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Zolezzi DM, Larsen DB, McPhee M, Graven-Nielsen T. Effects of pain on cortical homeostatic plasticity in humans: a systematic review. Pain Rep 2024; 9:e1141. [PMID: 38444774 PMCID: PMC10914232 DOI: 10.1097/pr9.0000000000001141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 12/09/2023] [Accepted: 12/28/2023] [Indexed: 03/07/2024] Open
Abstract
Homeostatic plasticity (HP) is a negative feedback mechanism that prevents excessive facilitation or depression of cortical excitability (CE). Cortical HP responses in humans have been investigated by using 2 blocks of noninvasive brain stimulation with a no-stimulation block in between. A healthy HP response is characterized by reduced CE after 2 excitatory stimulation blocks and increased CE when using inhibitory stimulation. Conversely, impaired HP responses have been demonstrated in experimental and chronic pain conditions. Therefore, this systematic review aimed to provide an overview of the effect of pain on cortical HP in humans. Scopus, Embase, and PubMed were searched from inception until November 20, 2023. The included studies (1) compared experimental or clinical pain conditions with healthy controls, (2) induced HP using 2 blocks of stimulation with a no-stimulation interval, and (3) evaluated CE measures such as motor-evoked potentials. Four studies were included, consisting of 5 experiments and 146 participants, of whom 63 were patients with chronic pain and 48 were subjected to an experimental pain model. This systematic review found support for an HP impairment in pain compared with that in pain-free states, reflected by a lack of CE reduction after excitatory-excitatory HP induction over the primary motor cortex. Inhibitory-inhibitory HP induction did not produce a consistent HP response across studies, independent of pain or pain-free states. Standardization of HP induction protocols and outcome calculations is needed to ensure reproducibility and study comparison. Future HP studies may consider investigating sensory domains including nociception, which would further our understanding of abnormal HP regulation in pain conditions.
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Affiliation(s)
- Daniela M. Zolezzi
- Center for Neuroplasticity and Pain (CNAP), Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Dennis B. Larsen
- Center for Neuroplasticity and Pain (CNAP), Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Megan McPhee
- Center for Neuroplasticity and Pain (CNAP), Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Thomas Graven-Nielsen
- Center for Neuroplasticity and Pain (CNAP), Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
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Chung SM, Wang JC, Lin CR, Liu SC, Wu PT, Kuan FC, Fang CJ, Tu YK, Hsu KL, Lai PC, Shih CA. Beyond traditional therapies: a network meta-analysis on the treatment efficacy for chronic phantom limb pain. Reg Anesth Pain Med 2024:rapm-2023-105104. [PMID: 38388020 DOI: 10.1136/rapm-2023-105104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Accepted: 01/24/2024] [Indexed: 02/24/2024]
Abstract
BACKGROUND Phantom limb pain (PLP) frequently affects individuals with limb amputations. When PLP evolves into its chronic phase, known as chronic PLP, traditional therapies often fall short in providing sufficient relief. The optimal intervention for chronic PLP remains unclear. OBJECTIVE The objectives of this network meta-analysis (NMA) were to examine the efficacy of different treatments on pain intensity for patients with chronic PLP. EVIDENCE REVIEW We searched Medline, EMBASE, Cochrane CENTRAL, Scopus, and CINAHL EBSCO, focusing on randomized controlled trials (RCTs) that evaluated interventions such as neuromodulation, neural block, pharmacological methods, and alternative treatments. An NMA was conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The primary outcome was pain score improvement, and the secondary outcomes were adverse events. FINDINGS The NMA, incorporating 12 RCTs, indicated that neuromodulation, specifically repetitive transcranial magnetic stimulation, provided the most substantial pain improvement when compared with placebo/sham groups (mean difference=-2.9 points, 95% CI=-4.62 to -1.18; quality of evidence (QoE): moderate). Pharmacological intervention using morphine was associated with a significant increase in adverse event rate (OR=6.04, 95% CI=2.26 to 16.12; QoE: low). CONCLUSIONS The NMA suggests that neuromodulation using repetitive transcranial magnetic stimulation may be associated with significantly larger pain improvement for chronic PLP. However, the paucity of studies, varying patient characteristics across each trial, and absence of long-term results underscore the necessity for more comprehensive, large-scale RCTs. PROSPERO REGISTRATION NUMBER CRD42023455949.
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Affiliation(s)
- Sun-Mei Chung
- Mackay Memorial Hospital, Taipei, Taiwan
- School of Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Jui-Chien Wang
- School of Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Taipei Veterans General Hospital, Taipei, Taiwan
| | - Chung-Ren Lin
- Department of Anesthesiology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Shu-Cheng Liu
- Department of Anesthesiology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Po-Ting Wu
- Department of Orthopedics, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Department of Orthopedics, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Fa-Chuan Kuan
- Department of Orthopedics, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Medical Device R & D Core Laboratory, National Cheng Kung University Hospital, Tainan, Taiwan
| | - Ching-Ju Fang
- Department of Secretariat, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Medical Library, National Cheng Kung University, Tainan, Taiwan
| | - Yu-Kang Tu
- Institute of Epidemiology and Preventive Medicine, National Taiwan University College of Public Health, Taipei, Taiwan
- Department of Dentistry, National Taiwan University Hospital, Taipei, Taiwan
| | - Kai-Lan Hsu
- Department of Orthopedics, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Medical Device R & D Core Laboratory, National Cheng Kung University Hospital, Tainan, Taiwan
| | - Pei-Chun Lai
- Education Center, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Chien-An Shih
- Department of Orthopedics, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Department of Orthopedics, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Medical Device R & D Core Laboratory, National Cheng Kung University Hospital, Tainan, Taiwan
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3
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Sparling T, Iyer L, Pasquina P, Petrus E. Cortical Reorganization after Limb Loss: Bridging the Gap between Basic Science and Clinical Recovery. J Neurosci 2024; 44:e1051232024. [PMID: 38171645 PMCID: PMC10851691 DOI: 10.1523/jneurosci.1051-23.2023] [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: 06/08/2023] [Revised: 08/28/2023] [Accepted: 09/29/2023] [Indexed: 01/05/2024] Open
Abstract
Despite the increasing incidence and prevalence of amputation across the globe, individuals with acquired limb loss continue to struggle with functional recovery and chronic pain. A more complete understanding of the motor and sensory remodeling of the peripheral and central nervous system that occurs postamputation may help advance clinical interventions to improve the quality of life for individuals with acquired limb loss. The purpose of this article is to first provide background clinical context on individuals with acquired limb loss and then to provide a comprehensive review of the known motor and sensory neural adaptations from both animal models and human clinical trials. Finally, the article bridges the gap between basic science researchers and clinicians that treat individuals with limb loss by explaining how current clinical treatments may restore function and modulate phantom limb pain using the underlying neural adaptations described above. This review should encourage the further development of novel treatments with known neurological targets to improve the recovery of individuals postamputation.Significance Statement In the United States, 1.6 million people live with limb loss; this number is expected to more than double by 2050. Improved surgical procedures enhance recovery, and new prosthetics and neural interfaces can replace missing limbs with those that communicate bidirectionally with the brain. These advances have been fairly successful, but still most patients experience persistent problems like phantom limb pain, and others discontinue prostheses instead of learning to use them daily. These problematic patient outcomes may be due in part to the lack of consensus among basic and clinical researchers regarding the plasticity mechanisms that occur in the brain after amputation injuries. Here we review results from clinical and animal model studies to bridge this clinical-basic science gap.
