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Kim YK, Gwerder M, Taylor WR, Baur H, Singh NB. Adaptive gait responses to varying weight-bearing conditions: Inferences from gait dynamics and H-reflex magnitude. Exp Physiol 2024; 109:754-765. [PMID: 38488681 PMCID: PMC11061628 DOI: 10.1113/ep091492] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 02/28/2024] [Indexed: 05/02/2024]
Abstract
This study investigates the effects of varying loading conditions on excitability in neural pathways and gait dynamics. We focussed on evaluating the magnitude of the Hoffman reflex (H-reflex), a neurophysiological measure representing the capability to activate motor neurons and the timing and placement of the foot during walking. We hypothesized that weight manipulation would alter H-reflex magnitude, footfall and lower body kinematics. Twenty healthy participants were recruited and subjected to various weight-loading conditions. The H-reflex, evoked by stimulating the tibial nerve, was assessed from the dominant leg during walking. Gait was evaluated under five conditions: body weight, 20% and 40% additional body weight, and 20% and 40% reduced body weight (via a harness). Participants walked barefoot on a treadmill under each condition, and the timing of electrical stimulation was set during the stance phase shortly after the heel strike. Results show that different weight-loading conditions significantly impact the timing and placement of the foot and gait stability. Weight reduction led to a 25% decrease in double limb support time and an 11% narrowing of step width, while weight addition resulted in an increase of 9% in step width compared to body weight condition. Furthermore, swing time variability was higher for both the extreme weight conditions, while the H-reflex reduced to about 45% between the extreme conditions. Finally, the H-reflex showed significant main effects on variability of both stance and swing phases, indicating that muscle-motor excitability might serve as feedback for enhanced regulation of gait dynamics under challenging conditions.
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Affiliation(s)
- Yong Kuk Kim
- Laboratory for Movement Biomechanics, Institute for Biomechanics, Department of Health Sciences and TechnologyETH ZurichZurichSwitzerland
| | - Michelle Gwerder
- Laboratory for Movement Biomechanics, Institute for Biomechanics, Department of Health Sciences and TechnologyETH ZurichZurichSwitzerland
- Department of Biomedical EngineeringUniversity of BaselBaselSwitzerland
| | - William R. Taylor
- Laboratory for Movement Biomechanics, Institute for Biomechanics, Department of Health Sciences and TechnologyETH ZurichZurichSwitzerland
| | - Heiner Baur
- School of Health Professions, PhysiotherapyUniversity of Applied SciencesBernSwitzerland
| | - Navrag B. Singh
- Laboratory for Movement Biomechanics, Institute for Biomechanics, Department of Health Sciences and TechnologyETH ZurichZurichSwitzerland
- Singapore‐ETH Centre, Future Health Technologies ProgramSingaporeSingapore
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Bogard AT, Hembree TG, Pollet AK, Smith AC, Ryder SC, Marzloff G, Tan AQ. Intermittent Hypoxia-Induced Enhancements in Corticospinal Excitability Predict Gains in Motor Learning and Metabolic Efficiency. RESEARCH SQUARE 2024:rs.3.rs-4259378. [PMID: 38746438 PMCID: PMC11092812 DOI: 10.21203/rs.3.rs-4259378/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Acute intermittent hypoxia (AIH) enhances human motor function after incomplete spinal cord injury. Although the underlying mechanisms in humans are unknown, emerging evidence indicates that AIH facilitates corticospinal excitability to the upper limb. However, the functional relevance of this plasticity remains unexplored, and it is unclear whether similar plasticity can be induced for lower limb motor areas. We recently demonstrated that AIH improves motor learning and metabolic efficiency during split-belt walking. Thus, we hypothesized that AIH increases lower limb excitability and that these enhancements would predict the magnitude of motor learning and the corresponding reductions in net metabolic power. We assessed tibialis anterior (TA) excitability using transcranial magnetic stimulation and quantified changes in spatiotemporal asymmetries and net metabolic power in response to split-belt speed perturbations. We show that AIH enhances TA excitability, and that the magnitude of this facilitation positively correlates with greater spatiotemporal adaptation. Notably, we demonstrate a novel association between increased excitability and reduced net metabolic power during motor learning and savings. Together, our results suggest that AIH-induced gains in excitability predict both the magnitude of motor learning and the associated metabolic efficiency. Determining indices of AIH-induced improvements in motor performance is critical for optimizing its therapeutic reach.
