What is the appropriate workup for a patient presenting with slow cognition?

Appropriate Workup for Slow Cognition

The appropriate workup for a patient presenting with slow cognition should include standardized cognitive assessment tools, comprehensive laboratory testing, neuroimaging, and consideration of specialty referral for advanced biomarker testing when indicated. 1, 2

Initial Assessment

• Obtain detailed history focusing on cognitive abilities, including onset (recent or chronic; abrupt or gradual), pace of decline, and nature of cognitive loss (short-term memory, instrumental ADLs) 3
• Collect corroborative history from a reliable informant using structured tools like AD8, Alzheimer's Questionnaire (AQ), or Quick Dementia Rating System 1, 2
• Assess for specific triggers that may contribute to cognitive symptoms, such as preceding viral infections or fever 2
• Evaluate medication use, as certain medications (especially anticholinergics or sedative hypnotics) can contribute to cognitive symptoms 3, 2

Cognitive Assessment

• If informant is available, use AQ or AD8; if no informant is available, use Memory Impairment Screen (MIS) or Montreal Cognitive Assessment (MoCA) 3
• Include assessment of specific cognitive domains: memory, executive function, visuospatial abilities, language functions, and personality/behavior changes 2, 4
• Consider Clock Drawing Test as a useful supplementary screening tool 2
• Recall tests show the best diagnostic performance for detecting mild cognitive impairment with 0.89 sensitivity and 0.84 specificity 5

Laboratory Testing

• Order complete blood count with differential to rule out anemia 3, 2
• Check comprehensive metabolic panel including electrolytes, calcium, magnesium, and liver function tests 3, 2
• Measure thyroid function tests, vitamin B12, homocysteine, folate levels 3, 2
• Include inflammatory markers (erythrocyte sedimentation rate and C-reactive protein) 3

Neuroimaging

• Obtain structural brain imaging with MRI (or head CT if MRI is contraindicated) 3, 2
• MRI is particularly important when there is onset of cognitive symptoms within past 2 years, unexpected decline in cognition/function, recent significant head trauma, unexplained neurological manifestations, or significant vascular risk factors 2, 4

Specialty Investigations to Clarify Diagnosis

• Consider referral to neurologist, geriatrician, geriatric psychiatrist, neuropsychologist, or dementia subspecialist 3
• Neuropsychological evaluation may be beneficial for detailed assessment of cognitive domains 3
• For suspected Alzheimer's disease, consider advanced biomarkers:
  • Lumbar puncture to assess for Aβ, tau, p-tau 3
  • Amyloid PET or Tau PET imaging 3
  • Blood-based biomarkers (BBMs) are emerging but should currently only be used in symptomatic patients at specialist clinics with results confirmed whenever possible with CSF or PET 3

Special Considerations

• Screen for depression and anxiety, which can manifest as or exacerbate cognitive symptoms 2
• Assess for risk factors for cognitive decline, including cerebrovascular risk factors and diabetes mellitus 3, 6
• For patients with subjective cognitive decline but normal cognitive testing, conduct appropriate diagnostic workup to identify reversible causes and consider annual follow-up if corroborative history is positive 2, 4, 7

Common Pitfalls to Avoid

• Failing to obtain corroborative history from an informant, which is essential for accurate assessment 2
• Overlooking medical conditions that can influence biomarker interpretation, such as obesity, chronic kidney disease, or certain medications 2
• Neglecting to assess for psychiatric conditions that can mimic or exacerbate cognitive symptoms 2
• Focusing solely on neurodegenerative causes while missing potentially treatable conditions 2

Follow-up and Monitoring

• Schedule follow-up visits every 6-12 months to track disease progression 1, 4
• Use a multi-dimensional approach to monitor cognition, functional autonomy, behavioral symptoms, and caregiver burden 1, 4
• Consider more frequent assessment for patients with behavioral symptoms 1