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Desmons M, Cherif A, Rohel A, de Oliveira FCL, Mercier C, Massé-Alarie H. Corticomotor Control of Lumbar Erector Spinae in Postural and Voluntary Tasks: The Influence of Transcranial Magnetic Stimulation Current Direction. eNeuro 2024; 11:ENEURO.0454-22.2023. [PMID: 38167617 PMCID: PMC10883751 DOI: 10.1523/eneuro.0454-22.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 11/30/2023] [Accepted: 12/16/2023] [Indexed: 01/05/2024] Open
Abstract
Lumbar erector spinae (LES) contribute to spine postural and voluntary control. Transcranial magnetic stimulation (TMS) preferentially depolarizes different neural circuits depending on the direction of electrical currents evoked in the brain. Posteroanterior current (PA-TMS) and anteroposterior (AP-TMS) current would, respectively, depolarize neurons in the primary motor cortex (M1) and the premotor cortex. These regions may contribute differently to LES control. This study examined whether responses evoked by PA- and AP-TMS are different during the preparation and execution of LES voluntary and postural tasks. Participants performed a reaction time task. A Warning signal indicated to prepare to flex shoulders (postural; n = 15) or to tilt the pelvis (voluntary; n = 13) at the Go signal. Single- and paired-pulse TMS (short-interval intracortical inhibition-SICI) were applied using PA- and AP-TMS before the Warning signal (baseline), between the Warning and Go signals (preparation), or 30 ms before the LES onset (execution). Changes from baseline during preparation and execution were calculated in AP/PA-TMS. In the postural task, MEP amplitude was higher during the execution than that during preparation independently of the current direction (p = 0.0002). In the voluntary task, AP-MEP amplitude was higher during execution than that during preparation (p = 0.016). More PA inhibition (SICI) was observed in execution than that in preparation (p = 0.028). Different neural circuits are preferentially involved in the two motor tasks assessed, as suggested by different patterns of change in execution of the voluntary task (AP-TMS, increase; PA-TMS, no change). Considering that PA-TMS preferentially depolarize neurons in M1, it questions their importance in LES voluntary control.
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Affiliation(s)
- Mikaël Desmons
- Center for Interdisciplinary Research in Rehabilitation and Social Integration (Cirris), CIUSSS de la Capitale-Nationale, Quebec City, Quebec G1M 2S8, Canada
- Rehabilitation Department, University Laval, Quebec City, Quebec G1V 0A6, Canada, G1V 0A6
| | - Amira Cherif
- Center for Interdisciplinary Research in Rehabilitation and Social Integration (Cirris), CIUSSS de la Capitale-Nationale, Quebec City, Quebec G1M 2S8, Canada
- Rehabilitation Department, University Laval, Quebec City, Quebec G1V 0A6, Canada, G1V 0A6
| | - Antoine Rohel
- Center for Interdisciplinary Research in Rehabilitation and Social Integration (Cirris), CIUSSS de la Capitale-Nationale, Quebec City, Quebec G1M 2S8, Canada
- Rehabilitation Department, University Laval, Quebec City, Quebec G1V 0A6, Canada, G1V 0A6
| | - Fábio Carlos Lucas de Oliveira
- Center for Interdisciplinary Research in Rehabilitation and Social Integration (Cirris), CIUSSS de la Capitale-Nationale, Quebec City, Quebec G1M 2S8, Canada
- Rehabilitation Department, University Laval, Quebec City, Quebec G1V 0A6, Canada, G1V 0A6
| | - Catherine Mercier
- Center for Interdisciplinary Research in Rehabilitation and Social Integration (Cirris), CIUSSS de la Capitale-Nationale, Quebec City, Quebec G1M 2S8, Canada
- Rehabilitation Department, University Laval, Quebec City, Quebec G1V 0A6, Canada, G1V 0A6
| | - Hugo Massé-Alarie
- Center for Interdisciplinary Research in Rehabilitation and Social Integration (Cirris), CIUSSS de la Capitale-Nationale, Quebec City, Quebec G1M 2S8, Canada
- Rehabilitation Department, University Laval, Quebec City, Quebec G1V 0A6, Canada, G1V 0A6
