| 1. |
- Lendaro, Eva, 1989, et al.
(författare)
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Alpha Oscillation in Phantom Limb Pain Patients: A Neuropathic Pain Signature
- 2019
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- People with acquired amputation face oftentimes the onset of chronic pain, which develops as either residual limb pain, neuroma or nociceptive phantom limb pain (PLP), or neuropathic PLP. To date, the pathophysiology giving raise to PLP is still object of debate, with previous literature mainly focusing on whether and how reorganization takes place in the primary somatosensory and motor cortices. Striving to understand how changes in somatotopy and mototopy relate to PLP, brain imaging studies have traditionally been conducted with a task-based fMRI approaches which measure the neural activity in an indirect way. Yet, little is known about the effect of amputation on the global brain organization and electrophysiological techniques, such as EEG, have not been taken fully advantage of. In this study we analyse the power of spontaneous and ongoing EEG activity as a function of frequency. The rationale for this choice stems from the assumption that brain at rest, in opposition to task-based paradigms, allows to capture dynamics related to the processing of pain which would otherwise be masked by other sensory or cognitive functions processes.
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| 2. |
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| 3. |
- Lendaro, Eva, 1989, et al.
(författare)
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Classification of non-weight bearing lower limb movements: Towards a potential treatment for phantom limb pain based on myoelectric pattern recognition
- 2016
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Ingår i: Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS. - 1557-170X. ; 2016-October, s. 5457-5460
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Konferensbidrag (refereegranskat)abstract
- Research in myoelectric pattern recognition (MPR) for the prediction of motor volition has primarily focused on the upper limbs. Recent studies in the lower limbs have mainly concentrated on prosthetic control, while MPR for lower limb rehabilitation purposes has received little attention. In this work we investigated the viability of a MPR system for the prediction of four degrees of freedom controlled in a near natural or physiologically appropriate fashion. We explored three different electrode configurations for acquiring electromyographic (EMG) signals: two targeted (bipolar and monopolar) and one untargeted (electrodes equally spaced axially). The targeted monopolar configuration yielded overall lower signal-to-noise ratios (SNR) but similar accuracy than those of the targeted bipolar configuration. The targeted bipolar and untargeted monopolar configurations were comparable in terms of SNR and offline accuracy when the same number of channels was used. However, the untargeted configuration tested with twice the channels yielded the best results in terms of accuracy. An advantage of the untargeted configuration is that it offers a simpler and more practical electrode placement. This work is the first step in our long-term goal of implementing a phantom limb pain (PLP) treatment for lower limb amputees based on MPR and augmented/virtual reality.
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| 4. |
- Lendaro, Eva, 1989, et al.
(författare)
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Common Spatial Pattern EEG decomposition for Phantom Limb Pain detection
- 2021
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Ingår i: Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS. - 1557-170X. ; , s. 726-729
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Konferensbidrag (refereegranskat)abstract
- Phantom Limb Pain (PLP) is a chronic condition frequent among individuals with acquired amputation. PLP has been often investigated with the use of functional MRI focusing on the changes that take place in the sensorimotor cortex after amputation. In the present study, we investigated whether a different type of data, namely electroencephalographic (EEG) recordings, can be used to study the condition. We acquired resting state EEG data from people with and without PLP and then used machine learning for a binary classification task that differentiates the two. Common Spatial Pattern (CSP) decomposition was used as the feature extraction method and two validation schemes were followed for the classification task. Six classifiers (LDA, Log, QDA, LinearSVC, SVC and RF) were optimized through grid search and their performance compared. Two validation approaches, namely all-subjects validation and leave-one-out cross-validation (LOOCV), resulted in high classification accuracy. Most notably, the 93.7% accuracy achieved with SVC in LOOCV holds promise for good diagnostic capabilities using EEG biomarkers. In conclusion, our findings indicate that EEG data is a promising target for future research aiming at elucidating the neural mechanisms underlying PLP and its diagnosis.
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| 5. |
- Lendaro, Eva, 1989, et al.
(författare)
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Differential Activation of Biceps Brachii Muscle Compartments for Human-Machine Interfacing
- 2018
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Ingår i: Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS. - 1557-170X. ; 2018-July, s. 4705-4709
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Konferensbidrag (refereegranskat)abstract
- A central challenge for myoelectric limb prostheses resides in the fact that, as the level of amputation becomes more proximal, the number of functions to be replaced increases, while the number of muscles available to collect input signals for control decreases. Differential activation of compartments from a single muscle could provide additional control sites. However, such feat is not naturally under voluntary control. In this study, we investigated the feasibility of learning to differentially activate the two heads of the bicep brachii muscle (BBM), by using biofeedback via high-density surface electromyography (HD-sEMG). Using a one degree of freedom Fitts' law test, we observed that eight subjects could learn to control the center of gravity of BBM's myoelectric activity. In addition, we examined the activations patterns of BBM that allow for the decoding of distal hand movements. These patterns were found highly individual, but different enough to allow for decoding of motor volition of distal joints. These findings represent promising venues to increase the functionality of myoelectrically controlled upper limb prostheses.
