Sunday, March 31, 2024

Use and Scoring of the ADAS-Cog Test


The Alzheimer's Disease Assessment Scale-Cognitive Subscale test is one of the most frequently used tests to measure cognition in research studies and clinical trials for new drugs and other interventions. It's more thorough than the Mini Mental State Exam, and it primarily measures language and memory. The ADAS-Cog consists of 11 parts and takes approximately 30 minutes to administer.

The ADAS-Cog was developed as a two-part scale: one that measured cognitive functions and one that measured non-cognitive functions such as mood and behavior. Most current research uses the ADAS-Cog, which is the subscale that measures cognitive ability.


When and Why the ADAS-Cog Was Developed

The ADAS was first published in 1984 by researchers who noted that there was not a good way to clearly measure the amount or degree of cognitive impairment.1 There were other scales and assessments that determined if there was a deficiency in cognition, but none that consistently and accurately identified how much dysfunction was present.

Kinds of Questions the ADAS Contains

The original version of the ADAS-Cog consists of 11 items, including:

1. Word Recall Task: You are given three chances to recall as many words as possible from a list of 10 words that you were shown. This tests short-term memory.

2. Naming Objects and Fingers: Several real objects are shown to you, such as a flower, pencil and a comb, and you are asked to name them. You then have to state the name of each of the fingers on the hand, such as pinky, thumb, etc. This is similar to the Boston Naming Test in that it tests for naming ability, although the BNT uses pictures instead of real objects, to prompt a reply.

3. Following Commands: You are asked to follow a series of simple but sometimes multi-step directions, such as, "Make a fist" and "Place the pencil on top of the card."

4. Constructional Praxis: This task involves showing you four different shapes, progressively more difficult such as overlapping rectangles, and then you will be asked to draw each one. Visuospatial abilities become impaired as dementia progresses and this task can help measure these skills.

5. Ideational Praxis: In this section, the test administrator asks you to pretend you have written a letter to yourself, fold it, place it in the envelope, seal the envelope, address it and demonstrate where to place the stamp. (While this task is still appropriate now, this could become less relevant as people write and send fewer letters through the mail.)

6. Orientation: Your orientation is measured by asking you what your first and last name are, the day of the week, date, month, year, season, time of day, and location. This will determine whether you are oriented x 1, 2, 3 or 4.

7. Word Recognition Task: In this section, you are asked to read and try to remember a list of twelve words. You are then presented with those words along with several other words and asked if each word is one that you saw earlier or not. This task is similar to the first task, with the exception that it measures your ability to recognize information, instead of recall it.

8. Remembering Test Directions: Your ability to remember directions without reminders or with a limited number of reminders is assessed.

9. Spoken Language: The ability to use language to make yourself understood is evaluated throughout the duration of the test.

10. Comprehension: Your ability to understand the meaning of words and language over the course of the test is assessed by the test administrator.

11. Word-Finding Difficulty: Throughout the test, the test administrator assesses your word-finding ability throughout spontaneous conversation.


What the ADAS-Cog Assesses

The ADAS-Cog helps evaluate cognition and differentiates between normal cognitive functioning and impaired cognitive functioning. It is especially useful for determining the extent of cognitive decline and can help evaluate which stage of Alzheimer's disease a person is in, based on his answers and score. The ADAS-Cog is often used in clinical trials because it can determine incremental improvements or declines in cognitive functioning.



The test administrator adds up points for the errors in each task of the ADAS-Cog for a total score ranging from 0 to 70. The greater the dysfunction, the greater the score. A score of 70 represents the most severe impairment and 0 represents the least impairment.3


How the Test Is Administered

Traditionally, the ADAS-Cog has been administered by paper and pencil; however, there is also an electronic version that has been shown to be comparable to the pencil and paper version.



The ADAS-Cog is quite accurate, both in differentiating people with normal cognition from those with impaired cognition, as well as in assessing the extent of cognitive impairment in individuals.

However, some research studies have concluded that the ADAS-Cog might not be difficult enough to consistently detect mild cognitive impairment.


Other Versions

The ADAS-Cog has been translated into several other languages, some of which have been tested for validity across language and culture.

There is also another version of the ADAS-Cog, which changes how the test is scored. It's called the ADAS-CogIRT, where "IRT" is an abbreviation for "item response theory." This version uses the same test but scores it differently, with the goal of improved detection of mild cognitive impairment.

Other versions of the ADAS-Cog include categories such as executive functioning and functional ability components, additions also meant to increase the test's ability to screen for mild cognitive impairment.




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