Observing neck movements evokes an excitatory response in the sympathetic nervous system associated with fear of movement in patients with chronic neck pain

Psychophysiological responses to a multimodal physiotherapy program in fighter pilots with flight-related neck pain: A pilot trial

BACKGROUND

The physical and cognitive demands of combat flying may influence the development and persistence of flight-related neck pain (FRNP). The aim of this pilot study was to analyse the effect of a multimodal physiotherapy program which combined supervised exercise with laser-guided feedback and interferential current therapy on psychophysiological variables in fighter pilots with FRNP.

METHODS

Thirty-one fighter pilots were randomly assigned to two groups (Intervention Group: n = 14; Control Group: n = 17). The intervention consisted of 8 treatment sessions (twice per week) delivered over 4 weeks. The following primary outcomes were assessed: perceived pain intensity (Numeric Pain Rating Scale-NPRS) and Heart Rate Variability (HRV; time-domain, frequency-domain and non-linear variables). A number of secondary outcomes were also assessed: myoelectric activity of the upper trapezius and sternocleidomastoid, pain catastrophizing (Pain Catastrophizing Scale-PCS) and kinesiophobia (TSK-11).

RESULTS

Statistically significant differences (p≤0.05) within and between groups were observed for all outcomes except for frequency domain and non-linear HRV variables. A significant time*group effect (one-way ANOVA) in favour of the intervention group was found for all variables (p<0.001). Effect sizes were large (d≥0.6).

CONCLUSIONS

The use of a multimodal physiotherapy program consisting of supervised exercise with laser-guided feedback and interferential current appears to show clinical benefit in fighter pilots with FRNP.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT05541848.

A single session of action observation therapy versus observing a natural landscape in adults with chronic neck pain - a randomized controlled trial

BACKGROUND

Action observation (AO) has emerged as a potential neurorehabilitation therapy for patients with neck pain (NP), but evidence of its effectiveness is scarce. This study aims to assess the effect of a single session of AO when compared to observing a natural landscape on NP intensity, fear of movement, fear-avoidance beliefs, neck muscles' strength, pressure pain threshold, and tactile acuity.

METHODS

Sixty participants with NP were randomly allocated to the AO group (n = 30) or control group (n = 30). Both groups watched an 11-minute video: the AO group watched a video of a person matched for age and sex performing neck exercises, while the control group watched a video of natural landscapes. Neck pain intensity, fear of movement, fear-avoidance beliefs, tactile acuity, pressure pain thresholds, and neck muscle strength were assessed both at baseline and post-intervention. General linear models of repeated measures (ANCOVA of two factors) were used to explore between-group differences at post-intervention.

RESULTS

There was a significant main effect of time for pain intensity (p = 0.02; η2p = 0.09; within-group mean change and 95% CI: AO=-1.44 (-2.28, -0.59); control=-1.90 (-2.74, -1.06), but no time versus group interaction (p = 0.46). A time versus group significant interaction was found for one out of the six measurement sites of two-point discrimination and the neck flexors strength (p < 0.05) favoring the control group. No other statistically significant differences were found for the remaining variables).

CONCLUSIONS

Results suggest a similar acute benefit for both a single session of AO and observing natural landscapes for promoting hypoalgesia, but no impact on kinesiophobia, fear-avoidance beliefs, or pressure pain thresholds. Also, AO had no positive effect on two-point discrimination and muscle strength. Further research is needed, with longer interventions.

TRIAL REGISTRATION

Clinialtrials.gov (NCT05078489).

Implicit Motor Imagery for Chronic Pelvic Pain: A Cross-Sectional Case-Control Study

Implicit motor imagery (IMI), with an image laterality discrimination (LD) task, has been proposed as a useful therapeutic tool to restore body schema in patients with chronic pelvic pain (CPP). The aim of this study was to analyse the existence of differences between patients with CPP and healthy individuals in order to justify the use of IMI. An observational, cross-sectional study with non-probabilistic sampling was designed as a one-to-one matched case-control study. Through a web link designed for this purpose, a total of 40 abdominoperineal images were shown to 130 participants during the laterality task. Outcome measures were pain intensity (visual analogue scale, VAS), accuracy, response time (RT), and CPPQ-Mohedo score (Chronic Pelvic Pain Questionnaire-Mohedo). This was an observational, cross-sectional study with a total of 64 CPP patients and 66 healthy individuals. The comparative analysis between groups revealed significant differences in accuracy, CPPQ-Mohedo and VAS (p < 0.001), but not in RT; in patients with CPP, accuracy was correlated with a lower CPPQ-Mohedo score and RT and, the greater the pain intensity, the higher the CPPQ-Mohedo score and RT, and the lower the accuracy. In the LD task, the patients with CPP made more mistakes than the healthy individuals. IMI could be a useful and complementary tool in the therapeutic approach for patients with CPP.

