Changes in Pain Sensitivity and Conditioned Pain Modulation During Recovery from Whiplash Associated Disorders

Numerous studies demonstrate elevated pain sensitivity and impaired conditioned pain modulation (CPM) in patients with chronic musculoskeletal pain compared to healthy individuals; however, the time course of changes in pain sensitivity and CPM after the development of a chronic pain condition is unclear. Secondary analysis of data from a prospective investigation examined changes in evoked pain sensitivity and CPM before and after development of chronic neck pain (CNP). 171 healthy office workers participated in a baseline assessment, followed by monthly online questionnaires to identify those who developed CNP over the subsequent year. These individuals (N=17) and a cohort of participants (N=10) who remained pain-free during the follow-up period returned for a 12-month follow-up assessment of mechanical and thermal pain sensitivity and CPM. Pain sensitivity measures did not differ between groups at baseline; however, cold pain threshold decreased in the CNP group at follow-up (p<0.05). CPM was lower at baseline in the CNP group compared to those who reported no neck pain (p<0.02) and remained unchanged one year later. These findings indicate that CPM is reduced in healthy individuals prior to the development of chronic neck pain and the subsequent reduction of thresholds for cold but not pressure pain.

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Autonomic Response to Pain in Patients with Chronic Whiplash Associated Disorders

January 2018 - Pain Physician ◽

10.36076/ppj.2013/16/e277 ◽

2013 ◽

Vol 3;16 (3;5) ◽

pp. E277-E285

Author(s):

Jo Nijs

Keyword(s):

Nervous System ◽

Autonomic Nervous System ◽

Pain Modulation ◽

Autonomic Response ◽

Conditioned Pain Modulation ◽

Healthy Controls ◽

Autonomic Nervous ◽

Whiplash Associated Disorders ◽

Chronic Whiplash ◽

Endogenous Analgesia

Background: Patients with chronic whiplash associated disorders (WAD) demonstrate altered central pain processing and impaired endogenous analgesia. In addition, previous research reported disturbances in the autonomic nervous system and the presence of post-traumatic stress reaction in patients with chronic WAD. The autonomic nervous system, in particular the autonomic stress response, might modulate central pain processing in this population. Objectives: The goal of this study was to compare the autonomic response to acute painful stimuli in patients with chronic WAD and healthy controls and to look for associations between endogenous analgesia and autonomic parameters. Study design: Case-control study. Methods: Thirty patients with chronic WAD and 31 healthy controls were subjected to an experiment evaluating the autonomic nervous system at rest and during experimental painful stimuli. Skin conductance, heart rate, and heart rate variability parameters were monitored continuously during the evaluation of conditioned pain modulation. The paradigm of heterotopic noxious conditioning stimulation was used to assess this conditioned pain modulation effect. Results: The data revealed no difference in autonomic response to pain between chronic WAD and healthy controls. The autonomic response was unrelated to pressure pain thresholds or the effect of conditioned pain modulation in either group. Limitations: The present study only investigates the autonomic response to a stress caused by pain. Conclusion: Results of this study refute autonomic dysfunction in response to pain in patients with chronic WAD. The autonomic nervous system activity or reactivity to acute pain appears unrelated to either pain thresholds or endogenous analgesia in patients with chronic WAD. Key words: chronic whiplash associated disorders, central sensitization, pain modulation; posttraumatic stress disorder ,sympathetic, heart rate variability

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Conditioned Pain Modulation in Women With Irritable Bowel Syndrome

Biological Research For Nursing ◽

10.1177/1099800413520486 ◽

2014 ◽

Vol 16 (4) ◽

pp. 368-377 ◽

Cited By ~ 14

Author(s):

Monica E. Jarrett ◽

Robert J. Shulman ◽

Kevin C. Cain ◽

Wimon Deechakawan ◽

Lynne T. Smith ◽

...

Keyword(s):

Irritable Bowel Syndrome ◽

Psychological Distress ◽

Salivary Cortisol ◽

Pain Sensitivity ◽

Pain Modulation ◽

Conditioned Pain Modulation ◽

Somatic Pain ◽

Before And After ◽

Cortisol Levels ◽

Irritable Bowel

Evidence suggests that patients with irritable bowel syndrome (IBS) are more vigilant to pain-associated stimuli. The aims of this study were to compare women with IBS ( n = 20) to healthy control (HC, n = 20) women on pain sensitivity, conditioned pain modulation (CPM) efficiency, and salivary cortisol levels before and after the CPM test and to examine the relationship of CPM efficiency with gastrointestinal pain, somatic pain, psychological distress symptoms, and salivary cortisol levels in each group. Women, aged 20–42 years, gave consent, completed questionnaires, and kept a symptom diary for 2 weeks. CPM efficiency was tested with a heat test stimulus and cold water condition stimulus in a laboratory between 8 and 10 a.m. on a follicular phase day. Salivary cortisol samples were collected just before and after the experimental testing. Compared to the HC group, women with IBS reported more days with gastrointestinal and somatic pain/discomfort, psychological distress, fatigue, and feeling stressed. During the CPM baseline testing, women with IBS reported greater pain sensitivity compared to the HC group. There was no significant group difference in salivary cortisol levels nor in CPM efficiency, though a post-hoc analysis showed a higher prevalence of impaired CPM efficiency among IBS subjects with more severe lower-GI symptoms. In the IBS group, reduced CPM efficiency was associated with daily abdominal pain/discomfort and psychological distress. Overall, women with IBS exhibited an increased sensitivity to thermal stimuli. Impaired CPM was present in a subset of women with IBS.

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