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Kim K, Oblak E, Manella K, Sulzer J. Simulated operant reflex conditioning environment reveals effects of feedback parameters. PLoS One 2024; 19:e0300338. [PMID: 38512998 PMCID: PMC10956789 DOI: 10.1371/journal.pone.0300338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 02/26/2024] [Indexed: 03/23/2024] Open
Abstract
Operant conditioning of neural activation has been researched for decades in humans and animals. Many theories suggest two parallel learning processes, implicit and explicit. The degree to which feedback affects these processes individually remains to be fully understood and may contribute to a large percentage of non-learners. Our goal is to determine the explicit decision-making processes in response to feedback representing an operant conditioning environment. We developed a simulated operant conditioning environment based on a feedback model of spinal reflex excitability, one of the simplest forms of neural operant conditioning. We isolated the perception of the feedback signal from self-regulation of an explicit unskilled visuomotor task, enabling us to quantitatively examine feedback strategy. Our hypothesis was that feedback type, biological variability, and reward threshold affect operant conditioning performance and operant strategy. Healthy individuals (N = 41) were instructed to play a web application game using keyboard inputs to rotate a virtual knob representative of an operant strategy. The goal was to align the knob with a hidden target. Participants were asked to "down-condition" the amplitude of the virtual feedback signal, which was achieved by placing the knob as close as possible to the hidden target. We varied feedback type (knowledge of performance, knowledge of results), biological variability (low, high), and reward threshold (easy, moderate, difficult) in a factorial design. Parameters were extracted from real operant conditioning data. Our main outcomes were the feedback signal amplitude (performance) and the mean change in dial position (operant strategy). We observed that performance was modulated by variability, while operant strategy was modulated by feedback type. These results show complex relations between fundamental feedback parameters and provide the principles for optimizing neural operant conditioning for non-responders.
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Affiliation(s)
- Kyoungsoon Kim
- University of Texas at Austin, Austin, Texas, United States of America
| | - Ethan Oblak
- RIKEN Center for Brain Science, Saitama, Japan
| | - Kathleen Manella
- Nova Southeastern University, Clearwater, Florida, United States of America
| | - James Sulzer
- MetroHealth Hospital and Case Western Reserve University, Cleveland, Ohio, United States of America
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Alvarado-Navarrete MDC, Pliego-Carrillo AC, Ledesma-Ramírez CI, Cuellar CA. Post-activation depression of the Hoffman reflex is not altered by galvanic vestibular stimulation in healthy subjects. Front Integr Neurosci 2023; 17:1234613. [PMID: 37711909 PMCID: PMC10499171 DOI: 10.3389/fnint.2023.1234613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 08/08/2023] [Indexed: 09/16/2023] Open
Abstract
The comprehension of the neural elements interacting in the spinal cord affected by vestibular input will contribute to the understanding of movement execution in normal and pathological conditions. In this context, Hoffman's reflex (H-reflex) has been used to evaluate transient excitability changes on the spinal cord descending pathways. The post-activation depression (P-AD) of the H-reflex consists of evoking consecutive responses (>1 Hz) provoking an amplitude depression, which has been shown to diminish in pathological conditions (i.e., spasticity, diabetic neuropathy). Galvanic Vestibular Stimulation (GVS) is a non-invasive method that activates the vestibular afferents and has been used to study the excitability of the H-reflex applied as a conditioning pulse. To our knowledge, there are no reports evaluating the P-AD during and after GVS. Our primary aim was to determine if GVS alters the P-AD evoked by stimulating the tibial nerve at 0.1, 1, 5, and 10 Hz, recording in the gastrocnemius and soleus muscles. Direct current stimulation of 2.0 ± 0.6 mA with the cathode ipsilateral (Ipsi) or contralateral (Contra) to the H-reflex electrode montage was applied bilaterally over the mastoid process in 19 healthy subjects. The P-AD's immediate post-GVS response (P Ipsi, P Contra) was also analyzed. Secondarily, we analyzed the excitability of the H-reflex during GVS. Responses evoked at 0.1 Hz with GVS, post-GVS, and a Control (no GVS) condition were used for comparisons. Our results show that P-AD persisted in all subjects despite increased excitability induced by GVS: statistical significance was found when comparing P-AD at 1, 5, and 10 Hz with the corresponding condition (Control, Ipsi, P Ipsi, Contra, P Contra) at 0.1 Hz (p < 0.001). Additionally, the increase in excitability produced by GVS was quantified for the first H-reflex of each P-AD stimulation frequency. The percentage change for all GVS conditions surpassed the Control by at least 20%, being statistically significant for Contra compared to Control (p < 0.01). In summary, although GVS increases the excitability of the vestibulospinal pathway at a premotor level, the neural inhibitory mechanism present in P-AD remains unaltered in healthy subjects.
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Affiliation(s)
| | - Adriana C. Pliego-Carrillo
- Biomedical Engineering, School of Medicine, Autonomous University of the State of Mexico, Toluca, Mexico
| | | | - Carlos A. Cuellar
- School of Sport Sciences, Universidad Anáhuac México, Huixquilucan, Mexico
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McKinnon ML, Hill NJ, Carp JS, Dellenbach B, Thompson AK. Methods for automated delineation and assessment of EMG responses evoked by peripheral nerve stimulation in diagnostic and closed-loop therapeutic applications. J Neural Eng 2023; 20:10.1088/1741-2552/ace6fb. [PMID: 37437593 PMCID: PMC10445400 DOI: 10.1088/1741-2552/ace6fb] [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: 03/17/2023] [Accepted: 07/12/2023] [Indexed: 07/14/2023]
Abstract
Objective.Surface electromyography measurements of the Hoffmann (H-) reflex are essential in a wide range of neuroscientific and clinical applications. One promising emerging therapeutic application is H-reflex operant conditioning, whereby a person is trained to modulate the H-reflex, with generalized beneficial effects on sensorimotor function in chronic neuromuscular disorders. Both traditional diagnostic and novel realtime therapeutic applications rely on accurate definitions of the H-reflex and M-wave temporal bounds, which currently depend on expert case-by-case judgment. The current study automates such judgments.Approach.Our novel wavelet-based algorithm automatically determines temporal extent and amplitude of the human soleus H-reflex and M-wave. In each of 20 participants, the algorithm was trained on data from a preliminary 3 or 4 min recruitment-curve measurement. Output was evaluated on parametric fits to subsequent sessions' recruitment curves (92 curves across all participants) and on the conditioning protocol's subsequent baseline trials (∼1200 per participant) performed nearHmax. Results were compared against the original temporal bounds estimated at the time, and against retrospective estimates made by an expert 6 years later.Main results.Automatic bounds agreed well with manual estimates: 95% lay within ±2.5 ms. The resulting H-reflex magnitude estimates showed excellent agreement (97.5% average across participants) between automatic and retrospective bounds regarding which trials would be considered successful for operant conditioning. Recruitment-curve parameters also agreed well between automatic and manual methods: 95% of the automatic estimates of the current required to elicitHmaxfell within±1.4%of the retrospective estimate; for the 'threshold' current that produced an M-wave 10% of maximum, this value was±3.5%.Significance.Such dependable automation of M-wave and H-reflex definition should make both established and emerging H-reflex protocols considerably less vulnerable to inter-personnel variability and human error, increasing translational potential.
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Affiliation(s)
| | - N. Jeremy Hill
- National Center for Adaptive Neurotechnologies, Stratton VA Medical Center, Albany, NY, USA
- Electrical and Computer Engineering Dept., State University of New York at Albany, NY, USA
| | - Jonathan S. Carp
- National Center for Adaptive Neurotechnologies, Stratton VA Medical Center, Albany, NY, USA
- School of Public Health, State University of New York at Albany, NY, USA
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Kim K, Oblak E, Manella K, Sulzer J. OPERANT REFLEX CONDITIONING SIMULATION ENVIRONMENT REVEALS EFFECTS OF FEEDBACK PARAMETERS. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.26.542391. [PMID: 37293099 PMCID: PMC10245997 DOI: 10.1101/2023.05.26.542391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Operant conditioning of neural activation has been researched for decades in humans and animals. Many theories suggest two parallel learning processes, implicit and explicit. The degree to which feedback affects these processes individually remains to be fully understood and may contribute to a large percentage of non-learners. Our goal is to determine the explicit decision-making processes in response to feedback representing an operant conditioning environment. We developed a simulated operant conditioning environment based on a feedback model of spinal reflex excitability, one of the simplest forms of neural operant conditioning. We isolated the perception of the feedback signal from self-regulation of an explicit unskilled visuomotor task, enabling us to quantitatively examine feedback strategy. Our hypothesis was that feedback type, signal quality and success threshold affect operant conditioning performance and operant strategy. Healthy individuals (N = 41) were instructed to play a web application game using keyboard inputs to rotate a virtual knob representative of an operant strategy. The goal was to align the knob with a hidden target. Participants were asked to "down-condition" the amplitude of the virtual feedback signal, which was achieved by placing the knob as close as possible to the hidden target. We varied feedback type (knowledge of performance, knowledge of results), success threshold (easy, moderate, difficult), and biological variability (low, high) in a factorial design. Parameters were extracted from real operant conditioning data. Our main outcomes were the feedback signal amplitude (performance) and the mean change in dial position (operant strategy). We observed that performance was modulated by variability, while operant strategy was modulated by feedback type. These results show complex relations between fundamental feedback parameters and provide the principles for optimizing neural operant conditioning for non-responders.