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Affiliation(s)
- Alysha T. Bogard
- Sensorimotor Recovery and Neuroplasticity Lab at the University of Colorado, Boulder, Dept. of Integrative Physiology, 80309, USA
| | - Thomas G. Hembree
- Sensorimotor Recovery and Neuroplasticity Lab at the University of Colorado, Boulder, Dept. of Integrative Physiology, 80309, USA
| | - Aviva K. Pollet
- Sensorimotor Recovery and Neuroplasticity Lab at the University of Colorado, Boulder, Dept. of Integrative Physiology, 80309, USA
| | - Andrew C. Smith
- University of Colorado School of Medicine, Dept. of Physical Medicine and Rehabilitation, Aurora, 80045, USA
| | | | - George Marzloff
- Rocky Mountain Regional VA Medical Center, Aurora, 80045, USA
| | - Andrew Q. Tan
- Sensorimotor Recovery and Neuroplasticity Lab at the University of Colorado, Boulder, Dept. of Integrative Physiology, 80309, USA
- Rocky Mountain Regional VA Medical Center, Aurora, 80045, USA
- Center for Neuroscience, University of Colorado, Boulder, 80309, USA
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Tan AQ, Tuthill C, Corsten AN, Barth S, Trumbower RD. A single sequence of intermittent hypoxia does not alter stretch reflex excitability in able-bodied individuals. Exp Physiol 2024; 109:576-587. [PMID: 38356241 PMCID: PMC10988685 DOI: 10.1113/ep091531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 12/21/2023] [Indexed: 02/16/2024]
Abstract
Spasticity attributable to exaggerated stretch reflex pathways, particularly affecting the ankle plantar flexors, often impairs overground walking in persons with incomplete spinal cord injury. Compelling evidence from rodent models underscores how exposure to acute intermittent hypoxia (AIH) can provide a unique medium to induce spinal plasticity in key inhibitory pathways mediating stretch reflex excitability and potentially affect spasticity. In this study, we quantify the effects of a single exposure to AIH on the stretch reflex in able-bodied individuals. We hypothesized that a single sequence of AIH will increase the stretch reflex excitability of the soleus muscle during ramp-and-hold angular perturbations applied to the ankle joint while participants perform passive and volitionally matched contractions. Our results revealed that a single AIH exposure did not significantly change the stretch reflex excitability during both passive and active matching conditions. Furthermore, we found that able-bodied individuals increased their stretch reflex response from passive to active matching conditions after both sham and AIH exposures. Together, these findings suggest that a single AIH exposure might not engage inhibitory pathways sufficiently to alter stretch reflex responses in able-bodied persons. However, the generalizability of our present findings requires further examination during repetitive exposures to AIH along with potential reflex modulation during functional movements, such as overground walking.
