Agency over Phantom Limb Enhanced by Short-Term Mirror Therapy

Examining heterogeneity and reporting of mirror therapy intervention for phantom limb pain: A scoping review

BACKGROUND

Mirror therapy shows promise in the treatment of phantom limb pain but lacks robust evidence.

OBJECTIVES

To address this gap, we conducted a scoping review aiming to comprehensively explore the landscape of mirror therapy practice, gather details about the session content, and offer recommendations for future research.

METHOD

We searched seven databases for published work from 1995 to May 2023. Two independent reviewers selected, assessed, and extracted data from eligible articles. Articles, regardless of study design, were considered eligible if they investigated mirror therapy as an intervention for phantom limb pain.

RESULTS

A total of 44 articles were included, comprising 16 randomized control trials, 14 prospective cohort studies, 15 case reports, and 3 protocols. These studies collectively involved 942 patients, with male patients representing 70 % of the participants. Lower limb amputation, primarily attributed to trauma, accounted for 88 % of the included patients. Pain intensity was predominantly assessed by a visual analog scale (61 %). However, there was a notable absence of detailed descriptions regarding mirror therapy sessions, particularly concerning the number of exercises, duration per exercise, and repetitions. Typically, sessions lasted 15 min each, conducted once daily. The exercises primarily focused on motor exercises targeting the distal part of the limb.

CONCLUSION

The practice of mirror therapy was characterized by poor description, showed significant heterogeneity, and a lack of standardized protocols, which contributes to an overall low level of evidence. Addressing these gaps in practice description and standardization is crucial for improving reproducibility and strengthening the evidence base for the prescription of mirror therapy.

The effects of the mirror therapy on shoulder function in patients with breast cancer following surgery: a randomized controlled trial

PURPOSE

Shoulder dysfunction is one of the most bothersome questions for breast cancer survivors. Studies show that mirror therapy can improve shoulder function in patients with a limited shoulder range of motion and shoulder pain. Here, this article reports the results of a randomized controlled trial investigating the effects of the mirror therapy on shoulder function in patients with breast cancer following surgical treatments.

METHODS

Totally, 79 participants were divided to two groups receiving active range-of-motion upper limb exercise based on the mirror therapy or active range-of-motion upper limb exercise respectively for 8 weeks. Shoulder range of motion, Constant-Murley Score, Disabilities of Arm, Shoulder, and Hand Questionnaire, Tampa Scale of Kinesiophobia, Visual analog scale, and grip strength were measured at baseline (T0), 2 weeks (T1), 4 weeks (T2), and 8 weeks (T3). The effects of the intervention on shoulder function were analyzed in generalized estimation equation, from group, time, and the interactions between group and time based on the data from participants who completed at least one post-baseline observation RESULTS: At least one post-baseline observation was performed by 69 participants (n=34 mirror group, n=35 control group). 28(82.35%) participants in the mirror group adhered to the exercise compared to 30(85.71%) in the control group. Generalized estimation equation model showed group had main effects on forward flexion (Waldχ²=6.476, P=0.011), with the Cohen's d=0.54. The effects of the group on abduction, Constant-Murley Score, and Disabilities of Arm, Shoulder, and Hand Questionnaire were significant when fix the effects of the time. At 8 weeks, participants in the mirror group showed an improvement in abduction compared to the control group (P=0.005), the Cohen's d was 0.70. At 8 weeks, participants in the mirror group had a higher Constant-Murley Score than control group (P=0.009), with Cohen's effect size value of d=0.64. The mirror group showed a greater improvement on the Disability of Arm, Shoulder, and Hand Questionnaire than control group at 2 weeks, 4 weeks, and 8 weeks (P≤0.032), but with a weak effect size value of all (r≤0.32). Group had main effects on Tampa Scale of Kinesiophobia (Waldχ²=6.631, P=0.010), with the Cohen's effect size value of d=0.56.

CONCLUSIONS

Mirror therapy improved shoulder flexion, abduction, shoulder function in daily life, and arm function and symptom of the affected shoulder in patients with breast cancer following surgical treatment, while decreasing fear of movement/(re)injury. Mirror configuration needs to be improved in further research to increase its feasibility.

IMPLICATIONS FOR CANCER SURVIVORS

Breast cancer survivors can try mirror therapy as a practical and effective method in shoulder rehabilitation for a promotion on effects.

TRIAL REGISTRATION

ClinicalTrial.gov Identifier: ChiCTR2000033080.

