The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Lunde Liao - One of the best experts on this subject based on the ideXlab platform.
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integrated treatment modality of cathodal transcranial direct current Stimulation with peripheral Sensory Stimulation affords neuroprotection in a rat stroke model
New Phytologist, 2017Co-Authors: Su Jing Chan, Aishwarya Bandla, Nicolas Kk King, You Yin Chen, Wai Hoe Ng, Lunde Liao, Peter T H Wong, Nitish V ThakorAbstract:Cathodal-transcranial direct current Stimulation induces therapeutic effects in animal ischemia models by preventing the expansion of ischemic injury during the hyperacute phase of ischemia. However, its efficacy is limited by an accompanying decrease in cerebral blood flow. On the other hand, peripheral Sensory Stimulation can increase blood flow to specific brain areas resulting in rescue of neurovascular functions from ischemic damage. Therefore, the two modalities appear to complement each other to form an integrated treatment modality. Our results showed that hemodynamics was improved in a photothrombotic ischemia model, as cerebral blood volume and hemoglobin oxygen saturation (SO2) recovered to 71% and 76% of the baseline values, respectively. Furthermore, neural activities, including somatoSensory-evoked potentials (110% increase), the alpha-to-delta ratio (27% increase), and the (delta+theta)/(alpha+beta) ratio (27% decrease), were also restored. Infarct volume was reduced by 50% with a 2-fold preservation in the number of neurons and a 6-fold reduction in the number of active microglia in the infarct region compared with the untreated group. Grip strength was also better preserved (28% higher) compared with the untreated group. Overall, this nonpharmacological, nonintrusive approach could be prospectively developed into a clinical treatment modality.
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integrated treatment modality of cathodal transcranial direct current Stimulation with peripheral Sensory Stimulation affords neuroprotection in a rat stroke model
Neurophotonics, 2017Co-Authors: Yu Hang Liu, Su Jing Chan, Aishwarya Bandla, You Yin Chen, Peter T H Wong, Nitish V Thakor, Hanchi Pan, Nicolas Kon Kam King, Lunde LiaoAbstract:Cathodal-transcranial direct current Stimulation induces therapeutic effects in animal ischemia models by preventing the expansion of ischemic injury during the hyperacute phase of ischemia. However, its efficacy is limited by an accompanying decrease in cerebral blood flow. On the other hand, peripheral Sensory Stimulation can increase blood flow to specific brain areas resulting in rescue of neurovascular functions from ischemic damage. Therefore, the two modalities appear to complement each other to form an integrated treatment modality. Our results showed that hemodynamics was improved in a photothrombotic ischemia model, as cerebral blood volume and hemoglobin oxygen saturation ([Formula: see text]) recovered to 71% and 76% of the baseline values, respectively. Furthermore, neural activities, including somatoSensory-evoked potentials (110% increase), the alpha-to-delta ratio (27% increase), and the [Formula: see text] ratio (27% decrease), were also restored. Infarct volume was reduced by 50% with a 2-fold preservation in the number of neurons and a 6-fold reduction in the number of active microglia in the infarct region compared with the untreated group. Grip strength was also better preserved (28% higher) compared with the untreated group. Overall, this nonpharmacological, nonintrusive approach could be prospectively developed into a clinical treatment modality.
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Peripheral Sensory Stimulation is neuroprotective in a rat photothrombotic ischemic stroke model
2016 38th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2016Co-Authors: Aishwarya Bandla, Lunde Liao, Chua Le Teng Sherry, Chan Kim Chuan, Nitish V ThakorAbstract:Ischemic stroke is one of the leading causes of death and disability in the world. Thrombolytic therapy using recombinant tissue plasminogen activator (rtPA), the only FDA-approved drug for acute ischemia, is limited by a narrow therapeutic time window and risk of hemorrhage. There is a serious need for a neuroprotective therapy which is clinically viable. We earlier demonstrated that peripheral Sensory Stimulation (PSS) is a potential therapeutic intervention for hyperacute ischemia resulting in recovery of neurovascular functions when administered immediately following ischemia onset in a rat model. Here, we investigated the potential neuroprotective effect of PSS during the hyperacute phase of stroke in a rat photothrombotic ischemia (PTI) model. We employed electrocorticography (ECoG) to image cortical neural activity responses pre-and post-ischemia. Results showed that the neural activity including somatoSensory evoked potentials (SSEPs) and alpha-to-delta ratio (ADR) were restored following administration of PSS. Further, immunohistochemistry and TTC staining also indicated the neuroprotective effect of PSS intervention, protecting more neurons and reduced infarct. Overall, the study demonstrated that PSS administered immediately following ischemia induction in a rat PTI model can significantly promote neuroprotection via inhibition of peri-infarct expansion and enhanced cortical neural activity functions, suggesting effective recovery. Future work utilizing multimodal imaging to probe changes in neurovascular functions, will explore application of PSS as an adjuvant intervention for improving rtPA thrombolysis therapy.
