What is the Mini‑Cog and how is it administered, scored, and interpreted for cognitive screening in older adults?

Mini-Cog: A Rapid Cognitive Screening Tool

What is the Mini-Cog?

The Mini-Cog is a 2-4 minute cognitive screening test that combines three-word recall with a clock drawing task, achieving 76% sensitivity and 89% specificity for detecting dementia, making it the preferred first-line screening tool in primary care settings. 1

The test is endorsed by the Alzheimer's Association for use during Medicare Annual Wellness Visits and can be administered by any trained healthcare team member. 1

How to Administer the Mini-Cog

Step 1: Three-Word Registration

• Present 3 unrelated words from a standardized word bank to the patient. 1
• Ask the patient to repeat the words immediately to ensure they heard them correctly. 1
• Instruct the patient to remember these words for later recall. 1
• You may repeat the 3 words up to 3 times if needed for initial registration. 1

Step 2: Clock Drawing Test

• Provide a preprinted large circle on paper. 1
• Instruct the patient to: "Fill in the numbers of a clock face and set the hands to show 10 past 11" (or "11:10"). 1
• Repeat directions if needed, but do not provide additional guidance on how to complete the task. 1

Step 3: Three-Word Recall

• Ask the patient to recall the 3 words presented at the beginning. 1
• Do not provide cues or hints. 1

Scoring the Mini-Cog

Standard Scoring Method (Most Common)

• Word Recall: 1 point for each word correctly recalled (0-3 points possible). 1
• Clock Drawing: Dichotomous scoring of 0 or 2 points. 1
  • 2 points: Clock is normal (all numbers present in correct sequence and position, hands clearly pointing to 11 and 2)
  • 0 points: Clock is abnormal (any error in number placement, sequence, or hand position)
• Total Score: 0-5 points possible. 1

Alternative Enhanced Scoring (Mini-Cog3)

Recent research suggests a more detailed 16-point scoring system (3-word immediate recall + 3-word delayed recall + 10-point clock drawing) may improve diagnostic accuracy, with AUCs of 0.82 for MCI and 0.95 for AD. 2 However, this is not yet standard practice in clinical guidelines.

Interpreting the Results

Score Interpretation

• Score < 3: Concerning for possible dementia; requires further evaluation. 1
• Score ≥ 3: Above threshold for concern, but does not rule out cognitive impairment. 3

Critical Caveats

• The Mini-Cog is a screening tool, not a diagnostic test—it provides probability estimates and cannot definitively rule in or rule out dementia. 3
• The test can miss approximately 24% of dementia cases (76% sensitivity). 1, 3
• It has limited sensitivity for detecting mild cognitive impairment (MCI), particularly in highly educated individuals. 1
• Patient characteristics significantly affect performance: education level, native language, cultural exposure to analog clocks, and age all influence results. 1, 4

Required Follow-Up for Abnormal Scores

Immediate Next Steps

When the Mini-Cog score is < 3, you must proceed with: 1, 3

1. Neurologic examination to assess for focal deficits or other neurological signs
2. Multidomain mental status testing such as the Montreal Cognitive Assessment (MoCA), which takes 10-15 minutes and provides more comprehensive evaluation 1, 3
3. Collateral history from family members or caregivers regarding functional decline in activities of daily living, behavioral changes, and medication adherence 3
4. Screen for dementia mimics:
   • Depression using PHQ-2 or PHQ-9 1, 3
   • Delirium using Confusion Assessment Method 1, 3
5. Laboratory studies to rule out reversible causes (CBC, CMP, TSH, vitamin B12, folate) 3
6. Brain imaging (MRI preferred) to evaluate for structural abnormalities 3

When Screening Results Are Borderline or Conflicting

If the Mini-Cog shows borderline results (score of 3) or conflicts with clinical suspicion, comprehensive neuropsychological assessment is indicated. 3 Do not assume normal cognition based on a single screening test when clinical concern persists. 3

Key Advantages of the Mini-Cog

• Speed: Takes only 2-4 minutes to administer, compared to 10-15 minutes for MoCA or MMSE. 1
• No copyright restrictions: Freely available, unlike the MMSE which has copyright limitations. 1
• Validated across diverse populations: Available in multiple languages and validated in heterogeneous primary care populations. 1
• High specificity: 89% specificity means fewer false positives compared to other brief screening tools. 1
• Minimal training required: Can be administered by any trained healthcare team member. 1, 5

Important Limitations and Pitfalls

• Cannot be used in nonliterate populations or those without cultural exposure to analog clocks without modification. 4
• Low sensitivity for MCI: May miss subtle cognitive changes, especially in intellectually capable individuals. 1
• Single test insufficient: Never rely on a single Mini-Cog result in isolation; serial testing and clinical context are essential. 3
• Not a substitute for comprehensive evaluation: Abnormal results always require full diagnostic workup. 1, 3

Performance Characteristics Across Settings

A 2024 meta-analysis of 14 studies (n=7,194 patients) demonstrated: 6

• Primary care setting (8 studies, n=5,620): 73% sensitivity, 84% specificity for detecting any cognitive impairment
• Secondary care setting (7 studies, n=1,499): 73% sensitivity, 76% specificity
• Dementia detection (6 studies, n=4,772): 76% sensitivity, 83% specificity
• MCI detection (2 studies, n=270): 84% sensitivity, 79% specificity