Dementia Screening in Primary Care: Mini-Cog, MoCA, the Reversible Causes Work-Up and Referral

Dementia screening in primary care is a two-stage task: a brief validated test when anyone raises a concern, then an evaluation that confirms a decline in function, looks for contributing and treatable causes, and decides who needs a specialist. The USPSTF (2020) gives routine screening of asymptomatic adults 65 and older an I statement, so the trigger is a symptom or an informant's report, not age alone. A Mini-Cog total of 0 to 2 out of 5, or a MoCA below 26 after the education adjustment, is a positive result that starts the work-up; it is never the diagnosis by itself.

When to test

Test when the patient, a family member or the provider notices a change: repeated questions, missed appointments, medication errors, unpaid bills, getting lost while driving, new difficulty with a familiar task, unexplained weight loss or a change in personality. The USPSTF, while not endorsing routine screening, asks clinicians to stay alert to early memory and language problems and evaluate them. Medicare's Annual Wellness Visit also includes detection of cognitive impairment, so many practices run a brief tool at that visit.

Before testing, correct what distorts the result: hearing aids in, glasses on, the test given in the patient's preferred language, and acute illness excluded. A new, fluctuating confusion over hours to days is delirium until proven otherwise, and it takes a same-day evaluation rather than a screening instrument.

The screening tools and their cut-offs

Two practical rules come from the table. First, a normal Mini-Cog does not close the question when the informant's account is convincing; follow it with a MoCA or a structured informant questionnaire. Second, the education point on the MoCA is added before applying the cut-off, which the exam tests directly.

Mild cognitive impairment, dementia, delirium or depression

The screening score says that cognition is impaired. The informant history says whether daily function is affected, and that distinction separates the diagnoses.

Ask the informant about instrumental activities of daily living: managing money, medications, transportation, shopping, cooking, the telephone. Loss of these with preserved basic activities (bathing, dressing, toileting, eating) is the usual picture in mild dementia. The 2024 Alzheimer's Association guideline (DETeCD-ADRD) calls for reliable informant input on cognition, daily function, mood and behavior, and sensory and motor change, ideally with structured instruments.

The contributing causes work-up

Few dementias are fully reversible, but many patients have a treatable contributor that worsens cognition. The evaluation has five parts.

1. Medication review

Look first for drugs on the 2023 Beers list to avoid in dementia or cognitive impairment: anticholinergics (diphenhydramine, hydroxyzine, oxybutynin, tricyclics, paroxetine, cyclobenzaprine), benzodiazepines, nonbenzodiazepine hypnotics and antipsychotics. Add opioids, anticonvulsants, muscle relaxants and alcohol. Stop or taper the offender and retest cognition several weeks later before labeling the decline neurodegenerative.

2. Tier 1 laboratory studies

The DETeCD-ADRD guideline recommends routine tier 1 studies in every patient: complete blood count with differential; comprehensive metabolic panel including calcium, magnesium and liver tests; TSH; vitamin B12; homocysteine; erythrocyte sedimentation rate; and C-reactive protein. Further tests, such as syphilis or HIV serology, are guided by risk and presentation.

3. Structural brain imaging

MRI of the brain without gadolinium is preferred; a non-contrast head CT is acceptable when MRI is unavailable or contraindicated. Imaging finds subdural hematoma, tumor, strokes and white matter disease, normal pressure hydrocephalus (gait change, urinary incontinence and cognitive decline), and patterns of atrophy that point toward a specific disease.

4. Other contributors

Screen for depression, obstructive sleep apnea, hearing and vision loss, alcohol use and poorly controlled vascular risk factors. Each is treatable and each lowers test scores.

5. Function and safety

Document ADLs and IADLs, driving, firearms in the home, financial vulnerability, wandering, living situation and the caregiver's capacity. These findings drive the plan as much as the diagnosis does.

Management after the diagnosis

Disclosure and planning

Disclose the diagnosis to the patient and, with consent, the care partner, in plain language, with written resources. Discuss advance directives, durable power of attorney for health care and finances, and driving while the patient can still take part in the decisions. Refer the caregiver to education and support; the USPSTF review found that caregiver interventions produce small improvements in caregiver burden and depression.

