-Mental State Examination, Frontal Assessment Battery, Clinical Dementia Rating Scale, Neuropsychiatric Inventory with Caregiver Distress scale) at baseline and 1 year later. A semi-automated image registration protocol was used to calculate annualized rates of brain atrophy (brain boundary shift integral [BBSI]) and ventricular expansion (ventricular boundary shift integral [VBSI]). Associations between these rates and changes in behavioral indices were investigated.
  
  
  RESULTS
  Rates of whole brain atrophy were greater in the entire FTLD cohort and in each subgroup compared with controls (all p < or = 0.004). Rates of ventricular expansion were greater in the entire cohort (p < 0.001) and the SemD (p = 0.002) and PNFA (p = 0.05) subgroups compared with controls. Changes in Mini-Mental State Examination, Frontal Assessment Battery, and Clinical Dementia Rating Scale scores were associated with MRI measures of progression, though not uniformly across FTLD subgroups. Both BBSI and VBSI yielded feasible sample size estimates for detecting meaningful treatment effects in SemD and PNFA language subgroups. Sample sizes were substantially larger using MRI biomarkers for the bvFTD subgroup, and using behavioral biomarkers in general.
  
  
  CONCLUSIONS
  Semi-automated MRI atrophy measures are potentially useful objective biomarkers of progression in frontotemporal lobar degeneration (FTLD); however, careful stratification of FTLD subtypes will be important in future clinical trials of disease-modifying therapies.
authors.affiliation: Dementia Research Centre, Institute of Neurology, University College London, UK WC1N 3BG.
authors.forename: E
authors.initials: E
authors.lastname: Gordon
authors.forename: J D
authors.initials: JD
authors.lastname: Rohrer
authors.forename: L G
authors.initials: LG
authors.lastname: Kim
authors.forename: R
authors.initials: R
authors.lastname: Omar
authors.forename: M N
authors.initials: MN
authors.lastname: Rossor
authors.forename: N C
authors.initials: NC
authors.lastname: Fox
authors.forename: J D
authors.initials: JD
authors.lastname: Warren
mesh_terms: D000368:Aged; D001284:Atrophy / Q000473:pathology; D001921:Brain / Q000473:pathology*; D001931:Brain Mapping; D016022:Case-Control Studies; D018450:Disease Progression; D005260:Female; D057174:Frontotemporal Lobar Degeneration / Q000473:pathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009460:Neurologic Examination; D009483:Neuropsychological Tests; D009929:Organ Size; D012720:Severity of Illness Index