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Moon HC, Kim A, Park YS. Brain structure comparison among Parkinson disease, essential tremor, and healthy controls using 7T MRI. Medicine (Baltimore) 2024; 103:e38139. [PMID: 38728497 PMCID: PMC11081548 DOI: 10.1097/md.0000000000038139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 04/15/2024] [Indexed: 05/12/2024] Open
Abstract
Both Parkinson disease (PD) and Essential tremor (ET) are movement disorders causing tremors in elderly individuals. Although PD and ET are different disease, they often present with similar initial symptoms, making their differentiation challenging with magnetic resonance imaging (MRI) techniques. This study aimed to identify structural brain differences among PD, ET, and health controls (HCs) using 7-Tesla (T) MRI. We assessed the whole-brain parcellation in gray matter volume, thickness, subcortical volume, and small regions of basal ganglia in PD (n = 18), ET (n = 15), and HCs (n = 18), who were matched for age and sex. Brain structure analysis was performed automatic segmentation through Freesurfer software. Small regions of basal ganglia were manually segmented by ITK-SNAP. Additionally, we examined the associations between clinical indicators (symptom duration, unified Parkinson diseases rating scale (UPDRS), and clinical rating scale for tremor (CRST)) and brain structure. PD showed a significant reduction in gray matter volume in the postcentral region compared to ET. ET showed a significant reduction in cerebellum volume compared to HCs. There was a negative correlation between CRST scores (B and C) and gray matter thickness in right superior frontal in ET. This study demonstrated potential of 7T MRI in differentiating brain structure differences among PD, ET, and HCs. Specific findings, such as parietal lobe atrophy in PD compared to ET and cerebellum atrophy in ET compared to HCs, the importance of advanced imaging techniques in accurately diagnosing and distinguishing between movement disorders that present with similar initial symptoms.
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Affiliation(s)
- Hyeong Cheol Moon
- Department of Neurosurgery, Gamma Knife Icon Center, Chungbuk National University Hospital, Cheongju, Republic of Korea
| | - Aryun Kim
- Department of Neurology, Chungbuk National University Hospital, Chungbuk National University College of Medicine, Cheongju, Republic of Korea
| | - Young Seok Park
- Department of Neurosurgery, Gamma Knife Icon Center, Chungbuk National University Hospital, Cheongju, Republic of Korea
- Department of Neurosurgery, Chungbuk National University College of Medicine, Cheongju, Republic of Korea
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2
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Yoo SW, Ha S, Lyoo CH, Kim Y, Yoo JY, Kim JS. Exploring the link between essential tremor and Parkinson's disease. NPJ Parkinsons Dis 2023; 9:134. [PMID: 37714868 PMCID: PMC10504235 DOI: 10.1038/s41531-023-00577-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 09/04/2023] [Indexed: 09/17/2023] Open
Abstract
Epidemiological studies have reported a link between essential tremor (ET) and Parkinson's disease (PD). Recent studies have suggested ET as a possible neurodegenerative disease whose subgroup contained Lewy bodies in the brainstem, as in PD. PD with antedated ET (PDconv) might exhibit traits different from those of the pure form of ET or PD. This study aimed to unveil the interplay between PD and premorbid ET, which might be the core pathobiology that differentiates PDconv from PD. The study included 51 ET, 32 PDconv, and 95 PD patients who underwent positron emission tomography using 18F-N-(3-fluoropropyl)-2beta-carbon ethoxy-3beta-(4-iodophenyl) nortropane and 123I-meta-iodobenzylguanidine myocardial scintigraphy to analyze central dopaminergic and peripheral noradrenergic integrity. The results show that PDconv group followed the typical striatal pathology of PD but with a delay in noradrenergic impairment as it caught up with the denervating status of PD a few years after PD diagnosis. Whereas the two PD subtypes displayed similar patterns of presynaptic dopamine transporter deficits, ET patients maintained high densities in all subregions except thalamus. Presynaptic dopaminergic availability decreased in a linear or quadratic fashion across the three groups (ET vs. PDconv vs. PD). The age at onset and duration of ET did not differ between pure ET and PDconv patients and did not influence the striatal monoamine status. The myocardium in PDconv patients was initially less denervated than in PD patients, but it degenerated more rapidly. These findings suggest that PDconv could be a distinctive subclass in which the pathobiology of PD interacts with that of ET in the early phase of the disease.
