Physical activity behavior in the first month after mild traumatic brain injury is associated with physiological and psychological risk factors for chronic pain

Characterizing Extreme Phenotypes for Pain Catastrophizing in Persons With Chronic Pain Following Mild to Severe Traumatic Brain Injury Requiring Inpatient Rehabilitation: A NIDILRR and VA TBI Model Systems Collaborative Project

OBJECTIVE

Define and characterize extreme phenotypes of pain catastrophizing for persons with chronic pain following mild to severe traumatic brain injury (TBI) requiring inpatient rehabilitation.

SETTING

18 TBI Model System (TBIMS) centers.

PARTICIPANTS

1762 TBIMS participants 1 to 30 years post-injury reporting chronic pain.

DESIGN

Cross-sectional, secondary analyses.

PRIMARY MEASURES

Catastrophizing, sociodemographic, injury, functional outcome, pain, and treatment characteristics.

RESULTS

Participants were male predominantly (73%), White (76%), middle-aged (mean 46.5 years), injured in motor vehicle accidents (53%) or falls (20%). Extreme phenotypes were identified based on upper and lower 25th percentiles to create low catastrophizing (N = 434) and high catastrophizing (N = 458) groups. Bivariate comparisons found significant differences (P < .001) on all measures of concurrent function and pain interference with those in the low catastrophizing phenotype experiencing better function and lower pain interference than those in the high catastrophizing phenotype. Combination Lasso and logistic regression identified multivariable predictors of phenotypes. Increased odds of high versus low catastrophizing extreme phenotypes were associated being younger (odds ratio [OR] = 1.24 for a 10-unit decrease), less than a college level of education (OR = 1.70-2.53), no military history (OR = 3.25), lower FIM motor (OR = 1.20 for a 5-unit decrease) and cognitive (OR = 1.53 for a 5-unit decrease) scores, increased pain intensity (OR = 1.22 for a 1 unit increase) and pain interference (OR = 1.93 for a 1-unit increase), neuropathic type pain (OR = 1.82-1.86), and migraine type pain versus no head pain (OR = 1.65).

CONCLUSION

High pain catastrophizing phenotypes were associated with a greater degree of pain and functional disability and higher likelihood of neuropathic pain and migraine headache. Given pain catastrophizing's contribution to pain-related disability and treatment outcomes, additional research is necessary to investigate its role in adjustment to chronic pain among individuals with TBI. Adapting evidence-based interventions for this population that specifically targets pain catastrophizing is warranted.

Revealing the Progression of Pain Pathways and Identifying Chronification of Pain Predictors After an Isolated Lateral Ankle Sprain: Project RECOIL

Persistent pain is a common complaint among civilians and military personnel after a lateral ankle sprain (LAS). Most individuals who experience pain after an LAS self-report a moderate pain intensity level that interferes with activity. This pain experience is mostly described through study designs and outcomes that limit the understanding of the acute to chronic pain transition after an LAS. The purpose of this prospective study is to quantify the prevalence rate of chronic ankle pain at 6-months post-injury and identify susceptibility and resiliency factors that contribute to pain chronification after an LAS. The objective of this study will be accomplished through a two-site prospective cohort study design with data collected at four timepoints (<7 days post-LAS, 3-, 6-, and 12-months post-LAS). A target sample size of 200 men or women (100 per site) between 18 and 45 years of age who sustain an acute LAS within the previous 7-days will be enrolled. Participants will complete a series of standardized electronic surveys at each timepoint to self-report the presence of chronic ankle pain, healthcare utilization patterns, subsequent musculoskeletal injury, and new co-morbid conditions. Additionally, participants will complete validated patient-reported outcomes (PROs) electronically to characterize the pain burden and undergo quantitative sensory testing to assess mechanical pain sensitivity via pressure pain thresholds, pain facilitation via temporal summation, and pain inhibition via a conditioned pain modulation response at all timepoints. Lastly, clinician-based outcomes will be completed at 3-, 6-, and 12-months post-LAS to examine dynamic postural control, functional performance, and walking mechanics. We hypothesize that 30% of participants will self-report chronic ankle pain at 6-months post-injury. In addition, chronic pain at 6-months will be predicted by a combination of healthcare utilization patterns, prolonged levels of peripheral sensitization and pain facilitation, and worse functional performance and PROs.

Predictors of Physical Activity One Year After Moderate to Severe Traumatic Brain Injury

OBJECTIVES

To identify predictors of moderate to vigorous physical activity (MVPA) at 12-months post-moderate-severe traumatic brain injury (TBI).

SETTING

Four inpatient rehabilitation centers.

PARTICIPANTS

Individuals enrolled in the TBI Model Systems with moderate to severe TBI, admitted to inpatient rehabilitation, and able to ambulate without physical assistance from another person.

DESIGN

Prospective longitudinal cohort study. MVPA was measured by having participants wear an ActiGraph GT3X on their wrist for 7 consecutive days.

