A nurse is caring for a client with Parkinson's disease who recently had deep brain stimulation. Which outcome indicates the treatment is effective?

Rationale: A. Deep brain stimulation (DBS) targets specific brain areas, most commonly the subthalamic nucleus or globus pallidus, to modulate abnormal neuronal activity. The primary goal of DBS in Parkinson’s disease is to reduce motor symptoms such as tremors, rigidity, and bradykinesia when medications are insufficient or cause significant side effects. A noticeable reduction in these symptoms indicates effective treatment. B. DBS primarily affects motor pathways, not autonomic regulation. While transient cardiovascular changes may occur during surgery, persistent hypertension or tachycardia is not a desired outcome and may indicate complications rather than therapeutic benefit. C. Although improved comfort and activity may indirectly enhance sleep or appetite, these are secondary outcomes. DBS is not designed to treat non-motor symptoms such as sleep disturbances or appetite changes, so improvement in these areas does not confirm the primary efficacy of the therapy. D. Speech issues in Parkinson’s disease, such as hypophonia or monotone speech, are less reliably improved by DBS. In some cases, DBS may even worsen speech due to stimulation parameters or target selection. Therefore, improved speech clarity is not a definitive indicator of treatment effectiveness.