Dementia with Lewy bodies is most accurately described as having features overlapping with which condition?

• A. Visual hallucinations with memory loss
• B. Alzheimer disease
• C. Parkinsonian features with fluctuating cognition
• D. Vascular dementia

Answer: (C)

Dementia with Lewy bodies blends motor and cognitive features in a way that mirrors Parkinson disease. The key overlapping element is fluctuating cognition—attention and alertness that wax and wane—together with parkinsonian motor signs like bradykinesia and rigidity. This combination makes Parkinson disease the best-fitting overlap, since both conditions share parkinsonism and variable cognition.

Alzheimer disease centers on memory impairment with a relatively different cognitive trajectory and lacks the early, prominent parkinsonian features and fluctuations that define the overlap with Parkinson disease. Vascular dementia presents with a more stepwise decline tied to vascular events and lacks the characteristic parkinsonism and cognitive fluctuations. While visual hallucinations can occur in DLB, they’re part of its own syndrome rather than a separate overlap with another disease.