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Holcomb JM, Maldjian JA, Xi Y, O'Suilleabhain PE, Louis ED, Shah BR. ELectronic Archimedes spiral Neural Network (ELANN). Parkinsonism Relat Disord 2023; 115:105837. [PMID: 37683422 DOI: 10.1016/j.parkreldis.2023.105837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 08/11/2023] [Accepted: 08/27/2023] [Indexed: 09/10/2023]
Abstract
The Archimedes spiral is a clinical tool that aids in the diagnosis and monitoring of essential tremor. However, spiral ratings may vary based on experience and training of the rating physician. This study sought to generate an objective standard model for tremor evaluation using convolutional neural networks. One senior movement disorders neurologist (Neurologist 1) with over 30 years of clinical experience used the Bain and Findley Spirography Rating Scale to rate 1653 Archimedes spiral images from 46 essential tremor patients (mild to severe tremor) and 75 control subjects (no to mild tremor). Neurologist 1's labels were used as the reference standard to train the model. After training the model, a randomly selected subset of spiral testing data was re-evaluated by Neurologist 1, by a second senior movement disorders neurologist (Neurologist 2) with over 27 years of clinical experience, and by our model. Cohen's Weighted Kappa 95% confidence intervals were calculated from all rater comparisons to determine if our model performs with the same proficiency as two senior movement disorders neurologists. The Cohen's Weighted Kappa 95% confidence intervals for the agreement between the reference standard scores and Neurologist 1's rerated scores, for the agreement between the reference standard scores and Neurologist 2's scores, and for the agreement between the reference standard scores and our model's scores were 0.93-0.98, 0.86-0.94, and 0.89-0.96, respectively. With overlapping Cohen's Weighted Kappa 95% confidence intervals for all agreement comparisons, we demonstrate that our model evaluates spirals with the same proficiency as two senior movement disorders neurologists.
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Affiliation(s)
- James M Holcomb
- Focused Ultrasound Lab and Program, Department of Radiology, UTSW Medical Center, Dallas, TX, USA; Advanced Neuroscience Imaging Research Lab, Department of Radiology, UTSW Medical Center, Dallas, TX, USA
| | - Joseph A Maldjian
- Focused Ultrasound Lab and Program, Department of Radiology, UTSW Medical Center, Dallas, TX, USA; Advanced Neuroscience Imaging Research Lab, Department of Radiology, UTSW Medical Center, Dallas, TX, USA; O'Donnell Brain Institute, UTSW Medical Center, Dallas, TX, USA; Advanced Imaging Research Center, UTSW Medical Center, Dallas, TX, USA; Center for Alzheimer's and Neurodegenerative Diseases, UTSW Medical Center, Dallas, TX, USA
| | - Yin Xi
- Focused Ultrasound Lab and Program, Department of Radiology, UTSW Medical Center, Dallas, TX, USA; Advanced Neuroscience Imaging Research Lab, Department of Radiology, UTSW Medical Center, Dallas, TX, USA
| | | | - Elan D Louis
- Department of Neurology, UTSW Medical Center, Dallas, TX, USA
| | - Bhavya R Shah
- Focused Ultrasound Lab and Program, Department of Radiology, UTSW Medical Center, Dallas, TX, USA; Advanced Neuroscience Imaging Research Lab, Department of Radiology, UTSW Medical Center, Dallas, TX, USA; O'Donnell Brain Institute, UTSW Medical Center, Dallas, TX, USA; Department of Neurological Surgery, UTSW Medical Center, Dallas, TX, USA; Advanced Imaging Research Center, UTSW Medical Center, Dallas, TX, USA.
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Sáenz-Farret M, Tijssen MAJ, Eliashiv D, Fisher RS, Sethi K, Fasano A. Antiseizure Drugs and Movement Disorders. CNS Drugs 2022; 36:859-876. [PMID: 35861924 DOI: 10.1007/s40263-022-00937-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/30/2022] [Indexed: 11/03/2022]
Abstract
The relationship between antiseizure drugs and movement disorders is complex and not adequately reviewed so far. Antiseizure drugs as a treatment for tremor and other entities such as myoclonus and restless leg syndrome is the most common scenario, although the scientific evidence supporting their use is variable. However, antiseizure drugs also represent a potential cause of iatrogenic movement disorders, with parkinsonism and tremor the most common disorders. Many other antiseizure drug-induced movement disorders are possible and not always correctly identified. This review was conducted by searching for all the possible combinations between 15 movement disorders (excluding ataxia) and 24 antiseizure drugs. The main objective was to describe the movement disorders treated and worsened or induced by antiseizure drugs. We also summarized the proposed mechanisms and risk factors involved in the complex interaction between antiseizure drugs and movement disorders. Antiseizure drugs mainly used to treat movement disorders are clonazepam, gabapentin, lacosamide, levetiracetam, oxcarbazepine, perampanel, phenobarbital, pregabalin, primidone, topiramate, and zonisamide. Antiseizure drugs that worsen or induce movement disorders are cenobamate, ethosuximide, felbamate, lamotrigine, phenytoin, tiagabine, and vigabatrin. Antiseizure drugs with a variable effect on movement disorders are carbamazepine and valproate while no effect on movement disorders has been reported for brivaracetam, eslicarbazepine, lacosamide, and stiripentol. Although little information is available on the adverse effects or benefits on movement disorders of newer antiseizure drugs (such as brivaracetam, cenobamate, eslicarbazepine, lacosamide, and rufinamide), the evidence collected in this review should guide the choice of antiseizure drugs in patients with concomitant epilepsy and movement disorders. Finally, these notions can lead to a better understanding of the mechanisms involved in the pathophysiology and treatments of movement disorders.
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Affiliation(s)
- Michel Sáenz-Farret
- Edmond J. Safra Program in Parkinson's Disease, Morton and Gloria Shulman Movement Disorders Clinic, Toronto Western Hospital, University Health Network, Division of Neurology, University of Toronto, 399 Bathurst St, Toronto, ON, M5T 2S8, Canada
| | - Marina A J Tijssen
- Department of Neurology, University of Groningen, Groningen, The Netherlands.,Expertise Center Movement Disorders Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Dawn Eliashiv
- UCLA Seizure Disorder Center, Department of Neurology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Robert S Fisher
- Departments of Neurology and Neurological Sciences and Neurosurgery, Stanford University, Stanford, CA, USA
| | - Kapil Sethi
- Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Alfonso Fasano
- Edmond J. Safra Program in Parkinson's Disease, Morton and Gloria Shulman Movement Disorders Clinic, Toronto Western Hospital, University Health Network, Division of Neurology, University of Toronto, 399 Bathurst St, Toronto, ON, M5T 2S8, Canada. .,Krembil Brain Institute, Toronto, ON, Canada. .,Center for Advancing Neurotechnological Innovation to Application (CRANIA), Toronto, ON, Canada.
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Wagle Shukla A. Reduction of neuronal hyperexcitability with modulation of T-type calcium channel or SK channel in essential tremor. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2022; 163:335-355. [PMID: 35750369 DOI: 10.1016/bs.irn.2022.02.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Essential tremor is one of the most prevalent movement disorders. Propranolol and primidone are the first-line pharmacological therapies. They provide symptomatic control in less than 50% of patients. Topiramate, alprazolam, clonazepam, gabapentin, and botulinum toxin injections are the next line of treatments. These medications lead to modest improvements and are therefore commonly used as add-on agents. Surgical therapies, including deep brain stimulation (DBS) surgery and focused ultrasound beam targeted to the thalamus, are considered for treating tremor refractory to medications and lead to greater than 75% improvements in tremor symptoms. However, DBS is a costly and an invasive procedure; some patients report tolerance to benefits. Focused ultrasound therapy leading to brain lesions is associated with a possibility for permanent clinical deficits. Therefore, research efforts to develop the next generation of oral medications with greater benefits and lesser adverse effects are warranted. There is considerable evidence that the increased functions of calcium channels (P/Q-type and T-type channels) and reduced functions of calcium-activated potassium channels (SK channels) located in the neuronal membranes lead to tremor oscillations. Consequently, many new pharmacological studies have targeted these channels to leverage better clinical outcomes. The current review will discuss the pathophysiology, the specific importance of these channels, and the early clinical experience of using compounds targeting these channels to treat essential tremor.
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Affiliation(s)
- Aparna Wagle Shukla
- Department of Neurology, Fixel Institute for Neurological Diseases, University of Florida, Gainesville, FL, United States.
