title: Frequency and clinical characteristics of early-onset dementia in consecutive patients in a memory clinic.
abstract: OBJECTIVE
  To investigate the frequency, rate of causes of dementia, and clinical characteristics of early-onset dementia in consecutive patients of a memory clinic.
  
  
  METHODS
  A total of 668 consecutive demented patients were involved in this study. We examined the distribution of patients' diagnosis, differences in sex, education, dementia severity and cognitive function at the first visit, and the duration from onset to consultation. We also examined the changes in the proportion of subjects during the research period.
  
  
  RESULTS
  There were 185 early-onset patients, 28% of all demented patients. No significant differences were observed between the early-onset and late-onset dementia groups in Clinical Dementia Rating and Mini-Mental State Examination score at the first consultation, but the duration from onset to consultation was significantly longer in the early-onset group. In the early-onset group, the rates of patients with Alzheimer's disease and dementia with Lewy bodies were relatively low and the rate of patients with frontotemporal lobar degeneration was relatively high. There were no significant differences in the proportion between either demented subjects and nondemented subjects or early-onset dementia patients and late-onset dementia patients during the research period.
  
  
  CONCLUSIONS
  We conclude that early-onset dementia is not rare and its clinical characteristics and causes are different from late-onset dementia.
authors.affiliation: Department of Neuropsychiatry, Neuroscience, Ehime University, Graduate School of Medicine, Ehime, Japan.
authors.forename: Shunichiro
authors.initials: S
authors.lastname: Shinagawa
authors.forename: Manabu
authors.initials: M
authors.lastname: Ikeda
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Toyota
authors.forename: Teruhisa
authors.initials: T
authors.lastname: Matsumoto
authors.forename: Naomi
authors.initials: N
authors.lastname: Matsumoto
authors.forename: Takaaki
authors.initials: T
authors.lastname: Mori
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Ishikawa
authors.forename: Ryuji
authors.initials: R
authors.lastname: Fukuhara
authors.forename: Kenjiro
authors.initials: K
authors.lastname: Komori
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Hokoishi
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Tanabe
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000453:epidemiology*; D000554:Ambulatory Care Facilities; D003430:Cross-Sectional Studies; D003704:Dementia / Q000453:epidemiology*; D005260:Female; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000175:diagnosis / Q000453:epidemiology* / Q000534:rehabilitation*; D008875:Middle Aged; D009483:Neuropsychological Tests; D015995:Prevalence; D012720:Severity of Illness Index