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rescue of cortical neurovascular functions during the hyperacute phase of ischemia by peripheral Sensory Stimulation
Neurobiology of Disease, 2015Co-Authors: Lunde Liao, Aishwarya Bandla, You Yin Chen, Yu Hang Liu, Hsin Yi Lai, Yenyu Ian Shih, Nitish V ThakorAbstract:Abstract To investigate the potential therapeutic effects of peripheral Sensory Stimulation during the hyperacute phase of stroke, the present study utilized electrophysiology and photoacoustic imaging techniques to evaluate neural and vascular responses of the rat cortex following ischemic insult. We employed a rat model of photothrombotic ischemia (PTI), which targeted the forelimb region of the primary somatoSensory cortex (S1FL), due to its high reproducibility in creating localized ischemic injury. We also established a hybrid, dual-modality system, including six-channel electrocorticography (ECoG) and functional photoacoustic microscopy (fPAM), termed ECoG–fPAM, to image brain functional responses to peripheral Sensory Stimulation during the hyperacute phase of PTI. Our results showed that the evoked cerebral blood volume (CBV) and hemoglobin oxygen saturation (SO2) recovered to 84 ± 7.4% and 79 ± 6.2% of the baseline, respectively, when Stimulation was delivered within 2.5 h following PTI induction. Moreover, neural activity significantly recovered, with 77 ± 8.6%, 76 ± 5.3% and 89 ± 8.2% recovery for the resting-state inter-hemispheric coherence, alpha-to-delta ratio (ADR) and somatoSensory evoked potential (SSEP), respectively. Additionally, we integrated the CBV or SO2 with ADR values as a recovery indicator (RI) to assess functional recovery after PTI. The RI indicated that 80 ± 4.2% of neurovascular function was preserved when Stimulation was delivered within 2.5 h. Additionally, Stimulation treatment within this optimal time window resulted in a minimal infarct volume in the ischemic hemisphere (4.6 ± 2.1%). In contrast, the infarct volume comprised 13.7 ± 1.7% of the ischemic hemisphere when no Stimulation treatment was applied.
Nitish V Thakor - One of the best experts on this subject based on the ideXlab platform.
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Sensory Stimulation enhances functional connectivity towards the somatoSensory cortex in upper limb amputation
International IEEE EMBS Conference on Neural Engineering, 2021Co-Authors: Keqin Ding, Luke Osborn, Rohit Bose, Andrei Dragomir, Manuel S Seet, Anastasios Bezerianos, Nitish V ThakorAbstract:Sensory Stimulation elicits sensations in the phantom hand of individuals with upper limb amputation. The reinstated Sensory information is important to improve phantom limb perception and motor performance. In this work, we aimed to characterize the cortical impact of Sensory Stimulation on sensorimotor integration in upper limb amputees. To this goal, we investigated dynamic functional connectivity computed from electroencephalogram (EEG) recorded while amputees executed phantom hand movements with and without Sensory Stimulation. We focused on the dynamic functional connections to the somatoSensory system and discovered that non-invasive Sensory Stimulation induced increased speed of information transfer, shown by decreased temporal distance, and increased number of connections from the motor, somatoSensory, and multiSensory processing systems. We show that the cortical impact of Sensory Stimulation is manifested not only through functional activities related to the primary somatoSensory system, but also those involving the secondary somatoSensory system.