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Treatment Patterns in Essential Tremor: A Retrospective Analysis. Tremor Other Hyperkinet Mov (N Y) 2022; 12:10. [PMID: 35415009 PMCID: PMC8954883 DOI: 10.5334/tohm.682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 03/05/2022] [Indexed: 11/21/2022] Open
Abstract
Background: Although first line therapies for essential tremor have been identified from small clinical trials, responses are variable. We conducted a survey of tremor management in a large sample of ET cases. Methods: The Movement Disorders Clinical Case Registry within a US Veterans Health Administration medical center was used to identify 1468 patients with ET. Results: Of 1468 charts reviewed, 1074 (73.19%) met criteria for ET with characterization of temporal course and treatment; 291/1074 subjects (27.1%) did not receive any treatment. Almost half (500/1074; 46.6%) of the patients received monotherapy, 196/1074 (18.2%) two, 66/1074 (6.1%) three, and 21/1074 (2.0%) four or more medications. Of all prescriptions, primidone was the most used (546/1172; 46.6%), followed by propranolol (419; 35.8%), topiramate (122; 10.4%) and gabapentin (35; 3.0%). Medication response was available for a total of 1030 prescriptions, of which 138 (13.4%) were discontinued due to side effects; 180 (17.5%) prescriptions were ineffective. Furthermore, 52/1074 patients (4.8%) were treated with botulinum toxin injections and 41/1074 (3.8%) underwent deep brain stimulation surgery. Discussion: Our data suggest that more widespread recognition of limitations underlying conventional approaches, as well as increased referrals for nonpharmacological therapies, may be necessary to achieve improved outcomes in ET populations.
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Gironell A. Is essential tremor a disorder of primary GABA dysfunction? Yes. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2022; 163:259-284. [PMID: 35750365 PMCID: PMC9446196 DOI: 10.1016/bs.irn.2022.02.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Dysfunction in gamma-aminobutyric acid (GABA) neurotransmission has emerged as a prime suspect for the underlying neurochemical dysfunction in essential tremor (ET). This dysfunction has been termed the GABA hypothesis. We review findings to date supporting the 4 steps in this hypothesis in studies of cerebrospinal fluid, pathology, genetics, animal models, imaging, computational models, and human drugs, while not overlooking the evidence of negative studies and controversies. It remains to be elucidated whether reduced GABAergic tone is a primary contributing factor to ET pathophysiology, a consequence of altered Purkinje cell function, or even a result of Purkinje cell death. More studies are clearly needed to confirm both the neurodegenerative nature of ET and the reduction in GABA activity in the cerebellum. Also necessary is to test further therapies to enhance GABA transmission specifically focused on the cerebellar area.
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Affiliation(s)
- Alexandre Gironell
- Movement Disorders Unit, Department of Neurology, Sant Pau Hospital, Autonomous University of Barcelona, Catalonia, Spain.
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Singh J, Lanzarini E, Nardocci N, Santosh P. Movement disorders in patients with Rett syndrome: A systematic review of evidence and associated clinical considerations. Psychiatry Clin Neurosci 2021; 75:369-393. [PMID: 34472659 PMCID: PMC9298304 DOI: 10.1111/pcn.13299] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 07/28/2021] [Accepted: 08/20/2021] [Indexed: 12/18/2022]
Abstract
AIM This systematic review identified and thematically appraised clinical evidence of movement disorders in patients with Rett syndrome (RTT). METHOD Using PRISMA criteria, six electronic databases were searched from inception to April 2021. A thematic analysis was then undertaken on the extracted data to identify potential themes. RESULTS Following the thematic analysis, six themes emerged: (i) clinical features of abnormal movement behaviors; (ii) mutational profile and its impact on movement disorders; (iii) symptoms and stressors that impact on movement disorders; (iv) possible underlying neurobiological mechanisms; (v) quality of life and movement disorders; and (vi) treatment of movement disorders. Current guidelines for managing movement disorders in general were then reviewed to provide possible treatment recommendations for RTT. CONCLUSION Our study offers an enriched data set for clinical investigations and treatment of fine and gross motor issues in RTT. A detailed understanding of genotype-phenotype relationships of movement disorders allows for more robust genetic counseling for families but can also assist healthcare professionals in terms of monitoring disease progression in RTT. The synthesis also showed that environmental enrichment would be beneficial for improving some aspects of movement disorders. The cerebellum, basal ganglia, alongside dysregulation of the cortico-basal ganglia-thalamo-cortical loop, are likely anatomical targets. A review of treatments for movement disorders also helped to provide recommendations for treating and managing movement disorders in patients with RTT.
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Affiliation(s)
- Jatinder Singh
- Department of Child and Adolescent Psychiatry, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK.,Centre for Interventional Paediatric Psychopharmacology and Rare Diseases, South London and Maudsley NHS Foundation Trust, London, UK.,Centre for Personalised Medicine in Rett Syndrome, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Evamaria Lanzarini
- Child and Adolescent Neuropsychiatry Unit, Infermi Hospital, Rimini, Italy
| | - Nardo Nardocci
- Department of Paediatric Neurology, Fondazione IRCCS Istituto Neurologico "Carlo Besta", Milan, Italy
| | - Paramala Santosh
- Department of Child and Adolescent Psychiatry, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK.,Centre for Interventional Paediatric Psychopharmacology and Rare Diseases, South London and Maudsley NHS Foundation Trust, London, UK.,Centre for Personalised Medicine in Rett Syndrome, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
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7
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Abstract
Essential tremor is one of the most common tremor syndromes. According to the recent tremor classification, tremor as a symptom is defined as an involuntary, rhythmic, oscillatory movement of a body part and is classified along two axes: axis 1-defining syndromes based on the clinical features such as historical features, tremor characteristics, associated signs, and laboratory tests; and axis 2-classifying the etiology (Bhatia et al., Mov Disord 33:75-87, 2018). The management of this condition has two major approaches. The first is to exclude treatable etiologies, as particularly during the onset of this condition the presentation of a variety of etiologies can be with monosymptomatic tremor. Once the few etiologies with causal treatments are excluded, all further treatment is symptomatic. Shared decision-making with enabling the patient to knowledgeably choose treatment options is needed to customize the management. Mild to moderate tremor severity can sometimes be controlled with occupational treatment, speech therapy of psychotherapy, or adaptation of coping strategy. First-line pharmacological treatments include symptomatic treatment with propranolol, primidone, and topiramate. Botulinum toxin is for selected cases. Invasive treatments for essential tremor should be considered for severe tremors. They are generally accepted as the most powerful interventions and provide not only improvement of tremor but also a significant improvement of life quality. The current standard is deep brain stimulation (DBS) of the thalamic and subthalamic region. Focused ultrasound thalamotomy is a new therapy attracting increasing interest. Radiofrequency lesioning is only rarely done if DBS or focused ultrasound is not possible. Radiosurgery is not well established. We present our treatment algorithm.
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Affiliation(s)
- Franziska Hopfner
- Department of Neurology, UKSH, Christian-Albrechts-University Kiel, Rosalind-Fraenklinstr. 10, 24105, Kiel, Germany
- Department of Neurology, Hannover Medical School, Hannover, Germany
| | - Günther Deuschl
- Department of Neurology, UKSH, Christian-Albrechts-University Kiel, Rosalind-Fraenklinstr. 10, 24105, Kiel, Germany.
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Isaacson SH, Peckham E, Tse W, Waln O, Way C, Petrossian MT, Dahodwala N, Soileau MJ, Lew M, Dietiker C, Luthra N, Agarwal P, Dhall R, Morgan J, Calakos N, Zesiewicz TA, Shamim EA, Kumar R, LeWitt P, Shill HA, Simmons A, Pagan FL, Khemani P, Tate J, Maddux B, Luo L, Ondo W, Hallett M, Rajagopal A, Chidester P, Rosenbluth KH, Delp SL, Pahwa R. Prospective Home-use Study on Non-invasive Neuromodulation Therapy for Essential Tremor. Tremor Other Hyperkinet Mov (N Y) 2020; 10:29. [PMID: 32864188 PMCID: PMC7427656 DOI: 10.5334/tohm.59] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Accepted: 06/14/2020] [Indexed: 02/07/2023] Open
Abstract
Highlights This prospective study is one of the largest clinical trials in essential tremor to date. Study findings suggest that individualized non-invasive neuromodulation therapy used repeatedly at home over three months results in safe and effective hand tremor reduction and improves quality of life for many essential tremor patients. Background Two previous randomized, controlled, single-session trials demonstrated efficacy of non-invasive neuromodulation therapy targeting the median and radial nerves for reducing hand tremor. This current study evaluated efficacy and safety of the therapy over three months of repeated home use. Methods This was a prospective, open-label, post-clearance, single-arm study with 263 patients enrolled across 26 sites. Patients were instructed to use the therapy twice daily for three months. Pre-specified co-primary endpoints were improvements on clinician-rated Tremor Research Group Essential Tremor Rating Assessment Scale (TETRAS) and patient-rated Bain & Findley Activities of Daily Living (BF-ADL) dominant hand scores. Other endpoints included improvement in the tremor power detected by an accelerometer on the therapeutic device, Clinical and Patient Global Impression scores (CGI-I, PGI-I), and Quality of Life in Essential Tremor (QUEST) survey. Results 205 patients completed the study. The co-primary endpoints were met (p≪0.0001), with 62% (TETRAS) and 68% (BF-ADL) of 'severe' or 'moderate' patients improving to 'mild' or 'slight'. Clinicians (CGI-I) reported improvement in 68% of patients, 60% (PGI-I) of patients reported improvement, and QUEST improved (p = 0.0019). Wrist-worn accelerometer recordings before and after 21,806 therapy sessions showed that 92% of patients improved, and 54% of patients experienced ≥50% improvement in tremor power. Device-related adverse events (e.g., wrist discomfort, skin irritation, pain) occurred in 18% of patients. No device-related serious adverse events were reported. Discussion This study suggests that non-invasive neuromodulation therapy used repeatedly at home over three months results in safe and effective hand tremor reduction in many essential tremor patients.
