title: Clinical and Neuropsychological  Comparisons of Early-Onset Versus  Late-Onset Frontotemporal Dementia:  A CREDOS-FTD Study.
abstract: BACKGROUND
  Cognitive performance changes with chronological aging. Previous studies investigating clinical heterogeneity in frontotemporal dementia (FTD) according to the age of symptom onset did not consider the effect of chronological aging on cognition.
  
  
  OBJECTIVE
  We compared cognitive and behavioral symptoms in patients with early-onset (EO) and late-onset (LO) FTD with consideration of chronological aging effect.
  
  
  METHODS
  A total of 166 FTD patients were enrolled consecutively from multi-center memory clinics using a nationwide FTD register. To control for the effects of chronological aging on neuropsychological scores, seven hundred and two subjects with normal cognition were also enrolled and regression models were set up. Neuropsychological scores that were detrended with the regression models and the behavioral symptoms of the EO-FTD and LO-FTD groups were compared. Subgroup analyses were performed for three main subtypes of FTD, behavioral variant frontotemporal dementia (bvFTD), semantic dementia (SD), and progressive non-fluent aphasia (PNFA).
  
  
  RESULTS
  Among 166 FTD patients, there were 76 bvFTD, 57 SD, and 33 PNFA patients who met new diagnostic criteria for bvFTD or primary progressive aphasia, respectively. LO-FTD (48.2%) was more common than previously thought and the proportions of EO and LO groups differed across FTD subtypes. EO-FTD patients had lower memory and frontal/executive scores and more prominent frontal/behavioral symptoms than LO-FTD patients.
  
  
  CONCLUSIONS
  Our study suggested that FTD could be heterogeneous with respect the age of symptom onset. After controlling for the effects of chronological aging, EO-FTD patients exhibited more profound memory and frontal/executive dysfunction and more behavioral symptoms than LO-FTD patients.
authors.affiliation: Department of Neurology, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Byoung Seok
authors.initials: BS
authors.lastname: Ye
authors.forename: Seong Hye
authors.initials: SH
authors.lastname: Choi
authors.forename: Seol-Heui
authors.initials: SH
authors.lastname: Han
authors.forename: SangYun
authors.initials: S
authors.lastname: Kim
authors.forename: Dong-Won
authors.initials: DW
authors.lastname: Yang
authors.forename: Kee Hyung
authors.initials: KH
authors.lastname: Park
authors.forename: Hyun Jeong
authors.initials: HJ
authors.lastname: Han
authors.forename: Young Chul
authors.initials: YC
authors.lastname: Youn
authors.forename: Byung-Ok
authors.initials: BO
authors.lastname: Choi
authors.forename: Seung H
authors.initials: SH
authors.lastname: Kim
authors.forename: Sook-young
authors.initials: SY
authors.lastname: Woo
authors.forename: Duk L
authors.initials: DL
authors.lastname: Na
authors.forename: Eun-Joo
authors.initials: EJ
authors.lastname: Kim
mesh_terms: D017668:Age of Onset; D000368:Aged; D001526:Behavioral Symptoms / Q000209:etiology*; D003072:Cognition Disorders / Q000175:diagnosis* / Q000209:etiology*; D005260:Female; D057180:Frontotemporal Dementia / Q000145:classification / Q000150:complications*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011569:Psychiatric Status Rating Scales; D012189:Retrospective Studies