Drug therapy

Cholinesterase inhibitors (donepezil, rivastigmine, galantamine) are used for mild to moderate Alzheimer disease, and memantine for moderate to severe disease. The USPSTF describes their effect on cognition as small and short term, so set expectations accordingly. Donepezil starts at 5 mg once daily at bedtime; the label allows an increase to 10 mg only after 4 to 6 weeks at 5 mg. Before starting, check the pulse and ask about syncope, because cholinesterase inhibitors cause bradycardia, syncope, nausea, diarrhea, weight loss and vivid dreams, and the Beers Criteria list them to avoid in patients with syncope. Memantine is titrated weekly toward its target dose (confirm the schedule in the current label).

Anti-amyloid monoclonal antibodies (lecanemab, donanemab) are specialist therapies for early symptomatic Alzheimer disease with confirmed amyloid pathology and need MRI surveillance for amyloid-related imaging abnormalities. The primary care role is to recognize eligibility and refer early.

For behavioral symptoms, start with nonpharmacologic approaches: identify triggers such as pain, constipation, infection, hunger, noise or an unfamiliar caregiver, and adjust routine and environment. Antipsychotics are on the Beers avoid list for behavioral symptoms of dementia because of increased stroke and mortality; reserve them for psychosis or danger after other measures fail, with a plan to reduce them.

Monitoring and follow-up

Reassess cognition with the same instrument at follow-up so scores are comparable, and reassess function, mood, weight, safety and caregiver strain at each visit. After starting a cholinesterase inhibitor, review pulse, gastrointestinal effects and weight at each dose step. In mild cognitive impairment, repeat structured testing over time, since some patients progress, some remain stable and some improve when a contributor is treated. A sudden decline in an established dementia is delirium or a new illness until shown otherwise.

Referral triggers

How the exam tests this

• The USPSTF trap. An option says the USPSTF recommends annual cognitive screening for everyone 65 and older. The 2020 statement is an I statement; symptomatic patients are evaluated regardless.
• The cut-off items. Mini-Cog 0 to 2 out of 5 is positive. MoCA below 26 is abnormal, after adding 1 point for 12 or fewer years of education. A stem with a MoCA of 25 and 11 years of education is a normal score.
• The wrong tool. The MMSE is insensitive to mild cognitive impairment; when the stem describes subtle executive problems in a well-educated patient, the MoCA is the better choice.
• Treat before diagnosing. Starting donepezil on a positive screen, before labs, imaging and medication review, is the classic distractor.
• Delirium disguised as dementia. Acute onset, inattention and fluctuation point to delirium; the next step is the precipitant (urinalysis, medication review, glucose, electrolytes), not a MoCA.
• Depression. A patient who answers "I don't know" and has low mood needs a depression screen and treatment before a dementia label.
• The hidden anticholinergic or benzodiazepine. The correct answer stops the drug and retests cognition.
• Donepezil adverse effects. Bradycardia and syncope are the reasons to hold it; vivid dreams are the reason to move the dose to the morning.

Practice question

A 77-year-old woman is brought in by her son, who reports that over the past 9 months she has missed two utility payments, repeated the same stories within a conversation and twice forgotten to take her blood pressure medication. She still bathes, dresses and cooks simple meals independently. She has hypertension and osteoarthritis and takes amlodipine 5 mg daily and acetaminophen as needed. She drinks one glass of wine weekly. She is alert and attentive, and her son describes no fluctuation. PHQ-9 score is 3. She completed 16 years of education. Mini-Cog total is 2 of 5, and MoCA is 21 of 30. Vital signs, including pulse 72/min, and neurologic examination are normal. Which of the following is the most appropriate next step?

• A. Start donepezil 5 mg at bedtime and reassess in 6 weeks.
• B. Order a CBC, comprehensive metabolic panel, TSH and vitamin B12, and obtain brain MRI without contrast.
• C. Reassure the son that these changes are consistent with normal aging and repeat the MoCA in 1 year.
• D. Order an amyloid PET scan to confirm Alzheimer disease.

Answer: B. Both screens are positive, the informant describes a gradual decline in instrumental activities with intact basic function, and delirium and depression are unlikely, so the next step is the evaluation for contributing causes: tier 1 laboratory studies and structural imaging, with MRI preferred. Option A starts treatment before the work-up has excluded treatable contributors and before a diagnosis has been made. Option C dismisses a MoCA of 21 in a highly educated patient with functional decline, which is not normal aging. Option D skips the primary care evaluation; amyloid biomarkers belong to specialist assessment, usually when anti-amyloid therapy is being considered.

Key points

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