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Affiliation(s)
- Stuart H. Isaacson
- Parkinson’s Disease and Movement Disorders of Boca Raton, Boca Raton, FL, US
| | | | - Winona Tse
- Mount Sinai Hospital, Department of Neurology, New York, NY, US
| | - Olga Waln
- Houston Methodist, Department of Neurology, Houston, TX, US
| | - Christopher Way
- Parkinson’s Institute and Clinical Center, Mountain View, CA, US
| | - Melita T. Petrossian
- Pacific Neuroscience Institute, Pacific Movement Disorders Center, Santa Monica, CA, US
| | - Nabila Dahodwala
- University of Pennsylvania, Department of Neurology, Philadelphia, PA, US
| | | | - Mark Lew
- University of Southern California, Department of Neurology, Los Angeles, CA, US
| | - Cameron Dietiker
- University of California San Francisco, Movement Disorder and Neuromodulation Center, San Francisco, CA, US
| | - Nijee Luthra
- University of California San Francisco, Movement Disorder and Neuromodulation Center, San Francisco, CA, US
| | - Pinky Agarwal
- EvergreenHealth, Department of Neurology, Kirkland, WA, US
| | - Rohit Dhall
- University of Arkansas for Medical Sciences, Department of Neurology, Little Rock, AR, US
| | - John Morgan
- Augusta University, Department of Neurology, Augusta, GA, US
| | - Nicole Calakos
- Duke University School of Medicine, Department of Neurology, Durham, NC, US
| | | | - Ejaz A. Shamim
- Kaiser Permanente MidAtlantic States, Department of Neurology, MidAtlantic Permanente Research Institute, Largo, MD, US
| | - Rajeev Kumar
- Rocky Mountain Movement Disorders Center, Englewood, CO, US
| | - Peter LeWitt
- Henry Ford Health System, Department of Neurology, West Bloomfield, MI, US
| | - Holly A. Shill
- Barrow Neurological Institute, Department of Neurology, Phoenix, AZ, US
| | - Adam Simmons
- Hospital for Special Care, Department of Research, New Britain, CT, US
| | - Fernando L. Pagan
- Georgetown University Medical Center, Department of Neurology, Washington DC, US
| | - Pravin Khemani
- Swedish Neuroscience Institute, Department of Neurology, Seattle, WA, US
| | - Jessica Tate
- Wake Forest Baptist Health, Department of Neurology, Winston-Salem, NC, US
| | | | - Lan Luo
- Beth Israel Deaconess Medical Center, Harvard Medical School, Department of Neurology, Boston, MA, US
| | - William Ondo
- Houston Methodist, Department of Neurology, Houston, TX, US
| | - Mark Hallett
- National Institute of Neurological Disorders and Stroke, Human Motor Control Section, Bethesda, MD, US
| | | | | | | | - Scott L. Delp
- Stanford University, Department of Bioengineering, Stanford, CA, US
| | - Rajesh Pahwa
- University of Kansas Medical Center, Department of Neurology, Kansas City, KS, US
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Abstract
Established medications that improve tremor include beta-adrenergic antagonists, primidone, topiramate, and ethanol. Less consistent efficacy is reported with many other medications, usually antiepileptic drugs. A number of investigational medications, including T-type calcium channel blockers and allosteric gamma-aminobutyric acid-A modulators, are being developed for tremor. Deep brain stimulation techniques continues to be refined and focused ultrasound thalamotomy now offers an incisionless surgical option. Finally a number of peripheral electrical and mechanical devices are under development for tremor.
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Affiliation(s)
- William George Ondo
- Movement Disorders-Methodist Neurological Institute, Weill Cornel Medical School, 6560 Fannin Suite 1002, Houston, TX 77025, USA.
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Alonso-Navarro H, García-Martín E, Agúndez JA, Jiménez-Jiménez FJ. Current and Future Neuropharmacological Options for the Treatment of Essential Tremor. Curr Neuropharmacol 2020; 18:518-537. [PMID: 31976837 PMCID: PMC7457404 DOI: 10.2174/1570159x18666200124145743] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 10/31/2019] [Accepted: 01/23/2020] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Essential Tremor (ET) is likely the most frequent movement disorder. In this review, we have summarized the current pharmacological options for the treatment of this disorder and discussed several future options derived from drugs tested in experimental models of ET or from neuropathological data. METHODS A literature search was performed on the pharmacology of essential tremors using PubMed Database from 1966 to July 31, 2019. RESULTS To date, the beta-blocker propranolol and the antiepileptic drug primidone are the drugs that have shown higher efficacy in the treatment of ET. Other drugs tested in ET patients have shown different degrees of efficacy or have not been useful. CONCLUSION Injections of botulinum toxin A could be useful in the treatment of some patients with ET refractory to pharmacotherapy. According to recent neurochemical data, drugs acting on the extrasynaptic GABAA receptors, the glutamatergic system or LINGO-1 could be interesting therapeutic options in the future.
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Affiliation(s)
| | | | | | - Félix J. Jiménez-Jiménez
- Address correspondence to this author at the Section of Neurology, Hospital Universitario del Sureste, Arganda del Rey, Madrid, Spain; Tel: +34636968395; Fax: +34913280704; E-mails: ;
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Sharma S, Pandey S. Treatment of essential tremor: current status. Postgrad Med J 2019; 96:84-93. [DOI: 10.1136/postgradmedj-2019-136647] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 08/14/2019] [Accepted: 09/13/2019] [Indexed: 12/18/2022]
Abstract
Essential tremor is the most common cause of tremor involving upper limbs, head and voice. The first line of treatment for limb tremor is pharmacotherapy with propranolol or primidone. However, these two drugs reduce the tremor severity by only half. In medication refractory and functionally disabling tremor, alternative forms of therapy need to be considered. Botulinum toxin injections are likely efficacious for limb, voice and head tremor but are associated with side effects. Surgical interventions include deep brain stimulation; magnetic resonance-guided focused ultrasound and thalamotomy for unilateral and deep brain stimulation for bilateral procedures. Recent consensus classification for essential tremor has included a new subgroup, ‘Essential tremor plus’, who have associated subtle neurological ‘soft signs’, such as dystonic posturing of limbs and may require a different treatment approach. In this review, we have addressed the current management of essential tremor with regard to different anatomical locations of tremor as well as different modalities of treatment.
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León Ruiz M, Benito-León J. The Top 50 Most-Cited Articles in Orthostatic Tremor: A Bibliometric Review. TREMOR AND OTHER HYPERKINETIC MOVEMENTS (NEW YORK, N.Y.) 2019; 9:tre-09-679. [PMID: 31413901 PMCID: PMC6691913 DOI: 10.7916/tohm.v0.679] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 07/06/2019] [Indexed: 12/20/2022]
Abstract
Background Article-level citation count is a hallmark indicating scientific impact. We aimed to pinpoint and evaluate the top 50 most-cited articles in orthostatic tremor (OT). Methods The ISI Web of Knowledge database and 2017 Journal Citation Report Science Edition were used to retrieve the 50 top-cited OT articles published from 1984 to April 2019. Information was collected by the Analyze Tool on the Web of Science, including number of citations, publication title, journal name, publication year, and country and institution of origin. Supplementary analyses were undertaken to clarify authorship, study design, level of evidence, and category. Results Up to 66% of manuscripts were recovered from five journals: Movement Disorders (n = 18), Brain (n = 4), Journal of Clinical Neurophysiology (n = 4), Neurology (n = 4), and Clinical Neurophysiology (n = 3). Articles were published between 1984 and 2018, with expert opinion as the predominant design (n = 22) and review as category (n = 17). Most articles had level 5 evidence (n = 26). According to their countries of origin, 34% of articles belonged to the United States (n = 17) leading the list, followed by United Kingdom (n = 15). University College London yielded the greater number of articles (n = 12), followed by the University of Kiel (n = 9). Most popular authors were G. Deuschl (n = 10), C.D. Marsden (n = 6), J. Jankovic (n = 5), P.D. Thompson (n = 5), J.C. Rothwell (n = 5), L.J. Findley (n = 4), and P. Brown (n = 4), who together accounted for 48% of them. All papers were in English. Discussion Publishing high-cited OT articles could be facilitated by source journal, study design, category, publication language, and country and institution of origin.
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Affiliation(s)
| | - Julián Benito-León
- Department of Neurology, Hospital Universitario 12 de Octubre, Madrid, ES.,Department of Medicine, Faculty of Medicine, Universidad Complutense de Madrid, Madrid, ES.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, ES
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Abstract
Essential tremor is one of the most common movement disorders in adults and can affect both children and adults. An updated consensus statement in 2018 redefined essential tremor as an isolated action tremor present in bilateral upper extremities for at least three years. Tremor may also be present in other locations, commonly the neck or the vocal cords. Patients with additional neurologic symptoms are now categorized as "essential tremor plus." Additional clinical features associated with the condition include but are not limited to cognitive impairment, psychiatric disorders, and hearing loss. When treatment is needed, propranolol and primidone are considered first line treatments. Patients who are severely affected are often offered deep brain stimulation. Although the ventral intermediate nucleus of the thalamus is the traditional surgical target, the caudal zona incerta is also being studied as a possible superior alternative. Magnetic resonance imaging guided high intensity focused ultrasound is a newer surgical alternative that may be ideal for patients with substantial medical comorbidities. Current research explores novel oral treatments, chemodenervation, and noninvasive neuromodulation for treatment of essential tremor.