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Affiliation(s)
- Andrew Q. Tan
- Department of Integrative PhysiologyUniversity of ColoradoBoulderColoradoUSA
| | - Christopher Tuthill
- Department of Physical Medicine and RehabilitationHarvard Medical SchoolBostonMassachusettsUSA
- Department of Physical Medicine and RehabilitationINSPIRE LaboratorySpaulding Rehabilitation HospitalBostonMassachusettsUSA
| | - Anthony N. Corsten
- Department of Physical Medicine and RehabilitationINSPIRE LaboratorySpaulding Rehabilitation HospitalBostonMassachusettsUSA
| | - Stella Barth
- Department of Physical Medicine and RehabilitationINSPIRE LaboratorySpaulding Rehabilitation HospitalBostonMassachusettsUSA
| | - Randy D. Trumbower
- Department of Physical Medicine and RehabilitationHarvard Medical SchoolBostonMassachusettsUSA
- Department of Physical Medicine and RehabilitationINSPIRE LaboratorySpaulding Rehabilitation HospitalBostonMassachusettsUSA
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Roumengous T, Thakkar B, Peterson CL. Paired pulse transcranial magnetic stimulation in the assessment of biceps voluntary activation in individuals with tetraplegia. Front Hum Neurosci 2022; 16:976014. [DOI: 10.3389/fnhum.2022.976014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 10/17/2022] [Indexed: 11/06/2022] Open
Abstract
After spinal cord injury (SCI), motoneuron death occurs at and around the level of injury which induces changes in function and organization throughout the nervous system, including cortical changes. Muscle affected by SCI may consist of both innervated (accessible to voluntary drive) and denervated (inaccessible to voluntary drive) muscle fibers. Voluntary activation measured with transcranial magnetic stimulation (VATMS) can quantify voluntary cortical/subcortical drive to muscle but is limited by technical challenges including suboptimal stimulation of target muscle relative to its antagonist. The motor evoked potential (MEP) in the biceps compared to the triceps (i.e., MEP ratio) may be a key parameter in the measurement of biceps VATMS after SCI. We used paired pulse TMS, which can inhibit or facilitate MEPs, to determine whether the MEP ratio affects VATMS in individuals with tetraplegia. Ten individuals with tetraplegia following cervical SCI and ten non-impaired individuals completed single pulse and paired pulse VATMS protocols. Paired pulse stimulation was delivered at 1.5, 10, and 30 ms inter-stimulus intervals (ISI). In both the SCI and non-impaired groups, the main effect of the stimulation pulse (paired pulse compared to single pulse) on VATMS was not significant in the linear mixed-effects models. In both groups for the stimulation parameters we tested, the MEP ratio was not modulated across all effort levels and did not affect VATMS. Linearity of the voluntary moment and superimposed twitch moment relation was lower in SCI participants compared to non-impaired. Poor linearity in the SCI group limits interpretation of VATMS. Future work is needed to address methodological issues that limit clinical application of VATMS.
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Balbinot G, Li G, Wiest MJ, Pakosh M, Furlan JC, Kalsi-Ryan S, Zariffa J. Properties of the surface electromyogram following traumatic spinal cord injury: a scoping review. J Neuroeng Rehabil 2021; 18:105. [PMID: 34187509 PMCID: PMC8244234 DOI: 10.1186/s12984-021-00888-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 05/27/2021] [Indexed: 12/23/2022] Open
Abstract
Traumatic spinal cord injury (SCI) disrupts spinal and supraspinal pathways, and this process is reflected in changes in surface electromyography (sEMG). sEMG is an informative complement to current clinical testing and can capture the residual motor command in great detail-including in muscles below the level of injury with seemingly absent motor activities. In this comprehensive review, we sought to describe how the sEMG properties are changed after SCI. We conducted a systematic literature search followed by a narrative review focusing on sEMG analysis techniques and signal properties post-SCI. We found that early reports were mostly focused on the qualitative analysis of sEMG patterns and evolved to semi-quantitative scores and a more detailed amplitude-based quantification. Nonetheless, recent studies are still constrained to an amplitude-based analysis of the sEMG, and there are opportunities to more broadly characterize the time- and frequency-domain properties of the signal as well as to take fuller advantage of high-density EMG techniques. We recommend the incorporation of a broader range of signal properties into the neurophysiological assessment post-SCI and the development of a greater understanding of the relation between these sEMG properties and underlying physiology. Enhanced sEMG analysis could contribute to a more complete description of the effects of SCI on upper and lower motor neuron function and their interactions, and also assist in understanding the mechanisms of change following neuromodulation or exercise therapy.
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Affiliation(s)
- Gustavo Balbinot
- KITE-Toronto Rehabilitation Institute, University Health Network, Toronto, ON, M5G 2A2, Canada.