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Desmons M, Rohel A, Desgagnés A, Mercier C, Massé-Alarie H. Influence of different transcranial magnetic stimulation current directions on the corticomotor control of lumbar erector spinae muscles during a static task. J Neurophysiol 2021; 126:1276-1288. [PMID: 34550037 DOI: 10.1152/jn.00137.2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Different directions of transcranial magnetic stimulation (TMS) can activate different neuronal circuits. Whereas posteroanterior current (PA-TMS) depolarizes mainly interneurons in primary motor cortex (M1), an anteroposterior current (AP-TMS) has been suggested to activate different M1 circuits and perhaps axons from the premotor regions. Although M1 is also involved in the control of axial muscles, no study has explored whether different current directions activate different M1 circuits that may have distinct functional roles. The aim of the study was to compare the effect of different current directions (PA- and AP-TMS) on the corticomotor control and spatial cortical organization of the lumbar erector spinae muscle (LES). Thirty-four healthy participants were recruited for two independent experiments, and LES motor-evoked potentials (MEPs) were recorded. In experiment 1 (n = 17), active motor threshold (AMT), MEP latencies, recruitment curve (90% to 160% AMT), and excitatory and inhibitory intracortical mechanisms by paired-pulse TMS (80% followed by 120% AMT stimuli at 2-, 3-, 10-, and 15-ms interstimulus intervals) were tested with a double-cone (n = 12) and a figure-of-eight (n = 5) coil. In experiment 2 (n = 17), LES cortical representations were tested with PA- and AP-TMS. AMT was higher for AP- compared with PA-TMS (P = 0.002). Longer latencies with AP-TMS were present compared with PA-TMS (P = 0.017). AP-TMS produced more inhibition compared with PA-TMS at 2 ms and 3 ms (P = 0.010), but no difference was observed for longer intervals. No difference was found for recruitment curve and mapping. These findings suggest that PA- and AP-TMS may activate different cortical circuits controlling low back muscles, as proposed for hand muscles.NEW & NOTEWORTHY For the first time, anteroposterior and posteroanterior induced electric currents in the brain were compared when targeting back muscle representation with transcranial magnetic stimulation. The use of the anteroposterior current resulted in later response latency, larger inhibition probed by paired-pulse stimulation, and higher motor threshold. These important differences between current directions suggest that each of the current directions may recruit specific cortical circuits involved in the control of back muscles, similar to that for hand muscles.
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Affiliation(s)
- Mikaël Desmons
- CIRRIS Research Centre, Université Laval, Quebec City, Quebec, Canada
| | - Antoine Rohel
- CIRRIS Research Centre, Université Laval, Quebec City, Quebec, Canada
| | - Amélie Desgagnés
- CIRRIS Research Centre, Université Laval, Quebec City, Quebec, Canada
| | - Catherine Mercier
- CIRRIS Research Centre, Université Laval, Quebec City, Quebec, Canada.,Rehabilitation Unit, Université Laval, Quebec City, Quebec, Canada
| | - Hugo Massé-Alarie
- CIRRIS Research Centre, Université Laval, Quebec City, Quebec, Canada.,Rehabilitation Unit, Université Laval, Quebec City, Quebec, Canada
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Sollmann N, Krieg SM, Säisänen L, Julkunen P. Mapping of Motor Function with Neuronavigated Transcranial Magnetic Stimulation: A Review on Clinical Application in Brain Tumors and Methods for Ensuring Feasible Accuracy. Brain Sci 2021; 11:brainsci11070897. [PMID: 34356131 PMCID: PMC8305823 DOI: 10.3390/brainsci11070897] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 06/29/2021] [Accepted: 07/02/2021] [Indexed: 12/15/2022] Open
Abstract
Navigated transcranial magnetic stimulation (nTMS) has developed into a reliable non-invasive clinical and scientific tool over the past decade. Specifically, it has undergone several validating clinical trials that demonstrated high agreement with intraoperative direct electrical stimulation (DES), which paved the way for increasing application for the purpose of motor mapping in patients harboring motor-eloquent intracranial neoplasms. Based on this clinical use case of the technique, in this article we review the evidence for the feasibility of motor mapping and derived models (risk stratification and prediction, nTMS-based fiber tracking, improvement of clinical outcome, and assessment of functional plasticity), and provide collected sets of evidence for the applicability of quantitative mapping with nTMS. In addition, we provide evidence-based demonstrations on factors that ensure methodological feasibility and accuracy of the motor mapping procedure. We demonstrate that selection of the stimulation intensity (SI) for nTMS and spatial density of stimuli are crucial factors for applying motor mapping accurately, while also demonstrating the effect on the motor maps. We conclude that while the application of nTMS motor mapping has been impressively spread over the past decade, there are still variations in the applied protocols and parameters, which could be optimized for the purpose of reliable quantitative mapping.