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Affiliation(s)
- Vicki Shanker
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
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Salcedo-Arellano MJ, Hagerman RJ, Martínez-Cerdeño V. [Fragile X associated tremor/ataxia syndrome: its clinical presentation, pathology, and treatment]. Rev Neurol 2019; 68:199-206. [PMID: 30805918 PMCID: PMC7001878 DOI: 10.33588/rn.6805.2018457] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The fragile X associated tremor/ataxia syndrome (FXTAS) is a neurodegenerative disease associated with the repetition of CGG triplets (55-200 CGG repetitions) in the FMR1 gene. The premutation of the FMR1 gene, contrasting with the full mutation (more than 200 CGG repetitions), presents an increased production of messenger and a similar or slightly decreased production of FMRP protein. FXTAS affects 40% of men and 16% of women carriers of the premutation. It presents with a wide constellation of neurological signs such as intention tremor, cerebellar ataxia, parkinsonism, executive function deficits, peripheral neuropathy and cognitive decline leading to dementia among others. In this review, we present what is currently known about the molecular mechanism, the radiological findings and the pathology, as well as the complexity of the diagnosis and management of FXTAS.
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Affiliation(s)
- María Jimena Salcedo-Arellano
- Department of Pediatrics, University of California Davis
School of Medicine, Sacramento, CA, USA
- Medical Investigation of Neurodevelopmental Disorders
(MIND) Institute, University of California Davis, Sacramento, CA, USA
| | - Randi J Hagerman
- Department of Pediatrics, University of California Davis
School of Medicine, Sacramento, CA, USA
- Medical Investigation of Neurodevelopmental Disorders
(MIND) Institute, University of California Davis, Sacramento, CA, USA
| | - Verónica Martínez-Cerdeño
- Medical Investigation of Neurodevelopmental Disorders
(MIND) Institute, University of California Davis, Sacramento, CA, USA
- Institute for Pediatric Regenerative Medicine and Shriners
Hospitals for Children Northern California, Sacramento, CA, USA
- Department of Pathology and Laboratory Medicine, UC Davis
School of Medicine, Sacramento, CA, USA
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Fleet JL, Dixon SN, Kuwornu PJ, Dev VK, Montero-Odasso M, Burneo J, Garg AX. Gabapentin dose and the 30-day risk of altered mental status in older adults: A retrospective population-based study. PLoS One 2018. [PMID: 29538407 PMCID: PMC5851574 DOI: 10.1371/journal.pone.0193134] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Gabapentin is an effective treatment for chronic neuropathic pain but may cause dizziness, drowsiness, and confusion in some older adults. The goal of this study was to assess the association between gabapentin dosing and adverse outcomes by obtaining estimates of the 30-day risk of hospitalization with altered mental status and mortality in older adults (mean age 76 years) in Ontario, Canada initiated on high dose (>600 mg/day; n = 34,159) compared to low dose (≤600 mg/day; n = 76,025) oral gabapentin in routine outpatient care. A population-based, retrospective cohort study assessing new gabapentin use between 2002 to 2014 was conducted. The primary outcome was 30-day hospitalization with an urgent head computed tomography (CT) scan in the absence of evidence of stroke (a proxy for altered mental status). The secondary outcome was 30-day all-cause mortality. The baseline characteristics measured in the two dose groups were similar. Initiation of a high versus low dose of gabapentin was associated with a higher risk of hospitalization with head CT scan (1.27% vs. 1.06%, absolute risk difference 0.21%, adjusted relative risk 1.29 [95% CI 1.14 to 1.46], number needed to treat 477) but not a statistically significant higher risk of mortality (1.25% vs. 1.16%, absolute risk difference of 0.09%, adjusted relative risk of 1.01 [95% CI 0.89 to 1.14]). Overall, the risk of being hospitalized with altered mental status after initiating gabapentin remains low, but may be reduced through the judicious use of gabapentin, use of the lowest dose to control pain, and vigilance for early signs of altered mental status.
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Affiliation(s)
- Jamie L. Fleet
- Department of Physical Medicine and Rehabilitation, McMaster University, Hamilton, Ontario, Canada
- * E-mail:
| | - Stephanie N. Dixon
- Institute for Clinical Evaluative Sciences, London, Ontario, Canada
- Department of Epidemiology & Biostatistics, Western University, London, Ontario, Canada
| | | | - Varun K. Dev
- Division of Nephrology, Department of Medicine, Sunnybrook Hospital, Toronto, Ontario, Canada
| | - Manuel Montero-Odasso
- Department of Epidemiology & Biostatistics, Western University, London, Ontario, Canada
- Division of Geriatrics, Department of Medicine, Western University, London, Ontario, Canada
| | - Jorge Burneo
- Department of Clinical Neurological Sciences, Western University, London, Ontario, Canada
| | - Amit X. Garg
- Institute for Clinical Evaluative Sciences, London, Ontario, Canada
- Department of Epidemiology & Biostatistics, Western University, London, Ontario, Canada
- Division of Nephrology, Department of Medicine, Western University, London, Ontario, Canada
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Abstract
BACKGROUND Essential tremor (ET) is one of the most common movement disorders. The treatment is primarily based on pharmacological agents. Although primidone and propranolol are well established treatments in clinical practice, they can be ineffective in 25% to 55% of patients, and can produce serious adverse events in a large percentage of them. For these reasons, it may be worthwhile evaluating the treatment alternatives for ET. Zonisamide has been suggested as a potentially useful agent for the treatment of ET but there is uncertainty about its efficacy and safety. OBJECTIVES To assess the effect on functional abilities and the safety profile of zonisamide in adults with essential tremor (ET). SEARCH METHODS We carried out a systematic search, without language restrictions to identify all relevant trials. We searched CENTRAL, MEDLINE, Embase, NICE, ClinicalTrials.gov, and the WHO International Clinical Trials Registry Platform (ICTRP) to January 2017. We searched BIOSIS Citation Index (2000 to January 2017) for conference proceedings. We handsearched grey literature and examined the reference lists of identified studies and reviews. SELECTION CRITERIA We included all randomised controlled trials (RCTs) of zonisamide versus placebo or any other treatment. We included studies in which the diagnosis of ET was made according to accepted and validated diagnostic criteria. We excluded studies conducted in patients presenting secondary forms of tremor or reporting only neurophysiological parameters to assess outcomes. DATA COLLECTION AND ANALYSIS Two review authors independently collected and extracted data using a data collection form. We assessed the risk of bias and the quality of evidence.We used inverse variance methods for continuous outcomes and measurement scales. We compared differences between treatment groups as mean differences. We combined results for dichotomous outcomes using Mantel-Haenszel methods and obtained risk differences to compare treatment groups. We used Review Manager 5 software for data management and analysis. MAIN RESULTS We only considered one study eligible for this review (20 participants). Assessments of risk of bias for most domains were unclear or low. Adverse events were only reported in participants from the zonisamide group, making it possible that they were aware of treatment group assignment. We are uncertain as to the effects of zonisamide on motor tasks (mean difference (MD) -0.00, 95% confidence interval (CI) -1.51 to 1.51, very low-quality evidence) and functional disabilities (MD -0.30, 95% CI -1.23 to 0.63, very low-quality evidence) when compared with placebo. Three participants in the zonisamide group (30%) and two participants in the placebo group (20%) discontinued the treatment and withdrew from the study for any reason (very low-quality evidence), however the increased risk of withdrawal in the zonisamide group was statistically non-significant (risk difference (RD) 0.1, 95% CI -0.28 to 0.48). Six participants in the zonisamide group (60%) and none of the participants in the placebo group (0%) developed adverse events (AEs), with a RD of 0.60 (95% CI 0.28 to 0.92; very low quality evidence). The most common AEs, experienced with zonisamide treatment, were headache, nausea, fatigue, sleepiness, and diarrhoea. Quality of life was not assessed in the study included. AUTHORS' CONCLUSIONS Based on currently available data, there is insufficient evidence to assess the efficacy and safety of zonisamide treatment for ET.