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Affiliation(s)
- Tawnee Sparling
- Department of Physical Medicine and Rehabilitation, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814
| | - Laxmi Iyer
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, Maryland 20817
| | - Paul Pasquina
- Department of Physical Medicine and Rehabilitation, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814
| | - Emily Petrus
- Department of Anatomy, Physiology and Genetics, Uniformed Services University, Bethesda, Maryland 20814
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Snow NJ, Kirkland MC, Downer MB, Murphy HM, Ploughman M. Transcranial magnetic stimulation maps the neurophysiology of chronic noncancer pain: A scoping review. Medicine (Baltimore) 2022; 101:e31774. [PMID: 36401490 PMCID: PMC9678597 DOI: 10.1097/md.0000000000031774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND Chronic noncancer pain is a global public health challenge. It is imperative to identify biological markers ("biomarkers") to understand the mechanisms underlying chronic pain and to monitor pain over time and after interventions. Transcranial magnetic stimulation (TMS) is a promising method for this purpose. OBJECTIVES To examine differences in TMS-based outcomes between persons with chronic pain and healthy controls (HCs) and/or before versus after pain-modulating interventions and relationships between pain measures and TMS outcomes; To summarize the neurophysiological mechanisms underlying chronic pain as identified by TMS. METHODS We searched the PubMed database for literature from January 1, 1985, to June 9, 2020, with the keywords "pain" and "transcranial magnetic stimulation." Eligible items included original studies of adult human participants with pain lasting for ≥ 6 months. We completed a narrative synthesis of the study findings stratified by chronic pain etiology (primary pain, neuropathic pain, and secondary musculoskeletal pain). RESULTS The search yielded 1265 records. The final 12 articles included 244 patients with chronic pain (192 females, aged 35-65 years) and 169 HCs (89 females, aged 28-59 years). Abnormalities in TMS outcomes that reflect GABAergic and glutamatergic activities were associated with many of the disorders studied and were distinct for each pain etiology. Chronic primary pain is characterized by reduced intracortical inhibition and corticospinal excitability, chronic neuropathic pain shows evidence of increased excitation and disinhibition, and chronic secondary musculoskeletal pain involves low corticospinal excitability. DISCUSSION TMS could be a useful tool for delineating the neurophysiological underpinnings of chronic pain syndromes.
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Affiliation(s)
- Nicholas Jacob Snow
- Recovery and Performance Laboratory, Faculty of Medicine, Memorial University of Newfoundland & Labrador, St. John’s, NL, Canada
| | - Megan Christine Kirkland
- Recovery and Performance Laboratory, Faculty of Medicine, Memorial University of Newfoundland & Labrador, St. John’s, NL, Canada
| | - Matthew Bruce Downer
- Recovery and Performance Laboratory, Faculty of Medicine, Memorial University of Newfoundland & Labrador, St. John’s, NL, Canada
| | - Hannah Margaret Murphy
- Recovery and Performance Laboratory, Faculty of Medicine, Memorial University of Newfoundland & Labrador, St. John’s, NL, Canada
| | - Michelle Ploughman
- Recovery and Performance Laboratory, Faculty of Medicine, Memorial University of Newfoundland & Labrador, St. John’s, NL, Canada
- * Correspondence: Michelle Ploughman, Recovery and Performance Laboratory, Rehabilitation Research Unit of NL, Faculty of Medicine, Memorial University of Newfoundland & Labrador, Dr. Leonard A. Miller Centre, Room 400, 100 Forest Road, St. John’s, Newfoundland and Labrador A1A 1E5, Canada (e-mail: )
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5
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Klinisches Update zu Phantomschmerz. Schmerz 2022; 37:195-214. [DOI: 10.1007/s00482-022-00629-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/02/2022] [Indexed: 10/18/2022]
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6
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Diao X, Lu Q, Qiao L, Gong Y, Lu X, Feng M, Su P, Shen Y, Yuan TF, He C. Cortical Inhibition State-Dependent iTBS Induced Neural Plasticity. Front Neurosci 2022; 16:788538. [PMID: 35250445 PMCID: PMC8891511 DOI: 10.3389/fnins.2022.788538] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Accepted: 01/11/2022] [Indexed: 11/13/2022] Open
Abstract
Background Intermittent theta burst stimulation (iTBS) is an effective stimulus for long-term potentiation (LTP)-like plasticity. However, iTBS-induced effects varied greatly between individuals. Ample evidence suggested that an initial decrease in local γ-aminobutyric acid (GABA) or enhancement in N-methyl-D-aspartate (NMDA) facilitation neurotransmission is of vital importance for allowing LTP-like plasticity to occur. Therefore, we aimed to investigate whether the individual level of GABA or NMDA receptor-mediated activity before stimulation is correlated with the after-effect in cortical excitability induced by iTBS. Methods Fifteen healthy volunteers were recruited for the present study. We measured short-interval intracortical inhibitory (SICI), long-interval intracortical inhibitory (LICI), and intracortical facilitation (ICF), which index GABAA receptor-, GABAB receptor-, and glutamate receptor-mediated activity, respectively, in the cortex before conducting iTBS. After iTBS intervention, the changes of motor-evoked potential (MEP) amplitude were taken as a measure for cortical excitability in response to iTBS protocol. Results There was a significant negative correlation between the amount of SICI measured before iTBS and the after-effect of iTBS-induced LTP-like plasticity at the time points of 5, 10, and 15 min after inducing iTBS. A multiple linear regression model indicated that SICI was a good predictor of the after-effect in cortical excitability induced by iTBS at 5, 10, and 15 min following stimulation. Conclusion The present study found that GABAA receptor-mediated activity measured before stimulation is negatively correlated with the after-effect of cortical excitability induced by iTBS. SICI, as the index of GABAA receptor-mediated activity measured before stimulation, might be a good predictor of iTBS-induced LTP-like plasticity for a period lasting 15 min following stimulation.
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Affiliation(s)
- Xiaoying Diao
- Department of Rehabilitation Medicine, The Affiliated Jiangsu Shengze Hospital of Nanjing Medical University, Suzhou, China
- Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Qian Lu
- Department of Rehabilitation Medicine, The Affiliated Jiangsu Shengze Hospital of Nanjing Medical University, Suzhou, China
| | - Lei Qiao
- Jiangsu Zhongshan Geriatric Rehabilitation Hospital, Nanjing, China
| | - Youhui Gong
- Department of Rehabilitation Medicine, The Affiliated Jiangsu Shengze Hospital of Nanjing Medical University, Suzhou, China
| | - Xiao Lu
- Department of Rehabilitation Medicine, The Affiliated Jiangsu Shengze Hospital of Nanjing Medical University, Suzhou, China
| | - Min Feng
- Department of Rehabilitation Medicine, The Affiliated Jiangsu Shengze Hospital of Nanjing Medical University, Suzhou, China
| | - Panpan Su
- Department of Rehabilitation Medicine, The Affiliated Jiangsu Shengze Hospital of Nanjing Medical University, Suzhou, China
| | - Ying Shen
- Rehabilitation Medicine Center, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
- *Correspondence: Ying Shen,
| | - Ti-Fei Yuan
- Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
- Translational Research Institute of Brain and Brain-Like Intelligence, Shanghai Fourth People’s Hospital Affiliated to Tongji University School of Medicine, Shanghai, China
- Ti-Fei Yuan,
| | - Chuan He
- Department of Rehabilitation Medicine, The Affiliated Jiangsu Shengze Hospital of Nanjing Medical University, Suzhou, China
- Chuan He,
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7
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Abstract
Symptomatic neuromas and chronic neuropathic pain are significant problems affecting patients' quality of life and independence that are challenging to treat. These symptoms are due to structural and functional changes that occur peripherally within neuromas, as well as alterations that occur centrally within the brain and spinal cord. A multimodal approach is most effective, with goals to minimize opioid use, to capitalize on the synergistic effects of nonopioid medications and to explore potential benefits of novel adjunctive treatments.
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Affiliation(s)
- Yusha Liu
- Department of Surgery, University of Washington, 325 9th Avenue, 7 CT 70, MS 359796, Seattle, WA 98104, USA
| | - Dennis S Kao
- Department of Surgery, University of Washington, 325 9th Avenue, 7 CT 70, MS 359796, Seattle, WA 98104, USA.
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8
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Teixeira PEP, Pacheco-Barrios K, Gunduz ME, Gianlorenço AC, Castelo-Branco L, Fregni F. Understanding intracortical excitability in phantom limb pain: A multivariate analysis from a multicenter randomized clinical trial. Neurophysiol Clin 2021; 51:161-173. [PMID: 33648819 DOI: 10.1016/j.neucli.2020.12.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 12/30/2020] [Accepted: 12/31/2020] [Indexed: 10/22/2022] Open
Abstract
OBJECTIVES To explore associations of intracortical excitability with clinical characteristics in a large sample of subjects with phantom limb pain (PLP). METHODS Ancillary study using baseline and longitudinal data from a large multicenter randomized trial that investigated the effects of non-invasive brain stimulation combined with sensorimotor training on PLP. Multivariate regression modeling analyses were used to investigate the association of intracortical excitability, measured by percentages of intracortical inhibition (ICI) and facilitation (ICF) with clinical variables. RESULTS Ninety-eight subjects were included. Phantom sensation of itching was positively associated with ICI changes and at baseline in the affected hemisphere (contralateral to PLP). However, in the non-affected hemisphere (ipsilateral to PLP), the phantom sensation of warmth and PLP intensity were negatively associated with ICI (both models). For the ICF, PLP intensity (baseline model only) and age (longitudinal model) were negatively associated, while time since amputation and amputation level (both for longitudinal model only) were positively associated in the affected hemisphere. Additionally, use of antidepressants led to lower ICF in the non-affected hemisphere for the baseline model while higher amputation level also led to less changes in the ICF. CONCLUSION Results revealed clear associations of clinical variables and cortical excitability in a large chronic pain sample. ICI and ICF changes appear not to be mainly explained by PLP intensity. Instead, other variables associated with duration of neuroplasticity changes (such as age and duration of amputation) and compensatory mechanisms (such as itching and phantom limb sensation) seem to be more important in explaining these variables.