Shaping corticospinal pathways in virtual reality: effects of task complexity and sensory feedback during mirror therapy in neurologically intact individuals

BACKGROUND

Restoration of limb function for individuals with unilateral weakness typically requires volitional muscle control, which is often not present for individuals with severe impairment. Mirror therapy-interventions using a mirror box to reflect the less-impaired limb onto the more-impaired limb-can facilitate corticospinal excitability, leading to enhanced recovery in severely impaired clinical populations. However, the mirror box applies limitations on mirror therapy, namely that all movements appear bilateral and are confined to a small area, impeding integration of complex activities and multisensory feedback (e.g., visuo-tactile stimulation). These limitations can be addressed with virtual reality, but the resulting effect on corticospinal excitability is unclear.

OBJECTIVE

Examine how virtual reality-based unilateral mirroring, complex activities during mirroring, and visuo-tactile stimulation prior to mirroring affect corticospinal excitability.

MATERIALS AND METHODS

Participants with no known neurological conditions (n = 17) donned a virtual reality system (NeuRRoVR) that displayed a first-person perspective of a virtual avatar that matched their motions. Transcranial magnetic stimulation-induced motor evoked potentials in the nondominant hand muscles were used to evaluate corticospinal excitability in four conditions: resting, mirroring, mirroring with prior visuo-tactile stimulation (mirroring + TACT), and control. During mirroring, the movements of each participant's dominant limb were reflected onto the nondominant limb of the virtual avatar, and the avatar's dominant limb was kept immobile (i.e., unilateral mirroring). The mirroring + TACT condition was the same as the mirroring condition, except that mirroring was preceded by visuo-tactile stimulation of the nondominant limb. During the control condition, unilateral mirroring was disabled. During all conditions, participants performed simple (flex/extend fingers) and complex (stack virtual blocks) activities.

RESULTS

We found that unilateral mirroring increased corticospinal excitability compared to no mirroring (p < 0.001), complex activities increased excitability compared to simple activities during mirroring (p < 0.001), and visuo-tactile stimulation prior to mirroring decreased excitability (p = 0.032). We also found that these features did not interact with each other.

DISCUSSIONS

The findings of this study shed light onto the neurological mechanisms of mirror therapy and demonstrate the unique ways in which virtual reality can augment mirror therapy. The findings have important implications for rehabilitation for design of virtual reality systems for clinical populations.

Effect of Mirror Therapy on Post-Needling Pain Following Deep Dry Needling of Myofascial Trigger Point in Lateral Elbow Pain: Prospective Controlled Pilot Trial

Background: This prospective randomized, controlled pilot trial to explore the immediate effect of adding Mirror Visual Feedback Therapy on pain sensitivity and motor performance among subjects suffering from post-needling pain diagnosed as Lateral Elbow Pain. Methods: A total of 49 participants (23 female, 26 male) were enrolled and randomly allocated to either the experimental group, which received Deep Dry Needling in the m. Brachioradialis, Ischemic Compression, Cold Spray, Stretching, and Mirror Visual Feedback Therapy (n = 25), or a control group without Mirror Visual Feedback Therapy (n = 24). Pre- and post-treatment evaluations included assessments of post-needling pain intensity, pressure pain threshold, two-point discrimination threshold, and maximum hand grip strength. Results: Intergroup analysis revealed a statistically significant reduction in post-needling pain intensity favoring the experimental group (U = 188.00, p = 0.034). Additionally, intragroup analysis showed significant improvements in post-needling pain intensity (MD = 0.400, SEM = 0.271, W = 137.00, p = 0.047) and pressure pain threshold (MD = 0.148 Kg/cm2, SEM = 0.038, W = 262.00, p < 0.001) within the experimental group following the intervention. Conclusions: These findings suggest a potential benefit of integrating Mirror Visual Feedback Therapy into treatment protocols for individuals with Lateral Elbow Pain experiencing post-needling discomfort. Further research is necessary to fully elucidate the clinical implications of these findings.

Graded motor imagery and its phases for individuals with phantom limb pain following amputation: A scoping review

OBJECTIVE

Three-phase graded motor imagery (limb laterality, explicit motor imagery, and mirror therapy) has been successful in chronic pain populations. However, when applied to phantom limb pain, an amputation-related pain, investigations often use mirror therapy alone. We aimed to explore evidence for graded motor imagery and its phases to treat phantom limb pain.

DATA SOURCES

A scoping review was conducted following the JBI Manual of Synthesis and Preferred Reporting Items for Systematic Review and Meta-Analyses extension for Scoping Reviews. Thirteen databases, registers, and websites were searched.

