1
|
Elble RJ, Ondo W. Tremor rating scales and laboratory tools for assessing tremor. J Neurol Sci 2022; 435:120202. [DOI: 10.1016/j.jns.2022.120202] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Revised: 08/08/2021] [Accepted: 02/17/2022] [Indexed: 12/29/2022]
|
2
|
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.
Collapse
Affiliation(s)
- Alexandre Gironell
- Movement Disorders Unit, Department of Neurology, Sant Pau Hospital, Autonomous University of Barcelona, Catalonia, Spain.
| |
Collapse
|
3
|
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.
Collapse
Affiliation(s)
- William George Ondo
- Movement Disorders-Methodist Neurological Institute, Weill Cornel Medical School, 6560 Fannin Suite 1002, Houston, TX 77025, USA.
| |
Collapse
|
4
|
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.
Collapse
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: ;
| |
Collapse
|
5
|
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.
Collapse
|
6
|
Khedr EM, El Fawal B, Abdelwarith A, Nasreldein A, Rothwell JC, Saber M. TMS excitability study in essential tremor: Absence of gabaergic changes assessed by silent period recordings. Neurophysiol Clin 2019; 49:309-315. [DOI: 10.1016/j.neucli.2019.05.065] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 05/15/2019] [Accepted: 05/15/2019] [Indexed: 10/26/2022] Open
|
7
|
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: 30] [Impact Index Per Article: 4.3] [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.
Collapse
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.
| |
Collapse
|
8
|
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.
Collapse
Affiliation(s)
- Elisa Bruno
- Department GF Ingrassia,Section of Neurosciences, University of Catania, Catania, Italy, 95123
| | | | | | | | | | | |
Collapse
|
9
|
Essential tremor: Update of therapeutic strategies (medical treatment and gamma knife thalamotomy). Rev Neurol (Paris) 2016; 172:408-415. [DOI: 10.1016/j.neurol.2016.07.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 07/06/2016] [Accepted: 07/25/2016] [Indexed: 11/18/2022]
|
10
|
Haubenberger D, Abbruzzese G, Bain PG, Bajaj N, Benito-León J, Bhatia KP, Deuschl G, Forjaz MJ, Hallett M, Louis ED, Lyons KE, Mestre TA, Raethjen J, Stamelou M, Tan EK, Testa CM, Elble RJ. Transducer-based evaluation of tremor. Mov Disord 2016; 31:1327-36. [PMID: 27273470 DOI: 10.1002/mds.26671] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 04/04/2016] [Accepted: 04/07/2016] [Indexed: 11/11/2022] Open
Abstract
The International Parkinson and Movement Disorder Society established a task force on tremor that reviewed the use of transducer-based measures in the quantification and characterization of tremor. Studies of accelerometry, electromyography, activity monitoring, gyroscopy, digitizing tablet-based measures, vocal acoustic analysis, and several other transducer-based methods were identified by searching PubMed.gov. The availability, use, acceptability, reliability, validity, and responsiveness were reviewed for each measure using the following criteria: (1) used in the assessment of tremor; (2) used in published studies by people other than the developers; and (3) adequate clinimetric testing. Accelerometry, gyroscopy, electromyography, and digitizing tablet-based measures fulfilled all three criteria. Compared to rating scales, transducers are far more sensitive to changes in tremor amplitude and frequency, but they do not appear to be more capable of detecting a change that exceeds random variability in tremor amplitude (minimum detectable change). The use of transducer-based measures requires careful attention to their limitations and validity in a particular clinical or research setting. © 2016 International Parkinson and Movement Disorder Society.
Collapse
Affiliation(s)
- Dietrich Haubenberger
- Clinical Trials Unit, Office of the Clinical Director, National Institutes of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA.