Effects of mental practice on pain, functionality, and quality of life in individuals with chronic neck pain: A systematic review

PURPOSE

There are conflicting reports in the literature regarding the effectiveness of motor imagery (MI) and action observation (AO) in individuals with chronic non-specific neck pain (CNSNP). This study sought to systematically investigate whether mental practice has any impact on pain, functionality and quality-of-life in individuals with CNSNP.

METHODS

This is a systematic review. Randomized controlled trials (RCTs) that explored the effects of mental practice on pain, functionality and quality-of-life in individuals with CNSNP were searched using databases PubMed, Cochrane library, Medline via Ovid, Scopus, and PEDro from inception to July 2022. Two reviewers independently extracted data and evaluated the quality of the studies utilizing the PEDro scale.

RESULTS

Six high-quality RCTs with 128 participants with CNSNP in the MI and AO groups, and 93 participants with CNSNP in the control group, were included in this review. Both AO and MI were effective in improving pain response and cervical joint position sense. However, AO was more efficient than MI and its effects were retained longer. Improvements in the visual analogue scale and neck disability index were retained when MI training lasted for 6 weeks. The pain and general health sub-parameters of the short form-36 health survey improved after MI training.

CONCLUSION

Mental practice, particularly AO, can improve neck pain intensity, joint position sense, functional disability, and some aspects of quality-of-life in individuals with CNSNP. These improvements dissipated over time. Although mental practice can be an alternative to exercise when pain exists, it can be more efficient when prescribed with simple movements and exercises.

REGISTRATION

The protocol of this review was registered with PROSPERO (CRD42022330240) Available from: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022330240.

Heart Rate Variability and Pain Sensitivity in Chronic Low Back Pain Patients Exposed to Passive Viewing of Photographs of Daily Activities

OBJECTIVE

Investigation if emotional reactivity by measuring heart rate variability (HRV) and pressure pain sensitivity during a passive visualization task in participants with chronic low back pain (CLBP).

MATERIALS AND METHODS

This case-control study was composed of 47 participants with CLBP and 47 asymptomatic participants. Both groups were submitted to a passive visualization task using 27 pictures from PHODA (Photograph Series of Daily Activities). HRV frequency domains were measured before, during, and after the task. Pressure pain threshold and pain intensity were also measured before and after the task.

RESULTS

The adjusted mean difference was statistically significant for HRV frequency domains during the visualization task, including low frequency [-5.92; 95% confidence interval (CI)=-9.60 to -2.23], high frequency (-0.71; 95% CI=-1.02 to -0.39), and low-frequency/high-frequency ratio (8.82; 95% CI=5.19 to 12.45). Pressure pain threshold decreased after the task in the CLBP group in all body sites, and pain intensity increased (-0.8; 95% CI=-1.16 to -0.39).

DISCUSSION

Aversive environmental stimuli, such as visual cues, may generate defensive physiological reactions. HRV can provide a measure that reflects the perceptions of threat and safety in the environment. Participants with CLBP presented changes in sympathovagal balance during passive visualization of pictures of daily activities, higher pain sensitivity, and high pain intensity when they were exposed to a passive visualization task using pictures of daily living that may arouse fears of harm.

Effect of adding motor imagery training to neck stabilization exercises on pain, disability and kinesiophobia in patients with chronic neck pain

PURPOSE

The investigation of this study was to compare the effect of adding motor imagery training to neck stabilization exercises on pain, disability, and kinesiophobia in patients with chronic neck pain.

MATERIAL AND METHODS

After screening, seventy-two volunteers with chronic neck pain were randomly allocated to 3 groups: neck stabilization exercises alone, n = 24, combined ( neck stabilization exercises + motor imagery training), n = 24, and a control group, n = 24. Pain intensity, disability, and kinesiophobia before and after the intervention exercises were measured by the Visual Analog Scale, Neck Disability Index, and the Tampa Scale of Kinesiophobia , respectively.

RESULTS

Statistically significant differences in pain intensity, the neck disability index, and kinesiophobia were found when a combined intervention group including neck stabilization and motor imagery training was compared with neck stabilization training alone at 6 weeks ) p ≤ 0.005). Also, there were significant between-group differences favoring experimental groups versus control for all outcomes (p ≤ 0.001).

CONCLUSION

neck stabilization exercises in combination with motor imagery training was superior to neck stabilization exercises alone in decreasing pain, disability, and kinesiophobia in patients with chronic neck pain.