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Affiliation(s)
| | - Ethan Oblak
- RIKEN Center for Brain Science, Saitama, Japan
| | | | - James Sulzer
- MetroHealth Hospital and Case Western Reserve University, Cleveland, OH, USA
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Kim SC, Cho SH. Effects of H-Reflex Onset Latency on Gait in Elderly and Hemiplegic Individuals. Medicina (B Aires) 2022; 58:medicina58060716. [PMID: 35743979 PMCID: PMC9228972 DOI: 10.3390/medicina58060716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 05/24/2022] [Accepted: 05/24/2022] [Indexed: 11/16/2022] Open
Abstract
Background and Objectives: The Hoffmann’s reflex (H-reflex) is important in electrodiagnostic testing because it improves sensitivity and specificity in diagnosing radiculopathies. Although quantitative electromyography (EMG) measurements for H-reflex amplitudes during the gait cycle have been performed in both hemiplegic and healthy individuals, research on the H-wave latency in these individuals during the gait cycle is lacking. Materials and Methods: The H-reflex latency of the soleus muscle was investigated in hemiplegic stroke patients and healthy elderly persons in this observational analytical study. Two groups of individuals participated in this study: healthy adults (n = 25) and stroke patients with hemiplegia (n = 25) were compared. An MP150 with Ag-Ag/Cl electrodes was utilized to record and analyse electromyography measurements. All individuals could walk independently indoors. Stimuli were administered to elicit the H-reflex in the four gait phases as the participant walked. Results: Stroke patients had a significantly shorter latency than did healthy patients in the mid-swing, mid-stance, and toe-off phases of the gait cycle; heel-strike latency did not significantly differ. Conclusions: These results can be used as diagnostic data to help account for patient characteristics or measure the recovery extent for treatment planning and gait training in hemiplegic individuals.
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Affiliation(s)
- Seon-Chil Kim
- Department of Biomedical Engineering, School of Medicine, Keimyung University, 1095 Dalgubeol-daero, Daegu 42601, Korea;
| | - Sung-Hyoun Cho
- Department of Physical Therapy, Nambu University, 23 Cheomdanjungang-ro, Gwangju 62271, Korea
- Correspondence: ; Tel.: +82-10-3060-1330
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Marshall PW, Melville GW, Cross R, Marquez J, Harrison I, Enoka RM. Fatigue, pain, and the recovery of neuromuscular function after consecutive days of full-body resistance exercise in trained men. Eur J Appl Physiol 2021; 121:3103-3116. [PMID: 34350481 DOI: 10.1007/s00421-021-04777-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 07/25/2021] [Indexed: 11/28/2022]
Abstract
PURPOSE This study measured the self-reported level of fatigue, pain, and neuromuscular function of the knee extensor muscles over a three-day period that included two consecutive days of full-body resistance exercises. METHODS 10 resistance-trained men performed two consecutive days of full-body resistance exercise. Muscle activation (electromyography and voluntary activation), contractility, and presynaptic inhibition of Ia afferents (homosynaptic and GABA mediated presynaptic inhibition) for the quadriceps were examined from femoral and posterior tibial nerve stimulation. RESULTS Fatigue and pain were elevated after Day 1, and were not reduced to pre-exercise levels at the start of Day 2 (p < 0.05). Maximal voluntary torque (- 51.4 Nm, 95% CI = 12.4-90.4 Nm, p = 0.005) and rate of torque development (- 469 Nm.s-1, 95% CI = 109-829 Nm.s-1, p = 0.006) were reduced after Day 1, had recovered by Day 2, and did not change after the second training session. The maximal amplitude and rate of rise for the quadriceps twitch were reduced after both training sessions (p < 0.01), with recovery 24 h each session. The maximal amplitude and rate of early muscle activation were reduced after Day 1 (p < 0.01), but no changes were observed for voluntary activation, H-reflex size and shape, or measures of Ia presynaptic inhibition. CONCLUSION Resistance exercise in the presence of elevated fatigue and pain from a previous training session does not worsen recovery, or lead to significant alterations in quadriceps neuromuscular function. Reduction in muscle contractility, in the absence of declines in muscle activation, does not lead to decreased voluntary torque.
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Affiliation(s)
- Paul W Marshall
- Human Performance Laboratory, School of Health Science, Western Sydney University, Penrith, Australia. .,Department of Exercise Science, University of Auckland, Building 907, Newmarket, Auckland, 1023, New Zealand.
| | - Geoffrey W Melville
- Faculty of Science, Medicine, and Health, University of Wollongong, Wollongong, Australia
| | - Rebecca Cross
- Human Performance Laboratory, School of Health Science, Western Sydney University, Penrith, Australia
| | - John Marquez
- Human Performance Laboratory, School of Health Science, Western Sydney University, Penrith, Australia
| | - Isaac Harrison
- Human Performance Laboratory, School of Health Science, Western Sydney University, Penrith, Australia
| | - Roger M Enoka
- Department of Integrative Physiology, University of Colorado, Boulder, CO, USA
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The contemporary model of vertebral column joint dysfunction and impact of high-velocity, low-amplitude controlled vertebral thrusts on neuromuscular function. Eur J Appl Physiol 2021; 121:2675-2720. [PMID: 34164712 PMCID: PMC8416873 DOI: 10.1007/s00421-021-04727-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 05/20/2021] [Indexed: 02/08/2023]
Abstract
Purpose There is growing evidence that vertebral column function and dysfunction play a vital role in neuromuscular control. This invited review summarises the evidence about how vertebral column dysfunction, known as a central segmental motor control (CSMC) problem, alters neuromuscular function and how spinal adjustments (high-velocity, low-amplitude or HVLA thrusts directed at a CSMC problem) and spinal manipulation (HVLA thrusts directed at segments of the vertebral column that may not have clinical indicators of a CSMC problem) alters neuromuscular function.
Methods The current review elucidates the peripheral mechanisms by which CSMC problems, the spinal adjustment or spinal manipulation alter the afferent input from the paravertebral tissues. It summarises the contemporary model that provides a biologically plausible explanation for CSMC problems, the manipulable spinal lesion. This review also summarises the contemporary, biologically plausible understanding about how spinal adjustments enable more efficient production of muscular force. The evidence showing how spinal dysfunction, spinal manipulation and spinal adjustments alter central multimodal integration and motor control centres will be covered in a second invited review. Results Many studies have shown spinal adjustments increase voluntary force and prevent fatigue, which mainly occurs due to altered supraspinal excitability and multimodal integration. The literature suggests physical injury, pain, inflammation, and acute or chronic physiological or psychological stress can alter the vertebral column’s central neural motor control, leading to a CSMC problem. The many gaps in the literature have been identified, along with suggestions for future studies. Conclusion Spinal adjustments of CSMC problems impact motor control in a variety of ways. These include increasing muscle force and preventing fatigue. These changes in neuromuscular function most likely occur due to changes in supraspinal excitability. The current contemporary model of the CSMC problem, and our understanding of the mechanisms of spinal adjustments, provide a biologically plausible explanation for how the vertebral column’s central neural motor control can dysfunction, can lead to a self-perpetuating central segmental motor control problem, and how HVLA spinal adjustments can improve neuromuscular function.
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Pulverenti TS, Zaaya M, Grabowski M, Grabowski E, Islam MA, Li J, Murray LM, Knikou M. Neurophysiological Changes After Paired Brain and Spinal Cord Stimulation Coupled With Locomotor Training in Human Spinal Cord Injury. Front Neurol 2021; 12:627975. [PMID: 34040572 PMCID: PMC8141587 DOI: 10.3389/fneur.2021.627975] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 04/01/2021] [Indexed: 11/13/2022] Open
Abstract
Neurophysiological changes that involve activity-dependent neuroplasticity mechanisms via repeated stimulation and locomotor training are not commonly employed in research even though combination of interventions is a common clinical practice. In this randomized clinical trial, we established neurophysiological changes when transcranial magnetic stimulation (TMS) of the motor cortex was paired with transcutaneous thoracolumbar spinal (transspinal) stimulation in human spinal cord injury (SCI) delivered during locomotor training. We hypothesized that TMS delivered before transspinal (TMS-transspinal) stimulation promotes functional reorganization of spinal networks during stepping. In this protocol, TMS-induced corticospinal volleys arrive at the spinal cord at a sufficient time to interact with transspinal stimulation induced depolarization of alpha motoneurons over multiple spinal segments. We further hypothesized that TMS delivered after transspinal (transspinal-TMS) stimulation induces less pronounced effects. In this protocol, transspinal stimulation is delivered at time that allows transspinal stimulation induced action potentials to arrive at the motor cortex and affect descending motor volleys at the site of their origin. Fourteen individuals with motor incomplete and complete SCI participated in at least 25 sessions. Both stimulation protocols were delivered during the stance phase of the less impaired leg. Each training session consisted of 240 paired stimuli delivered over 10-min blocks. In transspinal-TMS, the left soleus H-reflex increased during the stance-phase and the right soleus H-reflex decreased at mid-swing. In TMS-transspinal no significant changes were found. When soleus H-reflexes were grouped based on the TMS-targeted limb, transspinal-TMS and locomotor training promoted H-reflex depression at swing phase, while TMS-transspinal and locomotor training resulted in facilitation of the soleus H-reflex at stance phase of the step cycle. Furthermore, both transspinal-TMS and TMS-transspinal paired-associative stimulation (PAS) and locomotor training promoted a more physiological modulation of motor activity and thus depolarization of motoneurons during assisted stepping. Our findings support that targeted non-invasive stimulation of corticospinal and spinal neuronal pathways coupled with locomotor training produce neurophysiological changes beneficial to stepping in humans with varying deficits of sensorimotor function after SCI.
