EARLY DIAGNOSIS OF ALZHEIMER’S DISEASE

Evaluation of underlying causes can confirm the diagnosis, and inform counseling and recommendations for therapeutic strategies.1

Thoroughly evaluating patients with mild cognitive impairment (MCI) is an important first step in Alzheimer’s disease (AD) diagnosis and treatment

The American Academy of Neurology Practice Guidelines recommends1:

  • Clinicians assessing cognitive impairment should use a brief, validated cognitive assessment instrument in addition to eliciting a history of cognitive concerns
  • If patients test positive for MCI with brief assessment tools, clinicians should perform a more formal assessment for diagnosis of MCI
  • Clinicians should perform serial assessments over time to monitor changes in cognition
SEE HOW TESTING FOR AMYLOID BETA PATHOLOGY COMPLETES THE DIAGNOSIS

Support an MCI due to AD diagnosis with biomarkers.

Brief cognitive assessments may help identify patients with MCI

Evidence of progressive cognitive decline is essential for accurate Alzheimer's disease diagnosis and treatment. While no test represents a “gold standard,” use of brief cognitive assessment tools with appropriate patients can aid in the early identification of MCI and mild dementia.2,3

Screening assessments will vary based on clinical practice settings and patient response.

Common Brief Screening Tools for Cognitive Impairment2,4-8

MMSE
(Mini-Mental State Examination)
MoCA
(Montreal Cognitive Assessment)
The most widely used cognitive assessment tool; often serves as a reference to compare evaluations with other assessments, but does not include executive function assessment. A brief screener with excellent sensitivity for mild cognitive impairment. It includes an assessment of executive function and is available in nearly 100 languages.
MCI Detection
Less sensitive; patients with MCI may score as “normal” More sensitive for detecting MCI
Moderate/Severe Impairment
Appropriate for patients with more advanced AD dementia May be too difficult for patients with moderate or severe cognitive impairment
Administration Time
10 min 10 min
Scoring
Maximum of 30 points*
25 or above=normal cognitive function
20 to 24=mild dementia
13 to 20=moderate dementia
12 or lower=severe dementia
Maximum of 30 points
26 or above=normal cognitive function
25 or lower=cognitive impairment; either MCI or dementia

*Cutoff varies with age and education.9
The raw score is adjusted by educational attainment (1 extra point for 10 to 12 years of formal education; 2 points added for 4 to 9 years of formal education).6,10
Although there are many tests for assessing cognitive function, no test represents the “gold standard” and this review does not recommend one over another.2

Cognitive Areas Assessed
MMSE MoCA
Orientation
Attention and concentration
Language
Visual construction
Memory
Executive functions
Conceptual thinking
Calculation

Other brief screeners include: GPCOG (General Practitioner Assessment of Cognition), Mini-Cog, AMTS (Abbreviated Mental Test Score), ACE-R (Addenbrooke’s Cognitive Examination – Revised), Clock Drawing Test, 6-CIT (6-Item Cognitive Impairment Test), TYM (Test Your Memory), MIS (Memory Impairment Screen)2,4

These tests can generally be administered in 3 to 20 minutes.4

Using these early identification tools, HCPs can help remove the delays to early diagnosis—helping to improve quality of care, reduce dementia-related negative behaviors, and relieve caregiver stress and depression.²

More extensive cognitive assessment tools

Extensive cognitive assessment tools for patients with MCI (often used in specialty or clinical trial settings) include:

Extensive Cognitive Assessment Tools for Alzheimer's Disease11-16

CDR-SB
(Clinical Dementia Rating-Sum of Boxes)
ADAS-Cog
(Alzheimer’s Disease Assessment Scale-Cognitive subscale)
Assesses both cognition and function using semi-structured interviews with the patient and an informant. While use of this tool is limited by lengthy administration by a trained rater/scorer, it is responsive to changes over time in patients with MCI. It is currently used in clinical research. The original ADAS-Cog tool is widely used for AD assessment but is less responsive to change in patients with MCI due to AD.
The modified ADAS-Cog 13-item scale added tasks to increase the number of cognitive domains and range of symptom severity.
An augmented version includes executive functioning and informant-based functional assessment components (ADAS-Cog Plus EF and FA) to improve responsiveness in patients with MCI.
Purpose
To stage the severity of cognitive impairment based on interview with patient and informant To measure cognitive functioning
AD Stages (highest score)
All stages (18*) Mild to moderate (85)

*Higher score indicates greater AD severity.13
Higher score indicates greater impairment.12

Cognitive Domain
CDR-SB ADAS-Cog
Orientation
Attention and working memory
Memory
Visuospatial
Language
Executive functions
Functional Assessment
Activities of daily living (ADLs)

Early diagnosis includes assessing impairments beyond memory

In-depth investigation of multiple domains is necessary, since 16% of MCI patients have no memory impairment and many MCI patients present with multiple cognitive domains affected.17

  • In one 16-year longitudinal study, MCI affected visuospatial ability as well as memory over 5 years before the onset of dementia. In another longitudinal study, the visuospatial domain was affected before other domains—on average, 3 years before diagnosis of AD18,19

Testing focused on different cognitive domains

Because other cognitive domains can be impaired among individuals with MCI, it is important to examine domains in addition to memory.3

Icon for language skills

LANGUAGE

(eg, naming, fluency, expressive speech, and comprehension)2,3

See Tests >

LANGUAGE

  • Boston Naming Test (BNT)22

  • Boston Diagnostic Aphasia Examination (BDAE)22

  • Vocabulary22

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Icon for attentional control

ATTENTION CONTROL

(eg, simple and divided attention)2,3

See Tests >

ATTENTION CONTROL

  • Trail Making Test (TMT)22

  • Paced Auditory Serial Addition Test (PASAT)22

  • Digit Symbol Substitution Test22

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Icon for executive functions

EXECUTIVE FUNCTIONS

(eg, set-shifting, reasoning, problem-solving, planning)2,3

See Tests >

EXECUTIVE FUNCTIONS

  • Verbal Fluency22

  • Stroop Test22

  • Wisconsin Card Sorting Test (WCST)22

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Icon for visuospatial skills

VISUOSPATIAL SKILLS

(eg, visual perception, perceptual-motor coordination)2,3,20

See Tests >

VISUOSPATIAL SKILLS

  • Clock Drawing Test22

  • Rey Complex Figure Test (RCFT-Copy)22

  • Block Design22

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Neuropsychological tests that assess a range of cognitive domains produce greater diagnostic stability, with stronger links to cognition, biomarkers, and rates of progression to MCI.21

Cognitive Test Survey

Take part in this survey to see what tests are chosen the most.

What brief cognitive assessment tool do you prefer?

What cognitive test do you prefer to assess the memory domain?

What cognitive test do you prefer to assess the language domain?

What cognitive test do you prefer to assess the visuospatial skills domain?

What cognitive test do you prefer to assess the executive functioning domain?

What cognitive test do you prefer to assess the attention control domain?

Thank you for taking the survey.

Below are the top preferred cognitive tests per category according to survey-takers.

Brief cognitive assessment tool: MMSE

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Memory domain tool: California Verbal Learning Test

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Language domain tool: Boston Naming Test

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Visuospatial skills domain tool: Clock Drawing Test

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Executive functioning domain tool: Stroop Test

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Attentional control domain tool: I haven't tested for this domain

0

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