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Sensory feedback in upper limb amputees impacts cortical activity as revealed by multiscale connectivity analysis
International Conference of the IEEE Engineering in Medicine and Biology Society, 2020Co-Authors: Rohit Bose, Nitish V Thakor, Luke Osborn, Keqin Ding, Anastasios Bezerianos, Manuel Seet, Andrei DragomirAbstract:Sensory feedback in upper limb amputees is crucial for improving movement decoding and also to enhance embodiment of the prosthetic limb. Recently, an increasing number of invasive and noninvasive solutions for Sensory Stimulation have demonstrated the capability of providing a range of sensations to upper limb amputees. However, the cortical impact of restored sensation is not clearly understood. Particularly, understanding the cortical connectivity changes at multiple scales (nodal and modular) in response to Sensory Stimulation, can reveal crucial information on how amputees brain process the Sensory stimuli. Using Electroencephalography (EEG) signals, we compared the cortical connectivity network in response to Sensory feedback provided by targeted transcutaneous electrical nerve Stimulation (tTENS) in an upper limb amputee during phantom upper limb movements. We focused our cortical connectivity analysis on four functional modules comprising of 20 brain regions that are primarily associated with a visually guided motor task (visual, motor, somatoSensory and multiSensory integration (MI)) used in this study. At the modular level, we observed that the hubness (a graph theoretic measure quantifying the importance of brain regions in integrating brain function) of the motor module decreases whereas that of the somatoSensory module increases in presence of tTENS feedback. At the nodal level, similar observations were made for the visual and MI regions. This is the first work to reveal the impact of Sensory feedback at multiple scales in the cortex of amputees in response to Sensory Stimulation.
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integrated treatment modality of cathodal transcranial direct current Stimulation with peripheral Sensory Stimulation affords neuroprotection in a rat stroke model
New Phytologist, 2017Co-Authors: Su Jing Chan, Aishwarya Bandla, Nicolas Kk King, You Yin Chen, Wai Hoe Ng, Lunde Liao, Peter T H Wong, Nitish V ThakorAbstract:Cathodal-transcranial direct current Stimulation induces therapeutic effects in animal ischemia models by preventing the expansion of ischemic injury during the hyperacute phase of ischemia. However, its efficacy is limited by an accompanying decrease in cerebral blood flow. On the other hand, peripheral Sensory Stimulation can increase blood flow to specific brain areas resulting in rescue of neurovascular functions from ischemic damage. Therefore, the two modalities appear to complement each other to form an integrated treatment modality. Our results showed that hemodynamics was improved in a photothrombotic ischemia model, as cerebral blood volume and hemoglobin oxygen saturation (SO2) recovered to 71% and 76% of the baseline values, respectively. Furthermore, neural activities, including somatoSensory-evoked potentials (110% increase), the alpha-to-delta ratio (27% increase), and the (delta+theta)/(alpha+beta) ratio (27% decrease), were also restored. Infarct volume was reduced by 50% with a 2-fold preservation in the number of neurons and a 6-fold reduction in the number of active microglia in the infarct region compared with the untreated group. Grip strength was also better preserved (28% higher) compared with the untreated group. Overall, this nonpharmacological, nonintrusive approach could be prospectively developed into a clinical treatment modality.
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integrated treatment modality of cathodal transcranial direct current Stimulation with peripheral Sensory Stimulation affords neuroprotection in a rat stroke model
Neurophotonics, 2017Co-Authors: Yu Hang Liu, Su Jing Chan, Aishwarya Bandla, You Yin Chen, Peter T H Wong, Nitish V Thakor, Hanchi Pan, Nicolas Kon Kam King, Lunde LiaoAbstract:Cathodal-transcranial direct current Stimulation induces therapeutic effects in animal ischemia models by preventing the expansion of ischemic injury during the hyperacute phase of ischemia. However, its efficacy is limited by an accompanying decrease in cerebral blood flow. On the other hand, peripheral Sensory Stimulation can increase blood flow to specific brain areas resulting in rescue of neurovascular functions from ischemic damage. Therefore, the two modalities appear to complement each other to form an integrated treatment modality. Our results showed that hemodynamics was improved in a photothrombotic ischemia model, as cerebral blood volume and hemoglobin oxygen saturation ([Formula: see text]) recovered to 71% and 76% of the baseline values, respectively. Furthermore, neural activities, including somatoSensory-evoked potentials (110% increase), the alpha-to-delta ratio (27% increase), and the [Formula: see text] ratio (27% decrease), were also restored. Infarct volume was reduced by 50% with a 2-fold preservation in the number of neurons and a 6-fold reduction in the number of active microglia in the infarct region compared with the untreated group. Grip strength was also better preserved (28% higher) compared with the untreated group. Overall, this nonpharmacological, nonintrusive approach could be prospectively developed into a clinical treatment modality.