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Affiliation(s)
- Timothy S Pulverenti
- Klab4Recovery Research Laboratory, Department of Physical Therapy, College of Staten Island, The City University of New York, New York, NY, United States
| | - Morad Zaaya
- Klab4Recovery Research Laboratory, Department of Physical Therapy, College of Staten Island, The City University of New York, New York, NY, United States
| | - Monika Grabowski
- Klab4Recovery Research Laboratory, Department of Physical Therapy, College of Staten Island, The City University of New York, New York, NY, United States
| | - Ewelina Grabowski
- Klab4Recovery Research Laboratory, Department of Physical Therapy, College of Staten Island, The City University of New York, New York, NY, United States
| | - Md Anamul Islam
- Klab4Recovery Research Laboratory, Department of Physical Therapy, College of Staten Island, The City University of New York, New York, NY, United States
| | - Jeffrey Li
- Klab4Recovery Research Laboratory, Department of Physical Therapy, College of Staten Island, The City University of New York, New York, NY, United States
| | - Lynda M Murray
- Klab4Recovery Research Laboratory, Department of Physical Therapy, College of Staten Island, The City University of New York, New York, NY, United States
| | - Maria Knikou
- Klab4Recovery Research Laboratory, Department of Physical Therapy, College of Staten Island, The City University of New York, New York, NY, United States.,Ph.D. Program in Biology and Collaborative Neuroscience Program, Graduate Center of the City University of New York and College of Staten Island, New York, NY, United States
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Honguten A, Mekhora K, Pichaiyongwongdee S, Somprasong S. Effects of lymphatic drainage therapy on autonomic nervous system responses in healthy subjects: A single blind randomized controlled trial. J Bodyw Mov Ther 2021; 27:169-175. [PMID: 34391230 DOI: 10.1016/j.jbmt.2021.03.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 03/09/2021] [Accepted: 03/16/2021] [Indexed: 11/19/2022]
Abstract
OBJECTIVES This study aimed to determine effects of lymphatic drainage therapy (LDT) on autonomic nervous system (ANS) responses by comparing including Hoffmann reflex (H reflex), heart rate variability (HRV), salivary alpha-amylase (sAA) and muscle tone (via straight leg raise (SLR)) in healthy participants. METHODS A single blind randomized controlled trial evaluating sixty-six healthy participants including 58 females and 8 males aged between 40 and 65 years. All participants were blinded and randomized to either experimental group (EXP: LDT) or control group (CT: rest). LDT was applied to participants 45 min in experimental group. The LDT is light movement applied by an experienced physical therapist, starting from neck, deep abdomen, and along to the leg. While for the control group, participants received 45 min supine on the treatment table. Tests for evaluating ANS such as Hoffmann reflex (H reflex), heart rate variability (HRV), salivary alpha-amylase (sAA) and straight leg raise (SLR) were assessed at pre and post intervention. RESULTS The findings demonstrated that H reflex decreased significantly after applying LDT; within and between groups (p < 0.05). Whereas, it increased significantly in control group. First tension (R1) indicated by participants during SLR significantly improved within both groups. However, there were no significant differences of HRV and sAA in either LDT or control groups. CONCLUSION This study demonstrated that LDT decreased autonomic activity via decreased spinal reflex excitability and tension in healthy participants.
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Affiliation(s)
- Agsipa Honguten
- Faculty of Physical Therapy, Mahidol University, 999 Phuttamonthon 4 Road, Salaya, Phuttamonthon, Nakhon Pathom, 73170, Thailand.
| | - Keerin Mekhora
- Faculty of Physical Therapy, Mahidol University, 999 Phuttamonthon 4 Road, Salaya, Phuttamonthon, Nakhon Pathom, 73170, Thailand.
| | - Sopa Pichaiyongwongdee
- Faculty of Physical Therapy, Mahidol University, 999 Phuttamonthon 4 Road, Salaya, Phuttamonthon, Nakhon Pathom, 73170, Thailand.
| | - Sirikarn Somprasong
- Faculty of Physical Therapy, Mahidol University, 999 Phuttamonthon 4 Road, Salaya, Phuttamonthon, Nakhon Pathom, 73170, Thailand.
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Yurttutmuş Z, Ekici Zincirci D, Bardak AN, Topkara B, Aydın T, Karacan I, Türker KS. A stimulus rate that is not influenced by homosynaptic post-activation depression in chronic stroke. Somatosens Mot Res 2020; 37:271-276. [PMID: 32811248 DOI: 10.1080/08990220.2020.1807925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
PURPOSE To determine a stimulus rate that is not influenced by homosynaptic post-activation depression for H-reflex studies in patients with chronic spasticity. MATERIALS AND METHODS A cohort of 15 chronic stroke patients with soleus spasticity who received inpatient treatment at our rehabilitation centre participated in this study. The effect of stimulus frequency related depression on H-reflex size was tested using four different stimulus rates (0.1, 0.2, 0.3 and 1 Hz). The affected sides stibial nerve was stimulated by a bipolar electrode. The H-reflex was recorded from the affected sideed sidee sidehe affected smine stimulus frequency related depression of H-reflex size, amplitude of the first H-reflex response (H1) was used as control and amplitude of the second H-reflex response (H2) as test. RESULTS H2 amplitude for frequency of 1 Hz, 0.3 Hz, 0.2 Hz and 0.1 Hz were 74.3, 84.1, 85.5 and 92.7% of H1, respectively. Depression of H2 amplitude was statistically significant for 1 Hz, 0.3 Hz and 0.2 Hz (p < 0.001, p = 0.002, p = 0.024, respectively). CONCLUSIONS Higher frequency stimulation of Ia afferents than 0.1 Hz induced a stimulus frequency-related depression of H-reflex size in patients with chronic spasticity. The optimal stimulus rate for H-reflex was found to be 0.1 Hz.
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Affiliation(s)
- Zeynep Yurttutmuş
- Istanbul Physical Therapy Rehabilitation Training and Research Hospital, Istanbul, Turkey
| | - Dilara Ekici Zincirci
- Istanbul Physical Therapy Rehabilitation Training and Research Hospital, Istanbul, Turkey
| | - Ayse Nur Bardak
- Istanbul Physical Therapy Rehabilitation Training and Research Hospital, Istanbul, Turkey
| | - Betilay Topkara
- Physiology Department, Koç University School of Medicine, Istanbul, Turkey
| | - Tugba Aydın
- Istanbul Physical Therapy Rehabilitation Training and Research Hospital, Istanbul, Turkey
| | - Ilhan Karacan
- Istanbul Physical Therapy Rehabilitation Training and Research Hospital, Istanbul, Turkey
| | - Kemal S Türker
- Physiology Department, Koç University School of Medicine, Istanbul, Turkey
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Mendonca GV, Mouro M, Vila-Chã C, Pezarat-Correia P. Nerve conduction during acute blood-flow restriction with and without low-intensity exercise Nerve conduction and blood-flow restriction. Sci Rep 2020; 10:7380. [PMID: 32355236 PMCID: PMC7193597 DOI: 10.1038/s41598-020-64379-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Accepted: 02/07/2020] [Indexed: 11/09/2022] Open
Abstract
Despite being apparently safe for most individuals, the impact of low intensity (LI) blood-flow restricted (BFR) exercise on nerve function and integrity is still obscure. We explored whether BFR (with and without exercise) alters the properties of nerve conduction measured at the level of the restricted limb. Thirteen healthy, young men (22.0 ± 1.7 years) were included in this study. Arterial occlusion pressure was taken at rest. Soleus M- and H-recruitment curves were constructed for all participants. H-wave latencies and amplitudes were obtained in three testing conditions (non-BFR vs. 60 vs. 80% BFR) at four different time points: [#1] non-restricted baseline, [#2] time control either with or without BFR, [#3] non-restricted pre-exercise, [#4] LI exercise either with or without BFR. Nerve conduction was estimated using the difference between the latency of H and M wave. BFR did not affect H-wave amplitude, either with or without exercise. The changes in the difference between H- and M-wave latency of over time were similar between all conditions (condition-by-time interaction: F = 0.7, p = 0.47). In conclusion, our data indicate that performing LI exercise with BFR, set at 60 or 80% BFR, does not exert a negative impact on sciatic-tibial nerve function. Thus, from a neurological standpoint, we provide preliminary evidence that LI BFR exercise may be regarded as a safe mode of resistance training in healthy young men.
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Affiliation(s)
- Goncalo V Mendonca
- Neuromuscular Research Lab, Faculdade de Motricidade Humana, Universidade de Lisboa, Estrada da Costa, 1499-002, Cruz Quebrada, Dafundo, Portugal. .,CIPER, Faculdade de Motricidade Humana, Universidade de Lisboa, Estrada da Costa, 1499-002, Cruz Quebrada, Dafundo, Portugal.
| | - Miguel Mouro
- Neuromuscular Research Lab, Faculdade de Motricidade Humana, Universidade de Lisboa, Estrada da Costa, 1499-002, Cruz Quebrada, Dafundo, Portugal
| | - Carolina Vila-Chã
- Polytechnic Institute of Guarda, Av. Dr. Francisco Sá Carneiro, n. 50, Guarda, 6300-559, Portugal.,Research Center in Sports Sciences, Health and Human Development (CIDESD), Vila-Real, Portugal
| | - Pedro Pezarat-Correia
- Neuromuscular Research Lab, Faculdade de Motricidade Humana, Universidade de Lisboa, Estrada da Costa, 1499-002, Cruz Quebrada, Dafundo, Portugal.,CIPER, Faculdade de Motricidade Humana, Universidade de Lisboa, Estrada da Costa, 1499-002, Cruz Quebrada, Dafundo, Portugal
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12
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Changes in the quadriceps spinal reflex pathway after repeated sprint cycling are not influenced by ischemic preconditioning. Eur J Appl Physiol 2020; 120:1189-1202. [PMID: 32239310 DOI: 10.1007/s00421-020-04359-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 03/24/2020] [Indexed: 12/11/2022]
Abstract
PURPOSE We examined the effect of ischemic preconditioning (IPC) on changes in muscle force, activation, and the spinal reflex pathway during and after repeated sprint cycling. METHODS Eight recreationally active men (high-intensity cardiorespiratory training > 3 times per week, > 6 months) completed two exercise sessions (5 sets of 5 cycling sprints, 150% max W), preceded by either IPC (3 × 5 min leg occlusions at 220 mmHg) or SHAM (3 × 5 min at 20 mmHg). Knee extensor maximal force and rate of force were measured before (PRE), immediately post (POST), 1H, and 24H after cycling. Twitch interpolation and resting potentiated twitches were applied to estimate voluntary activation and muscle contractility, respectively. Quadriceps H-reflex recruitment curves were collected at all time-points using 10 Hz doublet stimulation to allow estimation of H-reflex post-activation depression. Surface electromyograms and tissue oxygenation (via near-infrared spectroscopy) were continuously recorded during cycling. RESULTS IPC did not affect any measure of neuromuscular function or performance during cycling. Maximal force and muscle contractility were significantly lower at POST and 1H compared to PRE and 24H by up to 50% (p < 0.01). Maximal force was lower than PRE at 24H by 8.7% (p = 0.028). Voluntary activation and rate of force were unchanged. A rightwards shift was observed for the H-reflex recruitment curve POST, and post-activation depression was higher than all other time-points at 24H (p < 0.05). Muscle activation and oxygenation decreased during cycling. CONCLUSIONS IPC has a nominal effect on mechanisms associated with neuromuscular function during and after exercise in healthy populations.