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| 6. |
- Lendaro, Eva, 1989
(författare)
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Investigating Phantom Motor Execution as treatment of Phantom Limb Pain
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Phantom Limb Pain (PLP) is commonly suffered by people with amputations and even though it has been studied for centuries, it remains a mysterious object of debate among researchers. For one thing, despite the vast number of proposed PLP treatments, no therapy has so far proved to be reliably effective. For another, studies attempting to provide a mechanistic explanation of the condition have produced mixed and inconsistent results, thus providing unreliable guidance for devising new treatment approaches. Phantom Motor Execution (PME) – exertion of voluntary phantom limb movements – aims at restoring control over the phantom limb and the exercise of such control has been hypothesized to reverse neural changes implicated in PLP. Preliminary evidence supporting this hypothesis has been provided by clinical investigations on upper limb amputees. The main purpose of this doctoral thesis was to provide high quality and unbiased evidence for the use of PME as a treatment of PLP, by probing its efficacy with a Randomized Controlled Trial (RCT) on both upper and lower limb amputees. However, the implementation of this clinical investigation required of additional technology development related the extraction of motor volition via Myoelectric Pattern Recognition (MPR). In practice, this doctoral work consisted in the extension of PME technology to lower limb amputations by proposing and validating a new and more user-friendly recording method to acquire myoelectric signals. The use of PME was then shown to be efficacious in relieving PLP even in the lower limb population with a case study. Another necessity for providing unbiased evidence was to ensure that the highest standards were met when designing, conducting, analysing and reporting the results of the RCT. For this reason, the protocol for the RCT and the prospective Statistical Analysis Plan (SAP) were designed and published. The RCT was established as an international, multi-center effort in 2017 and it is expected to reach its conclusion in September 2021. Preliminary results of the RCT regarding the primary outcome showed reduction of PLP above what is considered clinically relevant, and whereas a higher reduction was obtained with PME, this was not statistically significant over the control treatment. The available evidence at this stage indicates that the RCT will not be able to rule out the role of contextual factors other than PME in providing pain relief. Having at hand a way to alleviate PLP provided a unique opportunity to investigate and identify its neural correlates, therefore this became a secondary aim of this thesis. In particular, patients suffering from PLP were followed regarding their pain trajectory through the therapy and brain imaging studies with functional Magnetic Resonance Imaging (fMRI) and electroencephalography (EEG) were performed. The present doctoral thesis reports part of this work by showing the early results of a cross-sectional study on the EEG correlates of PLP. The results show that it is possible to use machine-learning techniques to discriminate EEG recorded from patients with and without PLP. The findings further point to this technique as a promising target for future longitudinal research aiming at elucidating the neural mechanisms underlying PLP.
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| 7. |
- Lendaro, Eva, 1989
(författare)
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On the use of Phantom Motor Execution for the treatment of Phantom Limb Pain
- 2020
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Phantom limb pain (PLP) is a common complaint among amputees and despite having been studied for centuries, it remains a mysterious object of debate among researcher. To date, a vast number of ways to treat PLP has been proposed in the literature, however none of them has proven to be universally effective, thus creating uncertainty on how to operate clinically. The uncertainty is largely attributable to the scarcity of well conducted randomized controlled trials (RCTs) to prove the efficacy of PLP treatments. Phantom Motor Execution (PME) -exertion of voluntary phantom limb movements – aims at restoring the control over the phantom limb and the exercise of such control has been hypothesized to reverse neural changes implicated in PLP. Preliminary evidence supporting this hypothesis has been provided by clinical investigations on upper limb amputees. The main purpose of this Licentiate thesis was to enable a RCT on the use of PME for the treatment of PLP in order to provide robust and unbiased evidence for clinical practice. However, the implementation and kick-off of this clinical investigation required to complete few preparatory steps. For example, most amputees and PLP patients have lower limb amputation, thus PME needed to be adapted and validated for this population. Further, the RCT protocol needed to be carefully planned and made openly accessible, as per guidelines for conducting and publishing clinical RCT. Finally, a secondary aim of this thesis emerged with the need of providing long term relief from PLP to patient. Preliminary evidence seemed to indicate that in order to maintain pain relief, periodic rehearsal of the phantom motor skills acquired through PME is necessary. This raised the question of whether it is beneficial and possible to translate the technology from clinic to home use, question that was explored employing both quantitative and qualitative methods from engineering, medical anthropology, and user interface design. The work conducted within this thesis resulted in the extension of PME to lower limb patients by proposal and validation of a new and more user-friendly recording configuration to record EMG signals. The use of PME was then shown to be efficacious in relieving PLP with a case study on a patient. The protocol for the RCT was then designed and published. These two first steps permitted the establishment of the RCT, which is currently ongoing and expected to close in March 2021. With regard to the secondary aim of this thesis, the work conducted enabled PME to be used by the patients in the comfort of their home, while it also allowed investigate the benefits and challenges generally faced (not only by PME) in the transition from the clinic to home and its effects on treatment adherence. The work conducted is presented in the three appended publications. Future work includes the presentation of the results of the RCT. Further, having a way to modulate PLP is an incredibly useful tool to study the neural basis of PLP. By capitalizing on this tool, we are currently conducting brain imaging studies using fMRI and electroencephalography that are the main focus of the work that lies ahead.
