Which of the following is indicative of bradykinesia in Parkinson's disease?

Bradykinesia, a core symptom of Parkinson's disease, refers specifically to the slowness of movement. Diminished movement speed is a straightforward representation of this symptom; individuals experiencing bradykinesia often find that their movements become slower and more difficult over time. This could manifest in a variety of daily activities, making simple actions take longer than they normally would.

While other symptoms like uncontrollable shaking (known as tremors) and cognitive issues such as severe memory deficits can accompany Parkinson's disease, they do not reflect the nature of bradykinesia itself. Similarly, reduced emotional engagement may be related to the impact of the disease on a person's overall functioning, but it does not directly indicate the characteristic slowness of movement associated with bradykinesia. Thus, diminished movement speed directly aligns with the hallmark features of bradykinesia in patients with Parkinson's disease.