Which dementia is characterized by fluctuations in cognition, parkinsonism, well-formed visual hallucinations, REM sleep disturbances, and early attention/executive deficits?

• A. Lewy body dementia
• B. Alzheimer's disease
• C. Frontotemporal dementia
• D. Creutzfeldt-Jakob disease

Answer: (D)

This item is testing the ability to recognize dementia syndromes by their characteristic clinical pattern. The combination of fluctuations in cognition, parkinsonism, well-formed visual hallucinations, REM sleep disturbances, and early attention and executive deficits most clearly fits dementia with Lewy bodies. Fluctuating attention and alertness reflect Lewy pathology affecting cortical networks; vivid visual hallucinations are a common and distinctive feature; parkinsonian motor signs arise from involvement of the nigrostriatal system; REM sleep behavior disorder is often present and can precede cognitive symptoms, tying the pattern together. Memory can be affected but is not the earliest and defining problem the way it is in Alzheimer's disease, where episodic memory loss is prominent early on. Other dementias don’t typically present with this exact combination: Creutzfeldt-Jakob disease tends to progress rapidly with myoclonus and characteristic EEG findings; Alzheimer's disease usually shows early prominent memory impairment with slower progression and fewer early visual hallucinations; frontotemporal dementia centers on behavioral or language changes rather than the visuospatial symptoms and REM disturbances described.