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Peripheral Sensory Stimulation is neuroprotective in a rat photothrombotic ischemic stroke model
2016 38th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2016Co-Authors: Aishwarya Bandla, Lunde Liao, Chua Le Teng Sherry, Chan Kim Chuan, Nitish V ThakorAbstract:Ischemic stroke is one of the leading causes of death and disability in the world. Thrombolytic therapy using recombinant tissue plasminogen activator (rtPA), the only FDA-approved drug for acute ischemia, is limited by a narrow therapeutic time window and risk of hemorrhage. There is a serious need for a neuroprotective therapy which is clinically viable. We earlier demonstrated that peripheral Sensory Stimulation (PSS) is a potential therapeutic intervention for hyperacute ischemia resulting in recovery of neurovascular functions when administered immediately following ischemia onset in a rat model. Here, we investigated the potential neuroprotective effect of PSS during the hyperacute phase of stroke in a rat photothrombotic ischemia (PTI) model. We employed electrocorticography (ECoG) to image cortical neural activity responses pre-and post-ischemia. Results showed that the neural activity including somatoSensory evoked potentials (SSEPs) and alpha-to-delta ratio (ADR) were restored following administration of PSS. Further, immunohistochemistry and TTC staining also indicated the neuroprotective effect of PSS intervention, protecting more neurons and reduced infarct. Overall, the study demonstrated that PSS administered immediately following ischemia induction in a rat PTI model can significantly promote neuroprotection via inhibition of peri-infarct expansion and enhanced cortical neural activity functions, suggesting effective recovery. Future work utilizing multimodal imaging to probe changes in neurovascular functions, will explore application of PSS as an adjuvant intervention for improving rtPA thrombolysis therapy.
Rohit Bose - One of the best experts on this subject based on the ideXlab platform.
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Sensory Stimulation enhances functional connectivity towards the somatoSensory cortex in upper limb amputation
International IEEE EMBS Conference on Neural Engineering, 2021Co-Authors: Keqin Ding, Luke Osborn, Rohit Bose, Andrei Dragomir, Manuel S Seet, Anastasios Bezerianos, Nitish V ThakorAbstract:Sensory Stimulation elicits sensations in the phantom hand of individuals with upper limb amputation. The reinstated Sensory information is important to improve phantom limb perception and motor performance. In this work, we aimed to characterize the cortical impact of Sensory Stimulation on sensorimotor integration in upper limb amputees. To this goal, we investigated dynamic functional connectivity computed from electroencephalogram (EEG) recorded while amputees executed phantom hand movements with and without Sensory Stimulation. We focused on the dynamic functional connections to the somatoSensory system and discovered that non-invasive Sensory Stimulation induced increased speed of information transfer, shown by decreased temporal distance, and increased number of connections from the motor, somatoSensory, and multiSensory processing systems. We show that the cortical impact of Sensory Stimulation is manifested not only through functional activities related to the primary somatoSensory system, but also those involving the secondary somatoSensory system.
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Sensory Stimulation enhances phantom limb perception and movement decoding
Journal of Neural Engineering, 2020Co-Authors: Luke Osborn, Keqin Ding, Mark Hays, Rohit Bose, Mark M Iskarous, Andrei Dragomir, Zied Tayeb, Gyorgy LevayAbstract:Objective. A major challenge for controlling a prosthetic arm is communication between the device and the user's phantom limb. We show the ability to enhance phantom limb perception and improve movement decoding through targeted transcutaneous electrical nerve Stimulation in individuals with an arm amputation. Approach. Transcutaneous nerve Stimulation experiments were performed with four participants with arm amputation to map phantom limb perception. We measured myoelectric signals during phantom hand movements before and after participants received Sensory Stimulation. Using electroencephalogram (EEG) monitoring, we measured the neural activity in sensorimotor regions during phantom movements and Stimulation. In one participant, we also tracked Sensory mapping over 2 years and movement decoding performance over 1 year. Main results. Results show improvements in the participants' ability to perceive and move the phantom hand as a result of Sensory Stimulation, which leads to improved movement decoding. In the extended study with one participant, we found that Sensory mapping remains stable over 2 years. Sensory Stimulation improves within-day movement decoding while performance remains stable over 1 year. From the EEG, we observed cortical correlates of sensorimotor integration and increased motor-related neural activity as a result of enhanced phantom limb perception. Significance. This work demonstrates that phantom limb perception influences prosthesis control and can benefit from targeted nerve Stimulation. These findings have implications for improving prosthesis usability and function due to a heightened sense of the phantom hand.