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13
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Siddique U, Rahman S, Frazer AK, Pearce AJ, Howatson G, Kidgell DJ. Determining the Sites of Neural Adaptations to Resistance Training: A Systematic Review and Meta-analysis. Sports Med 2020; 50:1107-1128. [DOI: 10.1007/s40279-020-01258-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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14
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Unger J, Andrushko JW, Oates AR, Renshaw DW, Barss TS, Zehr EP, Farthing JP. Modulation of the Hoffmann reflex in the tibialis anterior with a change in posture. Physiol Rep 2019; 7:e14179. [PMID: 31317660 PMCID: PMC6637197 DOI: 10.14814/phy2.14179] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 06/26/2019] [Indexed: 11/24/2022] Open
Abstract
Hoffmann (H-) reflex amplitudes in plantar flexor soleus muscle are modulated by posture, yet dorsiflexor tibialis anterior (TA) H-reflex parameters have sparingly been studied. The purpose was to investigate modulation of the TA H-reflex when postural demands are increased from sitting to standing. In this study, data from 18 participants (Age: 25 ± 4 years, Height: 170.9 ± 9.5 cm, Weight: 75.9 ± 17.2 kg) allowed comparison of two experimental conditions involving different postures (i.e. sitting and standing). Maximal amplitude of the TA H-reflex (Hmax ) as a percent of the maximal M-wave amplitude (Mmax ) (Hmax (% Mmax )) during sitting and standing was compared using ANOVA. Modulation of TA H-reflex amplitude was found: Eleven participants showed facilitation and seven showed no change of reflex amplitudes. Only participants in the facilitation group showed modulation related to changes in posture (sitting: 8.7 ± 2.9%; standing: 14.8 ± 6.7%, P = 0.005). These data provide evidence of the sensitivity to posture of TA H-reflexes. As with task-dependent changes in soleus H-reflexes, presynaptic regulation of Ia afferent transmission is a possible mechanism. Further investigations into causes of modulation are warranted.
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Affiliation(s)
- Janelle Unger
- College of KinesiologyUniversity of SaskatchewanSaskatoonSaskatchewanCanada
| | | | - Alison R. Oates
- College of KinesiologyUniversity of SaskatchewanSaskatoonSaskatchewanCanada
| | - Doug W. Renshaw
- College of KinesiologyUniversity of SaskatchewanSaskatoonSaskatchewanCanada
| | - Trevor S. Barss
- Rehabilitation Neuroscience Laboratory, Physical and Health EducationUniversity of VictoriaVictoriaBritish ColumbiaCanada
| | - E. Paul Zehr
- Rehabilitation Neuroscience Laboratory, Physical and Health EducationUniversity of VictoriaVictoriaBritish ColumbiaCanada
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15
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Murray LM, Knikou M. Transspinal stimulation increases motoneuron output of multiple segments in human spinal cord injury. PLoS One 2019; 14:e0213696. [PMID: 30845251 PMCID: PMC6405126 DOI: 10.1371/journal.pone.0213696] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Accepted: 02/26/2019] [Indexed: 12/13/2022] Open
Abstract
Targeted neuromodulation strategies that strengthen neuronal activity are in great need for restoring sensorimotor function after chronic spinal cord injury (SCI). In this study, we established changes in the motoneuron output of individuals with and without SCI after repeated noninvasive transspinal stimulation at rest over the thoracolumbar enlargement, the spinal location of leg motor circuits. Cases of motor incomplete and complete SCI were included to delineate potential differences when corticospinal motor drive is minimal. All 10 SCI and 10 healthy control subjects received daily monophasic transspinal stimuli of 1-ms duration at 0.2 Hz at right soleus transspinal evoked potential (TEP) subthreshold and suprathreshold intensities at rest. Before and two days after cessation of transspinal stimulation, we determined changes in TEP recruitment input-output curves, TEP amplitude at stimulation frequencies of 0.1, 0.125, 0.2, 0.33 and 1.0 Hz, and TEP postactivation depression upon transspinal paired stimuli at interstimulus intervals of 60, 100, 300, and 500 ms. TEPs were recorded at rest from bilateral ankle and knee flexor/extensor muscles. Repeated transspinal stimulation increased the motoneuron output over multiple segments. In control and complete SCI subjects, motoneuron output increased for knee muscles, while in motor incomplete SCI subjects motoneuron output increased for both ankle and knee muscles. In control subjects, TEPs homosynaptic and postactivation depression were present at baseline, and were potentiated for the distal ankle or knee flexor muscles. TEPs homosynaptic and postactivation depression at baseline depended on the completeness of the SCI, with minimal changes observed after transspinal stimulation. These results indicate that repeated transspinal stimulation increases spinal motoneuron responsiveness of ankle and knee muscles in the injured human spinal cord, and thus can promote motor recovery. This noninvasive neuromodulation method is a promising modality for promoting functional neuroplasticity after SCI.
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Affiliation(s)
- Lynda M. Murray
- Klab4Recovery Research Laboratory, Department of Physical Therapy, College of Staten Island, The City University of New York, Staten Island, New York, United States of America
| | - Maria Knikou
- Klab4Recovery Research Laboratory, Department of Physical Therapy, College of Staten Island, The City University of New York, Staten Island, New York, United States of America
- PhD Program in Biology and Collaborative Neuroscience Program, Graduate Center of The City University of New York, New York, New York, United States of America
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16
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The effects of a single session of chiropractic care on strength, cortical drive, and spinal excitability in stroke patients. Sci Rep 2019; 9:2673. [PMID: 30804399 PMCID: PMC6389925 DOI: 10.1038/s41598-019-39577-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 01/25/2019] [Indexed: 12/11/2022] Open
Abstract
The objective of this study was to investigate whether a single session of chiropractic care could increase strength in weak plantar flexor muscles in chronic stroke patients. Maximum voluntary contractions (strength) of the plantar flexors, soleus evoked V-waves (cortical drive), and H-reflexes were recorded in 12 chronic stroke patients, with plantar flexor muscle weakness, using a randomized controlled crossover design. Outcomes were assessed pre and post a chiropractic care intervention and a passive movement control. Repeated measures ANOVA was used to asses within and between group differences. Significance was set at p < 0.05. Following the chiropractic care intervention there was a significant increase in strength (F (1,11) = 14.49, p = 0.002; avg 64.2 ± 77.7%) and V-wave/Mmax ratio (F(1,11) = 9.67, p = 0.009; avg 54.0 ± 65.2%) compared to the control intervention. There was a significant strength decrease of 26.4 ± 15.5% (p = 0.001) after the control intervention. There were no other significant differences. Plantar flexor muscle strength increased in chronic stroke patients after a single session of chiropractic care. An increase in V-wave amplitude combined with no significant changes in H-reflex parameters suggests this increased strength is likely modulated at a supraspinal level. Further research is required to investigate the longer term and potential functional effects of chiropractic care in stroke recovery.
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17
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Özyurt MG, Shabsog M, Dursun M, Türker KS. Optimal location for eliciting the tibial H-reflex and motor response. Muscle Nerve 2018; 58:828-833. [DOI: 10.1002/mus.26308] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 07/09/2018] [Accepted: 07/17/2018] [Indexed: 11/10/2022]
Affiliation(s)
| | - Mohammed Shabsog
- School of Medicine; Koç University, Rumelifeneri Yolu, 34450; Istanbul Turkey
| | - Merve Dursun
- School of Medicine; Koç University, Rumelifeneri Yolu, 34450; Istanbul Turkey
| | - Kemal S. Türker
- School of Medicine; Koç University, Rumelifeneri Yolu, 34450; Istanbul Turkey
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18
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Leung H, Latella C, Lamon S, Hendy AM. The Reliability of Neurological Measurement in the Vastus Medialis: Implications for Research and Practice. Front Psychol 2018; 9:1857. [PMID: 30327634 PMCID: PMC6174212 DOI: 10.3389/fpsyg.2018.01857] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Accepted: 09/11/2018] [Indexed: 11/21/2022] Open
Abstract
The integrity of the corticomotor pathway is paramount in the optimal functioning of skeletal muscle. However, variability of neurophysiological assessment via peripheral nerve and transcranial magnetic stimulation can render interpretation difficult. Seldom evidence exists regarding the reliability of such measurements in the leg extensors, which have important locomotive and functional roles. This study aimed to assess the test-retest reliability of peripheral, corticospinal and intracortical responses in the vastus medialis. Transcranial magnetic and direct current electrical nerve stimulation were delivered to sixteen healthy young adults (8M and 8F) on two separate occasions. The Hoffmann reflex, maximal compound wave, motor evoked potential, corticospinal silent period, intracortical facilitation, and short-interval intracortical inhibition were recorded from the vastus medialis at rest, and during controlled submaximal voluntary contraction. Relative reliability was quantified using intra-class correlation coefficient (ICC2,1). Absolute reliability was quantified using standard error of measurement (SEm) and minimal detectable change (MDC). Corticospinal silent period, corticospinal silent period/motor evoked potential ratio, active motor evoked potential, maximal Hoffman reflex, and passive short-interval intracortical inhibition demonstrated “good to excellent” relative reliability (ICC ≥ 0.643). Intracortical facilitation demonstrated the lowest relative reliability (ICC = 0.420–0.908). Corticospinal silent period displayed the lowest absolute reliability (SEm ≤ 18.68%). Good reliability of the maximal compound wave, Hoffman reflex, motor evoked potential, and corticospinal silent period allow for reliable neurological evaluation of peripheral and corticospinal pathways in the vastus medialis. Future research should investigate reliability of the intracortical (short-interval intracortical inhibition and intracortical facilitation) measures by using different paired-pulse stimulus parameters. These findings hold important implications for neurophysiological assessment conducted in the leg extensor group.
