Towards efficient motor imagery interventions after lower-limb amputation
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ABSTRACT:
SUBMITTER: Saruco E
PROVIDER: S-EPMC11017566 | biostudies-literature | 2024 Jan
REPOSITORIES: biostudies-literature
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Project description:A potential contributor to impaired motor imagery in amputees is an alteration of the body schema as a result of the presence of a phantom limb. However, the nature of the relationship between motor imagery and phantom experiences remains unknown. In this study, the influence of phantom limb perception on motor imagery was investigated using a hand mental rotation task by means of behavioral and electrophysiological measures. Compared with healthy controls, significantly prolonged response time for both the intact and missing hand were observed specifically in amputees who perceived a phantom limb during the task but not in amputees without phantom limb perception. Event-related desynchronization of EEG in the beta band (beta-ERD) in central and parietal areas showed an angular disparity specifically in amputees with phantom limb perception, with its source localized in the right inferior parietal lobule. The response time as well as the beta-ERD values were significantly positively correlated with phantom vividness. Our results suggest that phantom limb perception during the task is an important interferential factor for motor imagery after amputation and the interference might be related to a change of the body representation resulting from an unnatural posture of the phantom limb.
| S-EPMC4754632 | biostudies-other
Project description:ObjectiveThe role of motor cortex reorganization in the development and maintenance of phantom limb pain (PLP) is still unclear. This study aims to evaluate neurophysiological and structural motor cortex asymmetry in patients with PLP and its relationship with pain intensity.MethodsCross-sectional analysis of an ongoing randomized-controlled trial. We evaluated the motor cortex asymmetry through two techniques: i) changes in cortical excitability indexed by transcranial magnetic stimulation (motor evoked potential, paired-pulse paradigms and cortical mapping), and ii) voxel-wise grey matter asymmetry analysis by brain magnetic resonance imaging.ResultsWe included 62 unilateral traumatic lower limb amputees with a mean PLP of 5.9 (SD = 1.79). We found, in the affected hemisphere, an anterior shift of the hand area center of gravity (23 mm, 95% CI 6 to 38, p = 0.005) and a disorganized and widespread representation. Regarding voxel-wise grey matter asymmetry analysis, data from 21 participants show a loss of grey matter volume in the motor area of the affected hemisphere. This asymmetry seems negatively associated with time since amputation. For TMS data, only the ICF ratio is negatively correlated with PLP intensity (r = -0.25, p = 0.04).ConclusionThere is an asymmetrical reorganization of the motor cortex in patients with PLP, characterized by a disorganized, widespread, and shifted hand cortical representation and a loss in grey matter volume in the affected hemisphere. This reorganization seems to reduce across time since amputation. However, it is not associated with pain intensity.SignificanceThese findings are significant to understand the role of the motor cortex reorganization in patients with PLP, showing that the pain intensity may be related with other neurophysiological factors, not just cortical reorganization.
| S-EPMC7494252 | biostudies-literature
Project description:Event-related desynchronization/synchronization (ERD/S) is an electroencephalogram (EEG) feature widely used as control signals for Brain-Computer Interfaces (BCIs). Nevertheless, the underlying neural mechanisms and functions of ERD/S are largely unknown, thus investigating them is crucial to improve the reliability of ERD/S-based BCIs. This study aimed to identify Motor Imagery (MI) conditions that enhance ERD/S. We investigated following three questions: 1) whether target-directed MI affects ERD/S, 2) whether MI with sound imagery affects ERD/S, and 3) whether ERD/S has a body part dependency of MI. Nine participants took part in the experiments of four MI conditions; they were asked to imagine right foot dorsiflexion (F), right foot dorsiflexion and the sound of a bass drum when the sole touched the floor (FS), right leg extension (L), and right leg extension directed toward a soccer ball (LT). Statistical comparison revealed that there were significant differences between conditions L and LT in beta-band ERD and conditions F and L in beta-band ERS. These results suggest that mental rehearsal of target-directed lower limb movement without real sensory stimuli can enhance beta-band ERD; furthermore, MI of foot dorsiflexion induces significantly larger beta-band ERS than that of leg extension. These findings could be exploited for the training of BCIs such as powered prosthetics for disabled person and neurorehabilitation system for stroke patients.
