Importance of the ADAS-Cog Test

All about the (ADAS-Cog)

The ADAS Helps Evaluate How Well the Brain Is Functioning
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The Alzheimer's Disease Assessment Scale- Cognitive Subscale test is one of the most frequently used tests to measure cognition in clinical trials. 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 sub-scale that measures cognitive ability.

When Was the ADAS-Cog Developed?

The ADAS was first published in 1984 by researchers who noted that there was not a good way to clearly measure the amount of cognitive impairment. 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.

What Kinds of Questions Does the ADAS Contain?

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

1. Word Recall Task

The person is given three chances to recall as many words as possible from a list of ten words that they were shown.

2. Naming Objects and Fingers

Several real objects are shown to the individual, such as a flower, pencil and a comb, and the individual is asked to name them.

The person then has to state the name of each of the fingers on the hand, such as pinky, thumb, etc.

3. Following Commands

The test-taker is 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 the person four different shapes, progressively more difficult such as overlapping rectangles, and asking them to draw each one.

5. Ideational Praxis

In this section, the test administrator asks the person to pretend he has written a letter to himself, fold it, place it in the envelop, seal the envelop, address it and demonstrate where to place the stamp.

6. Orientation

The person's orientation is measured by asking him what his first and last name are, the day of the week, date, month, year, season, time of day, and location.

7. Word Recognition Task

In this section, the participant is asked to read and try to remember a list of twelve words. She is then presented with those words along with several other words and asked if each word is one that she saw earlier or not.

8. Remembering Test Directions

The individual's ability to remember directions without reminders or with a limited amount of reminders is assessed.

9. Spoken Language

The ability to make use language to make herself understood is evaluated throughout the test.

10. Comprehension

The person's ability to understand 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 the word-finding ability throughout spontaneous conversation.

What Does the ADAS-Cog Assess?

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.

How Is the ADAS-Cog Scored?

The test administrator adds up points for each task of the ADAS-Cog for a total score. The greater the dysfunction, the greater the score.

A normal score for someone who does not have Alzheimer's or another type of dementia is five, according to research conducted in 2004 and published in the journal Alzheimer's Disease and Associated Disorders.

In contrast, research that involved more than 1,000 participants reported that 31.2 was the average score in that study for those who have been diagnosed with probable Alzheimer's disease or mild cognitive impairment.

How Is the ADAS-Cog Administered?

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

How Effective Is the ADAS-Cog in Measuring Cognitive Functioning?

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.

Sources:

Alzheimer Research Forum. Neuropsychological Testing. Accessed September 20, 2013.

Alzheimer's Disease and Associated Disorders. 2004 Oct-Dec;18(4):236-40. The Alzheimer's Disease Assessment Scale-Cognitive subscale: normative data for older adult controls.

Alzheimer's Disease and Associated Disorders. Vol.11, Suppl. 2,1997. Development of Cognitive Instruments for Use in Clinical Trials of Antidementia Drugs: Additions to the Alzheimer's Disease Assessment Scale that Broaden Its Scope.

American Journal of Psychiatry, Nov 1984; 141 (11); 1356-1364. A new rating scale for Alzheimer's disease. http://www.ncbi.nlm.nih.gov/pubmed/6496779

Current Alzheimer Research. Volume 8, Number 3, May 2011 , pp. 323-328(6). Psychometric Comparison of Standard and Computerized Administration of the Alzheimer's Disease Assessment Scale - Cognitive Subscale (ADASCog).

Dementia and Geriatric Cognitive Disorders. 2009;28:63–69. How Well Do the ADAS-cog and its Subscales Measure Cognitive Dysfunction in Alzheimer’s Disease? http://agingandcognition.tamu.edu/files/2012/01/Benge_2009.pdf

International Psychogeriatrics. 1997 Jun;9(2):123-38. Alzheimer's Disease Assessment Scale: reliability and validity in a multicenter clinical trial. http://www.ncbi.nlm.nih.gov/pubmed/9309486?dopt=Abstract

Journal of Alzheimer's Disease. 2008 November; 15(3): 461–464. Administration and Scoring Variance on the ADAS-Cog. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2727511/

National Institute on Aging. Alzheimer's Disease Assessment Scale-Cognitive Subscale. Accessed September 17, 2013. http://www.nia.nih.gov/research/cognitive-instrument/alzheimers-disease-assessment-scale-cognitive-subscale

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