Cross-national comparison and validation of the Alzheimer's Disease Assessment Scale: results from the European Harmonization Project for Instruments in Dementia (EURO-HARPID).

BACKGROUND: The Alzheimer's Disease Assessment Scale (ADAS) is often used in international multicenter trials. Use across countries presupposes correct translation and adaptation of the scale, and maintenance of its psychometric properties. OBJECTIVES: To compare the various translations of the ADAS used in Western Europe, to design internationally harmonized translations and to validate these. SETTING: International cooperative study in eight European countries. METHODS: An inventory was made of existing versions of the ADAS-Cog used in eight European countries, and adaptations were made. The concurrent validity of the harmonized versions of the ADAS was tested in 283 patients with probable or possible Alzheimer's disease. The Nurses Observation Scale for Geriatrics (NOSGER), CAMCOG-R and MMSE was used to assess concordance between cognitive and behavioral measures. RESULTS: Differences between the versions mainly involved object naming, items for verbal memory, such as the number of trials allowed, the imagery value of the words selected as targets or distractors, and the number of parallel versions. These differences were eliminated by adapting and harmonizing the various versions of the ADAS-Cog. Thereafter, only small differences between the different countries were found, and patterns of correlation between ADAS-Cog, and the NOSGER, CAMCOG-R and MMSE were consistent. CONCLUSIONS: The study underlines the need to use harmonized versions of instruments for rating dementia in multinational studies. The findings indicate that the harmonization of the ADAS-Cog was successful.

Cross-national comparisons of the Cambridge Cognitive Examination-revised: the CAMCOG-R: results from the European Harmonization Project for Instruments in Dementia.

BACKGROUND: Transnational and psychometrically appropriate versions of instruments used in the diagnosis of dementia are essential for comparing information between different countries. The Cambridge Examination for Mental Disorders of the Elderly incorporates a brief neuropsychological test battery, Cambridge Cognitive Examination (recently revised version), which provides objective data on performance across a number of cognitive domains. OBJECTIVE: To harmonise the Cambridge Cognitive Examination between seven European countries. METHOD: 40 patients with probable or possible Alzheimer's disease of each of the seven countries were administered the Cambridge Cognitive Examination. The Nurse Observation Scale for Geriatrics was used to assess concordance between cognitive and behavioural measures. RESULTS: Only small differences between the various Cambridge Cognitive Examination versions were found, and patterns of correlation between Cambridge Cognitive Examination and the Nurse Observation Scale for Geriatrics were consistent. CONCLUSION: These findings indicate that the harmonisation of the Cambridge Cognitive Examination was successful.