REVIEW METHODS

Published works on any date prior to the search (August 2023) were included that involved one or more graded motor imagery phases for participants ages 18+ with amputation and phantom limb pain. Extracted data included study characteristics, participant demographics, treatment characteristics, and outcomes.

RESULTS

Sixty-one works were included representing 19 countries. Most were uncontrolled studies (31%). Many participants were male (75%) and had unilateral amputations (90%) of varying levels, causes, and duration. Most works examined one treatment phase (92%), most often mirror therapy (84%). Few works (3%) reported three-phase intervention. Dosing was inconsistent across studies. The most measured outcome was pain intensity (95%).

CONCLUSION

Despite the success of three-phase graded motor imagery in other pain populations, phantom limb pain research focuses on mirror therapy, largely ignoring other phases. Participant demographics varied, making comparisons difficult. Future work should evaluate graded motor imagery effects and indicators of patient success. The represented countries indicate that graded motor imagery phases are implemented internationally, so future work could have a widespread impact.

Efficacy of a Rehabilitation Program Using Mirror Therapy and Cognitive Therapeutic Exercise on Upper Limb Functionality in Patients with Acute Stroke

Applying evidence-based therapies in stroke rehabilitation plays a crucial role in this process, as they are supported by studies and results that demonstrate their effectiveness in improving functionality, such as mirror therapy (MT), cognitive therapeutic exercise (CTE), and task-oriented training. The aim of this study was to assess the effectiveness of MT and CTE combined with task-oriented training on the functionality, sensitivity, range, and pain of the affected upper limb in patients with acute stroke. A longitudinal multicenter study recruited a sample of 120 patients with acute stroke randomly and consecutively, meeting specific inclusion and exclusion criteria. They were randomly allocated into three groups: a control group only for task-oriented training (TOT) and two groups undergoing either MT or CTE, both combined with TOT. The overall functionality of the affected upper limb, specific functionality, sensitivity, range of motion, and pain were assessed using the Fugl-Meyer Assessment Upper Extremity (FMA-UE) scale validated for the Spanish population. An initial assessment was conducted before the intervention, a second assessment after completing the 20 sessions, and another three months later. ANCOVA analysis revealed statistically significant differences between the assessments and the experimental groups compared to the control group, indicating significant improvement in the overall functionality of the upper limb in these patients. However, no significant differences were observed between the two experimental groups. The conclusion drawn was that both therapeutic techniques are equally effective in treating functionality, sensitivity, range of motion, and pain in the upper limb following a stroke.

Effectiveness of Intensively Applied Mirror Therapy in Older Patients with Post-Stroke Hemiplegia: A Preliminary Trial

INTRODUCTION

The present work was carried out to determine the effectiveness of neuromuscular stimulation triggered by mirror therapy (MT) in older patients with post-stroke hemiplegia by two different intervention protocols, either intensively or spaced.

METHODS

A preliminary trial conducted on Spanish rehabilitation centres was conducted. Forty older patients (>70 years) with diagnosed post-stroke hemiplegia were randomly distributed to intensive intervention group (5 times/week for 6 weeks) or to spaced intervention group (3 times/week for 10 weeks), which underwent a similar number of MT sessions (n = 30). Muscle strength and activity were measured at baseline and at the end of treatment. Functional ability was also evaluated.

RESULTS

Although both interventions improved muscle activity parameters, intensive MT showed a significantly and statistically higher intervention effect on electromyographic activity (p < 0.001) and muscle strength (p < 0.001) than the spaced over time protocol. Attending to the Barthel Index scores, the effect on functionality was also greater in the intensive therapy group (p < 0.001), although the functional improvement measured by the Fugl-Meyer test was similar (p = 0.235). The effect of the interventions was independent of age and clinical antecedents.

CONCLUSION

Intensive MT appears to be more effective than a more spaced over time therapy; therefore, at least in the older adults, this treatment protocol should be recommended in the post-stroke recovery of these patients. Further studies will confirm with certainty whether this treatment is the most suitable guideline for to treat these patients.

