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Single-Case Studies as a Hot Topic in Pain Research: A Conference Review

Updated: Jul 3

Author: Sara Laureen Bartels


The 12th Congress of the European Pain Federation EFIC 2022 took place in Dublin in a hybrid format from 27th-30th of April 2022 (https://efic-congress.org), and this event was my very first pain congress – and also the first face-to-face conference since 2019. The congress theme ‘Targeting pain and its comorbidities in the Digital Age’ was timely, as many healthcare professionals provided treatment and counselling to their pain patients via video-calls during the COVID-19 pandemic. It was also relevant because virtual reality, digital diaries, artificial intelligence, and eHealth interventions are gaining increased attention in the field.




Next to sessions on patient-therapist communication, sleep, uncertainty, and other aspects surrounding pain, single-case experimental designs (SCEDs) and N-of-1 trials were a hot topic at the congress. During the keynote lectures on Friday morning, international speakers presented their research and views on this methodological approach. Prof Sunita Vohra from the University of Alberta, Canada, opened the session, highlighting the possibilities of SCED studies to close the gap between research and practice, build rigorous evidence with every patient that a healthcare professional engages with, and evaluate therapies relevant for a patient. Following, Prof Luis Garcia-Larrea from the Lyon Neuroscience Research Centre, France, presented a N-of-1 trial of deep brain stimulation, which emphasized the wide applicability of single-case designs to pharmacological and behavioral treatments, and also medical devices. The third speaker, Dr Nadine Attal from the University Versailles Saint Quentin, France, provided a clear comparison between traditional RCTs and N-of-1 trials, and the advantages of N-of-1 trials especially for chronic conditions, rare disorders, and expensive treatments. Finally, Dr Rikard Wicksell from Karolinska Institutet, Sweden, provided an overview of using SCEDs in the field of chronic pain, and presented research studies comprising accumulated SCED data allowing for both individual and group-level analysis. For example, in the ongoing DAHLIA project, SCEDs will be applied in an interative optimization study to assess individual change processes while improving the feasibility of a digital intervention, and determine efficacy across participants and iterations though aggregated SCED data.


On Friday afternoon, a hybrid refresher course on SCEDs connected the congress attendees with SCED experts online, including Prof Johan Vlaeyen, from Maastricht University, Netherlands/ KU Leuven, Belgium; Prof Patrick Onghena from KU Leuven, Belgium; and Prof Kimberly Vannest from the University of Vermont, U.S.A. The refresher course had provided the audience with recorded presentations prior to the conference, and attendees could then discuss questions with the experts. This session was especially interesting for me, as I previously worked with the experience sampling method (ESM) and wondered how these two methods overlap. Methodological questions about imputation of missing data and digital diary items were fruitfully discussed. Prof Vlaeyen and Prof Onghena announced that the next international online N=1 symposium called ‘Small is Beautiful’ will take place 24th-27th of April 2023 and a workshop on using the ESM in SCEDs will be included (more details will be shared shortly). I am looking forward to learning more about how these two worlds merge.


Prof. Vlaeyen in the hybrid refresher course

I am excited to see SCED and N-of-1 trial approaches being discussed by researchers and clinicians in the field of chronic pain, as this methodology holds promise to understand and support a person in managing their everyday life, particularly in combination with the ESM. We need to critically reflect on RCTs as the “gold standard”, because through RCTs’ standardized pre-post intervention assessments and group-level analysis, researchers, clinicians and participants cannot observe individual response patterns. Nor can fine-graded changes over the course of intervention period be seen, as only a small number of sampling points is available. In SCEDs, repeated (momentary) assessments allow us to determine individual response patterns, including changes over time and relationships and interactions between variables, to understand the complexity of the personal situation. Prospectively, I hope to contribute through my research to more single-case designs and ESM studies in the field of chronic pain and beyond.


The EFIC 2022 conference put SCEDs and N-of-1trials on everyone’s agenda, stimulated knowledge exchange, and thanks to the collegial atmosphere, contributed to new research ideas and collaborations. I highly recommend this event and hope to see you in Budapest in September 2023 for the 13th Congress “Personalized Pain Management – the Future is Now”.


About the Author


Dr Sara Laureen Bartels is a Marie-Curie Alumni and works as a postdoctoral researcher at Karolinska Institutet and Maastricht University. Her research focusses on digital interventions for people with chronic pain, as well as for older adults with dementia and their relevant others. Dr Bartels has a growing interest in single-case observational and experimental designs.

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