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Sensory feedback in upper limb amputees impacts cortical activity as revealed by multiscale connectivity analysis
International Conference of the IEEE Engineering in Medicine and Biology Society, 2020Co-Authors: Rohit Bose, Nitish V Thakor, Luke Osborn, Keqin Ding, Anastasios Bezerianos, Manuel Seet, Andrei DragomirAbstract:Sensory feedback in upper limb amputees is crucial for improving movement decoding and also to enhance embodiment of the prosthetic limb. Recently, an increasing number of invasive and noninvasive solutions for Sensory Stimulation have demonstrated the capability of providing a range of sensations to upper limb amputees. However, the cortical impact of restored sensation is not clearly understood. Particularly, understanding the cortical connectivity changes at multiple scales (nodal and modular) in response to Sensory Stimulation, can reveal crucial information on how amputees brain process the Sensory stimuli. Using Electroencephalography (EEG) signals, we compared the cortical connectivity network in response to Sensory feedback provided by targeted transcutaneous electrical nerve Stimulation (tTENS) in an upper limb amputee during phantom upper limb movements. We focused our cortical connectivity analysis on four functional modules comprising of 20 brain regions that are primarily associated with a visually guided motor task (visual, motor, somatoSensory and multiSensory integration (MI)) used in this study. At the modular level, we observed that the hubness (a graph theoretic measure quantifying the importance of brain regions in integrating brain function) of the motor module decreases whereas that of the somatoSensory module increases in presence of tTENS feedback. At the nodal level, similar observations were made for the visual and MI regions. This is the first work to reveal the impact of Sensory feedback at multiple scales in the cortex of amputees in response to Sensory Stimulation.
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towards machine to brain interfaces Sensory Stimulation enhances sensorimotor dynamic functional connectivity in upper limb amputees
Journal of Neural Engineering, 2020Co-Authors: Keqin Ding, Luke Osborn, Rohit Bose, Andrei Dragomir, Manuel S Seet, Anastasios BezerianosAbstract:Objective Recent development of Sensory Stimulation techniques demonstrates the ability to elicit touch-like phantom sensations in upper limb amputees. The cortical processing of this phantom sensation and the corresponding influences on sensorimotor functional connectivity have not been studied. We hypothesize that Sensory Stimulation has a profound impact on the sensorimotor cortical functional interactions, which will be uncovered by dynamic functional connectivity (dFC) analysis of amputees' electroencephalogram (EEG) recordings. Approach We investigated dFC between cortical areas associated with somatoSensory, motor, visual, and multiSensory processing functions using EEG signals. We applied dFC to the EEG of two amputees performing hand movements with and without Sensory Stimulation and compared the results with those from three able-bodied subjects. We quantified the changes due to Sensory Stimulation using dFC metrics, namely temporal distance, number of connection paths, temporal global and local efficiencies, and clustering coefficient. Main results We show a significant effect of Sensory Stimulation on functional connectivity in the amputee brains, with notable facilitation on multiSensory processing among the cortical systems involved in sensorimotor processing. The dFC metrics reveal that Sensory Stimulation enhances the speed of information transfer (shown by decreases in temporal distance) and the number of connection paths between the brain systems involved in sensorimotor processing, including primary somatoSensory and motor, and higher order processing regions. Significance This is the first work to reveal dynamic communication between somatoSensory, motor, and higher order processing regions in the cortex of amputees in response to Sensory Stimulation. We believe that our work provides crucial insights into the cortical impact of Sensory Stimulation in amputees, which may lead to the design of personalized brain-informed Sensory feedback paradigms. This in turn may lead to building novel Machine to Brain Interfaces involving Sensory feedback and the resultant enhanced motor performance.
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Sensory Stimulation enhances phantom limb perception and movement decoding
medRxiv, 2020Co-Authors: Luke Osborn, Keqin Ding, Mark Hays, Rohit Bose, Mark M Iskarous, Andrei Dragomir, Zied Tayeb, Gyorgy Levay, Christopher L Hunt, Gordon ChengAbstract:Objective. A major challenge for controlling a prosthetic arm is communication between the device and the user9s phantom limb. We show the ability to enhance amputees9 phantom limb perception and improve movement decoding through targeted transcutaneous electrical nerve Stimulation (tTENS). Approach. Transcutaneous nerve Stimulation experiments were performed with four amputee participants to map phantom limb perception. We measured myoelectric signals during phantom hand movements before and after amputees received Sensory Stimulation. Using electroencephalogram (EEG) monitoring, we measure the neural activity in sensorimotor regions during phantom movements and Stimulation. In one participant, we also tracked Sensory mapping over 2 years and movement decoding performance over 1 year. Main results. Results show improvements in the amputees9 ability to perceive and move the phantom hand as a result of Sensory Stimulation, which leads to improved movement decoding. In the extended study with one amputee, we found that Sensory mapping remains stable over 2 years. Remarkably, Sensory Stimulation improves within-day movement decoding while performance remains stable over 1 year. From the EEG, we observed cortical correlates of sensorimotor integration and increased motor-related neural activity as a result of enhanced phantom limb perception. Significance. This work demonstrates that phantom limb perception influences prosthesis control and can benefit from targeted nerve Stimulation. These findings have implications for improving prosthesis usability and function due to a heightened sense of the phantom hand.
