What diagnostic tests can be done for forgetfulness and occasional attention lapses?

Diagnostic Testing for Forgetfulness and Attention Lapses

Begin with brief validated cognitive screening tools in the office—specifically the Montreal Cognitive Assessment (MoCA) or Mini-Cog—followed by basic laboratory testing and brain MRI to exclude reversible causes, then proceed to formal neuropsychological testing if screening suggests impairment. 1, 2, 3

Initial Office-Based Cognitive Screening

Start with a validated brief cognitive assessment instrument rather than relying on subjective reports alone. 1

Recommended Screening Tools

• MoCA (Montreal Cognitive Assessment): Takes 10-15 minutes, includes a 5-word immediate and delayed memory test, and demonstrates 90% sensitivity for detecting mild cognitive impairment—superior to the MMSE. 2

• Mini-Cog: Combines three-item word recall with clock drawing, requires only 2-4 minutes, and shows 76% sensitivity and 89% specificity for cognitive impairment. 2

• Standardized Assessment of Concussion (SAC) or Maddock's questions: Useful for rapid assessment of attention and memory function, particularly when evaluating acute changes. 1

Critical Consideration

Simple three-word recall tests (like those in the MMSE) have significant limitations and may miss subtle early-stage impairments, making them inadequate as standalone assessments. 4, 2

Essential Laboratory Evaluation

Order a comprehensive first-tier laboratory panel to identify reversible causes of cognitive symptoms. 3

Tier 1 Laboratory Tests (Order for All Patients)

• Complete metabolic panel 3
• Complete blood count 3
• Thyroid-stimulating hormone (TSH) 3
• Vitamin B12 level 3
• Liver function tests (ALT, AST)—particularly important as hepatic encephalopathy can present with attention deficits and forgetfulness 3, 1
• Hemoglobin A1c (HbA1c) for diabetes assessment 3

Tier 2 Testing (Based on Clinical Context)

• Lipid panel for vascular risk stratification 3

Neuroimaging

Brain MRI (non-contrast) is the preferred initial imaging modality to evaluate structural causes including stroke, white matter disease, atrophy patterns, hydrocephalus, and space-occupying lesions. 3

• CT scan is acceptable if MRI is contraindicated or unavailable, with coronal reformations to assess hippocampal atrophy. 3

Formal Neuropsychological Testing

If screening tests suggest impairment, proceed to comprehensive neuropsychological assessment focusing on attention and memory domains. 1

Attention Testing

Attention lapses are strongly correlated with memory failures and should be systematically evaluated. 5 Key tests include:

• Five-choice serial reaction time task (5-CSRTT) for sustained attention 1
• Attentional set shifting tasks 1
• Tests requiring vigilance with distracting stimuli (continuous performance tasks) 1

Memory Testing

Standardized word-list learning tests provide the most sensitive assessment: 4, 2

• Hopkins Verbal Learning Test-Revised (HVLT-R): Preferred for multiple alternate forms and brief administration time 2
• California Verbal Learning Test-Second Edition (CVLT-2): Provides additional information through cued recall and interference lists 2
• Free and Cued Selective Reminding Test 4, 2
• Rey Auditory Verbal Learning Test 4, 2

For nonverbal memory:

• Visual Reproduction subtests of the Wechsler Memory Scale-Revised I and II 2

Executive Function and Processing Speed

Include tests of executive function, psychomotor abilities, and speed of information processing, as these domains are commonly affected alongside attention. 1

Specialized Testing (When Indicated)

Consider These in Specific Scenarios:

• Lumbar puncture with CSF analysis: For early-onset symptoms (<65 years), rapidly progressive decline, or suspected autoimmune/infectious/paraneoplastic causes 3

• Blood biomarkers for amyloid pathology: Emerging tools that may reduce need for CSF or PET imaging when Alzheimer's disease is suspected after comprehensive workup 3

• Electroencephalography (EEG): When transient epileptic amnesia is suspected, particularly if there are episodic memory gaps or changes in forgetfulness patterns 6

• Blood ammonia levels: May be helpful in suspected hepatic encephalopathy, though hyperammonemia can occur without encephalopathy 3

Critical Clinical Pitfalls to Avoid

Do not dismiss subjective forgetfulness as "normal aging" without objective assessment. Changes that may be common with advancing age are not always normal and warrant diagnostic evaluation. 1

Recognize that forgetfulness is non-specific. At the population level, subjective forgetfulness is more commonly related to anxiety, depression, and somatic symptoms than to dementia. 7 However, this does not eliminate the need for systematic evaluation.

Interview both patient and informant separately when possible. Diminished insight is common in cognitive impairment, and divergent perspectives between patient and care partner provide valuable diagnostic clues. 1

Be alert for masking conditions. Pre-existing attention problems (such as ADHD) can mask new memory disorders like transient epileptic amnesia, delaying recognition of treatable conditions. 6

Assess for delirium first in acute presentations. Delirium represents a medical emergency characterized by acute onset (hours to days), fluctuating course, inattention, and altered consciousness—requiring immediate evaluation and treatment of underlying causes. 1

Interpretation Considerations

Test scores must be interpreted considering the patient's age, educational background, and professional experience. 4, 2 Scores alone are not diagnostic and must be integrated with comprehensive clinical evaluation. 2

Longitudinal evaluations are valuable for monitoring cognitive decline over time and identifying atypical presentations. 4