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Affiliation(s)
- Sang-Won Yoo
- Department of Neurology, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Seunggyun Ha
- Division of Nuclear Medicine, Department of Radiology, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Chul Hyoung Lyoo
- Department of Neurology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Yuna Kim
- Department of Neurology, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Ji-Yeon Yoo
- Department of Neurology, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Joong-Seok Kim
- Department of Neurology, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea.
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Riboldi GM, Frucht SJ. Is essential tremor a family of diseases or a syndrome? A family of diseases. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2022; 163:7-29. [PMID: 35750371 DOI: 10.1016/bs.irn.2022.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
It is now well-established that essential tremor (ET) can manifest with different clinical presentations and progressions (i.e., upper limb tremor, head tremor, voice tremor, lower limb tremor, task- or position-specific tremor, or a combination of those). Common traits and overlaps are identifiable across these different subtypes of ET, including a slow rate of progression, a response to alcohol and a positive family history. At the same time, each of these manifestations are associated with specific demographic, clinical and treatment-response characteristics suggesting a family of diseases rather than a spectrum of a syndrome. Here we summarize the most important clinical, demographic, neuropathological and imagingfeatures of ET and of its subtypes to support ET as a family of identifiable conditions. This classification has relevance for counseling of patients with regard to disease progression and treatment response, as well as for the design of therapeutic clinical trials.
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Affiliation(s)
- Giulietta M Riboldi
- The Marlene and Paolo Fresco Institute for Parkinson's and Movement Disorders, New York University Langone Health, New York, NY, United States
| | - Steven J Frucht
- The Marlene and Paolo Fresco Institute for Parkinson's and Movement Disorders, New York University Langone Health, New York, NY, United States.
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4
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Cho HJ. Is essential tremor a degenerative or an electrical disorder? Electrical disorder. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2022; 163:103-128. [PMID: 35750360 DOI: 10.1016/bs.irn.2022.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Essential tremor (ET) is one of the most common movement disorders, yet we do not have a complete understanding of its pathophysiology. From a phenomenology standpoint, ET is an isolated tremor syndrome of bilateral upper limb action tremor with or without tremor in other body locations. ET is a pathological tremor that arises from excessive oscillation in the central motor network. The tremor network comprises of multiple brain regions including the inferior olive, cerebellum, thalamus, and motor cortex, and there is evidence that a dynamic oscillatory disturbance within this network leads to tremor. ET is a chronic disorder, and the natural history shows a slow progression of tremor intensity with age. There are reported data suggesting that ET follows the disease model of a neurodegenerative disorder, however whether ET is a degenerative or electrical disorder has been a subject of debate. In this chapter, we will review cumulative evidence that ET as a syndrome is a fundamentally electric disorder. The etiology is likely heterogenous and may not be primarily neurodegenerative.
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Affiliation(s)
- Hyun Joo Cho
- Human Motor Control Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States.
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5
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Pan MK, Kuo SH. Essential tremor: Clinical perspectives and pathophysiology. J Neurol Sci 2022; 435:120198. [PMID: 35299120 PMCID: PMC10363990 DOI: 10.1016/j.jns.2022.120198] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 12/01/2021] [Accepted: 02/17/2022] [Indexed: 12/12/2022]
Abstract
Essential tremor (ET) is one of the most common neurological disorders and can be highly disabling. In recent years, studies on the clinical perspectives and pathophysiology have advanced our understanding of ET. Specifically, clinical heterogeneity of ET, with co-existence of tremor and other neurological features such as dystonia, ataxia, and cognitive dysfunction, has been identified. The cerebellum has been found to be the key brain region for tremor generation, and structural alterations of the cerebellum have been extensively studied in ET. Finally, four main ET pathophysiologies have been proposed: 1) environmental exposures to β-carboline alkaloids and the consequent olivocerebellar hyper-excitation, 2) cerebellar GABA deficiency, 3) climbing fiber synaptic pathology with related cerebellar oscillatory activity, 4) extra-cerebellar oscillatory activity. While these four theories are not mutually exclusive, they can represent distinctive ET subtypes, indicating multiple types of abnormal brain circuitry can lead to action tremor. This article is part of the Special Issue "Tremor" edited by Daniel D. Truong, Mark Hallett, and Aasef Shaikh.
