Residency · Residency · Internal Medicine

Cognitive Impairment and Dementia Screening

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Alright team, pull up a chair, even if it's just the edge of your seat. I know you're tired, but trust me, understanding the nuances of cognitive impairment and dementia screening is going to save you a lot of headaches, and more importantly, vastly improve the lives of your patients. Think of it like this: Mrs. Henderson, a delightful 82-year-old, comes in for her annual physical. Her daughter mentions, almost as an afterthought, that Mrs. Henderson has been forgetting appointments lately and had a fender bender she can't quite explain. You've got 15 minutes scheduled for this visit, a mountain of charts, and a pager buzzing in your pocket. What do you do? Do you shrug it off as "just old age," or do you dive into a rabbit hole of neurological workups?

The key here isn't to become a neurologist overnight, but to be a savvy internist who knows when to probe, what to ask, and who to call. Your role is often the first line of defense, the one who notices the subtle shifts that others might miss. That little comment from Mrs. Henderson's daughter? That’s your cue. It’s not about memorizing every single point on the Montreal Cognitive Assessment (MoCA), but understanding that if a patient, or their family, expresses concern about memory, it warrants a brief, targeted assessment. This isn't just about diagnosing a disease; it's about preserving dignity, ensuring safety, and empowering families to plan for the future.

So, when Mrs. Henderson’s daughter voices her concerns, you're not going to immediately order an expensive brain MRI. Instead, you'll reach for a quick, validated tool like the Mini-Cog, which takes about three minutes. If that raises a red flag, then you move to the next step: a slightly more in-depth screen and a focused history about functional impairment – are they still managing their finances, medications, and driving safely? This systematic approach helps you distinguish between normal age-related changes, mild cognitive impairment (MCI), and actual dementia, all while respecting the precious little time you have. And remember, sometimes, what looks like dementia is actually something reversible, like a medication side effect or a vitamin deficiency, and that’s where your detective skills truly shine.

Introduction

Cognitive impairment ranges from mild cognitive impairment (MCI) to overt dementia and affects an estimated 10-15% of adults over age 65. Early detection enables advance care planning, medication optimization, safety interventions, and caregiver support. Internists play a central role in screening, initial workup, and ongoing management.

Definitions and Classification

• Mild Cognitive Impairment (MCI): objective cognitive decline without significant functional impairment; approximately 10-15% progress to dementia annually
• Dementia: acquired cognitive decline in one or more domains sufficient to impair independent functioning
• Major subtypes: Alzheimer disease (60-80%), vascular dementia (15-20%), Lewy body dementia, frontotemporal dementia
• Delirium must be distinguished from dementia; delirium is acute, fluctuating, and often reversible

When to Screen

• Medicare Annual Wellness Visit includes a required cognitive assessment
• Screen when patient, family, or staff report memory concerns, confusion, or behavioral changes
• Assess cognition before major medical decisions or surgery in older adults
• Hospitalized patients with delirium should be reassessed for baseline cognitive impairment after resolution
• Routine screening in asymptomatic populations remains controversial (USPSTF: insufficient evidence)

Screening and Assessment Tools

Brief Screening Instruments

• Mini-Cog: 3-item recall + clock drawing; takes 3 minutes; excellent for initial screening
• Montreal Cognitive Assessment (MoCA): 30-point test; sensitive for MCI; score < 26 is abnormal
• Mini-Mental State Examination (MMSE): 30-point test; less sensitive for early impairment; score < 24 suggests dementia
• Saint Louis University Mental Status (SLUMS): 30-point test; better sensitivity than MMSE for MCI

Functional Assessment

• Activities of Daily Living (ADLs): bathing, dressing, toileting, transferring, eating
• Instrumental Activities of Daily Living (IADLs): finances, medications, transportation, cooking, shopping
• Functional impairment in IADLs often precedes ADL decline and is key to distinguishing MCI from dementia

Diagnostic Workup

Reversible Causes to Exclude

• Medications: anticholinergics, benzodiazepines, opioids, antihistamines
• Metabolic: hypothyroidism, vitamin B12 deficiency, folate deficiency, hepatic encephalopathy
• Infections: urinary tract infection, HIV, syphilis (in appropriate populations)
• Structural: normal pressure hydrocephalus (triad: gait apraxia, urinary incontinence, dementia), subdural hematoma
• Psychiatric: depression ("pseudodementia"), severe anxiety

Standard Laboratory Workup

• TSH, vitamin B12, comprehensive metabolic panel
• Consider HIV, RPR, folate based on clinical context
• Urinalysis to exclude UTI as contributing factor in acute presentations

Neuroimaging

• Non-contrast CT or MRI of the brain: recommended to exclude structural lesions
• MRI preferred for evaluating hippocampal atrophy, white matter disease, and vascular changes
• Amyloid PET imaging and CSF biomarkers (A-beta 42, phospho-tau) are increasingly used but typically reserved for specialist evaluation

