Abstract
Background
Preliminary evidence suggests that individuals with persistent post-concussion symptoms (PPCS) have a dysfunctional stress response, consisting of the autonomic nervous system (ANS) and hypothalamic pituitary adrenal-axis (HPA-axis).
Objectives
This review aims to explore the extent of evidence for dysfunction of the stress response in individuals with PPCS by individually mapping the literature surrounding quantifiable changes of the (1) ANS and (2) HPA-axis using non-invasive and clinical tools, and highlighting any (3) knowledge gaps.
Methods
Nine electronic databases and grey literature were searched on the 1st of June 2021 and 4th of October 2021. Studies were included if their population was classified with PPCS, and their study stated at least one quantifiable marker of the ANS or HPA-axis using non-invasive and clinical tools. Relevant studies were screened, and data extracted.
Results
A total of 37 articles were included in this scoping review. The majority of studies assessed quantifiable markers of the ANS (n = 34), in comparison to the HPA-axis (n = 2), and ANS and HPA-axis (n = 1). The most common quantifiable markers of the ANS included heart rate (n = 20), blood pressure (n = 16), and heart rate variability (n = 10). Cortisol was the only included quantifiable marker of the HPA-axis (n = 2).
Conclusions
Most of the evidence in this review supports quantifiable dysfunction of the ANS in those with PPCS. Further research is required investigating quantifiable dysfunction of the HPA-axis, and subsequently ANS and HPA-axis in unison, in those with PPCS.
Acknowledgements
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 relating to the studies search strategy. Gerard Farrell is a PhD candidate through the School of Physiotherapy, University of Otago. His PhD, and subsequently this project, is supported by the Stanley Paris PhD OMT Scholarship and the University of Otago Doctoral Scholarship.
Author contribution
GF, CC, EK, ASG, KS, CC, and ST: review’s conception and design, commented and edited protocol and final manuscript. GF: drafted and published the protocol, registration, search strategy, literature search, title/abstract screening, data extraction, interpretation, and manuscript preparation. GF and SW: full text screening. SW: verified data extraction.
Disclosure statement
The authors report there are no competing interests to declare.
Additional information
Notes on contributors
Gerard Farrell
Gerard Farrell is a PhD candidate 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.
Sizhong Wang
Sizhong Wang is as PhD candidate at the Centre for Health, Activity and Rehabilitation Research, School of Physiotherapy at the University of Otago. His research interests include manual therapy for shoulder pain and biomechanics of the lower limb.
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.
Angela Spontelli Gisselman
Dr. Angela Spontelli Gisselman is an assistant professor at Tufts University School of Medicine. 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.
Kesava Sampath
Dr. Kesava Sampath is a senior lecturer 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.
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.