07/12/2025
USMLE: Quick Cheat Sheet To Answer All The Dementia Questions Right on Your Step 1, Step 2 and Step 3
All Dementia Patients Are “Forgetful”. But on the USMLE and in clinic, memory loss isn’t always the first symptom.
If you jump straight to “Alzheimer’s” every time you see cognitive decline, you’ll miss the diagnosis.
You have to look at what happened first.
⏱️ The One-Minute Breakdown of the Major Dementias
1️⃣ The “Short-Term Memory” Type - Alzheimer’s 🧠
The first sign is forgetting recent conversations or where keys were placed.
This is anterograde amnesia.
Long-term memory stays intact until late.
Trap: Most common dementia, but a diagnosis of exclusion.
Pathology: Hippocampal atrophy.
2️⃣ The “Personality Change” Type - Frontotemporal (Pick’s) 😬
The first sign is behavior change.
A previously kind person becomes rude, disinhibited, or apathetic.
Memory is often preserved early.
Trap: Misdiagnosed as mania or depression.
Pathology: Frontal and temporal lobe atrophy.
3️⃣ The “Hallucination” Type - Lewy Body 👁️
The first sign is visual hallucinations.
Patients often see animals or people.
Parkinsonism with tremor and rigidity appears early.
Trap: Antipsychotics like haloperidol cause severe extrapyramidal symptoms.
Key clue: Symptoms fluctuate. Good days and bad days.
4️⃣ The “Step-Wise” Type - Vascular Dementia 🩸
The first sign is sudden decline after vascular events, followed by periods of stability, then another drop.
Trap: Look for risk factors.
Hypertension, diabetes, smoking.
Key: Focal neurologic deficits are common.
5️⃣ The “Wet, Wobbly, Wacky” Type - Normal Pressure Hydrocephalus 🚶
The first sign is gait apraxia.
Magnetic gait. Feet stuck to the floor.
Classic triad:
• Urinary incontinence (wet)
• Ataxia (wobbly)
• Dementia (wacky)
Key: Reversible with a VP shunt.
6️⃣ The “Rapid and Jerky” Type - Creutzfeldt–Jakob ⚡
The first sign is rapidly progressive dementia over weeks to months.
Plus myoclonus.
Key: 14–3–3 protein in CSF.
📌 Save this list. The 1st symptom is usually the answer key.