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Affiliation(s)
- Paulo E P Teixeira
- Neuromodulation and Clinical Research Learning Center, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Charlestown, MA, USA; Harvard Medical School, Boston, MA, USA; MGH Institute of Health Professions, Boston, MA, USA; Instituto Wilson Mello, Campinas, SP, Brazil.
| | - Kevin Pacheco-Barrios
- Neuromodulation and Clinical Research Learning Center, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Charlestown, MA, USA; Harvard Medical School, Boston, MA, USA; Universidad San Ignacio de Loyola, Vicerrectorado de Investigación, Unidad de Investigación para la Generación y Síntesis de Evidencias en Salud, Lima, Peru
| | - Muhammed Enes Gunduz
- Neuromodulation and Clinical Research Learning Center, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Charlestown, MA, USA; Harvard Medical School, Boston, MA, USA
| | - Anna Carolyna Gianlorenço
- Neuromodulation and Clinical Research Learning Center, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Charlestown, MA, USA; Harvard Medical School, Boston, MA, USA; Laboratory of neuroscience, Department of Physical Therapy, Federal University of Sao Carlos, SP, Brazil
| | - Luis Castelo-Branco
- Neuromodulation and Clinical Research Learning Center, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Charlestown, MA, USA; Harvard Medical School, Boston, MA, USA
| | - Felipe Fregni
- Neuromodulation and Clinical Research Learning Center, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Charlestown, MA, USA; Harvard Medical School, Boston, MA, USA; Harvard T. H. Chan School of Public Health, Boston, MA, USA
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9
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Abstract
Phantom limb pain is highly prevalent after amputation. Treatment results will probably benefit from an interdisciplinary team and individually adapted surgical, prosthetic and pain medicine approaches. Introduction: Most patients with amputation (up to 80%) suffer from phantom limb pain postsurgery. These are often multimorbid patients who also have multiple risk factors for the development of chronic pain from a pain medicine perspective. Surgical removal of the body part and sectioning of peripheral nerves result in a lack of afferent feedback, followed by neuroplastic changes in the sensorimotor cortex. The experience of severe pain, peripheral, spinal, and cortical sensitization mechanisms, and changes in the body scheme contribute to chronic phantom limb pain. Psychosocial factors may also affect the course and the severity of the pain. Modern amputation medicine is an interdisciplinary responsibility. Methods: This review aims to provide an interdisciplinary overview of recent evidence-based and clinical knowledge. Results: The scientific evidence for best practice is weak and contrasted by various clinical reports describing the polypragmatic use of drugs and interventional techniques. Approaches to restore the body scheme and integration of sensorimotor input are of importance. Modern techniques, including apps and virtual reality, offer an exciting supplement to already established approaches based on mirror therapy. Targeted prosthesis care helps to obtain or restore limb function and at the same time plays an important role reshaping the body scheme. Discussion: Consequent prevention and treatment of severe postoperative pain and early integration of pharmacological and nonpharmacological interventions are required to reduce severe phantom limb pain. To obtain or restore body function, foresighted surgical planning and technique as well as an appropriate interdisciplinary management is needed.
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10
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Candido Santos L, Gushken F, Gadotti GM, Dias BDF, Marinelli Pedrini S, Barreto MESF, Zippo E, Pinto CB, Piza PVDT, Fregni F. Intracortical Inhibition in the Affected Hemisphere in Limb Amputation. Front Neurol 2020; 11:720. [PMID: 32849197 PMCID: PMC7406670 DOI: 10.3389/fneur.2020.00720] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 06/12/2020] [Indexed: 12/18/2022] Open
Abstract
Phantom limb pain (PLP) affects up to 80% of amputees. Despite the lack of consensus about the etiology and pathophysiology of phantom experiences, previous evidence pointed out the role of changes in motor cortex excitability as an important factor associated with amputation and PLP. In this systematic review, we investigated changes in intracortical inhibition as indexed by transcranial magnetic stimulation (TMS) in amputees and its relationship to pain. Four electronic databases were screened to identify studies using TMS to measure cortical inhibition, such as short intracortical inhibition (SICI), long intracortical inhibition (LICI) and cortical silent period (CSP). Seven articles were included and evaluated cortical excitability comparing the affected hemisphere with the non-affected hemisphere or with healthy controls. None of them correlated cortical disinhibition and clinical parameters, such as the presence or intensity of PLP. However, most studies showed decreased SICI in amputees affected hemisphere. These results highlight that although SICI seems to be changed in the affected hemisphere in amputees, most of the studies did not investigate its clinical correlation. Thus, the question of whether they are a valid diagnostic marker remains unanswered. Also, the results were highly variable for both measurements due to the heterogeneity of study designs and group comparisons in each study. Although these results underscore the role of inhibitory networks after amputation, more studies are needed to investigate the role of a decreased inhibitory drive in the motor cortex to the cause and maintenance of PLP.
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Affiliation(s)
- Ludmilla Candido Santos
- Laboratory of Neuromodulation & Center for Clinical Research Learning, Department of Physical Medicine and Rehabilitation, Harvard Medical School, Spaulding Rehabilitation Hospital, Boston, MA, United States
| | | | | | | | | | | | - Emanuela Zippo
- Faculdade Israelita de Ciências da Saúde, São Paulo, Brazil
| | - Camila Bonin Pinto
- Laboratory of Neuromodulation & Center for Clinical Research Learning, Department of Physical Medicine and Rehabilitation, Harvard Medical School, Spaulding Rehabilitation Hospital, Boston, MA, United States
| | | | - Felipe Fregni
- Laboratory of Neuromodulation & Center for Clinical Research Learning, Department of Physical Medicine and Rehabilitation, Harvard Medical School, Spaulding Rehabilitation Hospital, Boston, MA, United States
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11
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Nardone R, Versace V, Sebastianelli L, Brigo F, Christova M, Scarano GI, Saltuari L, Trinka E, Hauer L, Sellner J. Transcranial magnetic stimulation in subjects with phantom pain and non-painful phantom sensations: A systematic review. Brain Res Bull 2019; 148:1-9. [DOI: 10.1016/j.brainresbull.2019.03.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2019] [Revised: 03/03/2019] [Accepted: 03/05/2019] [Indexed: 12/18/2022]
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12
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Kurian R, Raza K, Shanthanna H. A systematic review and meta-analysis of memantine for the prevention or treatment of chronic pain. Eur J Pain 2019; 23:1234-1250. [PMID: 30848504 DOI: 10.1002/ejp.1393] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 02/10/2019] [Accepted: 03/03/2019] [Indexed: 12/21/2022]
Abstract
BACKGROUND AND OBJECTIVE N-methyl-D-aspartate (NMDA) receptors are involved in pain signalling and neuroplasticity. Memantine has been shown to have analgesic properties in pre-clinical and small clinical studies. We conducted a systematic review and meta-analysis to assess the efficacy of memantine to prevent or reduce chronic pain. DATABASES AND DATA TREATMENT MEDLINE, EMBASE and CENTRAL databases were searched for comparative trials using memantine, either against placebo or active medications, for chronic pain in adults. Pain relief was considered our primary outcome. Meta-analyses were conducted if outcomes were reported in two or more studies. Outcomes were reported as mean differences (MD) or risk ratios (RR) with 95% confidence intervals (CI). Quality was assessed using the GRADE approach. RESULTS Among 454 citations, 15 studies were included with populations predominantly consisting of neuropathic conditions and fibromyalgia. Overall, we observed unclear reporting of randomization and allocation methods, apart from potential for publication bias. Among the 11 studies looking at chronic pain treatment, the difference in end pain score with memantine was not significant: MD = -0.58 units (95% CI -1.31, 0.14); I2 = 82% (low quality). In two surgical studies using memantine for pain prevention, memantine decreased pain intensity: MD = -1.02 units (95% CI -1.38, -0.66); I2 = 0%. Dizziness was significantly more common with memantine: RR = 4.90 (95% CI 1.26, 18.99); I2 = 52% (moderate quality). CONCLUSION The current evidence regarding the use of memantine for chronic pain is limited and uncertain. Despite its potential, pain relief achieved in clinical studies is small and is associated with an increase in dizziness. SIGNIFICANCE Despite a sound rationale, the benefit of using memantine for chronic pain is unclear. Our systematic review and meta-analysis show that memantine may have the potential to decrease pain. However, it can also increase common adverse effects. Considering the small number of studies with potential for bias and inconclusive evidence, there was low to very low certainty. Hence, no clear recommendations can be made about its routine clinical use until larger and more definitive studies are conducted.
