What is the recommended evaluation for a patient with suspected dementia?

Recommended Evaluation for Suspected Dementia

All patients with suspected dementia require a comprehensive history from both patient and informant, validated cognitive testing, routine laboratory studies (TSH, vitamin B12, CBC, metabolic panel), and structural brain imaging with MRI (or CT if MRI unavailable). 1, 2

Step 1: Obtain Corroborated History from Reliable Informant

The single most important diagnostic step is obtaining reliable informant reports about changes in cognition, daily function, and behavior—this carries critical prognostic significance. 1, 2

• Use structured informant-based tools such as AD-8, IQCODE, ECog, or Alzheimer's Questionnaire to systematically capture changes 1, 2
• Document the sequential order of symptom onset, frequency, tempo, and nature of change over time 1
• Characterize symptoms across all major cognitive domains: memory, attention, executive function, language, visuospatial abilities, and behavior 1
• Assess impact on instrumental activities of daily living: medication management, financial handling, transportation, household tasks, meal preparation, shopping, and technology use 1, 2
• Compare baseline functioning with current functioning over months-to-years to demonstrate insidious decline 1, 2

Step 2: Perform Office-Based Cognitive Assessment

Use the Montreal Cognitive Assessment (MoCA) for suspected mild cognitive impairment or early dementia, as it is more sensitive than MMSE for detecting mild deficits. 2, 3

• For moderate dementia screening, the Mini-Mental State Examination (MMSE) remains acceptable 2, 3
• Add the Clock Drawing Test as a supplementary assessment 2, 3
• For rapid office screening when time is limited, use Mini-Cog, MIS + Clock Drawing, AD-8, or GPCOG 2
• Document performance across specific domains: learning and memory (particularly delayed free and cued recall/recognition), attention, executive function, visuospatial function, and language 1

Step 3: Assess Functional Status with Validated Scales

Apply structured functional scales to objectively measure autonomy in daily activities and distinguish mild cognitive impairment from dementia. 1, 2

• Use Pfeffer Functional Activities Questionnaire (FAQ), Disability Assessment for Dementia (DAD), Lawton Instrumental Activities of Daily Living Scale, or ECog 1, 2
• The key distinction between MCI and dementia rests on whether cognitive changes significantly interfere with daily functioning 2
• In MCI, patients show subtle inefficiencies or errors on complex tasks but generally retain independence with minimal assistance 2

Step 4: Screen for Neuropsychiatric Symptoms and Mood Disorders

Systematically document behavioral and psychological symptoms, as depression and anxiety are the most frequent reversible causes of subjective cognitive concerns. 2, 4

• Use Neuropsychiatric Inventory-Questionnaire (NPI-Q) or Mild Behavioural Impairment Checklist (MBI-C) 1, 4
• Screen for depression with PHQ-2/PHQ-9 and anxiety with GAD-7 2
• Assess for apathy, psychosis, personality changes, and severe mood disturbances 1

Step 5: Obtain Routine Tier 1 Laboratory Studies

Order a focused laboratory panel in every patient to identify the small but important subset with potentially reversible cognitive impairment. 1, 2

• Thyroid-stimulating hormone (TSH) and free T4 2, 3, 5
• Vitamin B12 and folate levels 2, 3, 5
• Complete blood count (CBC) 2, 3
• Comprehensive metabolic panel 2, 3
• Hemoglobin A1C and fasting glucose to screen for diabetes 2
• Lipid panel to assess cardiovascular risk 2

Step 6: Obtain Structural Brain Imaging

MRI is preferred over CT, especially for detecting vascular lesions, and should not be postponed while awaiting laboratory results. 1, 2, 3

• Use noncontrast MRI as the preferred modality 1, 2, 3
• If MRI is unavailable or contraindicated, obtain noncontrast CT 1, 3
• Imaging helps identify structural changes including focal atrophy, infarcts, tumors, and cerebrovascular disease 1, 2

Step 7: Assess Individual Risk Factors

Systematically obtain knowledge regarding the patient's risk factors for neurodegenerative, cerebrovascular, and other diseases that may cause brain dysfunction. 1

• Document vascular risk factors: hypertension, diabetes, hyperlipidemia, stroke/TIA 1, 2
• Evaluate for sleep disorders, particularly obstructive sleep apnea 1, 2
• Assess sensory deficits: hearing loss, vision loss 1, 2
• Review medications for anticholinergic or cognitive-impairing properties 2
• Document family history of neurodegenerative disease 1, 4

When to Refer to a Specialist

Patients with atypical findings, diagnostic uncertainty, early-onset (age <65 years), or rapidly progressive cognitive-behavioral conditions should be further evaluated expeditiously, usually including referral to a dementia subspecialist. 1

Specific indications for specialist referral include:

• Atypical cognitive abnormalities: aphasia, apraxia, agnosia 1, 4
• Sensorimotor dysfunction: cortical visual abnormalities, movement or gait disorders 1
• Severe mood/behavioral disturbance: profound anxiety, depression, apathy, psychosis, personality changes 1
• Rapid progression or fluctuating course suggestive of delirium, Lewy body dementia, or vascular cognitive impairment 1
• Early-onset dementia (age <65 years) 1, 2, 3
• Patient or caregiver reports concerning symptoms but patient performs within normal limits on cognitive examination 1
• Examination shows cognitive-behavioral abnormalities but uncertainty exists about interpretation due to complex clinical profile or confounding demographic characteristics 1

When to Order Neuropsychological Testing

Neuropsychological evaluation is recommended when office-based cognitive assessment is not sufficiently informative. 1

• When patient or caregiver reports concerning symptoms in daily life but patient performs within normal limits on cognitive examination 1
• When cognitive-behavioral examination is abnormal but uncertainty exists about interpretation due to complex clinical profile or confounding demographics 1
• To detect very mild but clinically important cognitive impairment that brief office tests may not capture 1
• To distinguish neuropsychiatric disorders from effects of medical and emotional comorbidities or confounding patient characteristics such as limited or advanced education 1

When to Order Advanced Biomarker Testing

Do not order cerebrospinal fluid biomarkers or amyloid PET scans routinely; reserve these investigations for cases with diagnostic uncertainty, early-onset presentations, or atypical clinical features after specialist evaluation. 2

• CSF analysis for reduced Aβ₁₋₄₂ and elevated total tau and phosphorylated tau should be considered when diagnostic uncertainty persists, in early-onset presentations (<65 years), or when high diagnostic confidence is required for therapeutic decisions 2
• Routine ordering of amyloid PET or CSF biomarker studies in cognitively normal individuals with subjective cognitive decline is not recommended 2

Common Pitfalls to Avoid

• Relying solely on patient self-report without informant corroboration leads to missed diagnoses due to lack of insight 2
• Failing to use standardized, validated instruments reduces diagnostic accuracy and makes longitudinal tracking unreliable 2
• Overlooking medical conditions that can influence cognitive function: sleep apnea, pain, sensory deficits, metabolic disturbances, medication side effects 1, 2
• Not distinguishing delirium from dementia—delirium requires urgent or emergent care 1
• Attributing cognitive changes to "normal aging" without proper evaluation 3