Influence of age on clinical and psychometric assessment of subjects with very mild or mild dementia of the Alzheimer type
E. H. Rubin, M. Storandt, J. P. Miller, E. A. Grant, D. A. Kinscherf, J. C. Morris and L. Berg
Department of Psychiatry, Washington University, St Louis, Mo.
OBJECTIVE--The influence of age on performance on clinical and psychometric
assessments is examined in groups of nondemented persons and individuals
with either very mild or mild dementia of the Alzheimer type (DAT).
DESIGN--Initial clinical and psychometric assessments of persons enrolled
in longitudinal studies of DAT and nondemented control subjects.
SETTING--Alzheimer's Disease Research Center at Washington University, St
Louis, Mo. PARTICIPANTS--Volunteer samples of 108 people (44 men, 64 women)
with mild DAT, 61 people (30 men, 31 women) with very mild DAT, and 122
healthy nondemented people (45 men, 77 women) were recruited between 1979
and 1991. Age ranged from 54 to 87 years. Persons with confounding medical,
neurologic, or psychiatric disorders were excluded. Dementia severity was
staged using the Clinical Dementia Rating scale. MAIN OUTCOME
MEASURES--Five brief quantitative clinical tests included in the 90-minute
clinician administered protocol, as well as 14 tests included in a 2-hour
psychometric test battery. RESULTS--Dementia severity affected performance
on all measurements. Age did not influence performance on clinical
assessments. There was a significant interaction between age and dementia
severity on 10 of 14 psychometric measures. In general, older nondemented
individuals performed less well than younger nondemented individuals while
older mildly demented persons performed about the same as, or slightly
better than, their younger counterparts. CONCLUSIONS--Age does not affect
performance on brief clinical assessment instruments. However, age affects
psychometric performance differently in cognitively intact persons when
compared with persons with DAT. As a result, psychometric differentiation
between cognitively normal and demented individuals is more difficult in
older populations.
