An international core outcome set for primary progressive aphasia (COS‐PPA): Consensus‐based recommendations for communication interventions across research and clinical settings

Abstract
INTRODUCTION Interventions to treat speech‐language difficulties in primary progressive aphasia (PPA) often use word accuracy as a highly comparable outcome. However, there are more constructs of importance to people with PPA that have received less attention. METHODS Following Core Outcome Set Standards for Development Recommendations (COSSTAD), this study comprised: Stage 1 – systematic review to identify measures; Stage 2 – consensus groups to identify important outcome constructs for people with PPA (n = 82) and care partners (n = 91); Stage 3 – e‐Delphi consensus with 57 researchers. RESULTS The systematic review identified 84 Outcome Measurement Instruments. Core outcome constructs identified included: (1) Participate in conversations with family and friends, (2) get words out, (3) be more fluent, (4) convey a message by any means, and (5) understand what others are saying. Researchers were unable to reach a consensus on measurement instruments.
DISCUSSION Further work is required to develop appropriate measurement instruments that address all core outcome constructs important to key stakeholders. Highlights We introduce new symptom‐led perspectives on primary progressive aphasia (PPA). The focus is on non‐fluent/agrammatic (nfvPPA) and semantic (svPPA) variants. Foregrounding of early and non‐verbal features of PPA and clinical trajectories is featured. We introduce a symptom‐led staging scheme for PPA. We propose a prototype for a functional impairment scale, the PPA Progression Planning Aid.