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Affiliation(s)
- Elisa Bruno
- University of CataniaDepartment GF Ingrassia, Section of NeurosciencesCataniaItaly95123
| | - Alessandra Nicoletti
- University of CataniaDepartment GF Ingrassia, Section of NeurosciencesCataniaItaly95123
| | - Graziella Filippini
- Fondazione IRCCS, Istituto Neurologico Carlo BestaScientific Directionvia Celoria, 11MilanItaly20133
| | - Graziella Quattrocchi
- University of CataniaDepartment GF Ingrassia, Section of NeurosciencesCataniaItaly95123
| | - Carlo Colosimo
- Terni University HospitalDepartment of NeurologyTerniItaly05100
| | - Mario Zappia
- University of CataniaDepartment GF Ingrassia, Section of NeurosciencesCataniaItaly95123
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Bruno E, Nicoletti A, Quattrocchi G, Allegra R, Filippini G, Colosimo C, Zappia M. Topiramate for essential tremor. Cochrane Database Syst Rev 2017; 4:CD009683. [PMID: 28409827 PMCID: PMC6478240 DOI: 10.1002/14651858.cd009683.pub2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Essential tremor (ET) is one of the most common movement disorders. The management is primarily based on pharmacological agents and in clinical practice propranolol and primidone are considered the first-line therapy. However, these treatments can be ineffective in 25% to 55% of people and are frequently associated with serious adverse events (AEs). For these reasons, it is worthwhile evaluating other treatments for ET. Topiramate has been suggested as a potentially useful agent for the treatment of ET but there is uncertainty about its efficacy and safety. OBJECTIVES To assess the efficacy and safety of topiramate in the treatment of ET. SEARCH METHODS We carried out a systematic search without language restrictions to identify all relevant trials in the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (January 1966 to January 2017), Embase (January 1988 to January 2017), National Institute for Health and Care Excellence (1999 to January 2017), ClinicalTrials.gov (1997 to January 2017) and World Health Organization International Clinical Trials Registry Platform (ICTRP; 2004 to January 2017). We searched BIOSIS Citation Index (2000 to January 2017) for conference proceedings. We handsearched grey literature and the reference lists of identified studies and reviews. SELECTION CRITERIA We included all randomised controlled trials (RCTs) of topiramate versus placebo/open control or any other treatments. We included studies in which the diagnosis of ET was made according to accepted and validated diagnostic criteria. We excluded studies conducted in people presenting with secondary forms of tremor or reporting only neurophysiological parameters to assess outcomes. DATA COLLECTION AND ANALYSIS Two review authors independently collected and extracted data using a data collection form. We assessed the risk of bias and the quality of evidence. We used a fixed-effect meta-analysis for data synthesis. MAIN RESULTS This review included three trials comparing topiramate to placebo (309 participants). They were all at high overall risk of bias. The quality of evidence ranged from very low to low. Compared to placebo, participants treated with topiramate showed a significant improvement in functional disability and an increased risk of withdrawal (risk ratio (RR) 1.78, 95% confidence interval (CI) 1.23 to 2.60). There were more AEs for topiramate-treated participants, particularly paraesthesia, weight loss, appetite decrease and memory difficulty. AUTHORS' CONCLUSIONS This systematic review highlighted the presence of limited data and very low to low quality evidence to support the apparent efficacy and the occurrence of treatment-limiting AEs in people with ET treated with topiramate. Further research to assess topiramate efficacy and safety on ET is needed.
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Affiliation(s)
- Elisa Bruno
- University of CataniaDepartment GF Ingrassia, Section of NeurosciencesCataniaItaly95123
| | - Alessandra Nicoletti
- University of CataniaDepartment GF Ingrassia, Section of NeurosciencesCataniaItaly95123
| | - Graziella Quattrocchi
- University of CataniaDepartment GF Ingrassia, Section of NeurosciencesCataniaItaly95123
| | - Roberta Allegra
- Policlinico Universitario G. Martino MessinaDepartment of Neurological SciencesVia Consolare ValeriaMessinaItaly90100
| | - Graziella Filippini
- Fondazione IRCCS, Istituto Neurologico Carlo BestaScientific Directionvia Celoria, 11MilanItaly20133
| | - Carlo Colosimo
- Terni University HospitalDepartment of NeurologyTerniItaly05100
| | - Mario Zappia
- University of CataniaDepartment GF Ingrassia, Section of NeurosciencesCataniaItaly95123
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Marin-Lahoz J, Gironell A. Linking Essential Tremor to the Cerebellum: Neurochemical Evidence. THE CEREBELLUM 2017; 15:243-52. [PMID: 26498765 DOI: 10.1007/s12311-015-0735-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The pathophysiology and the exact anatomy of essential tremor (ET) is not well known. One of the pillars that support the cerebellum as the main anatomical locus in ET is neurochemistry. This review examines the link between neurochemical abnormalities found in ET and cerebellum. The review is based on published data about neurochemical abnormalities described in ET both in human and in animal studies. We try to link those findings with cerebellum. γ-aminobutyric acid (GABA) is the main neurotransmitter involved in the pathophysiology of ET. There are several studies about GABA that clearly points to a main role of the cerebellum. There are few data about other neurochemical abnormalities in ET. These include studies with noradrenaline, glutamate, adenosine, proteins, and T-type calcium channels. One single study reveals high levels of noradrenaline in the cerebellar cortex. Another study about serotonin neurotransmitter results negative for cerebellum involvement. Finally, studies on T-type calcium channels yield positive results linking the rhythmicity of ET and cerebellum. Neurochemistry supports the cerebellum as the main anatomical locus in ET. The main neurotransmitter involved is GABA, and the GABA hypothesis remains the most robust pathophysiological theory of ET to date. However, this hypothesis does not rule out other mechanisms and may be seen as the main scaffold to support findings in other systems. We clearly need to perform more studies about neurochemistry in ET to better understand the relations among the diverse systems implied in ET. This is mandatory to develop more effective pharmacological therapies.
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Affiliation(s)
- Juan Marin-Lahoz
- Movement Disorders Unit, Department of Neurology, Hospital de la Santa Creu i Sant Pau, Autonomous University of Barcelona, Av.Sant Antoni Maria Claret, 167, 08025, Barcelona, Catalonia, Spain
| | - Alexandre Gironell
- Movement Disorders Unit, Department of Neurology, Hospital de la Santa Creu i Sant Pau, Autonomous University of Barcelona, Av.Sant Antoni Maria Claret, 167, 08025, Barcelona, Catalonia, Spain.
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Bruno E, Nicoletti A, Quattrocchi G, Filippini G, Colosimo C, Zappia M. Pregabalin for essential tremor. Cochrane Database Syst Rev 2016; 10:CD009682. [PMID: 27763691 PMCID: PMC6461190 DOI: 10.1002/14651858.cd009682.pub2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Essential tremor is one of the most common movement disorders. Treatment primarily consists of pharmacological agents. While primidone and propranolol are well-established treatments in clinical practice, they may be ineffective in 25% to 55% of patients and can produce serious adverse events in a large percentage of them. For these reasons, it is worth evaluating the treatment alternatives for essential tremor. Some specialists have suggested that pregabalin could be a potentially useful agent, but there is uncertainty about its efficacy and safety. OBJECTIVES To assess the effects of pregabalin versus placebo or other treatment for essential tremor in adults. SEARCH METHODS We performed a systematic search without language restrictions to identify all relevant trials up to December 2015. We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, NICE, ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry Platform (ICTRP). We handsearched grey literature and examined the reference lists of identified studies and reviews. SELECTION CRITERIA We included all randomised controlled trials (RCTs) of pregabalin versus placebo or any other treatments. We included studies in which the diagnosis of ET was made according to accepted and validated diagnostic criteria. We excluded studies conducted in patients presenting secondary forms of tremor or reporting only neurophysiological parameters to assess outcomes. DATA COLLECTION AND ANALYSIS Two reviewers independently collected and extracted data using a data collection form. We assessed the risk of bias of the body of evidence, and we used inverse variance methods to analyse continuous outcomes and measurement scales. We compared the mean difference between treatment groups, and we combined results for dichotomous outcomes using Mantel-Haenszel methods and risk differences We used Review Manager software for data management and analysis. MAIN RESULTS We only found one study eligible for this review (22 participants). We assessed the risk of bias for most domains as unclear. We graded the overall quality of evidence as very low. Compared to placebo, patients treated with pregabalin showed no significant improvement of motor tasks on the 36-point subscale of the Fahn-Tolosa-Marin Tremor Rating Scale (TRS) (MD -2.15 points; 95% CI -9.16 to 4.86) or on the 32-point functional abilities subscale of the TRS (MD -0.66 points; 95% CI -2.90 to 1.58).The limited evidence showed no difference in study withdrawal (Mantel-Haenszel RD -0.09; 95% CI -0.48 to 0.30) and presentation of adverse events between pregabalin and placebo (Mantel-Haenszel RD 0.18; 95% CI -0.13 to 0.50). AUTHORS' CONCLUSIONS The effects of pregabalin for treating essential tremor are uncertain because the quality of the evidence is very low. One small study did not highlight any effect of this treatment; however, the high risk of bias and the lack of other studies on this topic limit further conclusion.
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Affiliation(s)
- Elisa Bruno
- Department GF Ingrassia,Section of Neurosciences, University of Catania, Catania, Italy, 95123
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Abstract
Movement disorders can be challenging to manage and often use a specific set of medications. Because it is a complex and broad field within neurology, many providers are unfamiliar with the classes of medications. This paper details medications used for specific conditions, explains why these medications are helpful, and shares pearls and pitfalls related to each agent, focusing on parameters such as dose titration, side effect profiles, and specific drug-drug interactions and challenges. We focus on the most commonly encountered movement disorders, including essential tremor, Parkinson's disease, rapid eye movement sleep behavior disorder, and restless leg syndrome.
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Affiliation(s)
- Anthony Julius
- VA Puget Sound, University of Washington Medical Center, 1660 South Columbian Way, Seattle, WA 98108, USA
| | - Katelan Longfellow
- VA Puget Sound, University of Washington Medical Center, 1660 South Columbian Way, Seattle, WA 98108, USA.