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Affiliation(s)
- Nico Sollmann
- Department of Diagnostic and Interventional Radiology, University Hospital Ulm, Albert-Einstein-Allee 23, 89081 Ulm, Germany
- Department of Diagnostic and Interventional Neuroradiology, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Ismaninger Str. 22, 81675 Munich, Germany
- TUM-Neuroimaging Center, Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany;
- Department of Radiology and Biomedical Imaging, University of California San Francisco, 185 Berry Street, San Francisco, CA 94143, USA
- Correspondence:
| | - Sandro M. Krieg
- TUM-Neuroimaging Center, Klinikum rechts der Isar, Technical University of Munich, 81675 Munich, Germany;
- Department of Neurosurgery, School of Medicine, Klinikum rechts der Isar, Technical University of Munich, Ismaninger Str. 22, 81675 Munich, Germany
| | - Laura Säisänen
- Department of Clinical Neurophysiology, Kuopio University Hospital, 70029 Kuopio, Finland; (L.S.); (P.J.)
- Department of Applied Physics, University of Eastern Finland, 70211 Kuopio, Finland
| | - Petro Julkunen
- Department of Clinical Neurophysiology, Kuopio University Hospital, 70029 Kuopio, Finland; (L.S.); (P.J.)
- Department of Applied Physics, University of Eastern Finland, 70211 Kuopio, Finland
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Cavaleri R, Chipchase LS, Summers SJ, Chalmers J, Schabrun SM. The Relationship Between Corticomotor Reorganization and Acute Pain Severity: A Randomized, Controlled Study Using Rapid Transcranial Magnetic Stimulation Mapping. PAIN MEDICINE 2021; 22:1312-1323. [PMID: 33367763 DOI: 10.1093/pm/pnaa425] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
OBJECTIVE Although acute pain has been shown to reduce corticomotor excitability, it remains unknown whether this response resolves over time or is related to symptom severity. Furthermore, acute pain research has relied upon data acquired from the cranial "hotspot," which do not provide valuable information regarding reorganization, such as changes to the distribution of a painful muscle's representation within M1. Using a novel, rapid transcranial magnetic stimulation (TMS) mapping method, this study aimed to 1) explore the temporal profile and variability of corticomotor reorganization in response to acute pain and 2) determine whether individual patterns of corticomotor reorganization are associated with differences in pain, sensitivity, and somatosensory organization. METHODS Corticomotor (TMS maps), pain processing (pain intensity, pressure pain thresholds), and somatosensory (two-point discrimination, two-point estimation) outcomes were taken at baseline, immediately after injection (hypertonic [n = 20] or isotonic saline [n = 20]), and at pain resolution. Follow-up measures were recorded every 15 minutes until 90 minutes after injection. RESULTS Corticomotor reorganization persisted at least 90 minutes after pain resolution. Corticomotor depression was associated with lower pain intensity than was corticomotor facilitation (r = 0.47 [P = 0.04]). These effects were not related to somatosensory reorganization or peripheral sensitization mechanisms. CONCLUSIONS Individual patterns of corticomotor reorganization during acute pain appear to be related to symptom severity, with early corticomotor depression possibly reflecting a protective response. These findings hold important implications for the management and potential prevention of pain chronicity. However, further research is required to determine whether these adaptations relate to long-term outcomes in clinical populations.
