Public defence: Pernille Marie Stähr Irgens

MSc Pernille Marie Stähr Irgens at Institute of Health and Society will be defending the thesis “Neck pain – clinical course and pain trajectories” for the degree of PhD (Philosophiae Doctor).

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Photo: Ragnar Hartvig.

Due to copyright issues, an electronic copy of the thesis must be ordered from the faculty. For the faculty to have time to process the order, the order must be received by the faculty at the latest 2 days before the public defence. Orders received later than 2 days before the defence will not be processed. After the public defence, please address any inquiries regarding the thesis to the candidate.

Trial Lecture – time and place

See Trial Lecture.

Adjudication committee

  • First opponent: Professor Raymond Ostelo, VU - Vrije Universiteit Amsterdam
  • Second opponent: Professor Kate Dunn, Keele University
  • Third member and chair of the evaluation committee: Professor Emeritus Magne Nylenna, University of Oslo

Chair of the Defence

Associate Professor Trond Tjerbo, Faculty of Medicine, University of Oslo

Principal Supervisor

Professor Hilde Stendal Robinson, Faculty of Medicine, University of Oslo


Neck pain is very common and costly to both society and individuals. Knowing how neck pain progresses over time could improve our understanding as well as aid in pain management.  Although prognosis is mostly favorable in the short term, studies on the clinical course of low back pain show that a large group of patients experience persistent and recurrent pain. However, there are few studies on neck pain.

In this thesis, we investigated if neck pain patients could be grouped according to the same trajectory definitions identified for low back pain. For 1 year, 1476 patients with neck pain in chiropractic practice answered weekly SMS with questions regarding number of days with pain and pain intensity the past week. Based on the SMS responses, we applied the trajectory definitions and found that they fit readily to our cohort. Most patients were classified as either persistent fluctuating or episodic, which is similar to findings on low back pain. We also assessed to what extent patients shifted from one trajectory to another in quarterly periods and found that 70% of patients experienced a stable trajectory.

Lastly, we explored if patients could identify retrospectively their own pain trajectory through a novel method using illustrations of common trajectories (visual trajectories). Overall, we found a general resemblance between the patients’ selected visual trajectory and their 1-year clinical course and trajectory definition (based on SMS data). However, there were large individual variations among patients within each visual trajectory. In particular, patients with mild pain and episodic pain were less able to identify a visual trajectory that most reflected their actual clinical course. Thus, these results may be influenced by recall bias.

Our results challenge the concept of ‘chronic pain’ and provide insights into how individual patients report their clinical course of neck pain, both prospectively and retrospectively.

Additional information

Contact the research support staff.

Published Nov. 8, 2022 12:23 PM - Last modified Nov. 18, 2022 1:16 PM