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Pascual-Valdunciel A, Rajagopal A, Pons JL, Delp S. Non-invasive electrical stimulation of peripheral nerves for the management of tremor. J Neurol Sci 2022; 435:120195. [PMID: 35220113 PMCID: PMC9590374 DOI: 10.1016/j.jns.2022.120195] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 12/06/2021] [Accepted: 02/17/2022] [Indexed: 12/22/2022]
Abstract
Pathological tremor in patients with essential tremor and Parkinsons disease is typically treated using medication or neurosurgical interventions. There is a widely recognized need for new treatments that avoid the side effects of current medications and do not carry the risks of surgical interventions. Building on decades of research and engineering development, non-invasive electrical stimulation of peripheral nerves has emerged as a safe and effective strategy for reducing pathologic tremor in essential tremor. This review surveys the peripheral electrical stimulation (PES) literature and summarizes effectiveness, safety, clinical translatability, and hypothesized tremor-reduction mechanisms of various PES approaches. The review also proposes guidelines for assessing tremor in the context of evaluating new therapies that combine the strengths of clinician assessments, patient evaluations, and novel motion sensing technology. The review concludes with a summary of future directions for PES, including expanding clinical access for patients with Parkinson's disease and leveraging large, at-home datasets to learn more about tremor physiology and treatment effect that will better characterize the state of tremor management and accelerate discovery of new therapies. Growing evidence suggests that non-invasive electrical stimulation of afferent neural pathways provides a viable new option for management of pathological tremor, with one specific PES therapy cleared for prescription and home use, suggesting that PES be considered along with medication and neurosurgical interventions for treatment of tremor. This article is part of the Special Issue "Tremor" edited by Daniel D. Truong, Mark Hallett, and Aasef Shaikh.
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Affiliation(s)
- Alejandro Pascual-Valdunciel
- Northwestern University, Evanston, IL, USA; E.T.S. Ingenieros de Telecomunicación, Universidad Politécnica de Madrid, Spain
| | | | - Jose L Pons
- Northwestern University, Evanston, IL, USA; Shirley Ryan AbilityLab, Chicago, IL, USA.
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Is essential tremor a degenerative disorder or an electric disorder? Degenerative disorder. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2022; 163:65-101. [PMID: 35750370 PMCID: PMC9846862 DOI: 10.1016/bs.irn.2022.02.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Essential tremor (ET) is a highly prevalent neurologic disease and is the most common of the many tremor disorders. ET is a progressive condition with marked clinical heterogeneity, associated with a spectrum of both motor and non-motor features. However, its disease mechanisms remain poorly understood. Much debate has centered on whether ET should be considered a degenerative disorder, with underlying pathological changes in brain causing progressive disease manifestations, or an electric disorder, with overactivity of intrinsically oscillatory motor networks that occur without underlying structural brain abnormalities. Converging data from clinical, neuroimaging and pathological studies in ET now provide considerable evidence for the neurodegenerative hypothesis. A major turning point in this debate is that rigorous tissue-based studies have recently identified a series of structural changes in the ET cerebellum. Most of these pathological changes are centered on the Purkinje cell and connected neuronal populations, which can result in partial loss of Purkinje cells and circuitry reorganizations that would disturb cerebellar function. There is significant overlap in clinical and pathological features of ET with other disorders of cerebellar degeneration, and an increased risk of developing other degenerative diseases in ET. The combined implication of these studies is that ET could be degenerative. The evidence in support of the degenerative hypothesis is presented.