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Affiliation(s)
- Rocco Cavaleri
- Brain Stimulation and Rehabilitation (BrainStAR) Lab, School of Health Sciences, Western Sydney University, Sydney, New South Wales, Australia
| | - Lucy S Chipchase
- Brain Stimulation and Rehabilitation (BrainStAR) Lab, School of Health Sciences, Western Sydney University, Sydney, New South Wales, Australia.,College of Nursing and Health Sciences, Flinders University, Adelaide, South Australia, Australia
| | - Simon J Summers
- Brain Stimulation and Rehabilitation (BrainStAR) Lab, School of Health Sciences, Western Sydney University, Sydney, New South Wales, Australia.,Discipline of Sport and Exercise Science, Faculty of Health, University of Canberra, Canberra, Australian Capital Territory, Australia
| | - Jane Chalmers
- Brain Stimulation and Rehabilitation (BrainStAR) Lab, School of Health Sciences, Western Sydney University, Sydney, New South Wales, Australia.,IIMPACT in Health, University of South Australia, Adelaide, South Australia, Australia
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Säisänen L, Könönen M, Niskanen E, Lakka T, Lintu N, Vanninen R, Julkunen P, Määttä S. Primary hand motor representation areas in healthy children, preadolescents, adolescents, and adults. Neuroimage 2020; 228:117702. [PMID: 33385558 DOI: 10.1016/j.neuroimage.2020.117702] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 12/16/2020] [Accepted: 12/19/2020] [Indexed: 01/28/2023] Open
Abstract
The development of the organization of the motor representation areas in children and adolescents is not well-known. This cross-sectional study aimed to provide an understanding for the development of the functional motor areas of the upper extremity muscles by studying healthy right-handed children (6-9 years, n = 10), preadolescents (10-12 years, n = 13), adolescents (15-17 years, n = 12), and adults (22-34 years, n = 12). The optimal representation site and resting motor threshold (rMT) for the abductor pollicis brevis (APB) were assessed in both hemispheres using navigated transcranial magnetic stimulation (nTMS). Motor mapping was performed at 110% of the rMT while recording the EMG of six upper limb muscles in the hand and forearm. The association between the motor map and manual dexterity (box and block test, BBT) was examined. The mapping was well-tolerated and feasible in all but the youngest participant whose rMT exceeded the maximum stimulator output. The centers-of-gravity (CoG) for individual muscles were scattered to the greatest extent in the group of preadolescents and centered and became more focused with age. In preadolescents, the CoGs in the left hemisphere were located more laterally, and they shifted medially with age. The proportion of hand compared to arm representation increased with age (p = 0.001); in the right hemisphere, this was associated with greater fine motor ability. Similarly, there was less overlap between hand and forearm muscles representations in children compared to adults (p<0.001). There was a posterior-anterior shift in the APB hotspot coordinate with age, and the APB coordinate in the left hemisphere exhibited a lateral to medial shift with age from adolescence to adulthood (p = 0.006). Our results contribute to the elucidation of the developmental course in the organization of the motor cortex and its associations with fine motor skills. It was shown that nTMS motor mapping in relaxed muscles is feasible in developmental studies in children older than seven years of age.
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Affiliation(s)
- Laura Säisänen
- Department of Clinical Neurophysiology, Kuopio University Hospital, P.O. Box 100, 70029 KYS, Kuopio, Finland; Institute of Clinical Medicine, University of Eastern Finland, Finland; Department of Applied Physics, University of Eastern Finland, Kuopio, Finland.