Comparative analysis of the autonomic nervous system response during movement representation in healthy individuals and patients with chronic low back pain: a prospective cohort study

OBJECTIVE

The primary objective was to compare the difference in autonomic nervous system (ANS) response between motor imagery (MI) group and action observation (AO) group. Both consisted of two subgroups: the control subgroup (CG), which consisted of asymptomatic individuals, and the patient subgroup (PG), which consisted of patients with chronic low back pain (CLBP). The secondary objective was to assess ANS activity during AO and MI training according to the fear-of-movement levels of the PGs.

METHODS

Sixty participants were randomly assigned. The autonomic outcome measures included skin conductance (SC), respiration rate (RR), and heart rate (HR).

RESULTS

Results showed that intergroup differences in RR were higher in the PG, with a large effect size (p = .007, d = 1.71). Only the PGs showed intragroup differences in SC (p <.05). In terms of ANS activity during the training, there were no statistically significant intergroup differences (p <.05). However, the strongest intragroup differences were among the AO_PG with greater levels of kinesiophobia. For the SC and HR variables, only this condition showed significant differences between baseline and the first and second movements, with a large effect size (p <.001 and p = .002, respectively, and d >.80).

CONCLUSIONS

The results showed that AO and MI training in the PG and CG resulted in similar but not identical ANS activation, with slightly higher activation in the PG. The differences in the PG could be associated with kinesiophobia when visually exposed to low-back movements that could be interpreted as hazardous or unsafe.

Effectiveness of Hydrogalvanic Bath on Improving Pain, Disability, and Quality of Life in Individuals with Chronic Nonspecific Neck Pain: A Randomized Controlled Trial

Background

Neck pain is one of the world's leading factors in years lived with disability. Ambiguity in the effect of electrotherapy modalities for the treatment of chronic nonspecific neck pains (CNSNP) needs to be examined further. This study sought to elucidate the effectiveness of hydrogalvanic bath on improving pain, disability, and quality of life among individuals with CNSNP.

Methods

Thirty-four individuals with a diagnosis of CNSNP were selected through convenient sampling and randomly divided into two groups by block randomization. The control group treatment underwent low Transcutaneous Electrical Nerve Stimulation (TENS) and exercise, and the experimental group was subjected to hydrogalvanic bath therapy (HGBT) and exercise. Individuals were evaluated for pain using a visual analog scale (VAS), disability with the Neck Disability Index (NDI), and quality of life with Short Form-36 (SF-36). These measures were applied at baseline and after 12 weeks of treatment.

Results

The pretreatment and posttreatment results for VAS, NDI, and SF-36 were compared for both control and experimental groups. We found that all the three variables showed significant differences between the two time points with p < 0.05 in both the groups but the experimental group improvements were more significant than the control group with p < 0.05.

Conclusion

Twelve weeks of low TENS or HGBT along with exercises can decrease pain and neck disability and increase the quality of life in individuals with CNSNP. However, HGBT along with exercise has superior effects relative to low TENS along with exercise. This randomized controlled trial was registered in the International Standard Randomized Controlled Trials Number-ISRCTN29695190 and registered on 05/02/2020. This study is a retrospective registration.

Hypoalgesic Effects of Aerobic and Isometric Motor Imagery and Action Observation Exercises on Asymptomatic Participants: A Randomized Controlled Pilot Trial

OBJECTIVES

The objective was to explore whether action observation (AO) and motor imagery (MI) of aerobic and isometric exercise could induce hypoalgesic responses in asymptomatic individuals compared with placebo observation (PO).

METHODS

A randomized controlled pilot trial was designed. Twenty-four healthy participants (mean age = 21.9 ± 2.1 years) were randomized into three groups: AO+MI (N = 8), AO, (N = 8), and PO (N = 8). All participants performed an actual aerobic running exercise (three series of 90 seconds at 85% of their VO2max and 30 seconds at 65% of their VO2max) and an isometric exercise protocol (isometric squats). A day later, they all performed the mental intervention, observing or imagining exercise execution performed the day before, according to their allocated group. Pressure pain thresholds (PPTs) of the quadriceps and epicondyle regions were assessed at baseline, postintervention, and 15 minutes postintervention.

RESULTS

Analysis of variance revealed statistically significant differences in the group*time interaction for PPT in the quadriceps. The AO group showed a statistically significant increase at postintervention and at 15 minutes postintervention. The AO+MI group obtained a statistically significant increase in the two PPT regions compared with the PO group at Δpre-post. The AO group obtained a greater increase in the PPT in the quadriceps femoris than the PO group at Δpre-post and Δpre-post 15 minutes.