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8
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Parkinsonism and tremor syndromes. J Neurol Sci 2021; 433:120018. [PMID: 34686357 DOI: 10.1016/j.jns.2021.120018] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 06/06/2021] [Accepted: 09/29/2021] [Indexed: 01/22/2023]
Abstract
Tremor, the most common movement disorder, may occur in isolation or may co-exist with a variety of other neurologic and movement disorders including parkinsonism, dystonia, and ataxia. When associated with Parkinson's disease, tremor may be present at rest or as an action tremor overlapping in phenomenology with essential tremor. Essential tremor may be associated not only with parkinsonism but other neurological disorders, suggesting the possibility of essential tremor subtypes. Besides Parkinson's disease, tremor can be an important feature of other parkinsonian disorders, such as atypical parkinsonism and drug-induced parkinsonism. In addition, tremor can be a prominent feature in patients with other movement disorders such as fragile X-associated tremor/ataxia syndrome, and Wilson's disease in which parkinsonian features may be present. This article is part of the Special Issue "Parkinsonism across the spectrum of movement disorders and beyond" edited by Joseph Jankovic, Daniel D. Truong and Matteo Bologna.
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9
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Louis ED, Huey ED, Cosentino S. Features of "ET plus" correlate with age and tremor duration: "ET plus" may be a disease stage rather than a subtype of essential tremor. Parkinsonism Relat Disord 2021; 91:42-47. [PMID: 34482193 DOI: 10.1016/j.parkreldis.2021.08.017] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Revised: 07/30/2021] [Accepted: 08/29/2021] [Indexed: 11/19/2022]
Abstract
BACKGROUND Essential tremor (ET) is characterized by considerable clinical heterogeneity. In 2018, the term "ET plus" was introduced to mark a potential stratification point for dividing ET into subtypes - ET vs ET plus (i.e., ET cases with neurological features other than action tremor). However, as ET progresses, patients often develop increasingly severe tremor, spread of tremor, tremor under different activation conditions, and other features. Given this situation, ET plus may represent a disease stage rather than a disease classification or subtype. In theory, if the defining characteristics of a disease subtype fluctuate with age or disease duration, it raises the distinct possibility the "subtype" is a disease stage. METHODS A cohort of 241 prospectively enrolled ET cases underwent a detailed motor and cognitive assessment in which the features of ET plus including cerebellar signs (intention tremor, tandem gait difficulty), rest tremor, dystonia, and cognitive performance were evaluated. We determined whether these features of ET plus correlated with action tremor duration and age. RESULTS We demonstrated that numerous ET plus features were significantly correlated with both age and action tremor duration (numerous p values < 0.05). The same relationships were observed in a series of sensitivity analyses. CONCLUSION We observed that the component parts of ET plus are highly age- and stage-dependent. These features are yearly-changing features conditional on a demographic and disease stage variable. These data support the notion that ET plus may represent a disease stage rather than a distinct disease subtype or disease classification.
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Affiliation(s)
- Elan D Louis
- University of Texas Southwestern Medical Center, Dallas, TX, USA.
| | - Edward D Huey
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, College of Physicians and Surgeons, Columbia University, New York, NY, USA; Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, USA; Department of Psychiatry, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Stephanie Cosentino
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, College of Physicians and Surgeons, Columbia University, New York, NY, USA; Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
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10
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Kim SH, Farrell K, Cosentino S, Vonsattel JPG, Faust PL, Cortes EP, Bennet DA, Louis ED, Crary JF. Tau Isoform Profile in Essential Tremor Diverges From Other Tauopathies. J Neuropathol Exp Neurol 2021; 80:835-843. [PMID: 34363663 DOI: 10.1093/jnen/nlab073] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Patients with essential tremor (ET) frequently develop concurrent dementia, which is often assumed to represent co-morbid Alzheimer disease (AD). Autopsy studies have identified a spectrum of tau pathologies in ET and tau isoforms have not been examined in ET. We performed immunoblotting using autopsy cerebral cortical tissue from patients with ET (n = 13), progressive supranuclear palsy ([PSP], n = 10), Pick disease ([PiD], n = 2), and AD (n = 7). Total tau in ET samples was similar to that in PSP and PiD but was significantly lower than that in AD. Abnormal tau levels measured using the AT8 phospho-tau specific (S202/T205/S208) monoclonal antibody in ET were similar to those in PSP but were lower than in PiD and AD. In aggregates, tau with 3 microtubule-binding domain repeats (3R) was significantly higher in AD than ET, while tau with 4 repeats (4R) was significantly higher in PSP. Strikingly, the total tau without N-terminal inserts in ET was significantly lower than in PSP, PiD, and AD, but total tau with other N-terminal inserts was not. Monomeric tau with one insert in ET was similar to that in PSP and PiD was lower than in AD. Thus, ET brains exhibit an expression profile of tau protein isoforms that diverges from that of other tauopathies.