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Abstract
Essential tremor is a common movement disorder that interferes with the performance of motor tasks and social activities. As a consequence, patients experience a reduction in quality of life. The pathophysiology remains not well understood. Differentiation of essential tremor from other tremor syndromes is important in order for clinicians to better provide patient education and therapy. When pharmacotherapy is indicated, the standard agents remain propranolol and primidone. However, additional agents such as benzodiazepines, gabapentin, topiramate, and zonisamide may provide additional symptomatic benefits. Surgical interventions, such as thalamic deep brain stimulation, and focal injections of botulinum toxin offer patients an alternative treatment modality when oral pharmacotherapy is inadequate. A treatment outline is provided to guide clinicians in the management of patients with essential tremor.
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Affiliation(s)
- Jack J. Chen
- Schools of Medicine and Pharmacy, Loma Linda University, Loma Linda, California,
| | - David M. Swope
- Department of Neurology and School of Medicine, Loma Linda University, Loma Linda, California
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Ondo W. Essential Tremor: What We Can Learn from Current Pharmacotherapy. Tremor Other Hyperkinet Mov (N Y) 2016; 6:356. [PMID: 26989572 PMCID: PMC4790207 DOI: 10.7916/d8k35tc3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 12/17/2015] [Indexed: 04/07/2023] Open
Abstract
BACKGROUND The pathophysiology of essential tremor, especially at the cellular level, is poorly understood. Although no drug has been specifically designed to treat essential tremor, several medications improve tremor, and others worsen it. Studying the mechanism of actions of these medications can help our understanding of tremor pathophysiology and contribute to future rational drug design. METHODS We reviewed literature, concentrating on mechanisms of action, of various medications that mitigate tremor. RESULTS Many medications have multiple mechanisms of actions, making simple correlations difficult. Medications that increase the duration of opening of gamma-aminobutyric acid (GABA)-A receptors are most consistently associated with tremor improvement. Interestingly, drugs that increase GABA availability have not been associated with improved tremor. Other mechanisms possibly associated with tremor improvement include antagonism of alpha-2 delta subunits associated with calcium channels, inhibition of carbonic anhydrase, and inhibition of the synaptic vesicle protein 2A. Drugs that block voltage-gaited sodium channels do not affect tremor. The ideal beta-adrenergic blocker requires B2 affinity (non-cardiac selective), has no sympathomimetic properties, does not require membrane stabilization properties, and may benefit from good central nervous system penetration. DISCUSSION To date, serendipitous observations have provided most of our understanding of tremor cellular physiology. Based on similarities to currently effective drugs or rational approximations and inferences, several currently available agents should be considered for tremor trials.
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Affiliation(s)
- William Ondo
- Methodist Neurological Institute, Houston, TX, USA
- *To whom correspondence should be addressed. E-mail:
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23
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News and controversies regarding essential tremor. Rev Neurol (Paris) 2015; 171:415-25. [DOI: 10.1016/j.neurol.2015.02.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 02/01/2015] [Accepted: 02/02/2015] [Indexed: 01/08/2023]
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Vaziri Z, Abbassian H, Sheibani V, Haghani M, Nazeri M, Aghaei I, Shabani M. The therapeutic potential of Berberine chloride hydrate against harmaline-induced motor impairments in a rat model of tremor. Neurosci Lett 2015; 590:84-90. [PMID: 25643620 DOI: 10.1016/j.neulet.2015.01.078] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2014] [Revised: 01/24/2015] [Accepted: 01/29/2015] [Indexed: 11/16/2022]
Abstract
Essential tremor (ET) is a progressive neurological disorder with motor and non-motor symptoms. It has conclusively been shown that modulation of glutamate receptors could ameliorate ET. Recent studies have suggested that Berberine (BBR) has an inhibitory effect on glutamate receptors. Therefore, BBR may have therapeutic effects on ET. In this study, male Wistar rats (n=10 in each group) weighing 40-60 g were divided into control, harmaline (30 mg/kg, i.p.) and berberine (10, 20 or 50mg/kg, i.p, 15 min before harmaline injection) groups. Open field, rotarod, wire grip and foot print tests were used to evaluate motor performance. The results indicated that the administration of BBR (10 and 20mg/kg) attenuated harmaline-induced tremor in rats, but the beneficial effects of BBR could not be identified at dose 50mg/kg. In addition, BBR ameliorated gait disturbance in doses of 10 and 20mg/kg. The high dose of BBR not only failed to recover step width but also showed an adverse effect on left and right step length. The results indicate that BBR only in dose of 20mg/kg recovers mobility duration. The current study found a dose-dependent manner for the therapeutic effects of BBR in ET. Our study provides the initial evidence for the effects of BBR on motor function. Since BBR exerts its effects mainly through regulation of neurotransmitter release or blocke of NMDA receptors, thus, it is predicted that BBR ameliorate harmaline effect through blockade of NMDA receptors or glutamate release. This is an important issue for future research to evaluate the possible mechanisms involved.
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Affiliation(s)
- Zohreh Vaziri
- Neuroscience Research Center, Neuropharmacology Institute, Kerman University of Medical Sciences, Kerman, Iran
| | - Hassan Abbassian
- Neuroscience Research Center, Neuropharmacology Institute, Kerman University of Medical Sciences, Kerman, Iran
| | - Vahid Sheibani
- Neuroscience Research Center, Neuropharmacology Institute, Kerman University of Medical Sciences, Kerman, Iran
| | - Masoud Haghani
- Histomorphometry and Stereology Research Centre, Shiraz University of Medical Sciences, Shiraz, Iran; Department of Physiology, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Masoud Nazeri
- Neuroscience Research Center, Neuropharmacology Institute, Kerman University of Medical Sciences, Kerman, Iran
| | - Iraj Aghaei
- Neuroscience Research Center, Neuropharmacology Institute, Kerman University of Medical Sciences, Kerman, Iran
| | - Mohammad Shabani
- Neuroscience Research Center, Neuropharmacology Institute, Kerman University of Medical Sciences, Kerman, Iran.
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Hickey P, Stacy M. Taxonomy and Clinical Features of Movement Disorders. Mov Disord 2015. [DOI: 10.1016/b978-0-12-405195-9.00001-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Gironell A. The GABA Hypothesis in Essential Tremor: Lights and Shadows. TREMOR AND OTHER HYPERKINETIC MOVEMENTS (NEW YORK, N.Y.) 2014; 4:254. [PMID: 25120944 PMCID: PMC4108714 DOI: 10.7916/d8sf2t9c] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Accepted: 06/16/2014] [Indexed: 02/07/2023]
Abstract
Background The gamma-aminobutyric acid (GABA) hypothesis in essential tremor (ET) implies a disturbance of the GABAergic system, especially involving the cerebellum. This review examines the evidence of the GABA hypothesis. Methods The review is based on published data about GABA dysfunction in ET, taking into account studies on cerebrospinal fluid, pathology, electrophysiology, genetics, neuroimaging, experimental animal models, and human drug therapies. Results Findings from several studies support the GABA hypothesis in ET. The hypothesis follows four steps: 1) cerebellar neurodegeneration with Purkinje cell loss; 2) a decrease in GABA system activity in deep cerebellar neurons; 3) disinhibition in output deep cerebellar neurons with pacemaker activity; and 4) an increase in rhythmic activity of the thalamus and thalamo-cortical circuit, contributing to the generation of tremor. Doubts have been cast on this hypothesis, however, by the fact that it is based on relatively few works, controversial post-mortem findings, and negative genetic studies on the GABA system. Furthermore, GABAergic drug efficacy is low and some GABAergic drugs do not have antitremoric efficacy. Discussion The GABA hypothesis continues to be the most robust pathophysiological hypothesis to explain ET. There is light in all GABA hypothesis steps, but a number of shadows cannot be overlooked. We need more studies to clarify the neurodegenerative nature of the disease, to confirm the decrease of GABA activity in the cerebellum, and to test more therapies that enhance the GABA transmission specifically in the cerebellum area.
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Affiliation(s)
- Alexandre Gironell
- Movement Disorders Unit, Department of Neurology, Sant Pau Hospital, Autonomous University of Barcelona, Catalonia, Spain
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Baek JH, Kinrys G, Nierenberg AA. Lithium tremor revisited: pathophysiology and treatment. Acta Psychiatr Scand 2014; 129:17-23. [PMID: 23834617 DOI: 10.1111/acps.12171] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/30/2013] [Indexed: 01/28/2023]
Abstract
OBJECTIVE Tremor occurs frequently as a side-effect of lithium, and it is, however, easily overlooked in the clinical setting. In this article, we attempt to review the pathophysiology and the clinical approach of lithium tremor. METHOD We searched the Pubmed and Cochrane Library for relevant articles up to the year 2012. Sixty-four articles including 10 review papers, 3 clinical trials, and 12 case reports were reviewed. RESULTS Lithium tremor is classified as a postural tremor and subcategorized as an exaggerated physiologic tremor. Differential diagnosis includes metabolic abnormalities, benign essential tremor, Parkinson's disease, and lithium toxicity. Various methods of evaluating lithium tremor and treatment options are discussed. CONCLUSION When lithium tremor has developed, thorough history taking, physical examination, and blood examination including serum lithium level are needed. Pharmacotherapy is indicated only in patients with disabling tremor.