| | - Guijin Li
- KITE-Toronto Rehabilitation Institute, University Health Network, Toronto, ON, M5G 2A2, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto, Canada
| | - Matheus Joner Wiest
- KITE-Toronto Rehabilitation Institute, University Health Network, Toronto, ON, M5G 2A2, Canada
| | - Maureen Pakosh
- Library & Information Services, Toronto Rehabilitation Institute, University Health Network, Toronto, Canada
| | - Julio Cesar Furlan
- KITE-Toronto Rehabilitation Institute, University Health Network, Toronto, ON, M5G 2A2, Canada
- Rehabilitation Sciences Institute, University of Toronto, Toronto, Canada
- Department of Medicine, Division of Physical Medicine and Rehabilitation, University of Toronto, Toronto, Canada
- Division of Physical Medicine and Rehabilitation, Toronto Rehabilitation Institute, University Health Network, Toronto, Canada
- Institute of Medical Sciences, University of Toronto, Toronto, Canada
| | - Sukhvinder Kalsi-Ryan
- KITE-Toronto Rehabilitation Institute, University Health Network, Toronto, ON, M5G 2A2, Canada
- Rehabilitation Sciences Institute, University of Toronto, Toronto, Canada
- Department of Physical Therapy, University of Toronto, Toronto, Canada
| | - Jose Zariffa
- KITE-Toronto Rehabilitation Institute, University Health Network, Toronto, ON, M5G 2A2, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto, Canada
- Rehabilitation Sciences Institute, University of Toronto, Toronto, Canada
- Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, Toronto, Canada
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Bochkezanian V, Newton RU, Trajano GS, Vieira A, Pulverenti TS, Blazevich AJ. Effect of tendon vibration during wide-pulse neuromuscular electrical stimulation (NMES) on muscle force production in people with spinal cord injury (SCI). BMC Neurol 2018; 18:17. [PMID: 29433467 PMCID: PMC5809925 DOI: 10.1186/s12883-018-1020-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Accepted: 02/02/2018] [Indexed: 12/13/2022] Open
Abstract
Background Neuromuscular electrical stimulation (NMES) is commonly used in skeletal muscles in people with spinal cord injury (SCI) with the aim of increasing muscle recruitment and thus muscle force production. NMES has been conventionally used in clinical practice as functional electrical stimulation (FES), using low levels of evoked force that cannot optimally stimulate muscular strength and mass improvements, and thus trigger musculoskeletal changes in paralysed muscles. The use of high intensity intermittent NMES training using wide-pulse width and moderate-intensity as a strength training tool could be a promising method to increase muscle force production in people with SCI. However, this type of protocol has not been clinically adopted because it may generate rapid muscle fatigue and thus prevent the performance of repeated high-intensity muscular contractions in paralysed muscles. Moreover, superimposing patellar tendon vibration onto the wide-pulse width NMES has been shown to elicit further increases in impulse or, at least, reduce the rate of fatigue in repeated contractions in able-bodied populations, but there is a lack of evidence to support this argument in people with SCI. Methods Nine people with SCI received two NMES protocols with and without superimposing patellar tendon vibration on different days (i.e. STIM and STIM+vib), which consisted of repeated 30 Hz trains of 58 wide-pulse width (1000 μs) symmetric biphasic pulses (0.033-s inter-pulse interval; 2 s stimulation train; 2-s inter-train interval) being delivered to the dominant quadriceps femoris. Starting torque was 20% of maximal doublet-twitch torque and stimulations continued until torque declined to 50% of the starting torque. Total knee extensor impulse was calculated as the primary outcome variable. Results Total knee extensor impulse increased in four subjects when patellar tendon vibration was imposed (59.2 ± 15.8%) but decreased in five subjects (− 31.3 ± 25.7%). However, there were no statistically significant differences between these sub-groups or between conditions when the data were pooled. Conclusions Based on the present results there is insufficient evidence to conclude that patellar tendon vibration provides a clear benefit to muscle force production or delays muscle fatigue during wide-pulse width, moderate-intensity NMES in people with SCI. Trial registration ACTRN12618000022268. Date: 11/01/2018. Retrospectively registered.
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Affiliation(s)
- Vanesa Bochkezanian
- Department of Exercise and Health Sciences, School of Health, Medical and Applied Sciences, Central Queensland University, Building 34.1.02, Bruce Highway, North Rockhampton, Qld, 4702, Australia. .,Exercise Medicine Research Clinic, Edith Cowan University, Perth, Australia. .,Centre for Sports and Exercise Science, School of Medical and Health Sciences, Edith Cowan University, Joondalup, Australia.
