Pain Education and Virtual Reality Improves Pain, Pain-related Fear of Movement, and Trunk Kinematics in Individuals With Persistent Low Back Pain.

OBJECTIVES: To evaluate the effect of combining pain education and virtual reality (VR) exposure therapy using a cognitive-behavioral therapy-informed approach (virtual reality-based cognitive behavioral therapy [VR-CBT]) on pain intensity, fear of movement, and trunk movement in individuals with persistent low back pain. MATERIALS AND METHODS: Thirty-seven participants were recruited in a single cohort repeated measures study, attending 3 sessions 1 week apart. The VR-CBT intervention included standardized pain education (session 1) and virtual reality-based exposure therapy (VRET; session 2) incorporating gameplay with mixed reality video capture and reflective feedback of performance. Outcome measures (pain intensity, pain-related fear of movement (Tampa Scale of Kinesiophobia), and trunk kinematics during functional movements (maximum amplitude and peak velocity) were collected at baseline (session 1) and 1 week after education (session 2) and VRET (session 3). One-way repeated measures analysis of variances evaluated change in outcomes from baseline to completion. Post hoc contrasts evaluated effect sizes for the education and VR components of VR-CBT. RESULTS: Thirty-four participants completed all sessions. Significant ( P < 0.001) reductions were observed in mean (SD) pain (baseline 5.9 [1.5]; completion 4.3 [2.1]) and fear of movement (baseline 42.6 [6.4]; completion 34.3 [7.4]). Large effect sizes (Cohen d ) were observed for education (pain intensity: 0.85; fear of movement: 1.28), whereas the addition of VRET demonstrated very small insignificant effect sizes (pain intensity: 0.10; fear of movement: 0.18). Peak trunk velocity, but not amplitude, increased significantly ( P < 0.05) across trunk movement tasks. CONCLUSION: A VR-CBT intervention improved pain, pain-related fear of movement, and trunk kinematics. Further research should explore increased VR-CBT dosage and mechanisms underlying improvement.

Assessing a GPS-Based 6-Minute Walk Test for People With Persistent Pain: Validation Study.

BACKGROUND: The 6-minute walk test (6MWT) is a commonly used method to assess the exercise capacity of people with many health conditions, including persistent pain. However, it is conventionally performed with in-person supervision in a hospital or clinic, therefore requiring staff resources. It may also be difficult when in-person supervision is unavailable, such as during the COVID-19 pandemic, or when the person is geographically remote. A potential solution to these issues could be to use GPS to measure walking distance. OBJECTIVE: The primary aim of this study was to assess the validity of a GPS-based smartphone app to measure walking distance as an alternative to the conventional 6MWT in a population with persistent pain. The secondary aim of this study was to estimate the difference between the pain evoked by the 2 test methods. METHODS: People with persistent pain (N=36) were recruited to complete a conventional 6MWT on a 30-m shuttle track and a 6MWT assessed by a smartphone app using GPS, performed on outdoor walking circuits. Tests were performed in random order, separated by a 15-minute rest. The 95% limits of agreement were calculated using the Bland-Altman method, with a specified maximum allowable difference of 100 m. Pain was assessed using an 11-point numerical rating scale before and after each walk test. RESULTS: The mean 6-minute walk distance measured by the GPS-based smartphone app was 13.2 (SD 46; 95% CI -2.7 to 29.1) m higher than that assessed in the conventional manner. The 95% limits of agreement were 103.9 (95% CI 87.4-134.1) m and -77.6 (95% CI -107.7 to -61) m, which exceeded the maximum allowable difference. Pain increased in the conventional walk test by 1.1 (SD 1.0) points, whereas pain increased in the app test by 0.8 (SD 1.4) points. CONCLUSIONS: In individuals with persistent pain, the 2 methods of assessing the 6MWT may not be interchangeable due to limited validity. Potential reasons for the differences between the 2 methods might be attributed to the variation in track layout (shuttle track vs continuous circuit); poor GPS accuracy; deviations from the 30-m shuttle track; human variability in walking speed; and the potential impact of a first test on the second test due to fatigue, pain provocation, or a learning effect. Future research is needed to improve the accuracy of the GPS-based approach. Despite its limitations, the GPS-based 6MWT may still have value as a tool for remote monitoring that could allow individuals with persistent pain to self-administer frequent assessments of their functional capacity in their home environment.

Chemically cross-linked hydrogels from repetitive protein arrays.