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Affiliation(s)
- J H Baek
- Bipolar Clinic and Research Program, Massachusetts General Hospital, Boston, MA, USA
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29
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Hedera P, Cibulčík F, Davis TL. Pharmacotherapy of essential tremor. J Cent Nerv Syst Dis 2013; 5:43-55. [PMID: 24385718 PMCID: PMC3873223 DOI: 10.4137/jcnsd.s6561] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Revised: 11/10/2013] [Accepted: 11/25/2013] [Indexed: 12/11/2022] Open
Abstract
Essential tremor (ET) is a common movement disorder but its pathogenesis remains poorly understood. This has limited the development of effective pharmacotherapy. The current therapeutic armamentaria for ET represent the product of careful clinical observation rather than targeted molecular modeling. Here we review their pharmacokinetics, metabolism, dosing, and adverse effect profiles and propose a treatment algorithm. We also discuss the concept of medically refractory tremor, as therapeutic trials should be limited unless invasive therapy is contraindicated or not desired by patients.
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Affiliation(s)
- Peter Hedera
- Department of Neurology, Vanderbilt University, Nashville, TN
| | - František Cibulčík
- Department of Neurology, Slovak Medical University and University Hospital Bratislava, Slovakia
| | - Thomas L Davis
- Department of Neurology, Vanderbilt University, Nashville, TN
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30
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Shaw JD, Allison KG, Staffetti JS, Zesiewicz TA. Diagnosis and treatment of essential tremor. Neurodegener Dis Manag 2013. [DOI: 10.2217/nmt.13.52] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
SUMMARY Essential tremor (ET) is one of the most prevalent movement disorders in the world, affecting millions of people. Medications that are commonly used to treat ET include antiepileptic or antihypertensive medications. Primidone and propranolol are considered effective, first-line agents for treating ET, while atenolol, alprazolam and topiramate are considered second-line agents. Gabapentin appears to improve ET when used as a monotherapy, although not as an adjunct therapy. Alternatives to pharmacologic treatment for refractory ET include botulinum toxin A injections, deep-brain stimulation of the ventral intermediate nucleus of the thalamus and thalamotomy. Future developments in the treatment of ET will depend on valid animal models and a greater understanding of its pathophysiology.
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Affiliation(s)
- Jessica Davenport Shaw
- University of South Florida, Department of Neurology, Frances J Zesiewicz Center & Foundation for Parkinson’s Disease & University of South Florida Ataxia Research Center, 12901 Bruce B Downs Boulevard, MDC Box 55, Tampa, FL 33612, USA
| | - Kevin G Allison
- University of South Florida, Department of Neurology, Frances J Zesiewicz Center & Foundation for Parkinson’s Disease & University of South Florida Ataxia Research Center, 12901 Bruce B Downs Boulevard, MDC Box 55, Tampa, FL 33612, USA
| | - Joseph S Staffetti
- University of South Florida, Department of Neurology, Frances J Zesiewicz Center & Foundation for Parkinson’s Disease & University of South Florida Ataxia Research Center, 12901 Bruce B Downs Boulevard, MDC Box 55, Tampa, FL 33612, USA
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31
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Abstract
OPINION STATEMENT Essential tremor is one of the most common movement disorders in the world. Although millions of people worldwide are affected by ET, only one medication, propranolol, is approved by the United States Food and Drug Administration to treat it. None of the medications currently used as ET therapy were developed specifically for this purpose, and select antihypertensive and antiepileptic medications remain at the forefront of ET therapy. Propranolol and primidone are considered "effective" agents that treat ET; topiramate, atenolol, and alprazolam are "probably effective", and nimodipine, nadolol, and clonazepam are "possibly effective". Medications that probably do not adequately treat ET include levetiracetam and pregabalin. Gabapentin appears to improve ET when used as monotherapy, but not when used as adjunct therapy. Sotalol has been found to be "probably effective" in treating ET in previous reviews, but it may be associated with arrhythmias and should not be routinely recommended. Botulinum toxin A may reduce limb tremor, but may cause dose dependent weakness. Deep brain stimulation (DBS) of the VIM is used as an alternative to pharmacological therapy of ET in patients who fail to adequately respond to medical therapy. The magnitude of effect from DBS is greater than from medical management, but more severe side effects are possible with surgery. Future treatment options for ET will depend on valid animal models, and a better understanding of its pathophysiology.
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32
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Impact of Essential Tremor and Its Medical and Surgical Treatment on Neuropsychological Functioning, Activities of Daily Living and Quality of Life. ACTA ACUST UNITED AC 2013. [DOI: 10.1201/b14115-10] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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33
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Carranza MA, Snyder MR, Elble RJ, Boutzoukas AE, Zesiewicz TA. Methodological issues in clinical drug development for essential tremor. TREMOR AND OTHER HYPERKINETIC MOVEMENTS (NEW YORK, N.Y.) 2013; 2. [PMID: 23440401 PMCID: PMC3570037 DOI: 10.7916/d8p55m7f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Accepted: 05/30/2012] [Indexed: 12/01/2022]
Abstract
Essential tremor (ET) is one of the most common tremor disorders in the world. Despite this, only two medications have received Level A recommendations from the American Academy of Neurology to treat it (primidone and propranolol). Even though these medications provide relief to a large group of ET patients, up to 50% of patients are non-responders. Additional medications to treat ET are needed. This review discusses some of the methodological issues that should be addressed for quality clinical drug development in ET.
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Affiliation(s)
- Michael A Carranza
- Department of Neurology, University of South Florida, Tampa, Florida, United States of America
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34
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[Essential tremor: update]. Med Clin (Barc) 2013; 140:128-33. [PMID: 22995841 DOI: 10.1016/j.medcli.2012.07.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Revised: 07/02/2012] [Accepted: 07/05/2012] [Indexed: 11/23/2022]
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35
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Zappia M, Albanese A, Bruno E, Colosimo C, Filippini G, Martinelli P, Nicoletti A, Quattrocchi G. Treatment of essential tremor: a systematic review of evidence and recommendations from the Italian Movement Disorders Association. J Neurol 2012; 260:714-40. [DOI: 10.1007/s00415-012-6628-x] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Revised: 07/12/2012] [Accepted: 07/12/2012] [Indexed: 10/28/2022]
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36
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Affiliation(s)
- Pramod Kumar Pal
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bangalore, India
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37
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Affiliation(s)
- Hrishikesh Kumar
- Movement Disorders Program, Division of Neurology, University of Western Ontario, London, Ont.
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38
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Gironell A, Kulisevsky J. Diagnosis and management of essential tremor and dystonic tremor. Ther Adv Neurol Disord 2011; 2:215-22. [PMID: 21179530 DOI: 10.1177/1756285609104791] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Essential tremor (ET) is the most common adult movement disorder. Traditionally considered as a benign disease, it can cause an important physical and psychosocial disability. Drug treatment for ET remains poor and often unsatisfactory. Current therapeutic strategies for ET are reviewed according to the level of discomfort caused by tremor. For mild tremor, nonpharmacological strategies consist of alcohol and acute pharmacological therapy; for moderate tremor, pharmacological therapies (propranolol, gabapentin, primidone, topiramate, alprazolam and other drugs); and for severe tremor, the role of functional surgery is emphasised (thalamic deep brain stimulation, thalamotomy). The more specific treatment of head tremor with the use of botulinum toxin is also discussed. Several points are discussed to guide the immediate research into this disease in the near future. Dystonic tremor is a common symptom in dystonia. Diagnostic criteria for dystonic tremor and differential diagnosis with psychogenic tremor and ET are described. Treatment of dystonic tremor matches the treatment of dystonia. In cases of symptomatic dystonic tremor similar to ET, therapeutic strategies would be the same as for ET.
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Affiliation(s)
- Alexandre Gironell
- Movement Disorders Unit, Department of Neurology, Sant Pau Hospital, Autonomous University of Barcelona, Catalonia and Ciberned (Centro de Enfermedades Neurodegenerativas en Red), Spain
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39
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Haubenberger D, Kalowitz D, Nahab FB, Toro C, Ippolito D, Luckenbaugh DA, Wittevrongel L, Hallett M. Validation of digital spiral analysis as outcome parameter for clinical trials in essential tremor. Mov Disord 2011; 26:2073-80. [PMID: 21714004 DOI: 10.1002/mds.23808] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Revised: 04/21/2011] [Accepted: 04/28/2011] [Indexed: 11/08/2022] Open
Abstract
Essential tremor, one of the most prevalent movement disorders, is characterized by kinetic and postural tremor affecting activities of daily living. Spiral drawing is commonly used to visually rate tremor intensity, as part of the routine clinical assessment of tremor and as a tool in clinical trials. We present a strategy to quantify tremor severity from spirals drawn on a digitizing tablet. We validate our method against a well-established visual spiral rating method and compare both methods on their capacity to capture a therapeutic effect, as defined by the change in clinical essential tremor rating scale after an ethanol challenge. Fifty-four Archimedes spirals were drawn using a digitizing tablet by nine ethanol-responsive patients with essential tremor before and at five consecutive time points after the administration of ethanol in a standardized treatment intervention. Quantitative spiral tremor severity was estimated from the velocity tremor peak amplitude after numerical derivation and Fourier transformation of pen-tip positions. In randomly ordered sets, spirals were scored by seven trained raters, using Bain and Findley's 0 to 10 rating scale. Computerized scores correlated with visual ratings (P < 0.0001). The correlation was significant at each time point before and after ethanol (P < 0.005). Quantitative ratings provided better sensitivity than visual rating to capture the effects of an ethanol challenge (P < 0.05). Using a standardized treatment approach, we were able to demonstrate that spirography time-series analysis is a valid, reliable method to document tremor intensity and a more sensitive measure for small effects than currently available visual spiral rating methods.