| | | | - Peter G Bain
- Department of Neurology, Imperial College London, Charing Cross Hospital, London, United Kingdom
| | - Nin Bajaj
- Department of Neurology, Nottingham University Hospitals NHS Trust, Nottingham, United Kingdom
| | - Julián Benito-León
- Department of Neurology, University Hospital "12 de Octubre", Madrid, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.,Department of Medicine, Complutense University, Madrid, Spain
| | - Kailash P Bhatia
- Sobell Department for Movement Neuroscience, UCL, Institute of Neurology, Queen Square, London, United Kingdom
| | - Günther Deuschl
- Department of Neurology, Christian-Albrechts-University Kiel, Kiel, Germany
| | - Maria João Forjaz
- National School of Public Health and Red de Investigación en Servicios Sanitarios y Enfermedades Crónicas (REDISSEC), Carlos III Institute of Health, Madrid, Spain
| | - Mark Hallett
- Human Motor Control Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Elan D Louis
- Departments of Neurology and Chronic Disease Epidemiology, Yale School of Medicine and Yale School of Public Health, Yale University, New Haven, Connecticut, USA
| | - Kelly E Lyons
- University of Kansas Medical Center, Kansas City, Kansas
| | - Tiago A Mestre
- Parkinson's disease and Movement Disorders Center, Division of Neurology, Department of Medicine, University of Ottawa, The Ottawa Hospital Research Institute, Ottawa Brain and Mind Research Institute, Ottawa, Ontario, Canada
| | - Jan Raethjen
- Department of Neurology, Christian-Albrechts-University Kiel, Kiel, Germany
| | - Maria Stamelou
- Neurology Department, University of Athens, Greece and Neurology Department, Philipps University, Marburg, Germany
| | - Eng-King Tan
- Department of Neurology, National Neuroscience Institute (SGH campus), Duke NUS Medical School, Singapore General Hospital, Singapore
| | - Claudia M Testa
- Department of Neurology and Parkinson's and Movement Disorders Center, Virginia Commonwealth University, Richmond, Virginia, USA
| | - Rodger J Elble
- Department of Neurology, Southern Illinois University School of Medicine, Springfield, Illinois, USA
| |
Collapse
|
11
|
Elble RJ, McNames J. Using Portable Transducers to Measure Tremor Severity. Tremor Other Hyperkinet Mov (N Y) 2016; 6:375. [PMID: 27257514 PMCID: PMC4872171 DOI: 10.7916/d8dr2vcc] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 03/23/2016] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND Portable motion transducers, suitable for measuring tremor, are now available at a reasonable cost. The use of these transducers requires knowledge of their limitations and data analysis. The purpose of this review is to provide a practical overview and example software for using portable motion transducers in the quantification of tremor. METHODS Medline was searched via PubMed.gov in December 2015 using the Boolean expression "tremor AND (accelerometer OR accelerometry OR gyroscope OR inertial measurement unit OR digitizing tablet OR transducer)." Abstracts of 419 papers dating back to 1964 were reviewed for relevant portable transducers and methods of tremor analysis, and 105 papers written in English were reviewed in detail. RESULTS Accelerometers, gyroscopes, and digitizing tablets are used most commonly, but few are sold for the purpose of measuring tremor. Consequently, most software for tremor analysis is developed by the user. Wearable transducers are capable of recording tremor continuously, in the absence of a clinician. Tremor amplitude, frequency, and occurrence (percentage of time with tremor) can be computed. Tremor amplitude and occurrence correlate strongly with clinical ratings of tremor severity. DISCUSSION Transducers provide measurements of tremor amplitude that are objective, precise, and valid, but the precision and accuracy of transducers are mitigated by natural variability in tremor amplitude. This variability is so great that the minimum detectable change in amplitude, exceeding random variability, is comparable for scales and transducers. Research is needed to determine the feasibility of detecting smaller change using averaged data from continuous long-term recordings with wearable transducers.
Collapse
Affiliation(s)
- Rodger J. Elble
- Department of Neurology, Southern Illinois University School of Medicine, Springfield, IL, USA
| | - James McNames
- Department of Electrical and Computer Engineering, Maseeh College of Engineering and Computer Science, Portland State University, Portland, OR, USA
| |
Collapse
|
12
|
Yang K, Xiong WX, Liu FT, Sun YM, Luo S, Ding ZT, Wu JJ, Wang J. Objective and quantitative assessment of motor function in Parkinson's disease-from the perspective of practical applications. ANNALS OF TRANSLATIONAL MEDICINE 2016; 4:90. [PMID: 27047949 DOI: 10.21037/atm.2016.03.09] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Parkinson's disease (PD) is a common neurodegenerative disorder with high morbidity because of the coming aged society. Currently, disease management and the development of new treatment strategies mainly depend on the clinical information derived from rating scales and patients' diaries, which have various limitations with regard to validity, inter-rater variability and continuous monitoring. Recently the prevalence of mobile medical equipment has made it possible to develop an objective, accurate, remote monitoring system for motor function assessment, playing an important role in disease diagnosis, home-monitoring, and severity evaluation. This review discusses the recent development in sensor technology, which may be a promising replacement of the current rating scales in the assessment of motor function of PD.
Collapse
Affiliation(s)
- Ke Yang
- Department & Institute of Neurology, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Wei-Xi Xiong
- Department & Institute of Neurology, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Feng-Tao Liu
- Department & Institute of Neurology, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Yi-Min Sun
- Department & Institute of Neurology, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Susan Luo
- Department & Institute of Neurology, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Zheng-Tong Ding
- Department & Institute of Neurology, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Jian-Jun Wu
- Department & Institute of Neurology, Huashan Hospital, Fudan University, Shanghai 200040, China
| | - Jian Wang
- Department & Institute of Neurology, Huashan Hospital, Fudan University, Shanghai 200040, China
| |
Collapse
|
13
|
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.
