Which of the following is a similarity between Alzheimer disease and Parkinson disease?

• A. Both are caused by the same genetic mutation.
• B. Both primarily present with hallucinations as the first symptom.
• C. Both are treated exclusively with dopamine replacement therapy.
• D. Both are neurodegenerative disorders that primarily affect older adults.

Answer: (D)

Verified step by step guidance

1. Step 1: Understand the nature of Alzheimer disease and Parkinson disease by defining each as neurodegenerative disorders, which means they involve progressive loss of structure or function of neurons, including death of neurons.
2. Step 2: Identify the typical age group affected by both diseases, noting that both Alzheimer and Parkinson diseases primarily affect older adults, usually those over 60 years of age.
3. Step 3: Examine the symptoms and causes of each disease to see if they share genetic mutations or initial symptoms such as hallucinations, and recognize that these aspects differ between the two diseases.
4. Step 4: Review treatment options for both diseases, understanding that while Parkinson disease often involves dopamine replacement therapy, Alzheimer disease does not, so treatment is not exclusively the same.
5. Step 5: Conclude that the key similarity is that both Alzheimer disease and Parkinson disease are neurodegenerative disorders that primarily affect older adults, which is the correct answer.