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.
Scoring
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.
Effectiveness
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.
Source: https://www.verywellhealth.com/alzheimers-disease-assessment-scale-98625