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Affiliation(s)
- Hans Leung
- School of Exercise and Nutrition Sciences, Institute for Physical Activity and Nutrition (IPAN), Deakin University, Geelong, VIC, Australia
| | - Christopher Latella
- School of Exercise and Nutrition Sciences, Institute for Physical Activity and Nutrition (IPAN), Deakin University, Geelong, VIC, Australia
| | - Séverine Lamon
- School of Exercise and Nutrition Sciences, Institute for Physical Activity and Nutrition (IPAN), Deakin University, Geelong, VIC, Australia
| | - Ashlee M Hendy
- School of Exercise and Nutrition Sciences, Institute for Physical Activity and Nutrition (IPAN), Deakin University, Geelong, VIC, Australia
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19
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Posture modulates the sensitivity of the H-reflex. Exp Brain Res 2018; 236:829-835. [DOI: 10.1007/s00221-018-5182-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 01/14/2018] [Indexed: 10/18/2022]
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20
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Transspinal Direct Current Stimulation Produces Persistent Plasticity in Human Motor Pathways. Sci Rep 2018; 8:717. [PMID: 29335430 PMCID: PMC5768745 DOI: 10.1038/s41598-017-18872-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Accepted: 12/19/2017] [Indexed: 11/25/2022] Open
Abstract
The spinal cord is an integration center for descending, ascending, and segmental neural signals. Noninvasive transspinal stimulation may thus constitute an effective method for concomitant modulation of local and distal neural circuits. In this study, we established changes in cortical excitability and input/output function of corticospinal and spinal neural circuits before, at 0–15 and at 30–45 minutes after cathodal, anodal, and sham transspinal direct current stimulation (tsDCS) to the thoracic region in healthy individuals. We found that intracortical inhibition was different among stimulation polarities, however remained unchanged over time. Intracortical facilitation increased after cathodal and anodal tsDCS delivered with subjects seated, and decreased after cathodal tsDCS delivered with subjects lying supine. Both cathodal and anodal tsDCS increased corticospinal excitability, yet facilitation was larger and persisted for 30 minutes post stimulation only when cathodal tsDCS was delivered with subjects lying supine. Spinal input/output reflex function was decreased by cathodal and not anodal tsDCS. These changes may be attributed to altered spontaneous neural activity and membrane potentials of corticomotoneuronal cells by tsDCS involving similar mechanisms to those mediating motor learning. Our findings indicate that thoracic tsDCS has the ability to concomitantly alter cortical, corticospinal, and spinal motor output in humans.
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21
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Christiansen TL, Niazi IK, Holt K, Nedergaard RW, Duehr J, Allen K, Marshall P, Türker KS, Hartvigsen J, Haavik H. The effects of a single session of spinal manipulation on strength and cortical drive in athletes. Eur J Appl Physiol 2018; 118:737-749. [PMID: 29327170 PMCID: PMC5843672 DOI: 10.1007/s00421-018-3799-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 01/01/2018] [Indexed: 11/11/2022]
Abstract
Purpose The primary purpose of this study was to investigate whether a single session of spinal manipulation (SM) increases strength and cortical drive in the lower limb (soleus muscle) of elite Taekwondo athletes. Methods Soleus-evoked V-waves, H-reflex and maximum voluntary contraction (MVC) of the plantar flexors were recorded from 11 elite Taekwondo athletes using a randomized controlled crossover design. Interventions were either SM or passive movement control. Outcomes were assessed at pre-intervention and at three post-intervention time periods (immediate post, post 30 min and post 60 min). A multifactorial repeated measures ANOVA was conducted to assess within and between group differences. Time and session were used as factors. A post hoc analysis was carried out, when an interactive effect was present. Significance was set at p ≤ 0.05. Results SM increased MVC force [F(3,30) = 5.95, p < 0.01], and V-waves [F(3,30) = 4.25, p = 0.01] over time compared to the control intervention. Between group differences were significant for all time periods (p < 0.05) except for the post60 force measurements (p = 0.07). Conclusion A single session of SM increased muscle strength and corticospinal excitability to ankle plantar flexor muscles in elite Taekwondo athletes. The increased MVC force lasted for 30 min and the corticospinal excitability increase persisted for at least 60 min.
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Affiliation(s)
- Thomas Lykke Christiansen
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark.,Nordic Institute of Chiropractic and Clinical Biomechanics, Odense, Denmark
| | - Imran Khan Niazi
- Center for Chiropractic Research, New Zealand College of Chiropractic, 6 Harrison Road, Mount Wellington, Auckland, New Zealand. .,SMI, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark.
| | - Kelly Holt
- Center for Chiropractic Research, New Zealand College of Chiropractic, 6 Harrison Road, Mount Wellington, Auckland, New Zealand
| | - Rasmus Wiberg Nedergaard
- Center for Chiropractic Research, New Zealand College of Chiropractic, 6 Harrison Road, Mount Wellington, Auckland, New Zealand
| | - Jens Duehr
- Center for Chiropractic Research, New Zealand College of Chiropractic, 6 Harrison Road, Mount Wellington, Auckland, New Zealand
| | - Kathryn Allen
- Center for Chiropractic Research, New Zealand College of Chiropractic, 6 Harrison Road, Mount Wellington, Auckland, New Zealand
| | - Paul Marshall
- School of Science and Health, Western Sydney University, Sydney, Australia
| | | | - Jan Hartvigsen
- Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark.,Nordic Institute of Chiropractic and Clinical Biomechanics, Odense, Denmark
| | - Heidi Haavik
- Center for Chiropractic Research, New Zealand College of Chiropractic, 6 Harrison Road, Mount Wellington, Auckland, New Zealand
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22
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Pontillo M, Costanzo F, Menghini D, Averna R, Santonastaso O, Tata MC, Vicari S. Use of Transcranial Direct Stimulation in the Treatment of Negative Symptoms of Schizophrenia. Clin EEG Neurosci 2018; 49:18-26. [PMID: 29243532 DOI: 10.1177/1550059417746531] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Schizophrenia is a debilitating disease that affects approximately 1% of the population. Negative symptoms are among the major determinants of the functional impairment and a significant proportion of patients with negative symptoms will continue to experience these symptoms despite antipsychotic medications. There are promising results in the application of brain stimulation, particularly transcranial direct current stimulation (tDCS), for the reduction of negative symptoms of schizophrenia. However, findings are still controversial. This is a selective review of the literature published between 2011 and 2017 on use of tDCS in treatment of negative symptoms of schizophrenia. We included only randomized controlled trials where schizophrenia and negative symptoms were assessed using any psychometrically validated scale (eg, Positive and Negative Symptoms Scale or Scale for the Assessment of Negative Symptoms). Studies of participants with neurological conditions were excluded, as were those that did not report any symptom outcome variables. Only 5 studies are included. Three studies showed a decrease of negative symptoms. The other studies did not show any therapeutic effects of tDCS in the severity of positive and negative symptoms compared to controls. Our findings suggest that negative symptoms in schizophrenia can be treated with tDCS over the dorsolateral prefrontal cortex, but results are affected by several factors, such as the electrode montage, the concomitant medication, the homogeneity of the sample, the intensity of the tDCS treatment. Further randomized, double-blinded, sham-controlled studies in large samples are still needed to establish the effectiveness of the tDCS in the treatment of negative symptoms in schizophrenia, but there is the potential for tDCS to become a useful complementary treatment option in this population.