Biomaterials for tissue regeneration must mimic the biophysical properties of the native physiological environment. A protein engineering approach allows the generation of protein hydrogels with specific and customised biophysical properties designed to suit a particular physiological environment. Herein, repetitive engineered proteins were successfully designed to form covalent molecular networks with defined physical characteristics able to sustain cell phenotype. Our hydrogel design was made possible by the incorporation of the SpyTag (ST) peptide and multiple repetitive units of the SpyCatcher (SC) protein that spontaneously formed covalent crosslinks upon mixing. Changing the ratios of the protein building blocks (ST:SC), allowed the viscoelastic properties and gelation speeds of the hydrogels to be altered and controlled. The physical properties of the hydrogels could readily be altered further to suit different environments by tuning the key features in the repetitive protein sequence. The resulting hydrogels were designed with a view to allow cell attachment and encapsulation of liver derived cells. Biocompatibility of the hydrogels was assayed using a HepG2 cell line constitutively expressing GFP. The cells remained viable and continued to express GFP whilst attached or encapsulated within the hydrogel. Our results demonstrate how this genetically encoded approach using repetitive proteins could be applied to bridge engineering biology with nanotechnology creating a level of biomaterial customisation previously inaccessible.

People at a persistent pain service can walk it, but some struggle to talk about it: Reliability, detectable difference and clinically important difference of the six-minute walk test.

OBJECTIVES: The six-minute walk test (6MWT) is a commonly used measure of functional capacity. This study is the first to investigate the test-retest reliability, minimal detectable difference (MDD) and the minimal clinically important difference (MCID) for people attending a persistent pain service. Relationships between change in 6MWT performance and change in self-reported physical, functional and psychological outcome measures were also explored. METHODS: A cross-sectional repeated measures design was used with people having >9 months of pain attending an 8-week outpatient persistent pain programme. For reliability and MDD, 27 people were recruited, for MCID calculations, 32 people were recruited. The MCID was examined by dichotomising people into "improvers", or "non-improvers" based upon the Global Rating of Change (GRC) in physical abilities score. RESULTS: The mean (SD) 6MWT distance was 389.4 (93.6) m at programme start, and 427.8 (83.0) m at week eight completion. The test-retest reliability was good (intraclass correlation coefficient = 0.89) and the MDD = 86.1 m. As there was no relationship between change in 6MWT distance and GRC physical abilities at week eight (r = 0.132, p = 0.472) the MCID could not be calculated. Furthermore, no relationships were found between change in 6MWT distance and other self-reported measures. Changes in GRC physical abilities and 6MWT were frequently discordant, with increased 6MWT for 7/11 "GRC non-improvers" and decreased 6MWT for 7/21 "GRC improvers". CONCLUSIONS: Amongst this cohort, change in physical ability may or may not be reflected by self-reported change. Objective tests of physical ability are recommended for people attending pain services, and validated tests should align with intervention aims.

INVESTIGATE-I (INVasive Evaluation before Surgical Treatment of Incontinence Gives Added Therapeutic Effect?): study protocol for a mixed methods study to assess the feasibility of a future randomised controlled trial of the clinical utility of invasive urodynamic testing.

BACKGROUND: Urinary incontinence is an important health problem to the individual sufferer and to health services. Stress and stress predominant mixed urinary incontinence are increasingly managed by surgery due to advances in surgical techniques. Despite the lack of evidence for its clinical utility, most clinicians undertake invasive urodynamic testing (IUT) to confirm a functional diagnosis of urodynamic stress incontinence before offering surgery for this condition. IUT is expensive, embarrassing and uncomfortable for women and carries a small risk. Recent systematic reviews have confirmed the lack of high quality evidence of effectiveness.The aim of this pilot study is to test the feasibility of a future definitive randomised control trial that would address whether IUT alters treatment decisions and treatment outcome in these women and would test its clinical and cost effectiveness. METHODS/DESIGN: This is a mixed methods pragmatic multicentre feasibility pilot study with four components:-(a) A multicentre, external pilot randomised trial comparing basic clinical assessment with non-invasive tests and IUT. The outcome measures are rates of recruitment, randomisation and data completion. Data will be used to estimate sample size necessary for the definitive trial.(b) Qualitative interviews of a purposively sampled sub-set of women eligible for the pilot trial will explore willingness to participate, be randomised and their overall trial experience.(c) A national survey of clinicians to determine their views of IUT in this context, the main outcome being their willingness to randomise patients into the definitive trial.(d) Qualitative interviews of a purposively sampled group of these clinicians will explore whether and how they use IUT to inform their decisions. DISCUSSION: The pilot trial will provide evidence of feasibility and acceptability and therefore inform the decision whether to proceed to the definitive trial. Results will inform the design and conduct of the definitive trial and ensure its effectiveness in achieving its research aim. TRIAL REGISTRATION NUMBER: Current Controlled Trials ISRCTN71327395 assigned 7th June 2010.