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Affiliation(s)
- Soong Ho Kim
- From the Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, New York, USA (SHK, KF, EC, JFC).,Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York, USA (SHK, JFC).,Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA (SHK, KF, EC, JFC).,Ronald M. Loeb Center for Alzheimer's Disease, Icahn School of Medicine at Mount Sinai, New York, New York, USA (SHK, KF, EC, JFC)
| | - Kurt Farrell
- From the Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, New York, USA (SHK, KF, EC, JFC).,Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA (SHK, KF, EC, JFC).,Ronald M. Loeb Center for Alzheimer's Disease, Icahn School of Medicine at Mount Sinai, New York, New York, USA (SHK, KF, EC, JFC)
| | - Stephanie Cosentino
- Cognitive Neuroscience Division, Department of Neurology, Columbia University Medical Center, New York, New York, USA (SC); G.H. Sergievsky Center, Columbia University Medical Center, New York, New York, USA (SC, JPV).,Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, New York, USA (SC, JPV)
| | - Jean-Paul G Vonsattel
- Cognitive Neuroscience Division, Department of Neurology, Columbia University Medical Center, New York, New York, USA (SC); G.H. Sergievsky Center, Columbia University Medical Center, New York, New York, USA (SC, JPV).,Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, New York, USA (SC, JPV).,Department of Pathology & Cell Biology, Columbia University Medical Center and the New York Presbyterian Hospital, New York, New York, USA (JPV, PLF)
| | - Phyllis L Faust
- Department of Pathology & Cell Biology, Columbia University Medical Center and the New York Presbyterian Hospital, New York, New York, USA (JPV, PLF)
| | - Etty P Cortes
- From the Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, New York, USA (SHK, KF, EC, JFC).,Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA (SHK, KF, EC, JFC).,Ronald M. Loeb Center for Alzheimer's Disease, Icahn School of Medicine at Mount Sinai, New York, New York, USA (SHK, KF, EC, JFC).,Neuropathology Brain Bank & Research CoRE, Icahn School of Medicine at Mount Sinai, New York, New York, USA (EC, JFC)
| | - David A Bennet
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, Illinois, USA (DAB)
| | - Elan D Louis
- Department of Neurology, University of Texas Southwestern, Dallas, Texas, USA (EDL)
| | - John F Crary
- From the Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, New York, USA (SHK, KF, EC, JFC).,Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York, USA (SHK, JFC).,Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA (SHK, KF, EC, JFC).,Ronald M. Loeb Center for Alzheimer's Disease, Icahn School of Medicine at Mount Sinai, New York, New York, USA (SHK, KF, EC, JFC).,Neuropathology Brain Bank & Research CoRE, Icahn School of Medicine at Mount Sinai, New York, New York, USA (EC, JFC)
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11
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Louis ED. The Essential Tremors: Evolving Concepts of a Family of Diseases. Front Neurol 2021; 12:650601. [PMID: 33841316 PMCID: PMC8032967 DOI: 10.3389/fneur.2021.650601] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 02/12/2021] [Indexed: 12/31/2022] Open
Abstract
The past 10 years has seen a remarkable advance in our understanding of the disease traditionally referred to as “essential tremor” (ET). First, the clinical phenotype of ET has been expanded from that of a bland, unidimensional, and monosymptomatic entity to one with a host of heterogeneous features. These features include a broader and more nuanced collection of tremors, non-tremor motor features (e.g., gait abnormalities) and a range of non-motor features, including cognitive, psychiatric, sleep, and other abnormalities. The natural history of these features, as well as their relationships with one another and with disease duration and severity, are better appreciated than they were previously. Studies of disease etiology have identified a number of candidate genes as well as explored several environmental determinants of disease. In addition, the decade has seen the beginnings and expansion of rigorous postmortem studies that have identified and described the postmortem changes in the brains of patients with ET. This emerging science has given rise to a new notion that the disease, in many cases, is one of cerebellar system degeneration. Across all of these studies (clinical, etiological, and pathophysiological) is the observation that there is heterogeneity across patients and that “essential tremor” is likely not a single disease but, rather, a family of diseases. The time has come to use the more appropriate terminology, “the essential tremors,” to fully describe and encapsulate what is now apparent. In this paper, the author will review the clinical, etiological, and pathophysiological findings, referred to above, and make the argument that the terminology should evolve to reflect advances in science and that “the essential tremors” is a more scientifically appropriate term.
