Evaluation of various methods of assessing symptoms of cognitive impairment and dementia

Background and Purpose: The effect of different diagnostic criteria for det ecting dementia in both epidemiological and stroke cohort studies has been shown, but comparison between different assessment methods has only seldom been done, We compared both assessment methods and diagnostic criteria for dementia in a large well-defined stroke cohort. Subject and Methods: A grou p of 227 of 486 patients aged 55 to 85 years who 3 months after ischemic st roke completed a comprehensive neuropsychological test battery, structured clinical mental status examination of defined cognitive domains with expand ed Mini-Mental State Examination. The criteria for dementia ere those of th e Diagnostic and Statistical Manual of Mental Disorders (DSM-III, DSM-III-R ) and the National Institute of Neurological Disorders and Stroke-Associate d Internationale pour la Reserche et l'Enseignement en Neurosciences (NINDS -AIREN). Results: The main differences between clinical and neuropsychologi cal examinations were seen in memory functions: clinically 24.7% and neurop sychologically 54.2% had impairment in short-term memory and 10.4% versus 5 .3% in long-term memory. Accordingly, the prevalence of dementia varied gre atly: It vas clinically 14.1% by DSNI-III. 9.7% by DSM-III-R and 8.4% by NI NDS-AIREN criteria. The corresponding frequencies based on neuropsychologic al evaluation were 27.3%, 4.0% and 25.6%. Between these 3 diagnostic criter ia the concordance varied in clinical testing between 59.4%-68.8% (kappa 0. 72-0.79) and in neuropsychological testing between 14.5%-81.1% (kappa 0.20- 0.86). The concordance between clinical and neuropsychological testing vas 56.8% (kappa 0.42) by DSM-III. 31.6% (kappa 0.35) by DSM-III-R and 25.5% (k appa 0.24) by NINDS-AIREN. Conclusions: The frequency of poststroke dementi a and cognitive decline varied sharply when different systems of diagnostic classification and methods were used. This may have serious influences on investigation and treatment of patients. We underline the importance of fur ther debate and studies to refine the categories of cognitive impairment us ed in the setting of CVD.