| | - Robert U Newton
- Exercise Medicine Research Clinic, Edith Cowan University, Perth, Australia.,Centre for Sports and Exercise Science, School of Medical and Health Sciences, Edith Cowan University, Joondalup, Australia.,UQ Centre for Clinical Research, The University of Queensland, Brisbane, Australia
| | - Gabriel S Trajano
- School of Exercise and Nutrition Sciences, Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, Australia
| | | | - Timothy S Pulverenti
- Centre for Sports and Exercise Science, School of Medical and Health Sciences, Edith Cowan University, Joondalup, Australia
| | - Anthony J Blazevich
- Centre for Sports and Exercise Science, School of Medical and Health Sciences, Edith Cowan University, Joondalup, Australia
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Tan AQ, Dhaher YY. Contralesional Hemisphere Regulation of Transcranial Magnetic Stimulation-Induced Kinetic Coupling in the Poststroke Lower Limb. Front Neurol 2017; 8:373. [PMID: 28824530 PMCID: PMC5545591 DOI: 10.3389/fneur.2017.00373] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 07/17/2017] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND The neural constraints underlying hemiparetic gait dysfunction are associated with abnormal kinetic outflow and altered muscle synergy structure. Recent evidence from our lab implicates the lesioned hemisphere in mediating the expression of abnormally coupled hip adduction and knee extension synergy, suggesting a role of cortical networks in the regulation of lower limb motor outflow poststroke. The potential contribution of contralesional hemisphere (CON-H) in regulating paretic leg kinetics is unknown. The purpose of this study is to characterize the effect of CON-H activation on aberrant across-joint kinetic coupling of the ipsilateral lower-extremity muscles poststroke. METHODS Amplitude-matched adductor longus motor-evoked potentials were elicited using single pulse transcranial magnetic stimulation (TMS) of the lesioned (L-H) and CON-Hs during an isometric adductor torque matching task from 11 stroke participants. For 10 control participants, TMS of the contralateral and ipsilateral hemisphere were given during the same task. TMS-induced torques were characterized at the hip and knee joints to determine the differential regulation of abnormal kinetic synergies by each motor cortices. The TMS-induced ratio of knee extension/hip adduction torques was quantified during 40 and 20% of maximum adduction torque. FINDINGS For both the 40 and 20% target adduction tasks, we find that contralesional stimulation significantly reduced but did not eliminate the TMS-induced ratio of knee extension/hip adduction torques for the stroke group (p = 0.0468, p = 0.0396). In contrast, the controls did not present a significantly different TMS-evoked torque following stimulation (p = 0.923) of the hemisphere ipsilateral to the test leg. INTERPRETATION The reduced expression of abnormal across-joint kinetic coupling suggests that the CON-H may contribute an adaptive role in lower limb control poststroke. Future study of neuromodulation paradigms that leverage adaptive CON-H activation may yield clinically relevant gains in lower limb motor function poststroke.
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Affiliation(s)
- Andrew Q. Tan
- Northwestern University Interdepartmental Neuroscience, Northwestern University, Chicago, IL, United States
- Searle Center for the Science of Walking, Shirley Ryan AbilityLab, Chicago, IL, United States
| | - Yasin Y. Dhaher
- Northwestern University Interdepartmental Neuroscience, Northwestern University, Chicago, IL, United States
- Searle Center for the Science of Walking, Shirley Ryan AbilityLab, Chicago, IL, United States
- Department of Biomedical Engineering, Northwestern University, Chicago, IL, United States
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Abstract
Context: Neuromuscular alterations are a major causal factor of primary and secondary injuries. Though injury prevention programs have experienced some success, rates of injuries have not declined, and after injury, individuals often return to activity with functionality below clinical recommendations. Considering alternative therapies to the conventional concentric exercise approach, such as one that can target neuromuscular injury risk and postinjury alterations, may provide for more effective injury prevention and rehabilitation protocols. Evidence Acquisition: Peer-reviewed sources available on the Web of Science and MEDLINE databases from 2000 through 2016 were gathered using searches associated with the keywords eccentric exercise, injury prevention, and neuromuscular control. Hypothesis: Eccentric exercise will reduce injury risk by targeting specific neural and morphologic alterations that precipitate neuromuscular dysfunction. Study Design: Clinical review. Level of Evidence: Level 4. Results: Neuromuscular control is influenced by alterations in muscle morphology and neural activity. Eccentric exercise beneficially modifies several underlying factors of muscle morphology (fiber typing, cross-sectional area, working range, and pennation angle), and emerging evidence indicates that eccentric exercise is also beneficial to peripheral and central neural activity (alpha motorneuron recruitment/firing, sarcolemma activity, corticospinal excitability, and brain activation). Conclusion: There is mounting evidence that eccentric exercise is not only a therapeutic intervention influencing muscle morphology but also targets unique alterations in neuromuscular control, influencing injury risk.