| S-EPMC5604945 | biostudies-literature
Project description:Background:Lower limb amputation (LLA) is a complication of lower limb atherosclerosis, infection and tissue gangrene. Following ipsilateral LLA, the risk of major amputation of the contralateral limb or of death is unknown. The aim of this study was to determine the incidence of a contralateral major LLA, comparing those with a non-malignant/non-traumatic ipsilateral major vs. ipsilateral minor LLA. Methods:We used pre-existing linked administrative health databases for the study. Data were provided by the Institute for Clinical Evaluation Sciences (ICES), Toronto, Ontario. This is a retrospective population-based cohort study across Ontario, Canada, 2002-2012. Cause-specific Cox regression models were used to obtain hazard ratios. Cumulative incidence functions were used to calculate the risk of contralateral major LLA and the risk of the competing event death. Individuals who did not survive at least 30 days after their first ipsilateral LLA were excluded since they were ineligible to have a contralateral LLA. Results:5,816 adults underwent an ipsilateral major and 4,143 an ipsilateral minor LLA. The incidences of contralateral major LLA were 4.8 and 2.2 (adjusted HR 2.41, 95% CI 2.04-2.84) after ipsilateral major and minor LLA, respectively. Incidence of death was 18.9 and 11.4 (adjusted HR 1.22, 95% CI 1.13-1.31) following ipsilateral major and minor LLA, respectively. Conclusion:There is high incidence of a contralateral major LLA and even higher risk of death following the ipsilateral LLA. Healthcare professionals should develop strategies for contralateral limb preservation in individuals with existing ipsilateral LLA.
| S-EPMC6180416 | biostudies-literature
Project description:ObjectiveThree-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 sourcesA 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 methodsPublished 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.ResultsSixty-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%).ConclusionDespite 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.
| S-EPMC10860367 | biostudies-literature
Project description:There has been increased interest in using residual muscle activity for neural control of powered lower-limb prostheses. However, only surface electromyography (EMG)-based decoders have been investigated. This study aims to investigate the potential of using motor unit (MU)-based decoding methods as an alternative to EMG-based intent recognition for ankle torque estimation. Eight people without amputation (NON) and seven people with amputation (AMP) participated in the experiments. Subjects conducted isometric dorsi- and plantarflexion with their intact limb by tracing desired muscle activity of the tibialis anterior (TA) and gastrocnemius (GA) while ankle torque was recorded. To match phantom limb and intact limb activity, AMP mirrored muscle activation with their residual TA and GA. We compared neuromuscular decoders (linear regression) for ankle joint torque estimation based on 1) EMG amplitude (aEMG), 2) MU firing frequencies representing neural drive (ND), and 3) MU firings convolved with modeled twitch forces (MUDrive). In addition, sensitivity analysis and dimensionality reduction of optimization were performed on the MUDrive method to further improve its practical value. Our results suggest MUDrive significantly outperforms (lower root-mean-square error) EMG and ND methods in muscles of NON, as well as both intact and residual muscles of AMP. Reducing the number of optimized MUDrive parameters degraded performance. Even so, optimization computational time was reduced and MUDrive still outperformed aEMG. Our outcomes indicate integrating MU discharges with modeled biomechanical outputs may provide a more accurate torque control signal than direct EMG control of assistive, lower-limb devices, such as exoskeletons and powered prostheses.
| S-EPMC10752569 | biostudies-literature
Project description:To explore the effectiveness of (active) lifestyle interventions for the health of people with a lower limb amputation in order to offer effective interventions during rehabilitation that may improve physical and psychosocial functioning of people with lower limb amputation. PubMed, CINAHL and Embase were searched from inception to February 2021. Inclusion criteria were (1) (quasi-)randomized controlled trial; (2) minimum of 10 participants with a lower limb amputation; (3) lifestyle intervention focusing on physical activity, smoking habits, alcohol use, nutrition, and/or stress management; (4) focus on health outcomes; (5) participants older than 18 years; (6) studies in Dutch, German, or English; and (7) primary research. Title, abstract, and full-text screening and quality assessment were performed by 2 independent assessors. Of 2460 studies identified, 13 studies were included in this review. Two studies were of moderate methodological quality, 2 studies were of medium quality, and 9 studies were of poor quality. Lifestyle interventions in the included studies focused on physical activity and stress management. These interventions seemed effective for improving physical fitness, walking capacity, changes in body mass, quality of life, and intensity of physical activity. Lifestyle interventions focusing on physical activity and stress management seem effective for improving physical and psychosocial functioning of people with a lower limb amputation. However, the findings should be interpreted with caution given the limited methodological quality of the included studies. Future research should evaluate the effectiveness of interventions on nutrition, smoking habits, and alcohol use and the effectiveness of combined interventions in people with a lower limb amputation.