Andrei Dragomir - One of the best experts on this subject based on the ideXlab platform.
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Sensory Stimulation enhances functional connectivity towards the somatoSensory cortex in upper limb amputation
International IEEE EMBS Conference on Neural Engineering, 2021Co-Authors: Keqin Ding, Luke Osborn, Rohit Bose, Andrei Dragomir, Manuel S Seet, Anastasios Bezerianos, Nitish V ThakorAbstract:Sensory Stimulation elicits sensations in the phantom hand of individuals with upper limb amputation. The reinstated Sensory information is important to improve phantom limb perception and motor performance. In this work, we aimed to characterize the cortical impact of Sensory Stimulation on sensorimotor integration in upper limb amputees. To this goal, we investigated dynamic functional connectivity computed from electroencephalogram (EEG) recorded while amputees executed phantom hand movements with and without Sensory Stimulation. We focused on the dynamic functional connections to the somatoSensory system and discovered that non-invasive Sensory Stimulation induced increased speed of information transfer, shown by decreased temporal distance, and increased number of connections from the motor, somatoSensory, and multiSensory processing systems. We show that the cortical impact of Sensory Stimulation is manifested not only through functional activities related to the primary somatoSensory system, but also those involving the secondary somatoSensory system.
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Sensory Stimulation enhances phantom limb perception and movement decoding
Journal of Neural Engineering, 2020Co-Authors: Luke Osborn, Keqin Ding, Mark Hays, Rohit Bose, Mark M Iskarous, Andrei Dragomir, Zied Tayeb, Gyorgy LevayAbstract:Objective. A major challenge for controlling a prosthetic arm is communication between the device and the user's phantom limb. We show the ability to enhance phantom limb perception and improve movement decoding through targeted transcutaneous electrical nerve Stimulation in individuals with an arm amputation. Approach. Transcutaneous nerve Stimulation experiments were performed with four participants with arm amputation to map phantom limb perception. We measured myoelectric signals during phantom hand movements before and after participants received Sensory Stimulation. Using electroencephalogram (EEG) monitoring, we measured the neural activity in sensorimotor regions during phantom movements and Stimulation. In one participant, we also tracked Sensory mapping over 2 years and movement decoding performance over 1 year. Main results. Results show improvements in the participants' ability to perceive and move the phantom hand as a result of Sensory Stimulation, which leads to improved movement decoding. In the extended study with one participant, we found that Sensory mapping remains stable over 2 years. Sensory Stimulation improves within-day movement decoding while performance remains stable over 1 year. From the EEG, we observed cortical correlates of sensorimotor integration and increased motor-related neural activity as a result of enhanced phantom limb perception. Significance. This work demonstrates that phantom limb perception influences prosthesis control and can benefit from targeted nerve Stimulation. These findings have implications for improving prosthesis usability and function due to a heightened sense of the phantom hand.
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Sensory feedback in upper limb amputees impacts cortical activity as revealed by multiscale connectivity analysis
International Conference of the IEEE Engineering in Medicine and Biology Society, 2020Co-Authors: Rohit Bose, Nitish V Thakor, Luke Osborn, Keqin Ding, Anastasios Bezerianos, Manuel Seet, Andrei DragomirAbstract:Sensory feedback in upper limb amputees is crucial for improving movement decoding and also to enhance embodiment of the prosthetic limb. Recently, an increasing number of invasive and noninvasive solutions for Sensory Stimulation have demonstrated the capability of providing a range of sensations to upper limb amputees. However, the cortical impact of restored sensation is not clearly understood. Particularly, understanding the cortical connectivity changes at multiple scales (nodal and modular) in response to Sensory Stimulation, can reveal crucial information on how amputees brain process the Sensory stimuli. Using Electroencephalography (EEG) signals, we compared the cortical connectivity network in response to Sensory feedback provided by targeted transcutaneous electrical nerve Stimulation (tTENS) in an upper limb amputee during phantom upper limb movements. We focused our cortical connectivity analysis on four functional modules comprising of 20 brain regions that are primarily associated with a visually guided motor task (visual, motor, somatoSensory and multiSensory integration (MI)) used in this study. At the modular level, we observed that the hubness (a graph theoretic measure quantifying the importance of brain regions in integrating brain function) of the motor module decreases whereas that of the somatoSensory module increases in presence of tTENS feedback. At the nodal level, similar observations were made for the visual and MI regions. This is the first work to reveal the impact of Sensory feedback at multiple scales in the cortex of amputees in response to Sensory Stimulation.
