A study of the Alzheimer's Disease Assessment Scale-Cognitive (ADAS-Cog) in an Icelandic elderly population

Abstract

The Alzheimer's Disease Assessment Scale (ADAS) is designed for screening of cognitive and non-cognitive dysfunctions characteristic of persons with probable Alzheimer's disease (AD). The cognitive part of the scale (ADAS-Cog) is both convenient for screening of probable AD and as a measure of cognitive functioning during drug intervention. The aim of this study was to translate the ADAS-Cognitive sub-test (ADAS-Cog) into Icelandic and to study its application in an elderly Icelandic population. The Mini-Mental State Examination (MMSE) and the ADAS-Cog were administered to 20 AD patients and 20 controls. Each patient was also rated on the Global Deterioration Scale (GDS). The probable AD patients were divided into two groups based on their GDS: 3-4 and 5-6 points. The patients were also divided into two groups based on their MMSE score: very mild to mild (23-30 points) and mild to moderate (15-22 points). Furthermore, the subjects were divided into two age groups: 65-76 and 77-92 years. Results revealed a highly significant difference on MMSE (22.3 - 3.4; 26.8 - 1.6; P < 0.05) and ADAS-Cog (18.4 - 7.7; 7.3 - 3.5; P < 0.05) scores for patients and controls respectively. AD patients also performed significantly worse than the elderly control group on eight of the 11 sub-tests. Thus, the present findings are mainly in line with those of previous studies. The scale exceeds other screening tests such as the MMSE in that it addresses in more detail the symptoms of AD and is valuable for early detection of the illness and staging. ADAS-Cog plays an important role in the diagnostic makeup of AD along with other detailed investigations, such as neuropsychological assessment.