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Normal ageing, impaired cognitive functioning and senile dementia – a mixture distribution analysis

Published online by Cambridge University Press:  09 July 2009

F. M. Reischies ,
R. T. Schaub  and
P. Schlattmann
F. M. Reischies*
Affiliation:
Department of Psychiatry, Freie Universität Berlin, Germany
R. T. Schaub
Affiliation:
Department of Psychiatry, Freie Universität Berlin, Germany
P. Schlattmann
Affiliation:
Department of Psychiatry, Freie Universität Berlin, Germany
*
1Address for correspondence: Dr Friedel M. Reischies, Department of Psychiatry, Freie Universität Berlin, Eschenallee 3, 14050 Berlin, Germany
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Synopsis

Dementia scores in the population of very old subjects (70 to > 95) do not demonstrate an obviously bimodal distribution. Heterogeneity analysis shows that the assumption of two distributions explains the data significantly better than a one-distribution model. The first distribution component can be regarded as representing the normal range of scores and the second the pathological range. An additional finding shows the normal range distribution shifting to the pathological range with increasing age.

Type
Original Articles
Information
Psychological Medicine , Volume 26 , Issue 4 , July 1996 , pp. 785 - 790
Copyright
Copyright © Cambridge University Press 1996

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