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towards machine to brain interfaces Sensory Stimulation enhances sensorimotor dynamic functional connectivity in upper limb amputees
Journal of Neural Engineering, 2020Co-Authors: Keqin Ding, Luke Osborn, Rohit Bose, Andrei Dragomir, Manuel S Seet, Anastasios BezerianosAbstract:Objective Recent development of Sensory Stimulation techniques demonstrates the ability to elicit touch-like phantom sensations in upper limb amputees. The cortical processing of this phantom sensation and the corresponding influences on sensorimotor functional connectivity have not been studied. We hypothesize that Sensory Stimulation has a profound impact on the sensorimotor cortical functional interactions, which will be uncovered by dynamic functional connectivity (dFC) analysis of amputees' electroencephalogram (EEG) recordings. Approach We investigated dFC between cortical areas associated with somatoSensory, motor, visual, and multiSensory processing functions using EEG signals. We applied dFC to the EEG of two amputees performing hand movements with and without Sensory Stimulation and compared the results with those from three able-bodied subjects. We quantified the changes due to Sensory Stimulation using dFC metrics, namely temporal distance, number of connection paths, temporal global and local efficiencies, and clustering coefficient. Main results We show a significant effect of Sensory Stimulation on functional connectivity in the amputee brains, with notable facilitation on multiSensory processing among the cortical systems involved in sensorimotor processing. The dFC metrics reveal that Sensory Stimulation enhances the speed of information transfer (shown by decreases in temporal distance) and the number of connection paths between the brain systems involved in sensorimotor processing, including primary somatoSensory and motor, and higher order processing regions. Significance This is the first work to reveal dynamic communication between somatoSensory, motor, and higher order processing regions in the cortex of amputees in response to Sensory Stimulation. We believe that our work provides crucial insights into the cortical impact of Sensory Stimulation in amputees, which may lead to the design of personalized brain-informed Sensory feedback paradigms. This in turn may lead to building novel Machine to Brain Interfaces involving Sensory feedback and the resultant enhanced motor performance.
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Sensory Stimulation enhances phantom limb perception and movement decoding
medRxiv, 2020Co-Authors: Luke Osborn, Keqin Ding, Mark Hays, Rohit Bose, Mark M Iskarous, Andrei Dragomir, Zied Tayeb, Gyorgy Levay, Christopher L Hunt, Gordon ChengAbstract:Objective. A major challenge for controlling a prosthetic arm is communication between the device and the user9s phantom limb. We show the ability to enhance amputees9 phantom limb perception and improve movement decoding through targeted transcutaneous electrical nerve Stimulation (tTENS). Approach. Transcutaneous nerve Stimulation experiments were performed with four amputee participants to map phantom limb perception. We measured myoelectric signals during phantom hand movements before and after amputees received Sensory Stimulation. Using electroencephalogram (EEG) monitoring, we measure the neural activity in sensorimotor regions during phantom movements and Stimulation. In one participant, we also tracked Sensory mapping over 2 years and movement decoding performance over 1 year. Main results. Results show improvements in the amputees9 ability to perceive and move the phantom hand as a result of Sensory Stimulation, which leads to improved movement decoding. In the extended study with one amputee, we found that Sensory mapping remains stable over 2 years. Remarkably, Sensory Stimulation improves within-day movement decoding while performance remains stable over 1 year. From the EEG, we observed cortical correlates of sensorimotor integration and increased motor-related neural activity as a result of enhanced phantom limb perception. Significance. This work demonstrates that phantom limb perception influences prosthesis control and can benefit from targeted nerve Stimulation. These findings have implications for improving prosthesis usability and function due to a heightened sense of the phantom hand.
Ela B Plow - One of the best experts on this subject based on the ideXlab platform.
