Dysfunction of the stress response in individuals with persistent post-concussion symptoms: a scoping review protocol

Abstract

Background

10-15% of individuals who sustain a concussion develop persistent post-concussion symptoms (PPCS). Presently, there is no consensus regarding the pathophysiology of PPCS. Preliminary evidence suggests that individuals with PPCS have either a dysfunctional autonomic nervous system (ANS) or hypothalamic-pituitary-adrenal axis (HPA-axis). The ANS and HPA-axis collectively make up the two arms of the peripheral stress response. In the presence of a stressor, the two arms work interchangeably to return the body back to homeostasis. With concussion as the stressor, it is plausible that the development and maintenance of PPCS are due to a dysfunctional stress response. Only one study has explored the relationship between PPCS and the two arms of the stress response (ANS and HPA-axis) in combination, which presents a clear gap in the literature.

Objective

The proposed protocol aims to determine the extent of evidence for dysfunction of the stress response in individuals with PPCS. This review will individually map the literature surrounding quantifiable changes in the (1) ANS and (2) HPA-axis in individuals with PPCS. The review will also highlight any (3) knowledge gaps in this emerging field of research.

Methods

A scoping review study design has been chosen to facilitate a thorough literature search on this broad exploratory topic. The scoping review proposed will follow the recommended methodological guidelines.

Conclusion

Understanding the potential role of a dysfunctional stress response in those with PPCS will create more effective treatment pathways and reduce the chronicity of this condition.

Keywords:

• Post-concussion syndrome (MeSH)
• autonomic nervous system (MeSH)
• HPA-axis
• hydrocortisone (MeSH)
• cortisol

Acknowledgments

We thank Mrs. Thelma Fisher, Physiotherapy Subject Librarian, University of Otago Library, for her advice and assistance with database selection and development of the search strategy. We would also like to collectively thank Mrs. Thelma Fisher and Mr. Richard German for their problem-solving skills related to the protocols search strategy.

Contributions by authors

The first author, Gerard Farrell (GF), developed the current protocol in conjunction with the listed authors. The protocol was piloted by GF and further refined as guided by the listed authors, and from the help of Mrs. Thelma Fisher and Mr. Richard German (see ‘acknowledgments’ section). The listed authors have had an active role throughout the development and progression of this protocol.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The completion of this protocol contributes to the first author’s, Gerard Farrell, Doctoral degree at the University of Otago, Dunedin, New Zealand. Subsequently, this protocol was supported by the Stanley Paris PhD OMT Scholarship and the University of Otago Doctoral Scholarship.

Notes on contributors

Gerard Farrell

Gerard Farrell is a PhD student at the Centre for Health, Activity and Rehabilitation Research, School of Physiotherapy at the University of Otago. His research interests include the neuroendocrine mechanisms of manual therapy and the role manual therapy plays in the treatment of persistent post-concussion symptoms.

Cathy Chapple

Dr. Cathy Chapple is a senior lecturer at the Centre for Health, Activity and Rehabilitation Research, School of Physiotherapy at the University of Otago. Her research interests are in the management of people with osteoarthritis. She is also investigating manual therapy for osteoarthritis patients and other musculoskeletal conditions including the role of the cervical spine in persistent post-concussion symptoms.

Ewan Kennedy

Dr. Ewan Kennedy is a lecturer at the Centre for Health, Activity and Rehabilitation Research, School of Physiotherapy at the University of Otago. His research interests are in musculoskeletal disorders, concussion and clinical education. Recent work has explored overlap between cervical spine and concussion injuries, with a focus on improving health service delivery.

Kesava Sampath

Dr. Kesava Sampath is a senior academic staff member at the Centre of Health and Social Practice, Waikato Institute of Technology, Hamilton, Waikato, New Zealand. His research work focuses on mechanisms underpinning manual therapy practice. Currently, he leads a research project investigating the usage of bio-psycho-social model of care by New Zealand osteopaths while treating people with persistent musculoskeletal pain. He is a visiting research fellow at the University of Technology, Sydney, where he is part of a global osteopathic network and actively collaborates/contributes to other projects. He is also an adjunct researcher at the Ara Institute of Canterbury and supervises post-graduate nursing research students.

Angela Spontelli Gisselman

Dr. Angela Spontelli Gisselman is a course director for Musculoskeletal Practice I and primary instructor for Musculoskeletal Practice II in High Point University’s Department of Physical Therapy program. Her main research interests are in the role of health metrics, such as heart rate variability (an index of the autonomic nervous system), and their ability to influence decision making in rehabilitation, such as post-concussion rehabilitation. In addition to this line of research, other areas of interest include heart rate variability and temporomandibular disorders; the use of thermal imaging in tendinopathy; examination and management of shoulder injuries; load monitoring technology and post-operative rehabilitation.

Chad Cook

Prof. Chad Cook is a clinical researcher, physical therapist, and profession advocate with a history of clinical care excellence and service. His passions include refining and improving the patient examination process and validating tools used in day-to-day physical therapist practice. Dr. Cook has authored or co-authored three textbooks, has published over 250 peer-reviewed manuscripts, and lectures internationally on orthopedic examination and treatment. He is a fellow of the American Academy of Orthopaedic Manual Physical Therapists; has specialized in manual therapy for over 19 years. His main areas of research interest are in examination and conservative or surgical treatment of orthopedic-related conditions.

Steve Tumilty

Assoc. Prof. Steve Tumilty is one of the few clinician scientists in Physiotherapy Worldwide and one of only nine Registered Physiotherapy Specialists in New Zealand. He has an interest in blurring the boundaries between the manual therapy professions. The majority of his clinical experience has been in the outpatient musculoskeletal practice setting in UK, Germany and New Zealand. He also has experience in professional sports and Occupational Health Physiotherapy. In 2002 he came to work at the School of Physiotherapy, Otago University and he has developed and now coordinates the specialist Masters degree for Sports and Orthopaedic Manipulative Therapy for which he provides teaching and clinical expertise. Dr Tumilty’s current research interests are in Tendinopathy, photobiomodulation, modulation of the Hypothalamus-Pituitary Axis using manual interventions, and the influence of the autonomic nervous system on musculoskeletal pain and healing.