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Affiliation(s)
- Rouvin Kurian
- McMaster School of Interdisciplinary Science, Faculty of Science, McMaster University, Hamilton, Ontario, Canada
| | - Kazim Raza
- Department of Anesthesiology, Michael DeGroote School of Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Harsha Shanthanna
- Department of Anesthesiology, Michael DeGroote School of Medicine, McMaster University, Hamilton, Ontario, Canada
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13
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Abstract
Pain management is complex regardless of whether the pain is acute or chronic in nature or non-cancer or cancer related. In addition, relatively few pain pharmacotherapy options with adequate efficacy and safety data currently exist. Consequently, interest in the role of NMDA receptor antagonists as a pharmacological pain management strategy has surfaced. This narrative review provides an overview of the NMDA receptor and elaborates on the pharmacotherapeutic profile and pain management literature findings for the following NMDA receptor antagonists: ketamine, memantine, dextromethorphan, and magnesium. The literature on this topic is characterized by small studies, many of which exhibit methodological flaws. To date, ketamine is the most studied NMDA receptor antagonist for both acute and chronic pain management. Although further research about NMDA receptor antagonists for analgesia is needed and the optimal dosage/administration regimens for these drugs have yet to be determined, ketamine appears to hold the most promise and may be of particular value in the perioperative pain management realm.
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14
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Abstract
OBJECTIVE To review the literature related to different treatment strategies for the general population of individuals with amputation, spinal cord injury, and cerebral palsy, as well as how this may impact pain management in a correlated athlete population. DATA SOURCES A comprehensive literature search was performed linking pain with terms related to different impairment types. MAIN RESULTS There is a paucity in the literature relating to treatment of pain in athletes with impairment; however, it is possible that the treatment strategies used in the general population of individuals with impairment may be translated to the athlete population. There are a wide variety of treatment options including both pharmacological and nonpharmacological treatments which may be applicable in the athlete. CONCLUSIONS It is the role of the physician to determine which strategy of the possible treatment options will best facilitate the management of pain in the individual athlete in a sport-specific setting.
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Wylde V, Dennis J, Beswick AD, Bruce J, Eccleston C, Howells N, Peters TJ, Gooberman‐Hill R. Systematic review of management of chronic pain after surgery. Br J Surg 2017; 104:1293-1306. [PMID: 28681962 PMCID: PMC5599964 DOI: 10.1002/bjs.10601] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 01/24/2017] [Accepted: 04/21/2017] [Indexed: 12/24/2022]
Abstract
BACKGROUND Pain present for at least 3 months after a surgical procedure is considered chronic postsurgical pain (CPSP) and affects 10-50 per cent of patients. Interventions for CPSP may focus on the underlying condition that indicated surgery, the aetiology of new-onset pain or be multifactorial in recognition of the diverse causes of this pain. The aim of this systematic review was to identify RCTs of interventions for the management of CPSP, and synthesize data across treatment type to estimate their effectiveness and safety. METHODS MEDLINE, Embase, PsycINFO, CINAHL and the Cochrane Library were searched from inception to March 2016. Trials of pain interventions received by patients at 3 months or more after surgery were included. Risk of bias was assessed using the Cochrane risk-of-bias tool. RESULTS Some 66 trials with data from 3149 participants were included. Most trials included patients with chronic pain after spinal surgery (25 trials) or phantom limb pain (21 trials). Interventions were predominantly pharmacological, including antiepileptics, capsaicin, epidural steroid injections, local anaesthetic, neurotoxins, N-methyl-d-aspartate receptor antagonists and opioids. Other interventions included acupuncture, exercise, postamputation limb liner, spinal cord stimulation, further surgery, laser therapy, magnetic stimulation, mindfulness-based stress reduction, mirror therapy and sensory discrimination training. Opportunities for meta-analysis were limited by heterogeneity. For all interventions, there was insufficient evidence to draw conclusions on effectiveness. CONCLUSION There is a need for more evidence about interventions for CPSP. High-quality trials of multimodal interventions matched to pain characteristics are needed to provide robust evidence to guide management of CPSP.
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Affiliation(s)
- V. Wylde
- Musculoskeletal Research Unit, School of Clinical SciencesUniversity of BristolBristolUK
| | - J. Dennis
- Musculoskeletal Research Unit, School of Clinical SciencesUniversity of BristolBristolUK
| | - A. D. Beswick
- Musculoskeletal Research Unit, School of Clinical SciencesUniversity of BristolBristolUK
| | - J. Bruce
- Warwick Clinical Trials UnitUniversity of WarwickWarwickUK
| | - C. Eccleston
- Centre for Pain ResearchUniversity of BathBathUK
- Department of Experimental‐Clinical and Health PsychologyGhent UniversityGhentBelgium
| | - N. Howells
- Avon Orthopaedic Centre, Department of Trauma and OrthopaedicsNorth Bristol NHS TrustBristolUK
| | - T. J. Peters
- Musculoskeletal Research Unit, School of Clinical SciencesUniversity of BristolBristolUK
| | - R. Gooberman‐Hill
- Musculoskeletal Research Unit, School of Clinical SciencesUniversity of BristolBristolUK
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Colnaghi S, Colagiorgio P, Versino M, Koch G, D'Angelo E, Ramat S. A role for NMDAR-dependent cerebellar plasticity in adaptive control of saccades in humans. Brain Stimul 2017; 10:817-827. [PMID: 28501325 DOI: 10.1016/j.brs.2017.05.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 05/02/2017] [Accepted: 05/03/2017] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Saccade pulse amplitude adaptation is mediated by the dorsal cerebellar vermis and fastigial nucleus. Long-term depression at the parallel fibre-Purkinjie cell synapses has been suggested to provide a cellular mechanism for the corresponding learning process. The mechanisms and sites of this plasticity, however, are still debated. OBJECTIVE To test the role of cerebellar plasticity phenomena on adaptive saccade control. METHODS We evaluated the effect of continuous theta burst stimulation (cTBS) over the posterior vermis on saccade amplitude adaptation and spontaneous recovery of the initial response. To further identify the substrate of synaptic plasticity responsible for the observed adaptation impairment, subjects were pre-treated with memantine, an N-methyl-d-aspartate receptor (NMDAR) antagonist. RESULTS Amplitude adaptation was altered by cTBS, suggesting that cTBS interferes with cerebellar plasticity involved in saccade adaptation. Amplitude adaptation and spontaneous recovery were not affected by cTBS when recordings were preceded by memantine administration. CONCLUSION The effects of cTBS are NMDAR-dependent and are likely to involve long-term potentiation or long-term depression at specific synaptic connections of the granular and molecular layer, which could effectively take part in cerebellar motor learning.
