Cut-off scores in MMSE: a moving target?
BACKGROUND
Cognitive tests are known to be influenced by language, culture and education. In addition, there may be an impact of 'epoch' in cognition, because there is secular increase in scores of IQ tests in children. If we assume this is a long lasting process, then it should persist later in life.


METHODS
To test this hypothesis, we compared the performance of two cohorts of individuals (>or=50 years of age), evaluated 20 years apart using the Mini-Mental State Examination (MMSE).


RESULTS
Study population included 135 participants in 1988 and 411 in 2008. MMSE scores were higher in 2008 than in 1988 for literacy x age-matched subgroups, the difference being significant for participants with lower literacy. Score variance was explained by literacy (beta = 0.479, t = 14.598, P = 0.00), epoch (beta = 0.34, t = 10.33, P = 0.00) and age (beta = -0.142, t = -4.184, P = 0.00).


CONCLUSIONS
The present results are in accordance with a lifelong secular improvement in cognitive performance. The operational cut-off values may change with time, which may have clinical impact in the diagnosis of disorders like mild cognitive impairment or dementia.
Morgado
J
J
Laboratory of Language Research, Faculty of Medicine of Lisbon, Institute of Molecular Medicine, Hospital de Santa Maria, Lisboa, Portugal.
Rocha
C S
CS
Maruta
C
C
Guerreiro
M
M
Martins
I P
IP
D000368:Aged; D000375:Aging / Q000523:psychology; D003071:Cognition / Q000502:physiology; D003072:Cognition Disorders / Q000145:classification / Q000175:diagnosis* / Q000523:psychology; D015331:Cohort Studies; D003469:Culture; D003704:Dementia / Q000145:classification / Q000175:diagnosis* / Q000523:psychology; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests / Q000592:standards*; D011237:Predictive Value of Tests; D015203:Reproducibility of Results