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| 8. |
- Lendaro, Eva, 1989, et al.
(författare)
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Out of the clinic, into the home: The in-home use of phantom motor execution aided by machine learning and augmented reality for the treatment of phantom limb pain
- 2020
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Ingår i: Journal of Pain Research. - 1178-7090. ; 13, s. 195-209
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Phantom motor execution (PME) facilitated by augmented/virtual reality (AR/ VR) and serious gaming (SG) has been proposed as a treatment for phantom limb pain (PLP). Evidence of the efficacy of this approach was obtained through a clinical trial involving individuals with chronic intractable PLP affecting the upper limb, and further evidence is currently being sought with a multi-sited, international, double blind, randomized, controlled clinical trial in upper and lower limb amputees. All experiments have been conducted in a clinical setting supervised by a therapist. Here, we present a series of case studies (two upper and two lower limb amputees) on the use of PME as a self-treatment. We explore the benefits and the challenges encountered in translation from clinic to home use with a holistic, mixed-methods approach, employing both quantitative and qualitative methods from engineering, medical anthropology, and user interface design. Patients and Methods: All patients were provided with and trained to use a myoelectric pattern recognition and AR/VR device for PME. Patients took these devices home and used them independently over 12 months. Results: We found that patients were capable of conducting PME as a self-treatment and incorporated the device into their daily life routines. Use patterns and adherence to PME practice were not only driven by the presence of PLP but also influenced by patients’ perceived need and social context. The main barriers to therapy adherence were time and availability of single-use electrodes, both of which could be resolved, or attenuated, by informed design considerations. Conclusion: Our findings suggest that adherence to treatment, and thus related outcomes, could be further improved by considering disparate user types and their utilization patterns. Our study highlights the importance of understanding, from multiple disciplinary angles, the tight coupling and interplay between pain, perceived need, and use of medical devices in patient-initiated therapy.
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| 9. |
- Lendaro, Eva, 1989, et al.
(författare)
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Phantom Motor Execution as a strategy to treat Phantom Limb Pain: A case study on a lower limb sufferer.
- 2017
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Ingår i: Phantom Motor Execution as a strategy to treat Phantom Limb Pain: A case study on a lower limb sufferer., 6th International Congress on Neuropathic Pain (NeuPSIG), June 15-18, 2017, Gothenburg, Sweden..
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Background and Aims:Phantom Motor Execution (PME) facilitated by Myoelectric Pattern Recognition (MPR) and Virtual Reality (VR) poses itself as an effective treatment for Phantom Limb Pain (PLP). Notably, a recent clinical control trial using the methodology on a population of 14 upper limb amputees with intractable PLP showed significant improvements (Ortiz-Catalan, 2016). The present study aims at assessing whether PME facilitated by MPR and VR can reduce PLP in lower limb.Methods:A 70-years-old male with trans-femoral amputation was treated for a total of 24 PME treatment sessions. Pain was assessed in terms of Weighted Pain Distribution (WDP) (Ortiz-Catalan, 2014) and Short Form of McGill Pain Questionnaire (SF-MPQ). The treatment consisted in using myoelectric signals produced by stump muscles during phantom motions in order to control a VR limb.Results:SF-MPQ showed a significant reduction (>%50) in the number of word chosen and in the Pain Rating Index (Figure 1). WDP (Figure 2) shows reduction of time spent in pain. Improvement of sleep (from 2h to 7h/night) was also reported.Conclusions:Although the results are limited to one subject, this study indicates that PME could potentially reduce PLP also in the lower limb.
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