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Affiliation(s)
- Maria Pontillo
- 1 Child and Adolescence Neuropsychiatry Unit, Department of Neuroscience, Children Hospital Bambino Gesù, Rome, Italy
| | - Floriana Costanzo
- 1 Child and Adolescence Neuropsychiatry Unit, Department of Neuroscience, Children Hospital Bambino Gesù, Rome, Italy
| | - Deny Menghini
- 1 Child and Adolescence Neuropsychiatry Unit, Department of Neuroscience, Children Hospital Bambino Gesù, Rome, Italy
| | - Roberto Averna
- 1 Child and Adolescence Neuropsychiatry Unit, Department of Neuroscience, Children Hospital Bambino Gesù, Rome, Italy
| | - Ornella Santonastaso
- 1 Child and Adolescence Neuropsychiatry Unit, Department of Neuroscience, Children Hospital Bambino Gesù, Rome, Italy
| | - Maria Cristina Tata
- 1 Child and Adolescence Neuropsychiatry Unit, Department of Neuroscience, Children Hospital Bambino Gesù, Rome, Italy
| | - Stefano Vicari
- 1 Child and Adolescence Neuropsychiatry Unit, Department of Neuroscience, Children Hospital Bambino Gesù, Rome, Italy
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23
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Botelho MB, Alvarenga BAP, Molina N, Ribas M, Baptista AF. Spinal Manipulative Therapy and Sports Performance Enhancement: A Systematic Review. J Manipulative Physiol Ther 2017; 40:535-543. [PMID: 29191288 DOI: 10.1016/j.jmpt.2017.03.014] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Revised: 03/04/2017] [Accepted: 03/14/2017] [Indexed: 12/16/2022]
Abstract
OBJECTIVE The purpose of this study was to review the literature regarding the relationship between spinal manipulative therapy (SMT) and sports performance. METHODS PubMed and Embase databases were searched for original studies published up to July 2016. Inclusion criteria were if SMT has been applied to athletes and if any sports performance-related outcome was measured. RESULTS Of the 581 potential studies, 7 clinical trials were selected. Most studies had adequate quality (≥6/11) when assessed by the PEDro scale. None of those studies assessed performance at an event or competition. Four studies revealed improvement in a sports performance test after SMT. Meta-analysis could not be performed because of the wide differences in methodologies, design, and outcomes measured. Spinal manipulative therapy influences a wide range of neurophysiological parameters that could be associated with sports performance. Of the 3 studies where SMT did not improve test performance, 2 used SMT not for therapeutic correction of a dysfunctional vertebral joint but to an arbitrary previously set joint. CONCLUSIONS Although 4 of 7 studies showed that SMT improved sports performance tests, the evidence is still weak to support its use. Spinal manipulative therapy may be a promising approach for performance enhancement that should be investigated with more consistent methodologic designs.
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Affiliation(s)
- Marcelo B Botelho
- Graduate Program in Medicine and Health, Faculty of Medicine, Federal University of Bahia, Salvador, Bahia, Brazil.
| | | | - Nícolly Molina
- Graduate Program in Medicine and Health, Faculty of Medicine, Federal University of Bahia, Salvador, Bahia, Brazil
| | - Marcos Ribas
- Graduate Program in Medicine and Health, Faculty of Medicine, Federal University of Bahia, Salvador, Bahia, Brazil
| | - Abrahão F Baptista
- Center for Mathematics, Computation and Cognition, Federal University of ABC, São Bernardo do Campo, São Paulo, Brazil
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24
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König N, Ferraro MG, Baur H, Taylor WR, Singh NB. What Is the Contribution of Ia-Afference for Regulating Motor Output Variability during Standing? Front Hum Neurosci 2017; 11:87. [PMID: 28303096 PMCID: PMC5332383 DOI: 10.3389/fnhum.2017.00087] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 02/13/2017] [Indexed: 12/20/2022] Open
Abstract
Motor variability is an inherent feature of all human movements, and describes the system's stability and rigidity during the performance of functional motor tasks such as balancing. In order to ensure successful task execution, the nervous system is thought to be able to flexibly select the appropriate level of variability. However, it remains unknown which neurophysiological pathways are utilized for the control of motor output variability. In responding to natural variability (in this example sway), it is plausible that the neuro-physiological response to muscular elongation contributes to restoring a balanced upright posture. In this study, the postural sway of 18 healthy subjects was observed while their visual and mechano-sensory system was perturbed. Simultaneously, the contribution of Ia-afferent information for controlling the motor task was assessed by means of H-reflex. There was no association between postural sway and Ia-afference in the eyes open condition, however up to 4% of the effects of eye closure on the magnitude of sway can be compensated by increased reliance on Ia-afference. Increasing the biomechanical demands by adding up to 40% bodyweight around the trunk induced a specific sway response, such that the magnitude of sway remained unchanged but its dynamic structure became more regular and stable (by up to 18%). Such regular sway patterns have been associated with enhanced cognitive involvement in controlling motor tasks. It therefore appears that the nervous system applies different control strategies in response to the perturbations: The loss of visual information is compensated by increased reliance on other receptors; while the specific regular sway pattern associated with additional weight-bearing was independent of Ia-afferent information, suggesting the fundamental involvement of supraspinal centers for the control of motor output variability.
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Affiliation(s)
- Niklas König
- Laboratory for Movement Biomechanics, Department of Health Sciences and Technology, Institute for Biomechanics, ETH Zürich Zurich, Switzerland
| | - Matteo G Ferraro
- Movement Laboratory, Department of Business, Health and Social Work, Bern University of Applied Sciences Bern, Switzerland
| | - Heiner Baur
- Movement Laboratory, Department of Business, Health and Social Work, Bern University of Applied Sciences Bern, Switzerland
| | - William R Taylor
- Laboratory for Movement Biomechanics, Department of Health Sciences and Technology, Institute for Biomechanics, ETH Zürich Zurich, Switzerland
| | - Navrag B Singh
- Laboratory for Movement Biomechanics, Department of Health Sciences and Technology, Institute for Biomechanics, ETH Zürich Zurich, Switzerland
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25
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Botter A, Vieira TM. Optimization of surface electrodes location for H-reflex recordings in soleus muscle. J Electromyogr Kinesiol 2017; 34:14-23. [PMID: 28342367 DOI: 10.1016/j.jelekin.2017.03.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 02/10/2017] [Accepted: 03/13/2017] [Indexed: 11/15/2022] Open
Abstract
The Hoffmann reflex (H reflex) is extensively used to investigate the spinal motor neuron excitability in healthy and pathological subjects. Obtaining a representative and robust amplitude estimation of the H reflex is of marked relevance in clinical as well as in research applications. As for the motor responses, this issue is strictly related to the electrode positioning, especially for large, pinnate muscles such as the triceps surae. In this study we investigated the effect of electrode position on soleus H-reflex amplitude. A grid of 96 electrodes was used to identify maximal H reflexes (Hmax) across the whole soleus region available for surface recording. The spatial distribution of Hmax amplitude detected in monopolar and single-differential derivations was used to determine where greatest reflex responses were detected from soleus. For both derivations and for all participants, largest Hmax were detected consistently over the central soleus region, in correspondence of the muscle superficial aponeurosis. Indeed, the amplitude of Hmax provided by conventional electrodes (1cm2 area, 2cm apart) located centrally was significantly greater (median: 35% for monopolar and 79% for single-differential derivations) than that obtained medially, where surface electromyograms are typically recorded from soleus. Computer simulations, used to assist in the interpretation of results, suggest the soleus pinnate architecture was the key determinant of the medio-lateral variability observed for the experimental Hmax. The presented results provide a clear indication for electrode positioning, of crucial relevance in applied studies aimed at eliciting H reflexes.
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Affiliation(s)
- Alberto Botter
- Laboratory for Engineering of the Neuromuscular System (LISiN), Dipartimento di Elettronica e Telecomunicazioni, Politecnico di Torino, Torino, Italy.
| | - Taian M Vieira
- Laboratory for Engineering of the Neuromuscular System (LISiN), Dipartimento di Elettronica e Telecomunicazioni, Politecnico di Torino, Torino, Italy
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Is the Frequency in Somatosensory Electrical Stimulation the Key Parameter in Modulating the Corticospinal Excitability of Healthy Volunteers and Stroke Patients with Spasticity? Neural Plast 2016; 2016:3034963. [PMID: 26881102 PMCID: PMC4736758 DOI: 10.1155/2016/3034963] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 11/23/2015] [Indexed: 11/20/2022] Open
Abstract
Somatosensory electrical stimulation (SES) has been proposed as an approach to treat patients with sensory-motor impairment such as spasticity. However, there is still no consensus regarding which would be the adequate SES parameters to treat those deficits. Therefore, the aim of this study was to evaluate the effects of applying SES over the forearm muscles at four different frequencies of stimulation (3, 30, 150, and 300 Hz) and in two intervals of time (5′ and 30′) by means of transcranial magnetic stimulation and Hoffmann's reflex (H-reflex) in healthy volunteers (Experiments I and II). A group of stroke patients (Experiment III) was also preliminary evaluated to ascertain SES effects at a low frequency (3 Hz) applied for 30′ over the forearm spastic flexors muscles by measuring the wrist joint passive torque. Motor evoked potentials and the H-reflex were collected from different forearm and hand muscles immediately before and after SES and up to 5′ (Experiment I) and 10′ (Experiments I and II) later. None of the investigated frequencies of SES was able to operate as a key in switching modulatory effects in the central nervous system of healthy volunteers and stroke patients with spasticity.
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Kawaishi Y, Domen K. The relationship between dynamic balancing ability and posture-related modulation of the soleus H-reflex. J Electromyogr Kinesiol 2016; 26:120-4. [DOI: 10.1016/j.jelekin.2015.11.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Revised: 11/20/2015] [Accepted: 11/30/2015] [Indexed: 11/25/2022] Open
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Stutzig N, Siebert T. Reproducibility of electromyographic and mechanical parameters of the triceps surae during submaximal and maximal plantar flexions. Muscle Nerve 2016; 53:464-70. [PMID: 26173034 DOI: 10.1002/mus.24767] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/07/2015] [Indexed: 12/17/2022]
Abstract
INTRODUCTION Neuromuscular parameters must be reproducible to examine neuromuscular adaptations in interventional and clinical studies. The reproducibility of neuromuscular parameters for the soleus (SOL), lateral gastrocnemius (LG), and medial gastrocnemius (MG) was assessed over a period of 2 weeks. METHODS Thirteen subjects (27.4 years, 69.5 kg) were tested for numerous electromyographic (e.g., voluntary and electrical evoked EMG) and mechanical (e.g., voluntary activation level) parameters in 3 test sessions. RESULTS The majority of the data (28 of 34) revealed moderate and substantial reproducibility. Hmax20% /Mmax20% and Vsup /Msup were less reproducible in LG than in MG and SOL. Muscle activity and M-waves did not differ between muscles. The ICC for the mechanical data was >0.79. CONCLUSIONS The H-reflex during voluntary contraction of the LG should be considered with caution. Mechanical data on muscle activation level are reproducible. The reproducibility of neuromuscular parameters is sufficient for interventional studies.