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Affiliation(s)
- Elan D Louis
- Department of Neurology, University of Texas Southwestern, Dallas, TX, United States
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12
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Chiu SY, Nozile-Firth K, Klassen BT, Adams A, Lee K, Van Gompel JJ, Hassan A. Ataxia and tolerance after thalamic deep brain stimulation for essential tremor. Parkinsonism Relat Disord 2020; 80:47-53. [PMID: 32950784 DOI: 10.1016/j.parkreldis.2020.09.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 09/03/2020] [Accepted: 09/07/2020] [Indexed: 10/23/2022]
Abstract
BACKGROUND Deep brain stimulation (DBS) of the ventral intermediate nucleus (VIM) thalamus is highly effective to treat medication-refractory essential tremor (ET). Complications of stimulation-induced ataxia and tolerance have been reported in limited series, ranging from 5 to 40%. OBJECTIVE We analyzed a large single-center cohort of ET patients treated with thalamic DBS to assess rates of ataxia and tolerance. METHODS Retrospective study of all ET patients that underwent VIM DBS at Mayo Clinic from 2010 to 2014. Demographic, clinical and DBS data were extracted. Risk factors, complications and time to onset of tolerance and ataxia were examined. RESULTS One hundred and thirteen ET patients (51% male) of mean age 68 ± 10 years and mean ET duration 27 ± 18 years underwent DBS during the study period. Of these, 98 (87%) had follow-up of ≥6 months (mean 4.0 ± 1.5 years) and were included for analysis. Complications of isolated ataxia (26%), isolated tolerance (4%), both tolerance and ataxia (9%), or neither (61%) were identified. Development of ataxia was about 3 times more common than tolerance (35% vs. 13%). The mean time to ataxia was 5.5 ± 0.3 years postoperatively. Risk factors for ataxia were baseline ataxic features, older age, and shorter ET disease duration. Small sample size limited calculation of risk factors and onset time for tolerance. CONCLUSIONS Stimulation-related ataxia occurred in one-third of ET patients, while tolerance was less common. Presence of baseline ataxia, age, and disease duration may aid counseling of stimulation-related ataxia risk. Larger studies are warranted to confirm these findings and further assess risk factors for tolerance.
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Affiliation(s)
- Shannon Y Chiu
- Department of Neurology, Mayo Clinic, Rochester, MN, USA; Department of Neurology, University of Florida, Gainesville, FL, USA.
