Frequency of early and late-onset dementias in a Japanese memory disorders clinic

Osamu Yokota, K. Sasaki, Y. Fujisawa, J. Takahashi, S. Terada, T. Ishihara, H. Nakashima, A. Kugo, T. Ata, H. Ishizu, S. Kuroda

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58 Citations (Scopus)


The aim of this study was to compare the diagnostic profiles of patients with early (age < 65 years) and late (age ≥65 years) onset of dementia in a memory disorders clinic in Japan. A total of 512 consecutive memory clinic patients were evaluated using clinical information and results of examinations. Diagnosis of dementia was made according to DSM-III-R, and that of subtypes according to standard diagnostic criteria. A total of 464 patients met the criteria for dementia. Amongst late-onset patients (n = 430), Alzheimer's disease (AD) (48.1%) was the most frequent cause of dementia, followed by AD with cerebrovascular disease (CVD) (31.4%), vascular dementia (VaD) (9.1%), dementia with Lewy bodies (DLB) (3.7%), frontotemporal lobar degeneration (FTLD) (1.6%), and others (5.8%). On the contrary, amongst early onset patients (n = 34), the most common dementia diagnosis was AD (38.2%), followed by VaD (23.5%), FTLD (14.7%), AD with CVD (5.9%), DLB (2.9%), and others (17.6%). FTLD and VaD were significantly more common in the early onset group. All patients, but one, with DLB and Parkinson's disease dementia were late-onset. The relative frequencies of AD, VaD, and DLB in our series are consistent with epidemiologic findings in several Western countries; however, the frequency of FTLD is not consistent with the previous findings presenting high frequency in late-onset patients in some Western countries.

Original languageEnglish
Pages (from-to)782-790
Number of pages9
JournalEuropean Journal of Neurology
Issue number10
Publication statusPublished - Oct 2005


  • Alzheimer's disease
  • Dementia with Lewy bodies
  • Early onset
  • Epidemiology
  • Frontotemporal dementia
  • Japan
  • Memory clinic
  • Vascular dementia

ASJC Scopus subject areas

  • Neurology
  • Clinical Neurology


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