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Affiliation(s)
- Norman Stutzig
- Institute of Sport and Movement Science, University of Stuttgart, Allmandring 28, 70569, Stuttgart, Germany
| | - Tobias Siebert
- Institute of Sport and Movement Science, University of Stuttgart, Allmandring 28, 70569, Stuttgart, Germany
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Recording and assessment of evoked potentials with electrode arrays. Med Biol Eng Comput 2015; 53:857-67. [PMID: 25863691 DOI: 10.1007/s11517-015-1292-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Accepted: 03/26/2015] [Indexed: 10/23/2022]
Abstract
In order to optimize procedure for the assessment of evoked potentials and to provide visualization of the flow of action potentials along the motor systems, we introduced array electrodes for stimulation and recording and developed software for the analysis of the recordings. The system uses a stimulator connected to an electrode array for the generation of evoked potentials, an electrode array connected to the amplifier, A/D converter and computer for the recording of evoked potentials, and a dedicated software application. The method has been tested for the assessment of the H-reflex on the triceps surae muscle in six healthy humans. The electrode array with 16 pads was positioned over the posterior aspect of the thigh, while the recording electrode array with 16 pads was positioned over the triceps surae muscle. The stimulator activated all the pads of the stimulation electrode array asynchronously, while the signals were recorded continuously at all the recording sites. The results are topography maps (spatial distribution of evoked potentials) and matrices (spatial visualization of nerve excitability). The software allows the automatic selection of the lowest stimulation intensity to achieve maximal H-reflex amplitude and selection of the recording/stimulation pads according to predefined criteria. The analysis of results shows that the method provides rich information compared with the conventional recording of the H-reflex with regard the spatial distribution.
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Changes in H-reflex and V-waves following spinal manipulation. Exp Brain Res 2015; 233:1165-73. [PMID: 25579661 DOI: 10.1007/s00221-014-4193-5] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 12/22/2014] [Indexed: 11/27/2022]
Abstract
This study investigates whether spinal manipulation leads to neural plastic changes involving cortical drive and the H-reflex pathway. Soleus evoked V-wave, H-reflex, and M-wave recruitment curves and maximum voluntary contraction (MVC) in surface electromyography (SEMG) signals of the plantar flexors were recorded from ten subjects before and after manipulation or control intervention. Dependent measures were compared with 2-way ANOVA and Tukey's HSD as post hoc test, p was set at 0.05. Spinal manipulation resulted in increased MVC (measured with SEMG) by 59.5 ± 103.4 % (p = 0.03) and force by 16.05 ± 6.16 4 % (p = 0.0002), increased V/M max ratio by 44.97 ± 36.02 % (p = 0.006), and reduced H-reflex threshold (p = 0.018). Following the control intervention, there was a decrease in MVC (measured with SEMG) by 13.31 ± 7.27 % (p = 0.001) and force by 11.35 ± 9.99 % (p = 0.030), decreased V/M max ratio (23.45 ± 17.65 %; p = 0.03) and a decrease in the median frequency of the power spectrum (p = 0.04) of the SEMG during MVC. The H-reflex pathway is involved in the neural plastic changes that occur following spinal manipulation. The improvements in MVC following spinal manipulation are likely attributed to increased descending drive and/or modulation in afferents. Spinal manipulation appears to prevent fatigue developed during maximal contractions. Spinal manipulation appears to alter the net excitability of the low-threshold motor units, increase cortical drive, and prevent fatigue.
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Smith AC, Rymer WZ, Knikou M. Locomotor training modifies soleus monosynaptic motoneuron responses in human spinal cord injury. Exp Brain Res 2014; 233:89-103. [PMID: 25205562 DOI: 10.1007/s00221-014-4094-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 08/29/2014] [Indexed: 01/15/2023]
Abstract
The objective of this study was to assess changes in monosynaptic motoneuron responses to stimulation of Ia afferents after locomotor training in individuals with chronic spinal cord injury (SCI). We hypothesized that locomotor training modifies the amplitude of the soleus monosynaptic motoneuron responses in a body position-dependent manner. Fifteen individuals with chronic clinical motor complete or incomplete SCI received an average of 45 locomotor training sessions. The soleus H-reflex and M-wave recruitment curves were assembled using data collected in both the right and left legs, with subjects seated and standing, before and after training. The soleus H-reflexes and M-waves, measured as peak-to-peak amplitudes, were normalized to the maximal M-wave (M(max)). Stimulation intensities were normalized to 50% M(max) stimulus intensity. A sigmoid function was also fitted to the normalized soleus H-reflexes on the ascending limb of the recruitment curve. After training, soleus H-reflex excitability was increased in both legs in AIS C subjects, and remained unchanged in AIS A-B and AIS D subjects during standing. When subjects were seated, soleus H-reflex excitability was decreased after training in many AIS C and D subjects. Changes in reflex excitability coincided with changes in stimulation intensities at H-threshold, 50% maximal H-reflex, and at maximal H-reflex, while an interaction between leg side and AIS scale for the H-reflex slope was also found. Adaptations of the intrinsic properties of soleus motoneurons and Ia afferents, the excitability profile of the soleus motoneuron pool, oligosynaptic inputs, and corticospinal inputs may all contribute to these changes. The findings of this study demonstrate that locomotor training impacts the amplitude of the monosynaptic motoneuron responses based on the demands of the motor task in people with chronic SCI.
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Affiliation(s)
- Andrew C Smith
- Northwestern University Interdepartmental Neuroscience Program, Chicago, IL, 60611, USA
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Fitzgerald PB, McQueen S, Daskalakis ZJ, Hoy KE. A negative pilot study of daily bimodal transcranial direct current stimulation in schizophrenia. Brain Stimul 2014; 7:813-6. [PMID: 25442152 DOI: 10.1016/j.brs.2014.08.002] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 08/06/2014] [Accepted: 08/06/2014] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND A small number of studies conducted to date have suggested that transcranial direct current stimulation (tDCS) applied to the temporoparietal cortex may reduce auditory hallucinations in patients with schizophrenia. Prefrontal brain stimulation with other methods, has also been shown to potentially improve the negative symptoms of this disorder. OBJECTIVE To investigate the therapeutic potential of daily bimodal tDCS: anodal stimulation to the prefrontal cortex and cathodal stimulation to the temporoparietal junction in patients with persistent hallucinations and negative symptoms of schizophrenia. METHODS We conducted two small randomized double-blind controlled trials comparing bimodal tDCS to sham stimulation. In one study, stimulation was provided unilaterally, in the second study it was provided bilaterally. RESULTS Neither unilateral nor bilateral tDCS resulted in a substantial change in either hallucinations or negative symptoms. Stimulation was well tolerated without side-effects. CONCLUSION Daily tDCS does not appear to have substantial potential in the treatment of hallucinations or negative symptoms and further research should investigate higher doses of stimulation or more frequently applied treatment schedules.
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Affiliation(s)
- Paul B Fitzgerald
- Monash Alfred Psychiatry Research Centre, The Alfred and Monash University Central Clinical School, Melbourne, Victoria 3004, Australia.
| | - Susan McQueen
- Monash Alfred Psychiatry Research Centre, The Alfred and Monash University Central Clinical School, Melbourne, Victoria 3004, Australia
| | - Zafiris J Daskalakis
- Centre for Addiction and Mental Health, Clarke Division, Toronto, Ontario, Canada
| | - Kate E Hoy
- Monash Alfred Psychiatry Research Centre, The Alfred and Monash University Central Clinical School, Melbourne, Victoria 3004, Australia
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Vangsgaard S, Taylor JL, Hansen EA, Madeleine P. Changes in H reflex and neuromechanical properties of the trapezius muscle after 5 weeks of eccentric training: a randomized controlled trial. J Appl Physiol (1985) 2014; 116:1623-31. [DOI: 10.1152/japplphysiol.00164.2014] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Trapezius muscle Hoffman (H) reflexes were obtained to investigate the neural adaptations induced by a 5-wk strength training regimen, based solely on eccentric contractions of the shoulder muscles. Twenty-nine healthy subjects were randomized into an eccentric training group ( n = 15) and a reference group ( n = 14). The eccentric training program consisted of nine training sessions of eccentric exercise performed over a 5-wk period. H-reflex recruitment curves, the maximal M wave (Mmax), maximal voluntary contraction (MVC) force, rate of force development (RFD), and electromyographic (EMG) voluntary activity were recorded before and after training. H reflexes were recorded from the middle part of the trapezius muscle by electrical stimulation of the C3/4 cervical nerves; Mmax was measured by electrical stimulation of the accessory nerve. Eccentric strength training resulted in significant increases in the maximal trapezius muscle H reflex (Hmax) (21.4% [5.5–37.3]; P = 0.01), MVC force (26.4% [15.0–37.7]; P < 0.01), and RFD (24.6% [3.2–46.0]; P = 0.025), while no significant changes were observed in the reference group. Mmax remained unchanged in both groups. A significant positive correlation was found between the change in MVC force and the change in EMG voluntary activity in the training group ( r = 0.57; P = 0.03). These results indicate that the net excitability of the trapezius muscle H-reflex pathway increased after 5 wk of eccentric training. This is the first study to investigate and document changes in the trapezius muscle H reflex following eccentric strength training.