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Affiliation(s)
- Dietrich Haubenberger
- Human Motor Control Section, Medical Neurology Branch, NINDS/NIH, Bethesda, Maryland, USA.
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40
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Dalvi A. Medical Treatment of Tremor. Dis Mon 2011; 57:135-41. [DOI: 10.1016/j.disamonth.2011.02.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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41
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Deuschl G, Raethjen J, Hellriegel H, Elble R. Treatment of patients with essential tremor. Lancet Neurol 2011; 10:148-61. [PMID: 21256454 DOI: 10.1016/s1474-4422(10)70322-7] [Citation(s) in RCA: 236] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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42
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Benito-León J, Louis ED. Management of essential tremor, including medical and surgical approaches. HANDBOOK OF CLINICAL NEUROLOGY 2011; 100:449-456. [PMID: 21496601 DOI: 10.1016/b978-0-444-52014-2.00034-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Essential tremor (ET) is one of the most common neurological disorders among adults. For many years, ET was viewed as a benign monosymptomatic condition, characterized by a kinetic arm tremor, yet over the last 10 years, a growing body of evidence suggests that this disorder is a progressive condition that is heterogeneous. Tremor may have a negative impact on health-related quality of life in some patients. Pharmacotherapy is initiated when the tremor interferes with the patient's ability to perform daily activities or when the tremor becomes embarrassing or affects health-related quality of life. For severe tremor, deep-brain stimulation of the thalamus may improve function.
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Affiliation(s)
- Julián Benito-León
- Department of Neurology, University Hospital "12 de Octubre" and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.
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43
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Prakash KM. An Overview of Surgical Therapy for Movement Disorders. PROCEEDINGS OF SINGAPORE HEALTHCARE 2010. [DOI: 10.1177/201010581001900405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Surgical treatments are an important consideration in the management of many movement disorders, particularly for patients refractory to medications. Increasing number of published reports have demonstrated an overall improvement in motor function, activities of daily living and quality of life particularly with deep brain stimulation. In addition the procedure is also relatively safe. In this article, we review the various types of movement disorders that may benefit from surgical intervention.
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Affiliation(s)
- Kumar M Prakash
- Department of Neurology, National Neuroscience Institute (Singapore General Hospital Campus), Singapore
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44
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45
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Abstract
Essential tremor (ET) is one of the most common movement disorders in the world. Despite this, only one medication (propranolol) is approved by the Food and Drug Administration (FDA) to treat it. Fortunately, recent studies have identified some additional medications as treatment of ET. Surgical procedures, such as deep brain stimulation of the ventral intermediate nucleus of the thalamus, offer treatment for refractory tremor. The epidemiology, pathogenesis, and medical and surgical treatment of ET will be discussed in this paper.
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Affiliation(s)
- Theresa A Zesiewicz
- Department of Neurology, Parkinson Research Foundation, James A. Haley Veterans Administration Hospital, University of South Florida, Tampa, FL, USA
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46
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García-Martín E, Martínez C, Alonso-Navarro H, Benito-León J, Lorenzo-Betancor O, Pastor P, Puertas I, Rubio L, López-Alburquerque T, Agúndez JAG, Jiménez-Jiménez FJ. Gamma-aminobutyric acid (GABA) receptor rho (GABRR) polymorphisms and risk for essential tremor. J Neurol 2010; 258:203-11. [PMID: 20820800 DOI: 10.1007/s00415-010-5708-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2010] [Accepted: 08/09/2010] [Indexed: 12/31/2022]
Abstract
Some clinical and experimental data suggest a possible role of gamma-aminobutyrate (GABA)-ergic mechanisms in the pathophysiology of essential tremor (ET), such as the improvement of ET with some GABAergic drugs and the development of an experimental model of ET in GABA A receptor alpha-1 knockout mice (postural and kinetic tremor and motor incoordination similar to human ET). To investigate the possible association between the GABA receptor subtype rho1, rho2, and rho3 (GABRR1, GABRR2, and GABRR3) genotypes and allelic variants of the single nucleotide polymorphisms GABRR1-M26V (Met26Val, rs12200969), GABRR1-H27R (His26Arg, rs1186902), GABRR2-T455M (Thr55Met, rs282129), and GABRR3-Y205X (Tyr205X, rs832032), and the risk for ET, we studied the frequency of the previously mentioned GABRR genotypes and allelic variants in 200 patients with ET and 250 healthy controls using TaqMan genotyping. The frequencies of the GABBR1 genotypes and allelic variants of the studied polymorphisms did not differ significantly between patients with ET and controls, and were unrelated with the age at onset of tremor, gender, localization of tremor, and response of tremor to ethanol. These data suggest that the single nucleotide polymorphisms studied in the GABBR genes are not related to the risk for ET.
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Affiliation(s)
- Elena García-Martín
- Department of Biochemistry and Molecular Biology, University of Extremadura, Badajoz, Spain
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47
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Boecker H, Weindl A, Brooks DJ, Ceballos-Baumann AO, Liedtke C, Miederer M, Sprenger T, Wagner KJ, Miederer I. GABAergic dysfunction in essential tremor: an 11C-flumazenil PET study. J Nucl Med 2010; 51:1030-5. [PMID: 20554735 DOI: 10.2967/jnumed.109.074120] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
UNLABELLED Essential tremor is the most common movement disorder, but the underlying pathophysiology is not well understood. A primary overactivity of cerebellothalamic output pathways is the most conspicuous finding, as indicated by animal and human studies. It has been argued that this overactivity may be due to impaired central inhibition, and converging evidence points toward a potential role of gamma-aminobutyric acid (GABA) dysfunction in tremor generation. METHODS Using (11)C-flumazenil and PET, we calculated the distribution volume, an index of availability of benzodiazepine receptor sites of the GABA(A) complex, in a group of 8 patients with bilateral essential tremor, as compared with 11 healthy controls. RESULTS Significant increases in binding of (11)C-flumazenil at the benzodiazepine receptor site of the GABA(A) receptor in the cerebellum, the ventrolateral thalamus, and the lateral premotor cortex were identified in the essential tremor group. CONCLUSION Essential tremor is associated with reduced GABAergic function and increased availability of benzodiazepine receptor sites in brain regions implicated specifically in tremor genesis. This finding is thought to reflect overactivity of cerebellothalamic circuits and, hence, lends support to the "GABA hypothesis" of essential tremor.
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Affiliation(s)
- Henning Boecker
- Nuklearmedizinische Klinik, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
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48
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49
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Abstract
OBJECTIVE The primary objective of this article is to review the clinical presentation and pharmacologic management of essential tremor and tardive dyskinesia. DATA SOURCES The MEDLINE (1966-August 2005), Cochrane Database of Systematic Reviews, and International Pharmaceutical Abstracts (1970-August 2005) databases were searched for original research and review articles published in English. The search terms were essential tremor and tardive dyskinesia. Reference lists from articles were also consulted. DATA SYNTHESIS Essential tremor is most commonly manifested as a postural or action tremor of the upper extremities. Midline regions such as the head and voice are also commonly affected. Based on review of the literature, propranolol and primidone are the current pharmacologic mainstays for treating essential tremor of the upper extremities. The choice of agent depends on patient-specific factors such as underlying medical conditions. Other agents with demonstrated efficacy include gabapentin and topiramate. Benzodiazepines are effective adjunctive agents, but should be utilized judiciously in the elderly. Botulinum toxin is effective for essential tremor of the voice and head. Surgery is very effective, but may not be appropriate in the frail elderly and should be avoided in the presence of cognitive impairment. Tardive dyskinesia is characterized by involuntary choreoathetoid movements of the orofacial region. For the management of tardive dyskinesia, emphasis is placed on primary prevention and early recognition of signs and symptoms. In some cases, discontinuation of the offending agent can result in reversal of symptoms. If a conventional neuroleptic is the causative agent, switching to an atypical antipsychotic may be helpful. Overall, few treatments have proven to be consistently useful. Other agents that may be helpful include acetylcholinesterase inhibitors, amantadine, baclofen, benzodiazepines, branched chain amino acids, gabapentin, levetiracetam, pyridoxine, verapamil, and vitamin E. CONCLUSION Current pharmacologic agents for essential tremor can be expected to provide partial benefit. However, agents for the symptomatic management of tardive dyskinesia are limited, and additional research is warranted in this area.
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Affiliation(s)
- Jack J Chen
- School of Pharmacy, Loma Linda University, California 92350, USA.
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50
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Gironell A, Martínez-Corral M, Pagonabarraga X, Kulisevsky J. Tiagabine for essential tremor: an open-label trial. Mov Disord 2009; 23:1955-6. [PMID: 18759354 DOI: 10.1002/mds.22094] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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