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Affiliation(s)
- S Colnaghi
- Department of Public Health, Experimental and Forensic Medicine, University of Pavia, Via Forlanini 2, 27100 Pavia, Italy; Laboratory of Neuro-otology and Neuro-ophtalmology, C. Mondino National Neurological Institute, via Mondino 2, 27100 Pavia, Italy.
| | - P Colagiorgio
- Department of Electrical, Computer and Biomedical Engineering, University of Pavia, via Ferrata 5, 27100 Pavia, Italy
| | - M Versino
- Laboratory of Neuro-otology and Neuro-ophtalmology, C. Mondino National Neurological Institute, via Mondino 2, 27100 Pavia, Italy; Department of Brain and Behavioral Sciences, University of Pavia, via Forlanini 6, 27100 Pavia, Italy
| | - G Koch
- Laboratorio di Neurologia Clinica e Comportamentale, Fondazione S. Lucia IRCCS, via Ardeatina 306, 00179 Rome, Italy; Dipartimento di Neurologia, Policlinico Tor Vergata, viale Oxford 81, 00133 Rome, Italy
| | - E D'Angelo
- Department of Brain and Behavioral Sciences, University of Pavia, via Forlanini 6, 27100 Pavia, Italy; Brain Connectivity Center, C. Mondino National Neurological Institute, via Mondino 2, 27100 Pavia, Italy
| | - S Ramat
- Department of Electrical, Computer and Biomedical Engineering, University of Pavia, via Ferrata 5, 27100 Pavia, Italy
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Loy BM, Britt RB, Brown JN. Memantine for the Treatment of Phantom Limb Pain: A Systematic Review. J Pain Palliat Care Pharmacother 2016; 30:276-283. [DOI: 10.1080/15360288.2016.1241334] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Abstract
BACKGROUND This is an updated version of the original Cochrane review published in Issue 12, 2011. Phantom limb pain (PLP) is pain that arises in the missing limb after amputation and can be severe, intractable, and disabling. Various medications have been studied in the treatment of phantom pain. There is currently uncertainty in the optimal pharmacologic management of PLP. OBJECTIVES This review aimed to summarise the evidence of effectiveness of pharmacologic interventions in treating PLP. SEARCH METHODS For this update, we searched the Cochrane Central Register of Controlled Trials (CENTRAL, the Cochrane Library), MEDLINE, and Embase for relevant studies. We ran the searches for the original review in September 2011 and subsequent searches for this update up to April 2016. We sought additional studies from clinical trials databases and reference lists of retrieved papers. SELECTION CRITERIA We included randomised and quasi-randomised trials studying the effectiveness of pharmacologic interventions compared with placebo, another active treatment, or no treatment, in established PLP. We considered the following outcomes: change in pain intensity, function, sleep, depression or mood, quality of life, adverse events, treatment satisfaction, and withdrawals from the study. DATA COLLECTION AND ANALYSIS We independently assessed issues of study quality and extracted efficacy and adverse event data. Due to the wide variability in the studies, we did not perform a meta-analysis for all the interventions and outcomes, but attempted to pool the results of some studies where possible. We prepared a qualitative description and narrative summary of results. We assessed clinical heterogeneity by making qualitative comparisons of the populations, interventions, outcomes/outcome measures, and methods. MAIN RESULTS We added only one new study with 14 participants to this updated review. We included a 14 studies (10 with low risk of bias and 4 with unclear risk of bias overall) with a total of 269 participants. We added another drug class, botulinum neurotoxins (BoNTs), in particular botulinum toxin A (BoNT/A), to the group of medications reviewed previously. Our primary outcome was change in pain intensity. Most studies did not report our secondary outcomes of sleep, depression or mood, quality of life, treatment satisfaction, or withdrawals from the study.BoNT/A did not improve phantom limb pain intensity during the six months of follow-up compared with lidocaine/methylprednisolone.Compared with placebo, morphine (oral and intravenous) was effective in decreasing pain intensity in the short term with reported adverse events being constipation, sedation, tiredness, dizziness, sweating, voiding difficulty, vertigo, itching, and respiratory problems.The N-methyl D-aspartate (NMDA) receptor antagonists ketamine (versus placebo; versus calcitonin) and dextromethorphan (versus placebo), but not memantine, had analgesic effects. The adverse events of ketamine were more serious than placebo and calcitonin and included loss of consciousness, sedation, hallucinations, hearing and position impairment, and insobriety.The results for gabapentin in terms of pain relief were conflicting, but combining the results favoured treatment group (gabapentin) over control group (placebo) (mean difference -1.16, 95% confidence interval -1.94 to -0.38; 2 studies). However, gabapentin did not improve function, depression score, or sleep quality. Adverse events experienced were somnolence, dizziness, headache, and nausea.Compared with an active control benztropine mesylate, amitriptyline was not effective in PLP, with dry mouth and dizziness as the most frequent adverse events based on one study.The findings for calcitonin (versus placebo; versus ketamine) and local anaesthetics (versus placebo) were variable. Adverse events of calcitonin were headache, vertigo, drowsiness, nausea, vomiting, and hot and cold flushes. Most of the studies were limited by their small sample sizes. AUTHORS' CONCLUSIONS Since the last version of this review, we identified another study that added another form of medical therapy, BoNTs, specifically BoNT/A, to the list of pharmacologic interventions being reviewed for clinical efficacy in phantom limb pain. However, the results of this study did not substantially change the main conclusions. The short- and long-term effectiveness of BoNT/A, opioids, NMDA receptor antagonists, anticonvulsants, antidepressants, calcitonins, and local anaesthetics for clinically relevant outcomes including pain, function, mood, sleep, quality of life, treatment satisfaction, and adverse events remain unclear. Based on a small study, BoNT/A (versus lidocaine/methylprednisolone) does not decrease phantom limb pain. Morphine, gabapentin, and ketamine demonstrate favourable short-term analgesic efficacy compared with placebo. Memantine and amitriptyline may not be effective for PLP. However, results must be interpreted with caution, as they were based mostly on a small number of studies with limited sample sizes that varied considerably and also lacked long-term efficacy and safety outcomes. The direction of efficacy of calcitonin, local anaesthetics, and dextromethorphan needs further clarification. Overall, the efficacy evidence for the reviewed medications is thus far inconclusive. Larger and more rigorous randomised controlled trials are needed for us to reach more definitive conclusions about which medications would be useful for clinical practice.
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Affiliation(s)
- Maria Jenelyn M Alviar
- University of Melbourne-Royal Melbourne Hospital, Grattan St, Melbourne, Victoria, Australia, 3010
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Volz MS, Finke C, Harms L, Jurek B, Paul F, Flöel A, Prüss H. Altered paired associative stimulation-induced plasticity in NMDAR encephalitis. Ann Clin Transl Neurol 2016; 3:101-13. [PMID: 26900584 PMCID: PMC4748309 DOI: 10.1002/acn3.277] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 11/19/2015] [Indexed: 12/14/2022] Open
Abstract
OBJECTIVE To determine whether neurophysiological mechanisms indicating cortical excitability, long-term potentiation (LTP)-like plasticity, GABAergic and glutamatergic function are altered in patients with anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis and whether they can be helpful as markers of diagnostic assessment, disease progression, and potentially therapy response. METHODS Neurophysiological characterizations of patients with NMDAR encephalitis (n = 34, mean age: 28 ± 11 years; 30 females) and age/gender-matched healthy controls (n = 27, 28.5 ± 10 years; 25 females) were performed using transcranial magnetic stimulation-derived protocols including resting motor threshold, recruitment curve, intracortical facilitation, short intracortical inhibition, and cortical silent period. Paired associative stimulation (PAS) was applied to assess LTP-like mechanisms which are mediated through NMDAR. Moreover, resting state functional connectivity was determined using functional magnetic resonance imaging. RESULTS PAS-induced plasticity differed significantly between groups (P = 0.0056). Cortical excitability, as assessed via motor-evoked potentials after PAS, decreased in patients, whereas it increased in controls indicating malfunctioning of NMDAR in encephalitis patients. Lower PAS-induced plasticity significantly correlated with the modified Rankin Scale (mRS) (r = -0.41; P = 0.0031) and was correlated with lower functional connectivity within the motor network in NMDAR encephalitis patients (P < 0.001, uncorrected). Other neurophysiological parameters were not significantly different between groups. Follow-up assessments were available in six patients and demonstrated parallel improvement of PAS-induced plasticity and mRS. INTERPRETATION Assessment of PAS-induced plasticity may help to determine NMDAR dysfunction and disease severity in NMDAR encephalitis, and might even aid as a sensitive, noninvasive, and well-tolerated "electrophysiological biomarker" to monitor therapy response in the future. CLINICAL TRIAL REGISTRATION ClinicalTrials.gov: Identifier: NCT01865578.