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treatment of upper limb paresis with repetitive peripheral nerve Sensory Stimulation and motor training study protocol for a randomized controlled trial
Frontiers in Neurology, 2020Co-Authors: Adriana Bastos Conforto, Andre G Machado, Isabella S Menezes, Nathalia H V Ribeiro, Rafael Luccas, Danielle S Pires, Claudia Da Costa Leite, Ela B PlowAbstract:Background: Repetitive peripheral nerve Sensory Stimulation (RPSS) has emerged as a potential adjuvant strategy to motor training in stroke rehabilitation. The aim of this study is to test the hypothesis that 3 h sessions of active RPSS associated with functional electrical Stimulation (FES) and task-specific training (TST) distributed three times a week, over 6 weeks, is more beneficial to improve upper limb motor function than sham RPSS in addition to FES and TST, in subjects with moderate to severe hand motor impairments in the chronic phase (>6 months) after stroke. Methods: In this single-center, randomized, placebo controlled, parallel-group, double-blind study we compare the effects of 18 sessions of active and sham RPSS as add-on interventions to FES and task-specific training of the paretic upper limb, in 40 subjects in the chronic phase after ischemic or hemorrhagic stroke, with Fugl-Meyer upper limb scores ranging from 7 to 50 and able to voluntarily activate any active range of wrist extension. The primary outcome measure is the Wolf Motor Function Test (WMFT) after 6 weeks of treatment. The secondary outcomes are the WMFT at 3, 10, and 18 weeks after beginning of treatment, as well as the following outcomes measured at 3, 6, 10, and 18 weeks: Motor Activity Log; active range of motion of wrist extension and flexion; grasp and pinch strength in the paretic and non-paretic sides (the order of testing is randomized within and across subjects); Modified Ashworth Scale; Fugl-Meyer Assessment-Upper Limb in the paretic arm; Barthel Index; Stroke Impact Scale. Discussion: This project represents a major step in developing a rehabilitation strategy with potential to have impact on the treatment of stroke patients with poor motor recovery in developing countries worldwide. The study preliminarily evaluates a straightforward, non-invasive, inexpensive intervention. If feasibility and preliminary efficacy are demonstrated, further investigations of the proposed intervention (underlying mechanisms/ effects in larger numbers of patients) should be performed. Trial Registration: NCT02658578.
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treatment of upper limb paresis with repetitive peripheral nerve Sensory Stimulation and motor training study protocol for a randomized controlled trial
Frontiers in Neurology, 2020Co-Authors: Adriana Bastos Conforto, Andre G Machado, Isabella S Menezes, Nathalia H V Ribeiro, Rafael Luccas, Danielle S Pires, Claudia Da Costa Leite, Ela B PlowAbstract:Background: Repetitive peripheral nerve Sensory Stimulation (RPSS) has emerged as a potential adjuvant strategy to motor training in stroke rehabilitation. The aim of this study is to test the hypothesis that 3-hour sessions of active RPSS associated with functional electrical Stimulation (FES) and task-specific training (TST) distributed three times a week, over six weeks, is more beneficial to improve upper limb motor function than sham RPSS in addition to FES and TST, in subjects with moderate to severe hand motor impairments in the chronic phase (> 6 months) after stroke. Methods: In this single-center, randomized, placebo controlled, parallel-group, double-blind study we compare the effects of 18 sessions of active and sham RPSS as add-on interventions to FES and task-specific training of the paretic upper limb, in 40 subjects in the chronic phase after ischemic or hemorrhagic stroke. The primary outcome measure is the Wolf Motor Function Test (WMFT) after 6 weeks of treatment. The secondary outcomes are the WMFT at 3, 10 and 18 weeks after beginning of treatment, as well as the following outcomes measured at 3 weeks 6, 10 and 18 weeks: Motor Activity Log; active range of motion of wrist extension and flexion; grasp and pinch strength in the paretic and nonparetic sides (the order of testing is randomized within and across subjects); Modified Ashworth Scale; Fugl-Meyer Assessment-Upper Limb in the paretic arm; Barthel Index; Stroke Impact Scale. Discussion: This project represents a major step in developing a rehabilitation strategy with potential to have impact on the treatment of stroke patients with poor motor recovery in developing countries worldwide. The study preliminarily evaluates a straightforward, non-invasive, inexpensive intervention. If feasibility and preliminary efficacy are demonstrated, further investigations of the proposed intervention (underlying mechanisms/ effects in larger numbers of patients) should be performed. Ethics and Dissemination: The protocol, registered at clinicaltrials.gov, was approved by the institutional and the Brazilian federal ethics committees. Dissemination will include presentation in conferences, peer-reviewed publications, presentation to patients and public groups.
