Patients switch topics mid-consultation: PRISM estimates clinical state as a hidden variable and lifts decision accuracy 22.40 points over the strongest baseline
In online medical consultation, patients often volunteer symptoms or pivot to new concerns, so the clinical state is only progressively revealed. PRISM splits triage into belief estimation, policy optimization and response realization: it maintains a posterior over plausible consultation states, then selects the next inquiry from the maximum a posteriori state. On 450 real online consultations, its structured decision accuracy exceeds the strongest baseline by 22.40 percentage points, and BERTScore_F1 by 5.51 points.