What finding would indicate that carbidopa-levodopa therapy is effective?

The effectiveness of carbidopa-levodopa therapy is primarily assessed by the improvement of motor symptoms associated with Parkinson's disease, as this medication is specifically aimed at replacing dopamine, which is deficient in this condition.

Improvement in spontaneous activity indicates that there is a reduction in the rigidity and bradykinesia experienced by individuals with Parkinson's disease, suggesting that the therapy is effectively alleviating the core motor symptoms. This increase in spontaneous activity manifests in the patient's ability to initiate and perform movements more freely, which is a key treatment goal.

Other findings related to cognitive function, visual disturbances, or dizziness may not directly reflect the effectiveness of carbidopa-levodopa on the primary motor symptoms, as this medication does not primarily aim to improve cognitive function or resolve non-motor symptoms, such as visual hallucinations or postural instability. Thus, improvement in spontaneous activity is the most relevant indicator of the therapy’s effectiveness in managing the fundamental aspects of Parkinson's disease.