Effect of one session of mirror therapy on phantom limb pain and recognition of limb laterality in military traumatic lower limb amputees: a pilot study

Reporting of Rehabilitation Outcomes in the Traumatic Lower Limb Amputation Literature: A Systematic Review

OBJECTIVE

To synthesize the outcomes reported in the rehabilitation and community literature for adults with traumatic lower limb amputation (LLA).

DATA SOURCES

The search strategy was conducted in 3 databases (Medline, EMBASE, and CINAHL) from inception to April 2022.

STUDY SELECTION

To be eligible, articles could be of any design but were required to have at least 50% adult individuals with traumatic LLA and had to report on interventions and outcomes in either a rehabilitation or community setting.

DATA EXTRACTION

The extracted outcomes were classified using Dodd's framework, which is designed for organizing research outcomes. Heterogeneity was observed in the outcome measures (OMs) used for evaluation. Two reviewers independently conducted the data extraction, which was verified by a third reviewer.

DATA SYNTHESIS

Of the 7,834 articles screened, 47 articles reporting data on 692 individuals with traumatic LLA, met our inclusion criteria. Four core areas encompassing 355 OMs/indicators were identified: life effect (63.4%), physiological/clinical (30.1%), resource use (5.1%), and adverse events (1.4%). Physical functioning (eg, gait, mobility) was the most frequently reported outcome domain across studies, followed by nervous system outcomes (eg, pain) and psychiatric outcomes (eg, depression, anxiety). Domains such as global quality of life and role/emotional functioning were seldomly reported.

CONCLUSION

The study provides a list of outcome indicators explicitly published for adults with traumatic LLA, highlighting inconsistent reporting of outcome indicators. The lack of a standardized set of OMs is a barrier to performing meta-analyses on interventions, preventing the identification of effective care models and clinical pathways. Developing a core outcome set that includes OMs relevant to the needs of the traumatic LLA population may address these issues.

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.

Visual responsiveness in sensorimotor cortex is increased following amputation and reduced after mirror therapy

Phantom limb pain (PLP) following amputation, which is experienced by the vast majority of amputees, has been reported to be relieved with daily sessions of mirror therapy. During each session, a mirror is used to view the reflected image of the intact limb moving, providing visual feedback consistent with the movement of the missing/phantom limb. To investigate potential neural correlates of the treatment effect, we measured brain responses in volunteers with unilateral leg amputation using functional magnetic resonance imaging (fMRI) during a four-week course of mirror therapy. Mirror therapy commenced immediately following baseline scans, which were repeated after approximately two and four week intervals. We focused on responses in the region of sensorimotor cortex corresponding to primary somatosensory and motor representations of the missing leg. At baseline, prior to starting therapy, we found a strong and unexpected response in sensorimotor cortex of amputees to visually presented images of limbs. This response was stronger for images of feet compared to hands and there was no such response in matched controls. Further, this response to visually presented limbs was no longer present at the end of the four week mirror therapy treatment, when perceived phantom limb pain was also reduced. A similar pattern of results was also observed in extrastriate and parietal regions typically responsive to viewing hand actions, but not in regions corresponding to secondary somatosensory cortex. Finally, there was a significant correlation between initial visual responsiveness in sensorimotor cortex and reduction in PLP suggesting a potential marker for predicting efficacy of mirror therapy. Thus, enhanced visual responsiveness in sensorimotor cortex is associated with PLP and modulated over the course of mirror therapy.

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Visual responsiveness to the sight of limbs in sensorimotor cortex of leg amputees but not matched controls

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Consistent with prior studies, mirror therapy over 4 weeks reduced phantom limb pain

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Visual responsiveness in sensorimotor cortex of amputees diminished following mirror therapy

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Visual responsiveness in sensorimotor cortex might be useful in predicting the potential efficacy of mirror therapy