Collapse
Affiliation(s)
- William Ondo
- Methodist Neurological Institute, Houston, TX, USA
- *To whom correspondence should be addressed. E-mail:
| |
Collapse
|
14
|
Chalah MA, Lefaucheur JP, Ayache SS. Non-invasive Central and Peripheral Stimulation: New Hope for Essential Tremor? Front Neurosci 2015; 9:440. [PMID: 26635516 PMCID: PMC4649015 DOI: 10.3389/fnins.2015.00440] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 11/01/2015] [Indexed: 12/31/2022] Open
Abstract
Essential tremor (ET) is among the most frequent movement disorders. It usually manifests as a postural and kinematic tremor of the arms, but may also involve the head, voice, lower limbs, and trunk. An oscillatory network has been proposed as a neural correlate of ET, and is mainly composed of the olivocerebellar system, thalamus, and motor cortex. Since pharmacological agents have limited benefits, surgical interventions like deep brain stimulation are the last-line treatment options for the most severe cases. Non-invasive brain stimulation techniques, particularly transcranial magnetic or direct current stimulation, are used to ameliorate ET. Their non-invasiveness, along with their side effects profile, makes them an appealing treatment option. In addition, peripheral stimulation has been applied in the same perspective. Hence, the aim of the present review is to shed light on the emergent use of non-invasive central and peripheral stimulation techniques in this interesting context.
Collapse
Affiliation(s)
- Moussa A Chalah
- EA 4391, Excitabilité Nerveuse et Thérapeutique, Université Paris-Est-Créteil Créteil, France ; Service de Physiologie - Explorations Fonctionnelles, Hôpital Henri Mondor, Assistance Publique - Hôpitaux de Paris Créteil, France
| | - Jean-Pascal Lefaucheur
- EA 4391, Excitabilité Nerveuse et Thérapeutique, Université Paris-Est-Créteil Créteil, France ; Service de Physiologie - Explorations Fonctionnelles, Hôpital Henri Mondor, Assistance Publique - Hôpitaux de Paris Créteil, France
| | - Samar S Ayache
- EA 4391, Excitabilité Nerveuse et Thérapeutique, Université Paris-Est-Créteil Créteil, France ; Service de Physiologie - Explorations Fonctionnelles, Hôpital Henri Mondor, Assistance Publique - Hôpitaux de Paris Créteil, France ; Neurology Division, University Medical Center Rizk Hospital Beirut, Lebanon
| |
Collapse
|
15
|
Fasano A, Deuschl G. Therapeutic advances in tremor. Mov Disord 2015; 30:1557-65. [DOI: 10.1002/mds.26383] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 07/29/2015] [Indexed: 12/12/2022] Open
Affiliation(s)
- Alfonso Fasano
- Morton and Gloria Shulman Movement Disorders Clinic and the Edmond J. Safra Program in Parkinson's Disease, Toronto Western Hospital-UHN, Division of Neurology, University of Toronto; Toronto Ontario Canada
| | - Günther Deuschl
- Department of Neurology; Christian-Albrechts-University Kiel; Germany
| |
Collapse
|
16
|
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]
|
17
|
|
18
|
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.
Collapse
Affiliation(s)
- Alexandre Gironell
- Movement Disorders Unit, Department of Neurology, Sant Pau Hospital, Autonomous University of Barcelona, Catalonia, Spain
| |
Collapse
|
19
|
Abstract
Tremor is a hyperkinetic movement disorder characterized by rhythmic oscillations of one or more body parts. It can be disabling and may impair quality of life. Various etiological subtypes of tremor are recognized, with essential tremor (ET) and Parkinsonian tremor being the most common. Here we review the current literature on tremor treatment regarding ET and head and voice tremor, as well as dystonic tremor, orthostatic tremor, tremor due to multiple sclerosis (MS) or lesions in the brainstem or thalamus, neuropathic tremor, and functional (psychogenic) tremor, and summarize main findings. Most studies are available for ET and only few studies specifically focused on other tremor forms. Controlled trials outside ET are rare and hence most of the recommendations are based on a low level of evidence. For ET, propranolol and primidone are considered drugs of first choice with a mean effect size of approximately 50 % tremor reduction. The efficacy of topiramate is also supported by a large double-blind placebo-controlled trial, while other drugs have less supporting evidence. With a mean effect size of about 90 % deep brain stimulation in the nucleus ventralis intermedius or the subthalamic nucleus may be the most potent treatment; however, there are no controlled trials and it is reserved for severely affected patients. Dystonic limb tremor may respond to anticholinergics. Botulinum toxin improves head and voice tremor. Gabapentin and clonazepam are often recommended for orthostatic tremor. MS tremor responds only poorly to drug treatment. For patients with severe MS tremor, thalamic deep brain stimulation has been recommended. Patients with functional tremor may benefit from antidepressants and are best be treated in a multidisciplinary setting. Several tremor syndromes can already be treated with success. But new drugs specifically designed for tremor treatment are needed. ET is most likely covering different entities and their delineation may also improve treatment. Modern study designs and long-term studies are needed.
Collapse
Affiliation(s)
- Susanne A. Schneider
- Department of Neurology, Christian-Albrechts-University Kiel, University-Hospital Schleswig-Holstein, Campus Kiel, Schittenhelmstr. 10, 24105 Kiel, Germany
| | - Günther Deuschl
- Department of Neurology, Christian-Albrechts-University Kiel, University-Hospital Schleswig-Holstein, Campus Kiel, Schittenhelmstr. 10, 24105 Kiel, Germany
| |
Collapse
|
20
|
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.
Collapse
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
| | | |
Collapse
|
21
|
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.
Collapse
|