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Affiliation(s)
- Magdalena Sarah Volz
- Department of Gastroenterology, Infectiology and RheumatologyCharité – Universitätsmedizin BerlinGermany
| | - Carsten Finke
- Department of NeurologyCharité – Universitätsmedizin BerlinGermany
- Berlin School of Mind and BrainHumboldt – Universität zu BerlinGermany
| | - Lutz Harms
- Department of NeurologyCharité – Universitätsmedizin BerlinGermany
- Center for Autoimmune Encephalitis and Paraneoplastic Neurological SyndromesCharité – Universitätsmedizin BerlinGermany
| | - Betty Jurek
- German Center for Neurodegenerative Diseases (DZNE)BerlinGermany
| | - Friedemann Paul
- Department of NeurologyCharité – Universitätsmedizin BerlinGermany
- NeuroCure Clinical Research Center and Experimental and Clinical Research Center and Max Delbrueck Center for Molecular MedicineCharité – Universitätsmedizin BerlinGermany
| | - Agnes Flöel
- Department of NeurologyCharité – Universitätsmedizin BerlinGermany
- NeuroCure Clinical Research Center and Experimental and Clinical Research Center and Max Delbrueck Center for Molecular MedicineCharité – Universitätsmedizin BerlinGermany
- Center for Stroke Research BerlinCharité – Universitätsmedizin BerlinGermany
| | - Harald Prüss
- Department of NeurologyCharité – Universitätsmedizin BerlinGermany
- Center for Autoimmune Encephalitis and Paraneoplastic Neurological SyndromesCharité – Universitätsmedizin BerlinGermany
- German Center for Neurodegenerative Diseases (DZNE)BerlinGermany
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Abstract
BACKGROUND Phantom limb pain (PLP) is a common complication after amputation, affecting up to 80% of the amputee population. However, only 5% to 10% of amputees have severe PLP impacting daily function. The present report details the management of severe, treatment-resistant PLP in a 72-year-old man with a traumatic left transradial amputation and a comorbid complication of heterotopic ossification (HO). OBJECTIVE To describe a case of PLP with HO and the possible role of calcitonin in the treatment of both conditions. METHODS A systematic review of the literature regarding the management of PLP. RESULTS Seventeen articles that directly addressed PLP were identified; 11 were randomized controlled trials. All involved small samples and follow-up ranged from 6 h to one year, with the majority limited to six weeks. DISCUSSION In the present case, medication management was limited by side effects, lack of response and the patient's desire to avoid long-term medication. Investigations revealed HO, which was suspected to envelop the median nerve in the proximal forearm. After several unsuccessful medication trials, the literature was reviewed in search of common variables between HO formation and persistent PLP. Ultimately, the biochemical effects associated with nerve injury were identified to be a possible factor in both HO and PLP development. Calcitonin's proposed mechanisms of action may help to manage HO and PLP at multiple stages of disease development and maintenance. In the present case, a four-week trial of intranasal calcitonin was successful, with pain control lasting at least 18 months. CONCLUSION The present case report provided a review of the current literature in PLP pharmacological management and the current understanding of the etiology of PLP and HO, as well as how the two may coexist. It also provided an opportunity to discuss the proposed mechanisms of action of calcitonin in the management of PLP and HO.
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Malavera Angarita MA, Carrillo Villa S, Gomezese Ribero OF, García RG, Silva Sieger FA. Pathophysiology and treatment of phantom limb pain. COLOMBIAN JOURNAL OF ANESTHESIOLOGY 2014. [DOI: 10.1016/j.rcae.2013.10.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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Malavera Angarita MA, Carrillo Villa S, Gomezese Ribero OF, García RG, Silva Sieger FA. Fisiopatología y tratamiento del dolor de miembro fantasma. ACTA ACUST UNITED AC 2014. [DOI: 10.1016/j.rca.2013.09.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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25
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Abstract
Postamputation pain (PAP) is highly prevalent after limb amputation but remains an extremely challenging pain condition to treat. A large part of its intractability stems from the myriad pathophysiological mechanisms. A state-of-art understanding of the pathophysiologic basis underlying postamputation phenomena can be broadly categorized in terms of supraspinal, spinal, and peripheral mechanisms. Supraspinal mechanisms involve somatosensory cortical reorganization of the area representing the deafferentated limb and are predominant in phantom limb pain and phantom sensations. Spinal reorganization in the dorsal horn occurs after deafferentataion from a peripheral nerve injury. Peripherally, axonal nerve damage initiates inflammation, regenerative sprouting, and increased "ectopic" afferent input which is thought by many to be the predominant mechanism involved in residual limb pain or neuroma pain, but may also contribute to phantom phenomena. To optimize treatment outcomes, therapy should be individually tailored and mechanism based. Treatment modalities include injection therapy, pharmacotherapy, complementary and alternative therapy, surgical therapy, and interventions aimed at prevention. Unfortunately, there is a lack of high quality clinical trials to support most of these treatments. Most of the randomized controlled trials in PAP have evaluated medications, with a trend for short-term Efficacy noted for ketamine and opioids. Evidence for peripheral injection therapy with botulinum toxin and pulsed radiofrequency for residual limb pain is limited to very small trials and case series. Mirror therapy is a safe and cost-effective alternative treatment modality for PAP. Neuromodulation using implanted motor cortex stimulation has shown a trend toward effectiveness for refractory phantom limb pain, though the evidence is largely anecdotal. Studies that aim to prevent PA P using epidural and perineural catheters have yielded inconsistent results, though there may be some benefit for epidural prevention when the infusions are started more than 24 hours preoperatively and compared with nonoptimized alternatives. Further investigation into the mechanisms responsible for and the factors associated with the development of PAP is needed to provide an evidence-based foundation to guide current and future treatment approaches.
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Affiliation(s)
- Eugene Hsu
- Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Steven P Cohen
- Johns Hopkins School of Medicine and Uniformed Services, University of the Health Sciences, Bethesda, MD, USA
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Schley M, Topfner S, Wiech K, Schaller HE, Konrad CJ, Schmelz M, Birbaumer N. Continuous brachial plexus blockade in combination with the NMDA receptor antagonist memantine prevents phantom pain in acute traumatic upper limb amputees. Eur J Pain 2012; 11:299-308. [PMID: 16716615 DOI: 10.1016/j.ejpain.2006.03.003] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2005] [Revised: 03/26/2006] [Accepted: 03/28/2006] [Indexed: 11/21/2022]
Abstract
BACKGROUND Hyperexcitability of N-methyl-d-aspartate acid (NMDA) receptors may play an important role in the development of phantom limb pain (PLP). AIM OF THE STUDY To investigate whether early treatment with the NMDA antagonist memantine attenuates phantom pain memory formation in traumatic amputees. METHODS In a randomized, double-blind, controlled trial 19 patients with acute traumatic amputation of the upper extremity were investigated. All patients received postoperative analgesia by continuous brachial plexus anesthesia (ropivacaine 0.375% 5 ml/h) for at least 7 days. In addition, the patients received either memantine (20-30 mg daily, n=10) or placebo (n=9) for 4 weeks. RESULTS Memantine treatment reduced the number of requested ropivacacine bolus injections during the first week and resulted in a significant decrease of PLP prevalence and intensity at 4 weeks and 6 months follow up, but not at 12 months follow up. CONCLUSIONS We conclude that memantine can reduce intensity of phantom limb pain and might also prevent the development of PLP. However, despite the very early begin of treatment; no long-term effect on established PLP was evident.
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Affiliation(s)
- M Schley
- Department of Anaesthesiology and Intensive Care Medicine, Experimental Pain Research/Pain Centre, University of Heidelberg, Faculty of Clinical Medicine, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany.