| S-EPMC9761262 | biostudies-literature
Project description:Human aging is associated with a decline in the capacity to memorize recently acquired motor skills. Motor imagery training is a beneficial method to compensate for this deterioration in old adults. It is not yet known whether these beneficial effects are maintained in very old adults (>80 years), who are more affected by the degeneration processes. The aim of this study was to evaluate the effectiveness of a mental training session of motor imagery on the memorization of new motor skills acquired through physical practice in very old adults. Thus, 30 very old adults performed 3 actual trials of a manual dexterity task (session 1) or a sequential footstep task (session 2) as fast as they could before and after a 20 min motor imagery training (mental-training group) or watching a documentary for 20 min (control group). Performance was improved after three actual trials for both tasks and both groups. For the control group, performance decreased in the manual dexterity task after the 20 min break and remained stable in the sequential footstep task. For the mental-training group, performance was maintained in the manual dexterity task after the 20 min motor imagery training and increased in the sequential footstep task. These results extended the benefits of motor imagery training to the very old population, showing that even a short motor imagery training session improved their performance and favored the motor memory process. These results confirmed that motor imagery training is an effective method to complement traditional rehabilitation protocols.
| S-EPMC9963345 | biostudies-literature
Project description:BackgroundTo evaluate cycling participation and identify barriers and facilitators related to cycling participation in people with a lower limb amputation (LLA) in the Netherlands.MethodsA questionnaire was sent to adults with a LLA between March and August 2019 to obtain information regarding prosthesis, individual's characteristics, amputation, cycling barriers and facilitators, and prosthetic satisfaction. The questionnaires were distributed via 8 orthopedic workshops, post and were given directly. To find cycling predictors, variables associated with cycling (p < 0.1) were entered into a logistic regression analysis. Non-significant variables were removed manually.ResultsParticipants (n = 207, 71% males) had a mean age of 62.0 ± 13.0 years. The most frequent level of amputation was transtibial (42%), and trauma was the most frequent cause of amputation (43%). After the LLA, 141 participants (68%) cycled for recreation (80%), physical fitness (74%), and transport (50%). In the past six months, cyclists cycled for recreation (79%) and transport (66%). Most cycled less than once a day. Recreational cyclists cycled alone (75%) for a median duration of 45 min or 14 km per ride. Cyclists with a transportation purpose usually cycled to go shopping (80%) or to visit friends (68%), with a median duration of 20 min or five kilometers per ride. Cyclists reported more facilitators (median (IQR) = 5 (3, 7) than non-cyclists 0 (0, 3). The majority of cyclists reported a positive attitude toward cycling (89%) and cycled because of health benefits (81%). A dynamic foot (odds ratio: 5.2, 95% CI 2.0, 13.3) and a higher number of facilitators (odds ratio: 1.3, 95% CI 1.2, 1.5) positively predicted cycling, whereas the presence of other underlying diseases (odds ratio: 0.4, 95% CI 0.2, 0.9) negatively predicted cycling (R2: 40.2%).ConclusionIn the Netherlands, the majority of adults cycled after a LLA, mainly for recreational purposes. A dynamic foot, a higher number of facilitators, and no other underlying diseases increases the likelihood of cycling after a LLA. The results suggest that personal motivation and a higher mobility level could be the key to increasing cycling participation. Future research should determine the association between motivation, mobility levels, and cycling with a LLA.
| S-EPMC8272388 | biostudies-literature
Project description:BackgroundAmbulatory individuals with lower-limb amputation perform a variety of locomotor activities, but the step count distribution of these activities is unknown.ObjectiveTo describe a novel method for activity monitoring and to use it to count steps taken while walking straight ahead on level ground, turning right and left, up and down stairs, and up and down ramps.Study designThis is an observational study.MethodsA portable instrument to record leg motion was placed on or inside the prosthetic pylon of 10 individuals with unilateral transtibial amputations. Participants first walked a defined course in a hospital environment to train and validate a machine learning algorithm for classifying locomotor activity. Participants were then free to pursue their usual activities while data were continuously collected over 1-2 d.ResultsOverall classification accuracy was 97.5% ± 1.5%. When participants were free to walk about their home, work, and community environments, 82.8% of all steps were in a straight line, 9.0% were turning steps, 4.8% were steps on stairs, and 3.6% were steps on ramps.ConclusionA novel activity monitoring method accurately classified the locomotion activities of individuals with lower-limb amputation. Nearly 1 in 5 of all steps taken involved turning or walking on stairs and ramps.
| S-EPMC8494105 | biostudies-literature