Decline in Cognition from Mid-Life Improves Specificity of Mini-Mental State Examination: Diagnostic Test Accuracy in Caerphilly Prospective Study (CaPs)
Affiliations: [a] School of Social and Community Medicine, University of Bristol, Bristol, UK
| [b] Department of Neurology, Royal Devon and Exeter Hospital, Exeter, UK
| [c] Division of Population Medicine, Cardiff University, Academic Centre, University Hospital Llandough, Cardiff, UK
| [d] Department of Psychiatry, Warneford Hospital, Oxford, UK
Correspondence:
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Correspondence to: Sam Creavin, PhD, MRCGP, School of Social and Community Medicine, University of Bristol, Canynge Hall, 39 Whatley Road, Bristol BS8 2PS, UK. E-mail: sam.creavin@bristol.ac.uk.
Abstract: Background:The merit of using baseline cognitive assessments in mid-life to help interpret cross-sectional cognitive tests scores in later life is uncertain. Objective:Evaluate how accuracy for diagnosing dementia is enhanced by comparing cross-sectional results to a midlife measure. Methods:Cohort study of 2,512 men with repeated measures of Mini-Mental State Examination (MMSE) over approximately 10 years. Index test MMSE at threshold of 24 indicating normal, as a cross-sectional measure and in combination with decline in MMSE score from mid-life. Reference standard consensus clinical diagnosis of dementia by two clinicians according to Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV). Results:1,150 men participated at phase 4 of whom 75 had dementia. A cross-sectional MMSE alone produced a sensitivity of 60% (50% to 70%) and specificity 95% (94% to 97%) with a threshold of≥24 points indicating normal. For lower-scoring men in late life, with cross sectional scores of < 22, combining cross-sectional AND a three-point or more decline over time had a sensitivity of 52% (39% to 64%) and specificity 99% (99% to 100%). For higher-scoring men in later life, with cross sectional scores < 26 combining cross-sectional OR decline of at least three points had a sensitivity of 98% (92% to 100%) and specificity 38% (32% to 44%). Conclusion:It may be helpful in practice to formally evaluate cognition in mid-life as a baseline to compare with if problems develop in future, as this may enhance diagnostic accuracy and classification of people in later life.
