An international core outcome set for primary progressive aphasia (COS-PPA): Consensus-based recommendations for communication interventions across research and clinical settings | Anna Volkmer et al. | ResearchPod

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

Alex: Welcome to another episode of ResearchPod. Today, we're looking at a study that asks a deceptively simple question: when we try to treat a brain condition that affects language, are we even measuring the right things?

Sam: That's an interesting way to frame it. What's the condition, and what's wrong with how we currently measure success?

Alex: The condition is called Primary Progressive Aphasia, or PPA. Imagine waking up one day and finding that the words you want to say are just... out of reach. Not because you've forgotten what you want to express, but because the part of your brain that handles language is slowly breaking down. That's PPA. It's a progressive neurological condition, meaning it gets worse over time, and it specifically targets a person's ability to speak, read, write, and understand language.

Sam: So it's not a memory problem — it's a language problem. And how have researchers been measuring whether a treatment is actually helping?

Alex: Traditionally, they've used tests that measure something called "word accuracy" — things like showing a patient a picture of a chair and asking them to name it. It's a clean, countable number. But the paper argues this approach misses the point entirely.

Sam: Because naming a picture in a clinic is very different from having a real conversation with your family at dinner.

Alex: Exactly. The patient's actual goal isn't to score well on a test. It's to be understood by the people around them — to participate in conversations, to get their meaning across even if the exact words won't come. Word accuracy tells you almost nothing about whether that's happening.

Sam: So the field has been optimizing for something easy to measure, rather than something that actually matters to the person living with the condition.

Alex: That's the central problem the paper identifies. And to fix it, the researchers set out to build what they call a Core Outcome Set. Think of it like a universal scorecard. Before this, every research team studying PPA was essentially playing by their own rules — one team measured vocabulary, another measured sentence length, another measured something else entirely. That makes it nearly impossible to compare results across studies or build on each other's work.

Sam: So how did they actually get everyone to agree on what should go on this shared scorecard?

Alex: They used a structured, three-stage process. First, they did a thorough review of every existing measurement tool used in PPA research — essentially cataloguing all the different "rules" that were already out there. Then, crucially, they brought in patients and their families, not just clinicians and researchers, to discuss what outcomes genuinely matter in daily life.

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

Anna Volkmer, Emily Viega Alves, Hagit Bar-Zeev, Elena Barbieri, Petronilla Battista, Ashleigh Beales, Barbara Costa Beber, Emilie Brotherhood, Ines Ribeiro Cadorio, Maria Teresa Carthery-Goulart, Jade Cartwright, Sebastian Crutch, Karen Croot, Maria Isabel d'Ávila Freitas, Jeanne Gallée, Stephanie M. Grasso, Katarina Haley, Heleen Hendriksen, Shalom Henderson, Lize Jiskoot, Isabel Junqueira Almeida, Jackie Kindell, Rachel Kingma, Lorinda L Y Kwan-Chen, Monica Lavoie, Adi Lifshitz-Ben-Basat, Regina Jokel, Aurore Mahut-Dubos, Jordi A. Matias-Guiu, Michèle Masson-Trottier, Marcus Meinzer, Ellen McGowan, Carolina Mendez-Orellana, Aaron M. Meyer, Carly Millanski, Núria Montagut, Aimee Mooney, Darby J. Morhardt, Lyndsey Nickels, Monica Norvik, Iris Edda Nowenstein, Avanthi Paplikar, Margaret Pozzebon, Antoine Renard, Leanne Ruggero, Emily Rogalski, Anna U. Rysop, Fredrik Sand Aronsson, Aida Suárez-González, Sharon Savage, Mai Tran Thi, Kyriana Tsapkini, Cathleen Taylor-Rubin, Donna C. Tippett, Nina Unger, Lizet van Ewijk, Sandra Wielaert, Ingvild Elisabeth Winsnes, Anne Whitworth, Ibrahim Can Yasa, David Copland, Maya L. Henry, Jason D. Warren, Rosemary Varley, Sarah J. Wallace, Chris J. D. Hardy

Jun 25, 2026·4:06·user_upload

Primary Progressive Aphasia (PPA)Core Outcome Set (COS)Communication InterventionsConsensus-based RecommendationsOutcome Measurement InstrumentsStakeholder Consensus

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4 min

Briefing

Research Context and Objectives

Primary progressive aphasia (PPA) is a neurodegenerative condition characterized by a gradual decline in language abilities. Historically, intervention research has relied heavily on word accuracy as a primary outcome measure. However, people living with PPA and their care partners have frequently reported that these measures do not capture the communication challenges that matter most to their daily lives. This study aimed to develop a Core Outcome Set (COS-PPA) to standardize how communication interventions are evaluated, ensuring that research outcomes are more relevant to patients and their families.

Methodology

Following the Core Outcome Set Standards for Development Recommendations (COSSTAD), the researchers conducted a three-stage process. First, a systematic review identified 84 existing outcome measurement instruments used in PPA intervention literature. Second, international consensus groups—involving 82 people with PPA and 91 care partners—used a nominal group technique to identify the most important communication constructs. Finally, a modified e-Delphi consensus exercise with 57 international researchers was conducted to reach agreement on these core constructs and potential measurement tools.

Key Findings

The study successfully identified five core outcome constructs that are prioritized by both patients and their families: participating in conversations with family and friends, getting words out, being more fluent, conveying a message by any means, and understanding what others are saying. While there was strong agreement on these constructs, the researchers could not reach a consensus on which specific measurement instruments should be used to assess them. This indicates that while the field now has a shared language for what to measure, it lacks a standardized agreement on how to measure it.

Why It Matters

By defining a core outcome set, this research provides a roadmap for future clinical trials to focus on patient-centered goals rather than narrow linguistic metrics. This shift is essential for improving the comparability of intervention studies and ensuring that the results of clinical research are meaningful to the people living with PPA. The findings highlight a critical gap in the field: the need for the development and validation of new assessment tools that can accurately capture these five core constructs in a progressive, neurodegenerative context.

Key Terms and Definitions

Primary Progressive Aphasia (PPA) — A group of neurodegenerative disorders where language impairment is the most prominent clinical feature.
Core Outcome Set (COS) — An agreed-upon, standardized collection of outcomes that should be measured and reported in all clinical trials for a specific health condition.
Nominal Group Technique (NGT) — A structured, consensus-building method used to prioritize items by having participants independently generate and rank ideas.
e-Delphi Exercise — An iterative, multi-round survey process used to reach consensus among a group of experts on a specific topic.
Outcome Measurement Instrument — A specific tool, such as a test, questionnaire, or rating scale, used to quantify a patient's health status or change in condition.

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