Which diagnosis is characterized by a preserved mental capacity?

The diagnosis characterized by a preserved mental capacity is Parkinson's disease. In this condition, individuals may experience motor symptoms such as tremors, rigidity, and bradykinesia, but their cognitive functions usually remain intact for a long time, especially in the early stages of the disease. This contrasts with conditions like Alzheimer's disease, where cognitive decline is a primary feature. Although some individuals with Parkinson's may experience cognitive changes later in the course of the disease, the initial symptoms primarily affect physical abilities rather than intellectual capacity.

In the case of multiple sclerosis, which is a demyelinating disease of the central nervous system, cognitive impairments can occur due to lesions affecting brain areas involved in cognitive processes. Similarly, cerebral palsy primarily affects muscle tone and motor skills, and while individuals can have varying degrees of intellectual disability, the disorder itself does not inherently preserve mental capacity as is typically seen in the early stages of Parkinson's disease. Thus, Parkinson's disease is the correct choice, as it best exemplifies a condition where mental capacity is preserved, particularly in its initial stages.