| | | | | | - Andrea Adams
- Department of Neurology, Mayo Clinic, Rochester, MN, USA
| | - Kendall Lee
- Department of Neurosurgery, Mayo Clinic, Rochester, MN, USA
| | | | - Anhar Hassan
- Department of Neurology, Mayo Clinic, Rochester, MN, USA
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Qi S, Cao H, Wang R, Jian Z, Bian Y, Yang J. Relative increase in cerebellar gray matter in young onset essential tremor: Evidence from voxel-based morphometry analysis. J Clin Neurosci 2020; 79:251-256. [PMID: 33070906 DOI: 10.1016/j.jocn.2020.07.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Accepted: 07/02/2020] [Indexed: 02/01/2023]
Abstract
This study is to investigate the presence of brain gray matter abnormalities in young onset essential tremor (ET) patients with arm tremor. Thirty ET patients together with 30 healthy volunteers were taken as candidates. Magnetic resonance imaging (MRI) was performed and voxel-based morphometry was used to compare gray matter density between the patients and volunteers. Washington Heights-Inwood Genetic Study of Essential Tremor (WHIGET) rating scale was applied to assess tremor severity in the patients. Eventually Twenty-Seven ET patients and Twenty-Seven volunteers were enrolled in the study. Voxel-based morphometry showed significant expansion of the bilateral cerebellum, occipital fusiform cortices, right inferior temporal gyrus, and precentral lobes (P < 0.05, TFCE corrected). Decrease in gray matter was detected only in the left parietal lobe. Region of interest analysis showed volume enlargement in thalamus, midbrain, and precuneus (P < 0.05, TFCE corrected). Importantly, significant negative correlation was found between the lateralized index of cerebellum and the tremor score which might implicate that the altered rightward lateralization in the cerebellum is possibly a response of the tremor effects in ET patients. Cerebellar gray matter expansion in young onset ET patients with arm tremor might be the result of compensation towards decline of cerebellar function.
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Affiliation(s)
- Shun Qi
- Department of Radiology, The First Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an 710061, PR China; Center for Brain Science and Intelligence Technology, Xi'an Jiaotong University, Xi'an 710061, PR China
| | - Hongmei Cao
- Department of Neurology, The First Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an 710061, PR China
| | - Rong Wang
- Department of Radiology, The First Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an 710061, PR China
| | - Zhijie Jian
- Department of Radiology, The First Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an 710061, PR China
| | - Yitong Bian
- Department of Radiology, The First Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an 710061, PR China
| | - Jian Yang
- Department of Radiology, The First Affiliated Hospital of Medical College, Xi'an Jiaotong University, Xi'an 710061, PR China; Department of Biomedical Engineering, The Key Laboratory of Biomedical Information Engineering of the Ministry of Education, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, PR China.
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14
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Huang H, Yang X, Zhao Q, Ning P, Shen Q, Wang H, Xie D, Lu H, Xu Y. Clinical characteristics of patients with essential tremor or essential tremor plus. Acta Neurol Scand 2020; 141:335-341. [PMID: 31863462 DOI: 10.1111/ane.13209] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 12/16/2019] [Accepted: 12/17/2019] [Indexed: 02/05/2023]
Abstract
BACKGROUND The International Parkinson and Movement Disorder Society introduced the category of essential tremor (ET)-plus in its new ET classification scheme, but how the clinical correlates of ET-plus differ from those of "pure" ET is unclear. By comparing the clinical characteristics of ET and ET-plus patients, we expect to better understand the impact and invoked questions of the new classification on clinical practice. METHODS We reviewed the medical records of 280 ET syndrome patients in an ongoing cross-sectional study in a Chinese population and reclassified them according to the new criteria. Clinico-demographic characteristics were compared between ET and ET-plus patients. Risk factors of diagnosis of ET-plus were explored using logistic regression. RESULTS A total of 121 patients (50.8%) were reclassified as having ET and 117 as having ET-plus. ET-plus group was significantly older at tremor onset, less educated, and more likely to have cranial tremor, depression symptom, anxiety symptom, and probable REM sleep behavior disorder. ET-plus group also showed more severe upper limb tremor and cognition impairment. Regression analysis identified four independent risk factors associated with ET-plus: late tremor onset (OR 3.04, 95%CI 1.60-5.79), less educated (OR 0.91, 95%CI 0.85-0.97), severe upper limb tremor (OR 2.46, 95%CI 1.30-4.62), and presence of cranial tremor (OR 2.30, 95%CI 1.20-4.41). CONCLUSIONS The new classification scheme emphasized that ET syndrome is heterogeneous. ET-plus cannot be seen as a subtype or a diagnosis of ET syndrome, but rather as a placeholder, representing an area of current scientific uncertainty.