CONCLUSIONS

AO and MI induce hypoalgesic responses compared with PO. AO isolated training showed pain modulation responses in the PPTs of the quadriceps region in young physically active adults. These findings highlight the potential role of brain training in pain management.

Action observation as a treatment option for fear avoidance behavior in chronic spinal pain

Psychological factors play an essential role in the maintenance of various chronic pain states, with fear avoidance beliefs contributing to significant functional limitation and disability in chronic spinal pain. Fear avoidance behaviors are typically managed with cognitive-behavioral interventions such as graded exposure to feared movements and graded activity programs. However, attempts to make patients with high pain-related fear perform painful actions using graded exposure therapy can be very challenging. These fear avoidance beliefs in individuals with pain are usually acquired through previous pain experiences, observation, and threating verbal input from others that movement is harmful to the spinal structures. Observational learning of fear has been recently demonstrated in several experimental studies, where participants acquired fear of pain after observing the distressed painful expressions of the volunteers performing a painful cold pressor task. The primary purpose of this paper is to propose action observation, a cognitive rehabilitation technique, as one of the treatment options for reducing fear avoidance behavior in chronic spinal pain. Action observation involves the visualization of others performing a movement or an action to influence motor behavior positively and is mainly used in stroke rehabilitation. The paper hypothesizes that the pain-related fear of movement may be reduced through observation of others performing threatening movements successfully without displaying pain or discomfort. Action observation of others successfully executing a strenuous task may break the preexisting cognitive association between movement and pain among patients with high pain-related fear. Other possible mechanisms through which observation may influence pain-related fear could be the activation of mirror neuron systems and subsequent modulation of nociceptive information through the interconnections between the amygdala (one of the brain centers for fear), descending pain modulatory system and higher cortical centers. Few initial studies that investigated the effects of action observation on other outcomes of pain, such as pain severity are described to review the hypothesis. Considering the influence of observational learning on pain-related fear, action observation may be explored as potential adjunctive treatment to reduce fear avoidance behavior in chronic spinal pain.

Mental practice in isolation improves cervical joint position sense in patients with chronic neck pain: a randomized single-blind placebo trial

Objective

The main objective of this trial was to assess whether action observation (AO) training and motor imagery (MI) produced changes in the cervical joint position sense (CJPS) both at the end of the intervention and 10 min postintervention compared with a placebo intervention in patients with nonspecific chronic neck pain (NSCNP).

Methods

A single-blind placebo clinical trial was designed. A total of 30 patients with NSCNP were randomly assigned to the AO group, MI group or placebo observation (PO) group. CJPS in flexion, extension and rotation movements in both planes were the main variables.

Results

The results obtained in the vertical plane showed that the AO group obtained greater improvements than the PO group in the CJPS in terms of cervical extension movement both at the end of the intervention and 10 min postintervention (p = .001, d = 1.81 and p = .004, d = 1.74, respectively), and also in cervical flexion movement, although only at 10 min after the intervention (p = .035, d = 0.72). In addition, the AO group obtained greater improvements than the MI group in the CJPS only at the end of the intervention in cervical extension movement (p = .041, d = 1.17). Regarding the left rotation cervical movement, both the MI and AO groups were superior to the PO group in both planes at the end of the intervention (p < .05, d > 0.80).

Conclusions

Although both AO and MI could be a useful strategy for CJPS improvement, the AO group showed the strongest results. The therapeutic potential of the application of mental practice in a clinical context in the early stages of rehabilitation of NSCNP should be considered.

Motor Imagery and Action Observation of Specific Neck Therapeutic Exercises Induced Hypoalgesia in Patients with Chronic Neck Pain: A Randomized Single-Blind Placebo Trial

The aim of the present study was to explore the pain modulation effects of motor imagery (MI) and action observation (AO) of specific neck therapeutic exercises both locally, in the cervical region, and remotely. A single-blind, placebo clinical trial was designed. A total of 30 patients with chronic neck pain (CNP) were randomly assigned to an AO group, MI group, or placebo observation (PO) group. Pain pressure thresholds (PPTs) of C2/C3, trapezius muscles, and epicondyle were the main outcome variables. Secondary outcomes included heart rate measurement. Statistically significant differences were observed in PPTs of the cervical region in the AO and MI groups between the preintervention and first postintervention assessment. Significant differences were found in the AO group in the epicondyle between the preintervention, first and second post-intervention assessments. Regarding heart rate response, differences were found in the AO and MI groups between the preintervention and average intervention measurements. AO and MI induce immediate pain modulation in the cervical region and AO also induces remote hypoalgesia. OA appears to lead to greater pain modulation as well as a greater heart rate response, however, both should be clinically considered in patients with CNP.