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Affiliation(s)
- Lindsey K Lepley
- Department of Kinesiology, University of Connecticut, Storrs, Connecticut
| | - Adam S Lepley
- Department of Kinesiology, University of Connecticut, Storrs, Connecticut
| | - James A Onate
- School of Health and Rehabilitative Sciences, College of Medicine, The Ohio State University, Columbus, Ohio
| | - Dustin R Grooms
- Ohio Musculoskeletal & Neurological Institute, Ohio University, Athens, Ohio.,Division of Athletic Training, School of Applied Health Sciences and Wellness, College of Health Sciences and Professions, Ohio University, Athens, Ohio
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Peterson CL, Bednar MS, Bryden AM, Keith MW, Perreault EJ, Murray WM. Voluntary activation of biceps-to-triceps and deltoid-to-triceps transfers in quadriplegia. PLoS One 2017; 12:e0171141. [PMID: 28253262 PMCID: PMC5333805 DOI: 10.1371/journal.pone.0171141] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2016] [Accepted: 01/14/2017] [Indexed: 11/18/2022] Open
Abstract
The biceps or the posterior deltoid can be transferred to improve elbow extension function for many individuals with C5 or C6 quadriplegia. Maximum strength after elbow reconstruction is variable; the patient’s ability to voluntarily activate the transferred muscle to extend the elbow may contribute to the variability. We compared voluntary activation during maximum isometric elbow extension following biceps transfer (n = 5) and deltoid transfer (n = 6) in three functional postures. Voluntary activation was computed as the elbow extension moment generated during maximum voluntary effort divided by the moment generated with full activation, which was estimated via electrical stimulation. Voluntary activation was on average 96% after biceps transfer and not affected by posture. Individuals with deltoid transfer demonstrated deficits in voluntary activation, which differed by posture (80% in horizontal plane, 69% in overhead reach, and 70% in weight-relief), suggesting inadequate motor re-education after deltoid transfer. Overall, individuals with a biceps transfer better activated their transferred muscle than those with a deltoid transfer. This difference in neural control augmented the greater force-generating capacity of the biceps leading to increased elbow extension strength after biceps transfer (average 9.37 N-m across postures) relative to deltoid transfer (average 2.76 N-m across postures) in our study cohort.
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Affiliation(s)
- Carrie L. Peterson
- Edward Hines, Jr. VA Hospital, Hines, IL, United States of America
- Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Chicago, IL, United States of America
- Department of Physical Medicine & Rehabilitation Northwestern University Feinberg School of Medicine, Chicago, IL, United States of America
- * E-mail:
| | - Michael S. Bednar
- Edward Hines, Jr. VA Hospital, Hines, IL, United States of America
- Department of Orthopaedic Surgery and Rehabilitation, Stritch School of Medicine, Loyola University Maywood, IL, United States of America
| | - Anne M. Bryden
- The Cleveland FES Center at MetroHealth, Cleveland, OH, United States of America
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States of America
| | - Michael W. Keith
- The Cleveland FES Center at MetroHealth, Cleveland, OH, United States of America
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States of America
- Department of Orthopaedics, School of Medicine, Case Western Reserve University, Cleveland, OH, United States of America
| | - Eric J. Perreault
- Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Chicago, IL, United States of America
- Department of Physical Medicine & Rehabilitation Northwestern University Feinberg School of Medicine, Chicago, IL, United States of America
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, United States of America
| | - Wendy M. Murray
- Edward Hines, Jr. VA Hospital, Hines, IL, United States of America
- Sensory Motor Performance Program, Rehabilitation Institute of Chicago, Chicago, IL, United States of America
- Department of Physical Medicine & Rehabilitation Northwestern University Feinberg School of Medicine, Chicago, IL, United States of America
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, United States of America
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