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Abstract
BACKGROUND Phantom limb pain (PLP) is pain that arises in the missing limb after amputation and can be severe, intractable and disabling. Various medications have been studied in the treatment of phantom pain. Presently there is uncertainty in the optimal pharmacologic management of PLP. OBJECTIVES This review aims to summarize the evidence of effectiveness of pharmacologic interventions in treating PLP. SEARCH METHODS We searched the Cochrane Pain, Palliative and Supportive Care Review Group (PaPaS) Trials Register, the Cochrane Controlled Trials Register (CENTRAL, The Cochrane Library), MEDLINE and EMBASE up to September 2011 for randomised and quasi-randomised trials comparing pharmacologic treatment with placebo, another active treatment, or no treatment. SELECTION CRITERIA We included randomised and quasi-randomised trials studying the effectiveness of pharmacologic interventions in patients with established PLP. The outcomes considered were change in pain intensity, function, mood, sleep, quality of life, satisfaction and adverse effects. DATA COLLECTION AND ANALYSIS Three review authors independently assessed the methodologic quality of the studies and extracted the data. We reported continuous and dichotomous data on change in pain intensity, function, mood/depression scores, sleep, quality of life, satisfaction for each study, where available. Because of the wide variability in the studies, we did not perform a meta-analysis for all the interventions and outcomes but we attempted to pool the results of some studies where possible. We prepared a qualitative description and narrative summary of results and described adverse effects. We assessed clinical heterogeneity by making qualitative comparisons in terms of the populations, interventions, outcomes/outcome measures and methods. MAIN RESULTS From 583 references/publications, we selected 13 studies involving 255 participants. Six groups of medications were reviewed, namely, N-methyl D-aspartate (NMDA) receptor antagonists, antidepressants, anticonvulsants, anaesthetics, opioids, and calcitonin. Ten studies were of high quality and three were of moderate quality based on both Jadad and Van Tulder criteria. Because of the wide variation (heterogeneity) in the pharmacologic interventions, outcome measures, analyses, reporting of results, duration of follow-ups and study designs, it was not possible to pool the results for most of the interventions and outcomes. Morphine (oral and intravenous) was effective in decreasing pain intensity in the short-term with reported adverse effects being constipation, sedation, tiredness, dizziness, sweating, voiding difficulty, vertigo, itching, and respiratory problems. The NMDA receptor antagonists, ketamine and dextromethorphan but not memantine, had analgesic effects. The adverse effects of ketamine were more serious and included loss of consciousness, sedation, hallucinations, hearing and position impairment, and insobriety. The results for gabapentin in terms of pain relief were conflicting but combining the results showed a trend towards benefit. Gabapentin, however, did not improve function, depression score and sleep quality. Side effects experienced were somnolence, dizziness, headache and nausea. Amitryptiline was not effective in PLP with dry mouth and dizziness as side effects based on one study. The findings for calcitonin and anaesthetics were variable. Adverse effects of calcitonin were headache, vertigo, drowsiness, nausea, vomiting, and hot and cold flushes. Most of the studies were limited by their small sample sizes. AUTHORS' CONCLUSIONS The short- and long-term effectiveness of opioids, NMDA receptor antagonists, anticonvulsants, antidepressants, calcitonins, and anaesthetics for clinically relevant outcomes that include pain, function, mood, sleep, quality of life, satisfaction and adverse effects remains unclear. Morphine, gabapentin and ketamine demonstrate trends towards short-term analgesic efficacy. Memantine and amitriptyline were ineffective for PLP. Results, however, are to be interpreted with caution as these were based mostly on a small number of studies with limited sample sizes that varied considerably and also lacked long-term efficacy and safety outcomes. The direction of efficacy of calcitonin, anaesthetics and dextromethorphan need further clarification. Larger and more rigorous randomised controlled trials are needed to make stronger recommendations about which medications would be useful for clinical practice.
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Affiliation(s)
- Maria Jenelyn M Alviar
- University of Melbourne-Royal Melbourne Hospital, Grattan St, Melbourne, Victoria, Australia, 3010
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Bekrater-Bodmann R, Foell J, Flor H. Relationship between bodily illusions and pain syndromes. Pain Manag 2011; 1:217-28. [DOI: 10.2217/pmt.11.20] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
SUMMARY Apart from their contribution to the overall knowledge of perception and related processes, sensory illusions have been used in recent years to treat and better understand pain disorders such as phantom limb pain or complex regional pain syndrome. With the help of modern imaging techniques, we can examine connections between basic processes of integrative perception and the occurrence of chronic pain. This article gives an overview of recent developments in the area of body illusions and pain, and provides suggestions on how they might lead to novel and effective treatments for chronic pain.
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Affiliation(s)
- Robin Bekrater-Bodmann
- Department of Cognitive & Clinical Neuroscience, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Jens Foell
- Department of Cognitive & Clinical Neuroscience, Central Institute of Mental Health, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
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Schwenkreis P, Voigt M, Hasenbring M, Tegenthoff M, Vorgerd M, Kley RA. Central mechanisms during fatiguing muscle exercise in muscular dystrophy and fibromyalgia syndrome: A study with transcranial magnetic stimulation. Muscle Nerve 2011; 43:479-84. [DOI: 10.1002/mus.21920] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/13/2010] [Indexed: 12/21/2022]
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Hackworth RJ, Tokarz KA, Fowler IM, Wallace SC, Stedje-Larsen ET. Profound Pain Reduction After Induction of Memantine Treatment in Two Patients with Severe Phantom Limb Pain. Anesth Analg 2008; 107:1377-9. [DOI: 10.1213/ane.0b013e31817f90f1] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Ketz AK. The experience of phantom limb pain in patients with combat-related traumatic amputations. Arch Phys Med Rehabil 2008; 89:1127-32. [PMID: 18503810 DOI: 10.1016/j.apmr.2007.11.037] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2007] [Revised: 10/25/2007] [Accepted: 11/01/2007] [Indexed: 01/12/2023]
Abstract
OBJECTIVES To describe the prevalence and characteristics of phantom limb pain (PLP) and the use and perceived effectiveness of standard medical and self-treatment methods by traumatic amputees with combat-related injuries. DESIGN A retrospective descriptive questionnaire study. SETTING Outpatient amputee clinic at a major military medical center. PARTICIPANTS Convenience sample of military members (N=30) with single or multiple traumatic amputations from combat and/or training. Inclusion criteria were 18 to 50 years old and amputation within 5 years of the study. Exclusion criteria were nontraumatic amputees and amputation or most recent surgical revision within 3 months before the study. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES The primary dependent variables were pain and relief, as measured by an investigator-developed questionnaire. RESULTS Seventy-seven percent of participants experienced PLP at some time since their amputation. Of those with PLP, the mean average intensity was 3.3+/-2.0 out of 10 and the mean worst intensity was 5.4+/-2.6 out of 10. The PLP was intermittent, and 78% reported episodes of PLP at least weekly. Sixty-eight percent of participants with PLP were receiving treatment from their health care providers. The most common medical treatment was gabapentin, although some patients reported greater pain relief from self-treatment methods such as distraction and relaxation techniques. CONCLUSIONS With over 750 service members living with amputations from recent combat, PLP will continue to be a troubling problem that requires effective interventions. The discrepancy between perceived effectiveness of different treatment types supports the need for highly individualized pain management plans.
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Affiliation(s)
- Ann K Ketz
- Landstuhl Regional Medical Center, Landstuhl, Germany.
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Wilson JA, Nimmo AF, Fleetwood-Walker SM, Colvin LA. A randomised double blind trial of the effect of pre-emptive epidural ketamine on persistent pain after lower limb amputation. Pain 2008; 135:108-18. [PMID: 17583431 DOI: 10.1016/j.pain.2007.05.011] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2006] [Revised: 05/09/2007] [Accepted: 05/14/2007] [Indexed: 01/19/2023]
Abstract
Persistent pain has been reported in up to 80% of patients after limb amputation. The mechanisms are not fully understood, but nerve injury during amputation is important, with evidence for the crucial involvement of the spinal N-methyl d-aspartate (NMDA) receptor in central changes. The study objective was to assess the effect of pre-emptively modulating sensory input with epidural ketamine (an NMDA antagonist) on post-amputation pain and sensory processing. The study recruited 53 patients undergoing lower limb amputation who received a combined intrathecal/epidural anaesthetic for surgery followed by a randomised epidural infusion (Group K received racemic ketamine and bupivacaine; Group S received saline and bupivacaine). Neither general anaesthesia nor opioids were used during the peri-operative period. Pain characteristics were assessed for 12 months. The primary endpoint was incidence and severity of post-amputation pain. Persistent pain at one year was much less in both groups than in comparable studies, with no significant difference between groups (Group K=21% (3/14) and 50% (7/14); and Group S=33% (5/15) and 40% (6/15) for stump and phantom pain, respectively). Post-operative analgesia was significantly better in Group K, with reduced stump sensitivity. The intrathecal/epidural technique used, with peri-operative sensory attenuation, may have reduced ongoing sensitisation, reducing the overall incidence of persistent pain. The improved short-term analgesia and reduced mechanical sensitivity in Group K may reflect acute effects of ketamine on central sensitisation. Longer term effects on mood were detected in Group K that requires further study.
