Functional assessment scales in detecting dementia

Aim: to evaluate the use of different functional scales in detecting dementia Methods: the study is part of the Helsinki Ageing Study. A random sample of 795 subjects aged 75 (n = 274), 80 (n = 266) and 85 years (n = 255) was taken. The prevalences of dementia (DSM-III-R criteria) in these age groups were 4.6, 13.1 and 26.7% respectively. The functional scale scores were known for 71% of the non-demented and 66% of the demented subjects. A structured questionnaire completed by a close informant included four functional scales: the index of activities of daily living (ADL), the modified Blessed dementia scale (DS), the instrumental activities of daily Living scale (IADL) and the Functional Assessment Questionnaire (FAQ). Results: all the functional scales discriminated demented from non-demented subjects. Based on receiver operating characteristics analysis, the area under the curve (95% confidence interval) was 0.90 (0.80-0.94) for the ADL, 0.94 (0.87-0.97) for the DS, 0.95 (0.90-0.98) for the IADL and 0.96 (0.92-0.98) for the FAQ. The effects of age, sex and education in detecting dementia were minor or nonexistent in the ADL, DS and FAQ scales, but age had an effect on the performance of the IADL scale. All the scales detected even mild dementia adequately. Conclusions: functional scales can be used in detecting dementia when functional assessment is already used for other purposes, such as among elderly primary care patients.