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March 1995

Patterns of Deterioration in Senile Dementia of the Alzheimer Type

Author Affiliations

From the Departments of Psychology (Dr Helmes), Psychiatry (Drs Helmes and Merskey), and Clinical Neurological Sciences (Drs Bowler and Hachinski), University of Western Ontario; St Joseph's Health Centre (Dr Helmes); the Robarts Research Institute (Drs Helmes, Merskey, Fox, and Hachinski and Mr Fry); the Research Department, London Psychiatric Hospital (Drs Merskey and Fox); and University Hospital (Drs Bowler and Hachinski), London, Ontario.

Arch Neurol. 1995;52(3):306-310. doi:10.1001/archneur.1995.00540270102026

Objective:  To determine rates of decline in Alzheimer's disease.

Design:  A longitudinal review of patients diagnosed as having dementia during life, tested serially with the Extended Scale for Dementia, and confirmed by autopsy as having Alzheimer's disease.

Subjects and Setting:  Twenty-nine dead patients with Alzheimer's disease from the participants in the University of Western Ontario Dementia Study Project, confirmed at autopsy as having Alzheimer's disease.

Methods:  Analysis of the Extended Scale for Dementia data according to a trilinear model.

Findings:  In the middle phase of the trilinear model, there was a mean annual change of 13% (range, 2.5% to 51.7%).

Conclusions:  It is likely that the common method of averaging a group of different individual scores from the initial and middle phases of observation of Alzheimer's disease collapses together individuals at different stages of the disorder, some of whom are in the initial plateau phase and whose conditions are not declining rapidly. The trilinear model of decline avoids this difficulty and the present study provides postmortem confirmed figures on rate of change.

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