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Affiliation(s)
- John A Wilson
- Department of Anaesthesia Critical Care and Pain Medicine, Clinical and Surgical Sciences, The University of Edinburgh, Royal Infirmary, Little France, Edinburgh EH16 4SA, UK
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Langguth B, Kleinjung T, Marienhagen J, Binder H, Sand PG, Hajak G, Eichhammer P. Transcranial magnetic stimulation for the treatment of tinnitus: effects on cortical excitability. BMC Neurosci 2007; 8:45. [PMID: 17605764 PMCID: PMC1929114 DOI: 10.1186/1471-2202-8-45] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2006] [Accepted: 07/02/2007] [Indexed: 11/29/2022] Open
Abstract
Background Low frequency repetitive transcranial magnetic stimulation (rTMS) has been proposed as an innovative treatment for chronic tinnitus. The aim of the present study was to elucidate the underlying mechanism and to evaluate the relationship between clinical outcome and changes in cortical excitability. We investigated ten patients with chronic tinnitus who participated in a sham-controlled crossover treatment trial. Magnetic-resonance-imaging and positron-emission-tomography guided 1 Hz rTMS were performed over the auditory cortex on 5 consecutive days. Active and sham treatments were separated by one week. Parameters of cortical excitability (motor thresholds, intracortical inhibition, intracortical facilitation, cortical silent period) were measured serially before and after rTMS treatment by using single- and paired-pulse transcranial magnetic stimulation. Clinical improvement was assessed with a standardized tinnitus-questionnaire. Results We noted a significant interaction between treatment response and changes in motor cortex excitability during active rTMS. Specifically, clinical improvement was associated with an increase in intracortical inhibition, intracortical facilitation and a prolongation of the cortical silent period. These results indicate that intraindividual changes in cortical excitability may serve as a correlate of response to rTMS treatment. Conclusion The observed alterations of cortical excitability suggest that low frequency rTMS may evoke long-term-depression like effects resulting in an improvement of subcortical inhibitory function.
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Affiliation(s)
- Berthold Langguth
- Department of Psychiatry, Psychosomatics and Psychotherapy, University of Regensburg, Universitaetsstraße 84, 93053 Regensburg, Germany
| | - Tobias Kleinjung
- Department of Otorhinolaryngology and Audiology, University of Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany
| | - Joerg Marienhagen
- Department of Nuclear Medicine, University of Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany
| | - Harald Binder
- Department of Medical Biometry and Statistics, University of Freiburg, Stefan-Meier-Strasse 26, 79104 Freiburg, Germany
| | - Philipp G Sand
- Department of Psychiatry, Psychosomatics and Psychotherapy, University of Regensburg, Universitaetsstraße 84, 93053 Regensburg, Germany
| | - Göran Hajak
- Department of Psychiatry, Psychosomatics and Psychotherapy, University of Regensburg, Universitaetsstraße 84, 93053 Regensburg, Germany
| | - Peter Eichhammer
- Department of Psychiatry, Psychosomatics and Psychotherapy, University of Regensburg, Universitaetsstraße 84, 93053 Regensburg, Germany
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Huang YZ, Chen RS, Rothwell JC, Wen HY. The after-effect of human theta burst stimulation is NMDA receptor dependent. Clin Neurophysiol 2007; 118:1028-32. [PMID: 17368094 DOI: 10.1016/j.clinph.2007.01.021] [Citation(s) in RCA: 418] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2006] [Revised: 01/29/2007] [Accepted: 01/31/2007] [Indexed: 11/17/2022]
Abstract
OBJECTIVE To provide pharmacological evidence that the after-effects of theta burst stimulation (TBS) involve plasticity like changes in cortical synaptic connections, using the N-methyl-D-aspartate receptor antagonist memantine. METHODS We performed a double blind, placebo-controlled study to evaluate the effect of memantine on the response of six healthy volunteers to TBS. We measured rest (RMT) and active (AMT) motor thresholds, and the amplitude of MEPs before and after continuous and intermittent TBS (cTBS/iTBS) after the administration of placebo or memantine. RESULTS Memantine had no effect on RMT and AMT, while it blocked the suppressive effect of cTBS and the facilitatory effect of iTBS. CONCLUSIONS The effects of iTBS and cTBS rely on NMDARs to produce after-effects in the motor cortex of conscious humans. SIGNIFICANCE The NMDA dependency of the after-effects of TBS adds to the understanding of the underlying mechanism of TBS, and suggests that these after-effects are likely to involve plasticity like changes at synaptic connections in motor cortex.
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Affiliation(s)
- Ying-Zu Huang
- Department of Neurology, Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Taipei 10507, Taiwan.
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Eisenberg E, Chistyakov AV, Yudashkin M, Kaplan B, Hafner H, Feinsod M. Evidence for cortical hyperexcitability of the affected limb representation area in CRPS: a psychophysical and transcranial magnetic stimulation study. Pain 2005; 113:99-105. [PMID: 15621369 DOI: 10.1016/j.pain.2004.09.030] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2004] [Revised: 09/09/2004] [Accepted: 09/28/2004] [Indexed: 02/06/2023]
Abstract
Functional alterations in noxious, sensory and motor circuits within the central nervous system may play an important role in the pathophysiology of complex regional pain syndrome (CRPS). The aim of the present study was to search for further evidence of hyperexcitability in the hemisphere contralateral to the affected limb in patients with CRPS by employing both psychophysical and transcranial magnetic stimulation (TMS) methods. Twelve patients with CRPS type I, confined to the distal part of a limb (six in an upper-limb and six in a lower-limb), were enrolled in the study. The quantitative thermal, mechanical and 'wind-up' like pain testing was performed at the most painful site in the affected limb and in the ipsilateral limb. Results were then compared to those found at mirror sites in the contralateral limbs. TMS was used to assess the inter-hemispheric difference in parameters of corticospinal excitability, intracortical inhibition, and intracortical facilitation. The quantitative thermal and mechanical testing showed significant differences in cold, heat and mechanical pain thresholds, as well as in the first and last 'wind-up' stimuli between the affected and the contralateral limbs of the CRPS patients. No significant differences between the ipsilateral unaffected limbs and their contralateral pair limbs were found. A significant reduction in the short intracortical inhibition associated with a significant increase of the I-wave facilitation was found in the hemisphere contralateral to the affected side in the upper-limb CRPS group. No significant inter-hemispheric asymmetry between the affected and the non-affected sides was revealed in the lower-limb CRPS group. Taken together, these results suggest that in patients with well-localized CRPS, there is evidence for sensory and motor CNS hyperexcitability, though it seems to involve only corresponding regions within the CNS rather than the entire hemisphere.
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Affiliation(s)
- Elon Eisenberg
- Pain Relief Uniti, Rambam (Maimonides) Medical Center, P.O. Box 9602, Haifa 31096, Israel.
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Langguth B, Eichhammer P, Zowe M, Kleinjung T, Jacob P, Binder H, Sand P, Hajak G. Altered motor cortex excitability in tinnitus patients: a hint at crossmodal plasticity. Neurosci Lett 2005; 380:326-9. [PMID: 15862911 DOI: 10.1016/j.neulet.2005.01.069] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2004] [Revised: 01/20/2005] [Accepted: 01/24/2005] [Indexed: 11/21/2022]
Abstract
Idiopathic tinnitus is a frequent and often debilitating auditory phantom perception of largely unknown pathological conditions. In electrophysiological and functional neuroimaging studies, affected subjects have shown excessive spontaneous activity in the central auditory system. To further investigate the underlying central nervous component, we assessed motor cortex excitability in 19 patients with chronic tinnitus by means of transcranial magnetic stimulation (TMS). When results were compared with data from 19 healthy controls matched for age and sex, we found significantly enhanced intracortical facilitation in tinnitus patients. These findings parallel excitability changes after limb amputation and experimental deafferentation. Our results give further support to crossmodal interactions involving neuroplastic changes in some forms of tinnitus and may help to better understand mechanisms of maladaptive cortical reorganisation involved in phantom perceptions.
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Affiliation(s)
- Berthold Langguth
- Department of Psychiatry and Psychotherapy, University of Regensburg, Universitaetsstrasse 84, 93053 Regensburg, Germany.
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Schwenkreis P, Maier C, Tegenthoff M. Fluctuations of motor cortex excitability in pain syndromes. ACTA ACUST UNITED AC 2004; 56:394-9. [PMID: 14677416 DOI: 10.1016/s1567-424x(09)70243-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/21/2023]
Affiliation(s)
- Peter Schwenkreis
- Department of Neurology, BG-Kliniken Bergmannsheil, Ruhr-University, D-44789 Bochum, Germany.
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