Effects of free range-of-motion upper limb exercise based on mirror therapy on shoulder function in patients after breast cancer surgery: study protocol for a randomized controlled trial

Background

Shoulder function complications are common after treatment for breast cancer. Quite a few survivors still report a limited shoulder range of motion, even though the free range-of-motion upper limb exercise is helpful to restore shoulder function. Mirror therapy (MT) is a classical and effective rehabilitation technique to recover motor and sensory function for the limbs; in addition, studies have reported that MT has an influence on patients with shoulder functional dysfunction including increasing shoulder range of motion, improving shoulder function scores, and decreasing pain scores. Here, we describe a protocol of a randomized controlled trial to explore if free range-of-motion upper limb exercise based on MT has efficacy on shoulder function in survivors after surgery of breast cancer.

Methods/design

This is a prospective, single-blind, two-arm randomized controlled trial. An estimated 70 participants will be randomly allocated to (1) the MT group or (2) the control group. The participants in the control group receive free range-of-motion upper limb exercise, and participants in the MT group will engage in free range-of-motion upper limb exercise based on MT. The intervention will start on the first day after surgery and be completed at 8 weeks after surgery. The primary outcome in this protocol is shoulder range of motion (ROM), while the Constant-Murley Score (CMS); Disability of the Arm, Shoulder, and Hand Questionnaire (DASH); Tampa Scale of Kinesiophobia (13-item TSK); visual analog scale (VAS); grip strength; arm circumference; and lymphedema are the secondary outcomes. Assessment will be conducted before allocation (baseline) and at 2 weeks, 4 weeks, and 8 weeks after surgery.

Discussion

Based on the results that MT has an influence on shoulder function immediately after intervention in patients without nerve injury, this randomized controlled trial is to observe the efficacy of MT on shoulder function after a long-term intervention in breast cancer survivors. We look forward to the innovation of this study for both breast cancer rehabilitation and MT.

Trial registration

Chinese Clinical Trial Registry (ChiCTR) ChiCTR2000033080. Registered on 19 May 2020

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05789-2.

Parieto-Occipital Alpha and Low-Beta EEG Power Reflect Sense of Agency

The sense of agency (SoA) is part of psychophysiological modules related to the self. Disturbed SoA is found in several clinical conditions, hence understanding the neural correlates of the SoA is useful for the diagnosis and determining the proper treatment strategies. Although there are several neuroimaging studies on SoA, it is desirable to translate the knowledge to more accessible and inexpensive EEG-based biomarkers for the sake of applicability. However, SoA has not been widely investigated using EEG. To address this issue, we designed an EEG experiment on healthy adults (n = 15) to determine the sensitivity of EEG on the SoA paradigm using hand movement with parametrically delayed visual feedback. We calculated the power spectral density over the traditional EEG frequency bands for ten delay conditions relative to no delay condition. Independent component analysis and equivalent current dipole modeling were applied to address artifact rejection, volume conduction, and source localization to determine the effect of interest. The results revealed that the alpha and low-beta EEG power increased in the parieto-occipital regions in proportion to the reduced SoA reported by the subjects. We conclude that the parieto-occipital alpha and low-beta EEG power reflect the sense of agency.

Mirror therapy versus augmented/virtual reality applications: towards a tailored mechanism-based treatment for phantom limb pain

Phantom limb pain (PLP) is a clinically relevant consequence of limb amputation and its treatment is still challenging. Mirror therapy, in other words, observing and engaging in the intact limb's mirrored movements, offers a promising, mechanism-based treatment for PLP. However, intervention and patient characteristics, such as the realism of mirrored exercises and perceptions related to the phantom limb, might influence treatment effectiveness. Novel approaches using augmented and virtual reality setups represent an alternative to traditional mirror therapy. In this paper, based on recent studies in the field, we compare both approaches and discuss their unique advantages and disadvantages. We argue for the necessity of a tailored treatment for PLP that is personalized to the patients’ characteristics, preferences and psychological needs.

Assistive technologies for pain management in people with amputation: a literature review

The prevalence of limb amputation is increasing globally as a devastating experience that can physically and psychologically affect the lifestyle of a person. The residual limb pain and phantom limb pain are common disabling sequelae after amputation surgery. Assistive devices/technologies can be used to relieve pain in people with amputation. The existing assistive devices/technologies for pain management in people with amputation include electrical nerve block devices/technologies, TENS units, elastomeric pumps and catheters, residual limb covers, laser systems, myoelectric prostheses and virtual reality systems, etc. There is a great potential to design, fabricate, and manufacture some portable, wireless, smart, and thin devices/technologies to stimulate the spinal cord or peripheral nerves by electrical, thermal, mechanical, and pharmaceutical stimulus. Although some preliminary efforts have been done, more attention must be paid by researchers, clinicians, designers, engineers, and manufacturers to the post amputation pain and its treatment methods.