MAIN ANALYSES

We used multivariate regression to predict minutes per week of MVPA at 12 months after TBI. Three classes of predictors were entered hierarchically-demographic and clinical variables (age, sex, body mass index, education, TBI severity, neighborhood walkability score, and self-reported preinjury physical activity [PA] level), baseline TBI-related comorbid conditions (eg, measures of sleep, pain, mood, fatigue, and cognition), and intention to exercise and exercise self-efficacy assessed approximately 1 week after discharge from inpatient rehabilitation.

RESULTS

180 participants (ages 17.7-90.3 years) were enrolled, and 102 provided at least 5 days of valid accelerometer data at 12 months. At 12 months, participants recorded an average of 703 (587) minutes per week of MVPA. In univariate and multivariate analyses, age was the only significant predictor of 12-month MVPA ( r = -0.52). A sharp decline in MVPA was observed in the tertile of participants who were over the age of 61.

CONCLUSIONS

Older adults with TBI are at elevated risk of being physically inactive. Assuming PA may enhance health after TBI, older adults are a logical target for prevention or early intervention studies. Studies with longer outcomes are needed to understand the trajectory of PA levels after TBI.

White matter microstructural changes in post-traumatic headache: A diffusion tensor imaging (DTI) study

Introduction

Post-traumatic headache (PTH) is a common consequence of mild traumatic brain injury (mTBI) that can severely impact an individual's quality of life and rehabilitation. However, the underlying neuropathogenesis mechanisms contributing to PTH are still poorly understood. This study utilized diffusion tensor imaging (DTI) to detect microstructural alterations in the brains of mTBI participants with or at risk of developing PTH.

Method

This study investigated associations between DTI metrics 1-month postinjury and pain sensitivity, as well as psychological assessments 6-months postinjury to identify differences between mTBI (n = 12) and healthy controls (HC; n = 10). MRI scans, including T1-weighted anatomical imaging and DTI were acquired at 1-month postinjury. Pain sensitivity assays included quantitative sensory testing and psychological assessment questionnaires at 1-month and 6-months postinjury.

Results

Significant aberrations of mean axial diffusivity in the forceps major were observed in mTBI relative to HCs at 1-month postinjury (p =0.02). Within the mTBI group, DTI metrics at 1-month postinjury were significantly associated (p's < 0.05) with pain-related measures and psychological outcomes at 6-month postinjury in several white matter tracts (right sagittal stratum, left anterior thalamic radiation, left corticospinal tract, left insula, left superior longitudinal fasciculus). Notably, the associations between DTI metrics at 1-month postinjury and pain-related measures at 6-month postinjury showed significant group differences in the right sagittal stratum (p's < 0.01), white matter tract in left insula (p < 0.04), and left superior longitudinal fasciculus (p's < 0.05).

Conclusion

This study suggests that "Post-Traumatic Stress Disorder for DSM-5" and "Center for Epidemiological Studies-Depression Scale" are the most sensitive psychological measures to early microstructural changes after mTBI, and that the DTI metrics are predictive of pain and psychological measures in mTBI. Together, these results suggest that white matter microstructure plays an important role in the PTH following mTBI.

Physical Activity to Prevent the Age-Related Decline of Endogenous Pain Modulation

As humans age, the capacity of the central nervous system to endogenously modulate pain significantly deteriorates, thereby increasing the risk for the development of chronic pain. Older adults are the least physically active cohort of all age groups. We hypothesize that a sedentary lifestyle and decreased physical activity may contribute to the decline of endogenous pain modulation associated with aging.

Effect of Voluntary Exercise on Endogenous Pain Control Systems and Post-traumatic Headache in Mice

Traumatic brain injury (TBI) can cause acute and chronic pain along with motor, cognitive, and emotional problems. Although the mechanisms are poorly understood, previous studies suggest disruptions in endogenous pain modulation may be involved. Voluntary exercise after a TBI has been shown to reduce some consequences of injury including cognitive impairment. We hypothesized, therefore, that voluntary exercise could augment endogenous pain control systems in a rodent model of TBI. For these studies, we used a closed-head impact procedure in male mice modeling mild TBI. We investigated the effect of voluntary exercise on TBI-induced hindpaw nociceptive sensitization, diffuse noxious inhibitory control failure, and periorbital sensitization after bright light stress, a model of post-traumatic headache. Furthermore, we investigated the effects of exercise on memory, circulating markers of brain injury, neuroinflammation, and spinal cord gene expression. We observed that exercise significantly reduced TBI-induced hindpaw allodynia and periorbital allodynia in the first week following TBI. We also showed that exercise improved the deficits associated with diffuse noxious inhibitory control and reduced bright light stress-induced allodynia up to 2 months after TBI. In addition, exercise preserved memory and reduced TBI-induced increases in spinal BDNF, CXCL1, CXCL2, and prodynorphin expression, all genes previously linked to TBI-induced nociceptive sensitization. Taken together, our observations suggest that voluntary exercise may reduce pain after TBI by reducing TBI-induced changes in nociceptive signaling and preserving endogenous pain control systems. PERSPECTIVE: This article evaluates the effects of exercise on pain-related behaviors in a preclinical model of traumatic brain injury (TBI). The findings show that exercise reduces nociceptive sensitization, loss of diffuse noxious inhibitory control, memory deficits, and spinal nociception-related gene expression after TBI. Exercise may reduce or prevent pain after TBI.