Investigating the Causal Mechanisms of Symptom Recovery in Chronic Whiplash-associated Disorders Using Bayesian Networks

Abstract

Objectives: The present study's objective is to understand the causal mechanisms underpinning the recovery of individuals with whiplash-associated disorders (WAD). We applied Bayesian Networks (BN) to answer two study aims: 1) to identify the causal mechanism(s) of recovery underpinning neck-specific exercise, and 2) quantify if the cyclical pathway of the fear avoidance model (FAM) is supported by the present data. Methods: We analysed a prospective cohort dataset of 216 individuals with chronic WAD. Fifteen variables were used to build a BN model: treatment group (neck-specific exercise with or without a behavioural approach, or general physical activity), muscle endurance, range of motion, hand strength, neck proprioception, pain catastrophizing, fear, anxiety, depression, self-efficacy, perceived work ability, disability, pain intensity, sex, and follow-up time. Results: The BN model showed that neck pain reduction rate was greater after neck-specific exercise compared to physical activity prescription (β = 0.59 points/month [P < 0.001]) only in the presence of two mediators: global neck muscle endurance and perceived work ability. We also found the following pathway of variables that constituted the FAM: anxiety, followed by depressive symptoms, fear, catastrophizing, self-efficacy, and consequently pain Conclusion: We uncovered two mediators which explained the mechanisms of effect behind neck-specific exercise, and proposed an alternative FAM pathway. The present study is the first to apply BN modelling to understand the causal mechanisms of recovery in WAD. In doing so, it is anticipated that such analytical methods could increase the precision of treatment in individuals with chronic WAD.

Mechanisms of recovery after neck‐specific or general exercises in patients with cervical radiculopathy

“…Abbreviation: Suffix with "_3", variables at 3rd month follow-up; Suffix with "_6", variables at 6th month follow-up; Suffix with "_12", variables at 12th month follow-up; Anx, Hospital Anxiety and Depression Scale, anxiety sub-score; Dep, Hospital Anxiety and Depression Scale, depression sub-score; SES, self-efficacy scale score; PCS, pain catastrophizing scale score; NDI, neck disability index; NST, Neck-Specific Training; PPA, Prescribed Physical Activity In contrast to the present finding, a study on chronic whiplash associated disorders (WAD) using BNs reported that selfefficacy partially mediated the greater effect a neck-specific training had on neck pain intensity compared to a general physical activity program (Liew et al, 2019). The different findings between the present study and Liew et al (2019) occurred despite both studies incorporating similar cognitive behavioural components into the neck-specific training programs (Dedering et al, 2014;Peolsson et al, 2014). This suggests that the same training program may have different mechanism of action in different musculoskeletal disorders affecting the same spinal region.…”

“…There is some evidence that changes in self-efficacy is a mechanism by which ACT positively influenced the outcome of disability in a heterogeneous cohort of individuals with musculoskeletal pain disorders (Craner et al, 2020), although it is inconsistent (Wicksell et al, 2010). Independent studies from a heterogeneous group of individuals with musculoskeletal pain disorders have identified self-efficacy as an important mechanism driving recovery (Fordham et al, 2017;Liew et al, ,2019Liew et al, , , 2020Mansell et al, 2016;O'Neill et al, 2020;Sherman et al, 2013). Given its importance, it may be prudent to speculate on the reasons underpinning the importance of self-efficacy as a mediator.…”

“…To date, no studies to our knowledge have investigated the mechanism(s) of action (if any) which different exercise programs act upon to improve recovery in individuals with CR. In other spinal musculoskeletal pain disorders, different exercise programs have been shown to reduce pain-related disability by influencing catastrophizing (Hall et al, 2016;Smeets et al, 2006) and self-efficacy levels (Liew et al, 2019;O'Neill et al, 2020;Sherman et al, 2013).…”

How does individualised physiotherapy work for people with low back pain? A Bayesian Network analysis using randomised controlled trial data

“…BN may therefore reveal new relationships that have not been previously hypothesised. BN have previously been used to determine recovery pathways for some musculoskeletal disorders including whiplash [ 22 ] and postoperative cervical radiculopathy [ 23 ], but not for individuals with LBP.…”

Randomized controlled trial of exercise interventions for chronic whiplash-associated disorders: One-year follow-up of the effect on neck muscle endurance, active cervical range of motion and grip strength.

“…Self-reported pain and neck-related disability which affect personal care, lifting, reading, work, driving, and recreation can predict recovery after whiplash injury (12), but the relations between physical capacity and neck pain and disability are inconclusive (13,14). Improved neck muscle endurance was an important factor in decreasing neck pain in WAD (15). Decreased cervical range of motion can affect daily activities, for example can skill driving be restricted by less than 40° cervical rotation (16).…”