| | - Mervi Könönen
- Department of Clinical Neurophysiology, Kuopio University Hospital, P.O. Box 100, 70029 KYS, Kuopio, Finland; Department of Applied Physics, University of Eastern Finland, Kuopio, Finland; Department of Clinical Radiology, Kuopio University Hospital, Kuopio, Finland
| | - Eini Niskanen
- Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
| | - Timo Lakka
- Institute of Biomedicine, Faculty of Health Sciences, University of Eastern Finland, Finland; Department of Clinical Physiology and Nuclear Medicine, Kuopio University Hospital, Kuopio, Finland
| | - Niina Lintu
- Institute of Biomedicine, Faculty of Health Sciences, University of Eastern Finland, Finland
| | - Ritva Vanninen
- Institute of Clinical Medicine, University of Eastern Finland, Finland; Department of Clinical Radiology, Kuopio University Hospital, Kuopio, Finland
| | - Petro Julkunen
- Department of Clinical Neurophysiology, Kuopio University Hospital, P.O. Box 100, 70029 KYS, Kuopio, Finland; Department of Applied Physics, University of Eastern Finland, Kuopio, Finland
| | - Sara Määttä
- Department of Clinical Neurophysiology, Kuopio University Hospital, P.O. Box 100, 70029 KYS, Kuopio, Finland
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Repetitive transcranial magnetic stimulation of the primary motor cortex expedites recovery in the transition from acute to sustained experimental pain: a randomised, controlled study. Pain 2019; 160:2624-2633. [DOI: 10.1097/j.pain.0000000000001656] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Charalambous CC, Liang JN, Kautz SA, George MS, Bowden MG. Bilateral Assessment of the Corticospinal Pathways of the Ankle Muscles Using Navigated Transcranial Magnetic Stimulation. J Vis Exp 2019. [PMID: 30855569 DOI: 10.3791/58944] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Distal leg muscles receive neural input from motor cortical areas via the corticospinal tract, which is one of the main motor descending pathway in humans and can be assessed using transcranial magnetic stimulation (TMS). Given the role of distal leg muscles in upright postural and dynamic tasks, such as walking, a growing research interest in the assessment and modulation of the corticospinal tracts relative to the function of these muscles has emerged in the last decade. However, methodological parameters used in previous work have varied across studies making the interpretation of results from cross-sectional and longitudinal studies less robust. Therefore, use of a standardized TMS protocol specific to the assessment of leg muscles' corticomotor response (CMR) will allow for direct comparison of results across studies and cohorts. The objective of this paper is to present a protocol that provides the flexibility to simultaneously assess the bilateral CMR of two main ankle antagonistic muscles, the tibialis anterior and soleus, using single pulse TMS with a neuronavigation system. The present protocol is applicable while the examined muscle is either fully relaxed or isometrically contracted at a defined percentage of maximum isometric voluntary contraction. Using each subject's structural MRI with the neuronavigation system ensures accurate and precise positioning of the coil over the leg cortical representations during assessment. Given the inconsistency in CMR derived measures, this protocol also describes a standardized calculation of these measures using automated algorithms. Though this protocol is not conducted during upright postural or dynamic tasks, it can be used to assess bilaterally any pair of leg muscles, either antagonistic or synergistic, in both neurologically intact and impaired subjects.
