ADAS-Cog

The Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog) is a brief neuropsychological assessment used to assess the severity of cognitive symptoms of dementia. It is one of the most widely used cognitive scales in clinical trials^[1] and is considered to be the “gold standard” for assessing antidementia treatments.^[2]

The ADAS-Cog is one half of the Alzheimer's Disease Assessment Scale (ADAS), which also contains a non-cognitive subscale (ADAS-Noncog), which includes 10 tasks which assess mood and behavioural changes which may occur in Alzheimer's disease and other forms of dementia.^[2]

The ADAS-Cog consists of 11 tasks:

• Word Recall Task
• Naming Objects and Fingers
• Following Commands
• Constructional Praxis
• Ideational Praxis
• Orientation
• Word Recognition Task
• Remembering Test Directions
• Spoken Language
• Comprehension
• Word-Finding Difficulty

Different versions

Since its original creation in 1980s there have been many alternate versions of the ADAS-Cog created for various reasons. A review found 31 modified versions of the ADAS-Cog,^[2] these include:

• ADAS-Cog-IRT: Uses the standard 11 items from the ADAS-Cog but calculates the score based on item response theory. Using this method each question in the test is given a different value based on the difficulty, which is determined by how frequently it is answered correctly or incorrectly by a large reference group of participants.^[3]
• ADAS-Cog Plus: Developed to be more responsive to the early stage deficits seen is mild cognitive impairment. It includes the standard ADAS-Cog with additional tests to assess executive function and day-to-day function.^[4]
• VADAS-Cog: The VADAS-Cog is a variant the ADAS-Cog adapted to assess people with vascular dementia. It consists of the standard ADAS-Cog with additional measures for attention, working memory, executive function and verbal fluency.^[5]