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Affiliation(s)
- Steffen Vangsgaard
- Center for Sensory-Motor Interaction, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark; and
| | - Janet L. Taylor
- Neuroscience Research Australia and the University of New South Wales, Sydney, Australia
| | - Ernst A. Hansen
- Center for Sensory-Motor Interaction, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark; and
| | - Pascal Madeleine
- Center for Sensory-Motor Interaction, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark; and
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Vangsgaard S, Nørgaard LT, Flaskager BK, Søgaard K, Taylor JL, Madeleine P. Eccentric exercise inhibits the H reflex in the middle part of the trapezius muscle. Eur J Appl Physiol 2012; 113:77-87. [DOI: 10.1007/s00421-012-2412-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Accepted: 04/23/2012] [Indexed: 10/28/2022]
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Vila-Chã C, Falla D, Correia MV, Farina D. Changes in H reflex and V wave following short-term endurance and strength training. J Appl Physiol (1985) 2012; 112:54-63. [DOI: 10.1152/japplphysiol.00802.2011] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This study examined the effects of 3 wk of either endurance or strength training on plasticity of the neural mechanisms involved in the soleus H reflex and V wave. Twenty-five sedentary healthy subjects were randomized into an endurance group ( n = 13) or strength group ( n = 12). Evoked V-wave, H-reflex, and M-wave recruitment curves, maximal voluntary contraction (MVC), and time-to-task-failure (isometric contraction at 40% MVC) of the plantar flexors were recorded before and after training. Following strength training, MVC of the plantar flexors increased by 14.4 ± 5.2% in the strength group ( P < 0.001), whereas time-to-task-failure was prolonged in the endurance group (22.7 ± 17.1%; P < 0.05). The V wave-to-maximal M wave (V/Mmax) ratio increased significantly (55.1 ± 28.3%; P < 0.001) following strength training, but the maximal H wave-to-maximal M wave (Hmax/Mmax) ratio remained unchanged. Conversely, in the endurance group the V/Mmax ratio was not altered, whereas the Hmax/Mmax ratio increased by 30.8 ± 21.7% ( P < 0.05). The endurance training group also displayed a reduction in the H-reflex excitability threshold while the H-reflex amplitude on the ascending limb of the recruitment curve increased. Strength training only elicited a significant decrease in H-reflex excitability threshold, while H-reflex amplitudes over the ascending limb remained unchanged. These observations indicate that the H-reflex pathway is strongly involved in the enhanced endurance resistance that occurs following endurance training. On the contrary, the improvements in MVC following strength training are likely attributed to increased descending drive and/or modulation in afferents other than Ia afferents.
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Affiliation(s)
- Carolina Vila-Chã
- Polytechnic Institute of Bragança, Bragança
- Universidade do Porto, Faculdade de Engenharia, Porto, Portugal
| | - Deborah Falla
- Department of Neurorehabilitation Engineering, Bernstein Center for Computational Neuroscience, University Medical Center Göttingen, Georg-August University; and
- Pain Clinic, Center for Anesthesiology, Emergency and Intensive Care Medicine, University Hospital Göttingen, Göttingen, Germany
| | | | - Dario Farina
- Department of Neurorehabilitation Engineering, Bernstein Center for Computational Neuroscience, University Medical Center Göttingen, Georg-August University; and
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Chen YS, Zhou S. Soleus H-reflex and its relation to static postural control. Gait Posture 2011; 33:169-78. [PMID: 21211976 DOI: 10.1016/j.gaitpost.2010.12.008] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2010] [Revised: 11/19/2010] [Accepted: 12/09/2010] [Indexed: 02/02/2023]
Abstract
The Hoffmann reflex (H-reflex) test has been extensively used to investigate the responsiveness of Ia afferent spinal loop in animal and human studies. The H-reflex response is influenced by multiple neural pathways and the assessment of H-reflex variation is a useful tool in understanding the neural mechanisms in control of movement. Recently, several studies have examined the relationship between the H-reflex modulation and postural stability. For example, it has been reported that the amplitude of soleus (SOL) H-reflex is depressed in relation to increased body sway during upright standing on a soft surface compared to that on a solid surface. It has been suggested that the SOL H-reflex modulation under such condition is predominately affected by the presynaptic inhibitory mechanisms for avoiding oversaturation of the spinal motoneurons. It has also been reported that after balance training, the SOL H-reflex amplitude is down-modulated in parallel with improvement in balance control, suggesting a functional adaptation at the supraspinal levels. The aim of this review is to examine the current literature on the relationship between H-reflex modulation and postural control for a better understanding of the physiological mechanisms involved in control of posture in humans.
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Affiliation(s)
- Yung-Sheng Chen
- School of Health and Human Sciences, Southern Cross University, Lismore, New South Wales, Australia
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Bhatia BD, Kumar A, Prakash U. Effect of prematurity and intrauterine growth restriction on H-reflex recovery cycle in neonates. Neurosci Lett 2011; 488:107-11. [PMID: 20816919 DOI: 10.1016/j.neulet.2010.08.087] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2010] [Revised: 07/27/2010] [Accepted: 08/28/2010] [Indexed: 11/17/2022]
Abstract
OBJECTIVE The purpose of this work was to assess the effects of prematurity and intrauterine growth restriction on spinal cord synapses using H-reflex. METHODS 33 babies were investigated at birth. 14 were full term appropriate for gestational age (FT AGA), 10 were full term intrauterine growth restricted (FT IUGR) and 9 were preterm appropriate for gestational age (PT AGA). The maximum amplitude of H-reflex (Hmax), H-reflex latency (HRL), H/M ratio, H-reflex conduction velocity (HRCV), and H-reflex response to double stimuli (conditioning and test) for H-reflex recovery cycle (HRRC) were recorded in right lower limb (soleus muscle) in all the three groups. RESULTS Percentage recovery values of H-reflex were significantly higher in FT AGA and FT IUGR babies compared to PT AGA neonates for most of inter-stimulus intervals. No significant differences were observed in H-reflex parameters between FT AGA and FT IUGR groups, but HRL and HRCV were significantly affected in PT AGA group. CONCLUSIONS Delayed H-reflex recovery in preterms may be due to a prolonged state of neurotransmitter delay in Ia terminals following initial activation by the conditioning stimuli. The cause of such prolonged depletion of neurotransmitters could be attributed to a poor neurotransmitter store in synaptic vesicles of spinal cord in preterm neonates.
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Affiliation(s)
- B D Bhatia
- Department of Pediatrics, Unit of Neonatology, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India. baldev
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Knikou M, Angeli CA, Ferreira CK, Harkema SJ. Soleus H-reflex gain, threshold, and amplitude as function of body posture and load in spinal cord intact and injured subjects. Int J Neurosci 2010; 119:2056-73. [PMID: 19863261 DOI: 10.1080/00207450903139747] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
In this study, we established parameters of the soleus H-reflex excitability in response to changes of posture and load in 8 chronic spinal cord injured (SCI) and 10 spinal-intact subjects. The soleus H-reflex recruitment curve was established in all subjects while they were supine, seated, and standing on a stable treadmill. During standing, body weight support (BWS) was provided via an upper body harness and ranged in SCI subjects from 20%-50% and in spinal-intact subjects was set at 0% and 50%. Stimuli corresponding to the H-threshold (H(th)), maximal H-reflex amplitude (H(max)), and 50% of H(max) as well as the reflex gain were estimated based on a sigmoid function of the ascending limb of the soleus H-reflex recruitment curve. The soleus H-reflex gain, H(max) amplitude, and stimuli corresponding to H(th), 50% of H(max), and H(max) were increased in SCI subjects regardless of the body position and loading. Further, the reflex gain was not modulated appropriately during conditions of weight bearing in SCI subjects. Impaired spinal reflex excitability in SCI subjects is accompanied by changes of the H-reflex recruitment curve parameters regardless of presence or absence of body loading.
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Affiliation(s)
- Maria Knikou
- Health Science Doctoral Programs, City University of New York, Staten Island, New York 10314, USA.
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Soleus H-reflex graded depression by contralateral hip afferent feedback in humans. Brain Res 2010; 1310:77-86. [DOI: 10.1016/j.brainres.2009.11.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2009] [Revised: 11/03/2009] [Accepted: 11/05/2009] [Indexed: 11/20/2022]
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Tuncer M, Tucker KJ, Türker KS. Influence of tooth clench on the soleus H-reflex. Arch Oral Biol 2007; 52:374-6. [PMID: 17254544 DOI: 10.1016/j.archoralbio.2006.12.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2006] [Revised: 12/15/2006] [Accepted: 12/18/2006] [Indexed: 10/23/2022]
Abstract
The Hoffmann (H) reflex is elicited by electrical stimulation of a mixed nerve and is used to measure the excitability of the spindle-motoneuron synapse. Recent investigations have indicated a positive correlation between increases in bite force and H-reflex facilitation. However, these investigations did not examine the H-reflex in detail or the possible role of periodontal mechanoreceptors (PMRs) in this facilitation. The current investigation was performed to determine whether PMRs play a role in H-reflex facilitation during tooth clench (TC). The H-reflex was elicited in the soleus muscle of human subjects while bite level was maintained at rest (0 N), 40 N, 80 N and maximal TC. The front teeth that contributed to the (40 N and 80 N) bite force were then locally anaesthetised (LA), and the protocol was repeated. The current data suggest that the effect of TC on the H-reflex amplitude in the human limb muscles is variable from one subject to the next. Statistical analysis has shown that the H-reflex was significantly smaller during the rest condition than during the 80 N bite (p<0.05) in both non-LA and LA conditions. Since LA did not alter the response, our results do not support that the PMRs play a major role in the facilitation of distal muscle activity.
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Affiliation(s)
- Meltem Tuncer
- Hacettepe University, Faculty of Medicine, Department of Physiology, Sihhiye, Ankara 06100, Turkey
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