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Affiliation(s)
- Charalambos C Charalambous
- Department of Neurology, New York University School of Medicine; Department of Health Sciences and Research, Medical University of South Carolina;
| | - Jing Nong Liang
- Department of Physical Therapy, University of Nevada Las Vegas; Department of Health Professions, Medical University of South Carolina
| | - Steve A Kautz
- Department of Health Sciences and Research, Medical University of South Carolina; Ralph H. Johnson VA Medical Center
| | - Mark S George
- Ralph H. Johnson VA Medical Center; Department of Psychiatry, Medical University of South Carolina
| | - Mark G Bowden
- Department of Health Sciences and Research, Medical University of South Carolina; Ralph H. Johnson VA Medical Center; Division of Physical Therapy, Medical University of South Carolina
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Cavaleri R, Thapa T, Beckenkamp PR, Chipchase LS. The influence of kinesiology tape colour on performance and corticomotor activity in healthy adults: a randomised crossover controlled trial. BMC Sports Sci Med Rehabil 2018; 10:17. [PMID: 30410769 PMCID: PMC6211494 DOI: 10.1186/s13102-018-0106-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 10/18/2018] [Indexed: 11/10/2022]
Abstract
Background There exists conflicting evidence regarding the impact of kinesiology tape on performance and muscle function. One variable that may account for disparities in the findings of previous studies is the colour of the tape applied. Colour is hypothesised to influence sporting performance through modulation of arousal and aggression. However, few studies have investigated the influence of colour on products designed specifically to enhance athletic performance. Further, no studies have investigated the potential influence of colour on other drivers of performance, such as corticomotor activity and neuromuscular function. Thus, the aim of this study was to investigate the influence of kinesiology tape colour on athletic performance, knee extensor torque, and quadriceps neuromuscular function. Methods Thirty two healthy participants were assessed under five conditions, applied in random order: (1) no kinesiology tape (control), (2) beige-coloured kinesiology tape applied with tension (sham A), (3) beige-coloured kinesiology tape applied with no tension (sham B), (4) red-coloured kinesiology tape applied with tension, and (5) blue-coloured kinesiology tape applied with tension. Athletic performance was assessed using a previously validated hop test, knee extensor torque was measured using an isokinetic dynamometer, and transcranial magnetic stimulation was utilised to provide insight into the neuromuscular functioning of the quadriceps musculature. Results Kinesiology tape had no beneficial impact on lower limb performance or muscle strength in healthy adults. The colour of the tape did not influence athletic performance (F (4, 120) = 0.593, p = 0.669), quadriceps strength (F (4, 120) = 0.787, p = 0.536), or neuromuscular function (rectus femoris: F (2.661, 79.827) = 1.237, p = 0.301). Conclusion This study found that kinesiology tape does not alter lower limb performance or muscle function in healthy adults, irrespective of the colour of the tape applied. Future research should seek to confirm these findings beyond the research setting, across a range of sports, and at a range of skill levels. Trial registration Australian New Zealand Clinical Trials Registry. ACTRN12616001506482. Prospectively registered on 01/11/2016.
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Affiliation(s)
- Rocco Cavaleri
- 1Brain Rehabilitation and Neuroplasticity Unit, School of Science and Health, Western Sydney University, Sydney, NSW 2560 Australia
| | - Tribikram Thapa
- 1Brain Rehabilitation and Neuroplasticity Unit, School of Science and Health, Western Sydney University, Sydney, NSW 2560 Australia
| | - Paula R Beckenkamp
- 1Brain Rehabilitation and Neuroplasticity Unit, School of Science and Health, Western Sydney University, Sydney, NSW 2560 Australia.,2Musculoskeletal Health, Faculty of Health Sciences, Discipline of Physiotherapy, The University of Sydney, Sydney, NSW Australia
| | - Lucy S Chipchase
- 2Musculoskeletal Health, Faculty of Health Sciences, Discipline of Physiotherapy, The University of Sydney, Sydney, NSW Australia.,3Faculty of Health, University of Canberra, Canberra, ACT Australia
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The reliability and validity of rapid transcranial magnetic stimulation mapping. Brain Stimul 2018; 11:1291-1295. [PMID: 30025980 DOI: 10.1016/j.brs.2018.07.043] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2017] [Revised: 07/06/2018] [Accepted: 07/09/2018] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Traditional transcranial magnetic stimulation mapping involves systematically delivering stimuli over a predefined grid. The pseudorandom walk method seeks to improve map acquisition times by abandoning the grid in favour of delivering stimuli randomly over a given area. OBJECTIVES To i) determine the minimum interstimulus interval (ISI) required for reliable mapping outcomes within and between sessions using the pseudorandom walk method and ii) assess the validity of the pseudorandom walk method by testing its equivalence with traditional mapping. METHODS Maps collected using the pseudorandom walk method at four ISIs (4, 3, 2, and 1s) were compared to maps collected using traditional mapping in twenty healthy individuals. Outcomes included map area, volume, centre of gravity, mean MEP amplitude, and number of discrete peaks. RESULTS AND CONCLUSIONS The pseudorandom walk method was valid and reliable with a 2-second ISI for all outcomes except number of discrete peaks, which was less reliable than other measures.
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