Pharmacologic Management

Alzheimer Disease

• Cholinesterase inhibitors (donepezil, rivastigmine, galantamine): modest symptomatic benefit in mild-moderate disease
• Memantine: NMDA receptor antagonist for moderate-severe Alzheimer disease; may be combined with cholinesterase inhibitors
• Anti-amyloid therapies (lecanemab, donanemab): disease-modifying agents for early-stage Alzheimer disease with confirmed amyloid pathology; require ARIA monitoring with MRI
• Reassess benefit periodically; consider deprescribing in advanced disease

Behavioral and Psychological Symptoms of Dementia (BPSD)

• Non-pharmacologic interventions first: structured routines, music therapy, caregiver education, environmental modification
• Antipsychotics (risperidone, quetiapine): reserved for severe agitation or psychosis unresponsive to non-pharmacologic measures; carry FDA black box warning for increased mortality
• SSRIs (citalopram, sertraline): may help with agitation and depression
• Avoid benzodiazepines and anticholinergics

Non-Pharmacologic Management and Caregiver Support

• Advance care planning: discuss goals of care, health care proxy, and living will early
• Driving assessment: critical safety concern; refer for formal evaluation when indicated
• Caregiver burden: screen for depression and provide resources for respite care and support groups
• Safety evaluation: home safety assessment, medication management, wandering prevention
• Referral to social work, geriatrics, and community resources

Key Clinical Pearls

• The Mini-Cog is a rapid, validated screening tool suitable for busy clinical settings.
• Always exclude reversible causes of cognitive impairment including medications, metabolic derangements, and depression.
• Functional assessment (ADLs/IADLs) is essential to distinguish MCI from dementia.
• Non-pharmacologic strategies should be the first-line approach for behavioral symptoms of dementia.
• Early advance care planning and caregiver support are as important as pharmacotherapy.

References

1. Livingston G, Huntley J, Sommerlad A, et al. Dementia Prevention, Intervention, and Care: 2020 Report of the Lancet Commission. The Lancet. 2020;396(10248):413-446.
2. Nasreddine ZS, Phillips NA, Bedirian V, et al. The Montreal Cognitive Assessment, MoCA: A Brief Screening Tool for Mild Cognitive Impairment. Journal of the American Geriatrics Society. 2005;53(4):695-699.
3. Petersen RC, Lopez O, Armstrong MJ, et al. Practice Guideline Update: Mild Cognitive Impairment. Neurology. 2018;90(3):126-135.
4. van Dyck CH, Swanson CJ, Aisen P, et al. Lecanemab in Early Alzheimer's Disease. New England Journal of Medicine. 2023;388(1):9-21.

For the intern

At 3am, focus on excluding delirium and acute reversible causes rather than initiating dementia screening. Check fingerstick glucose, vital signs, urinalysis, and review the medication list for new anticholinergics or sedatives. A comprehensive cognitive workup—including screening tools like Mini-Cog or MoCA, TSH, vitamin B12, and brain imaging—can wait until morning clinic hours when collateral history from family is available and the patient is rested. If the patient is agitated, attempt non-pharmacologic redirection first; use low-dose antipsychotics only for severe, dangerous agitation after discussing risks.

Common pitfalls

• Screening without assessing function: A low MoCA score alone doesn't diagnose dementia. You must document impairment in IADLs (finances, medications, transportation) or ADLs to distinguish dementia from MCI.
• Mistaking delirium for dementia: Delirium is acute and fluctuating; dementia is chronic and progressive. Always search for precipitants (infection, medications, metabolic derangements) before attributing confusion to baseline dementia.
• Reflexively prescribing antipsychotics for agitation: These carry a black box warning for increased mortality in dementia. Exhaust behavioral strategies (reorientation, music, familiar faces) and treat underlying causes (pain, constipation, urinary retention) first.
• Forgetting reversible causes: Always check B12, TSH, and review medications. Depression can mimic dementia ("pseudodementia"), and normal pressure hydrocephalus presents with the classic triad of gait disturbance, incontinence, and cognitive decline.

Make it stick

Imagine Mrs. Rodriguez, a 78-year-old admitted for pneumonia. On hospital day 2, she's disoriented, pulling at her IVs, and misidentifying staff. Your first thought might be, "She has dementia." But before jumping to conclusions or ordering a stat head CT, consider the acute change from her baseline. Is she hypoxic? Is her infection worsening? Did a new medication like diphenhydramine get started? This acute confusional state, fluctuating and often reversible, is delirium, not dementia. Your priority is to identify and treat the underlying medical cause, not to initiate a full dementia workup.

If you remember one thing

Always differentiate between acute delirium and chronic cognitive impairment; never attribute an acute change in mental status to "just her dementia" without a thorough search for reversible causes. Your initial response should be to rule out immediate, treatable precipitants of delirium.

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