THE IMPORTANCE OF EARLY DETECTION OF ALZHEIMER’S DISEASE

It is important for initial care to identify Alzheimer's disease (AD) in its early symptomatic stages. The mild cognitive impairment (MCI) stage of AD is the first symptomatic stage of AD.1

An opportunity to take action

Pathophysiological changes due to AD may occur many years before symptoms appear. The MCI stage provides a potential window to detect and diagnose Alzheimer’s disease before significant neurodegeneration has begun.1-3

Yet, AD remains underdiagnosed and underreported. In fact, the average diagnosis is delayed by an average of 2 to 3 years after symptom onset.2,4

The MCI stage is the earliest stage when symptoms may be evident5

AD is the most common cause of MCI,* accounting for an estimated 34% to 75% of all patients.6,7 Patients with suspected MCI should undergo a comprehensive history and physical examination to distinguish MCI from normal aging or dementia, and separate it from other causes.8 Alzheimer’s disease biomarkers may provide evidence of the underlying cause.9

*In the Aging, Demographics, and Memory Study (ADAMS), individuals were classified as having cognitive impairment without dementia.6

Stages of Alzheimer's Disease10

Early symptoms of AD are often subtle and are difficult to distinguish from normal aging

Studies show that cognitive impairment may remain unrecognized in up to 80% of affected patients in primary care. 

However, among patients with cognitive impairment, 60% to 80% have AD.10,11

Understanding and overcoming barriers to early diagnosis of AD

Low recognition of AD may be caused by several barriers, including11,12:

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The time burden associated with testing and counseling
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Reluctance of patients and caregivers to report signs or symptoms due to stigma around AD
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Lack of diagnostic resources

Detection of early-stage AD

Early detection and diagnosis of AD may be possible during the MCI stage when the earliest symptoms of AD first appear. The following steps may be helpful for building a process to detect and diagnose.1,3,5

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Assess if the patient has concerns about changes in cognition or if there is evidence of cognitive deterioration
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Screen for MCI and determine if the patient is still functioning independently and does not suffer from dementia
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Rule out other pathologies including vascular, traumatic, or medical causes
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Determine if the patient’s memory is affected
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Decide if biomarker assessments such as magnetic resonance imaging (MRI), amyloid beta positron emission tomography (PET) scan, or cerebrospinal fluid (CSF) analysis are appropriate for confirming disease pathology13,14
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Early symptoms of AD are often subtle and are difficult to distinguish from normal aging.10

Cognitive Tests Inform the Alzheimer's Disease Diagnosis

Read these patient profiles to see how cognitive tests can strengthen assessments and biomarker testing can confirm the diagnosis of different patient types.

Diagnosing the MCI stage of AD in a high-functioning patient

MARK
64-Year-old male
Diagnosis: MCI stage of AD
MARK
64-Year-old male
DETECT
HISTORY

Family history of AD/dementia: No
Patient reports: Missed appointments
Informant reports: Noticeable memory loss, repeats himself
Psychiatric symptoms: None

LAB TESTS

Blood cell count, electrolytes, glucose, calcium, thyroid function, vitamin B12, folate: Within Normal Range

COMORBIDITIES

Hypertension (controlled)

ASSESS
NEUROLOGIC EXAM

Normal with some mild bilateral upper-extremity action tremor

COGNITIVE ASSESSMENT

MCI-sensitive test conducted, MoCA=25/30; Wechsler Memory Scale-Logical Memory (WMS-LM): 100% immediate recall, 69% delayed recall

FUNCTIONAL DEPENDENCE

Informant report: Fully independent (3/30 on FAQ)

MAGNETIC RESONANCE IMAGING (MRI)

Hippocampal atrophy, periventricular white matter hyperintensities

CONFIRM
BIOMARKER CONFIRMATION (CSF)

Amyloid positive

DIAGNOSIS
MCI stage of AD

Diagnosing the mild AD dementia stage of AD in a patient with declining function

LINDA
75-Year-old female
Diagnosis: Mild AD dementia
LINDA
75-Year-old female
DETECT
HISTORY

Family history of AD/dementia: No
Patient reports: Increased memory loss, visuospatial issues
Informant reports: Loss of balance, needs to be accompanied
Psychiatric symptoms: Mild anxiety

LAB TESTS

Blood cell count, electrolytes, glucose, calcium, thyroid function, vitamin B12, folate: Within Normal Range

COMORBIDITIES

Coronary artery disease and diabetes (controlled)

ASSESS
NEUROLOGIC EXAM

Difficulty with ideomotor praxis testing, like combing her hair, and some diminished balance

COGNITIVE ASSESSMENT

MMSE®=24/30

FUNCTIONAL DEPENDENCE

Informant report: Increased dependence (13/30 on FAQ). Dependent for financial matters; traveling out of neighborhood

MAGNETIC RESONANCE IMAGING

Ventricular dilation, mild frontal and anterior temporal atrophy temporal atrophy

CONFIRM
BIOMARKER CONFIRMATION (CSF)

Amyloid- and tau-positive

DIAGNOSIS
Mild AD dementia

MMSE is a registered trademark of Psychological Assessment Resources.
FAQ=Functional Activities Questionnaire; MMSE=Mini Mental State Examination.

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Learn more with these practical examples of
early-stage Alzheimer’s disease diagnosis
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