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Affiliation(s)
- Hongyan Huang
- Department of Neurology West China Hospital Sichuan University Chengdu China
| | - Xinglong Yang
- Department of Geriatric Neurology First Affiliated Hospital of Kunming Medical University Kunming China
| | - Quanzhen Zhao
- Department of Neurology West China Hospital Sichuan University Chengdu China
| | - Pingping Ning
- Department of Neurology West China Hospital Sichuan University Chengdu China
| | - Qiuyan Shen
- Department of Neurology West China Hospital Sichuan University Chengdu China
| | - Hui Wang
- Department of Neurology West China Hospital Sichuan University Chengdu China
| | - Dan Xie
- Department of Neurology West China Hospital Sichuan University Chengdu China
| | - Haitao Lu
- Department of Neurology West China Hospital Sichuan University Chengdu China
| | - Yanming Xu
- Department of Neurology West China Hospital Sichuan University Chengdu China
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15
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Essential tremor pathology: neurodegeneration and reorganization of neuronal connections. Nat Rev Neurol 2020; 16:69-83. [PMID: 31959938 DOI: 10.1038/s41582-019-0302-1] [Citation(s) in RCA: 92] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/10/2019] [Indexed: 01/26/2023]
Abstract
Essential tremor (ET) is the most common tremor disorder globally and is characterized by kinetic tremor of the upper limbs, although other clinical features can also occur. Postmortem studies are a particularly important avenue for advancing our understanding of the pathogenesis of ET; however, until recently, the number of such studies has been limited. Several recent postmortem studies have made important contributions to our understanding of the pathological changes that take place in ET. These studies identified abnormalities in the cerebellum, which primarily affected Purkinje cells (PCs), basket cells and climbing fibres, in individuals with ET. We suggest that some of these pathological changes (for example, focal PC axonal swellings, swellings in and regression of the PC dendritic arbor and PC death) are likely to be primary and degenerative. By contrast, other changes, such as an increase in PC recurrent axonal collateral formation and hypertrophy of GABAergic basket cell axonal processes, could be compensatory responses to restore cerebellar GABAergic tone and cerebellar cortical inhibitory efficacy. Such compensatory responses are likely to be insufficient, enabling the disease to progress. Here, we review the results of recent postmortem studies of ET and attempt to place these findings into an anatomical-physiological disease model.
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16
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Becktepe JS, Gövert F, Kasiske L, Yalaz M, Witt K, Deuschl G. Pupillary response to light and tasks in early and late onset essential tremor patients. Parkinsonism Relat Disord 2019; 66:62-67. [PMID: 31327629 DOI: 10.1016/j.parkreldis.2019.07.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 05/23/2019] [Accepted: 07/05/2019] [Indexed: 01/22/2023]
Abstract
INTRODUCTION Late-onset essential tremor is characterised by shorter life expectancy and more advanced aging parameters and may therefore be an 'aging-related' tremor. Brainstem functions involved in pupillary responses are hypothesized to reflect such earlier aging. The pupillary light response (PLR) and a task evoked pupillary response (TEPR) were used to test this hypothesis in same-aged patients with early onset (EOET) and late onset (LOET) essential tremor and healthy controls. SUBJECTS AND METHODS Age related changes of the PLR and TEPR during the paced auditory serial addition test (PASAT) were tested in 57 normal subjects. Subsequently, 13 patients with LOET and 16 patients with EOET were compared with 15 age matched healthy controls. Standard parameters of PLR were recorded, amongst others the time to maximum acceleration of the PLR (T1) and the time to maximum velocity (T2). The TEPR was determined during the PASAT as the percentage change in pupil size (PCPS). Data were analysed with ANOVA and post-hoc testing. RESULTS In normal subjects the pupil diameter, latency, maximum acceleration/velocity and percentage amplitude were correlated with age. Latency of the pupillary light response was significantly longer in LOET compared to controls and EOET while no differences were found between EOET and controls. The TEPR showed no significant differences between the three groups. CONCLUSION LOET showed a prolonged latency of the PLR compared to EOET possibly indicating premature aging or rather pathophysiological differences on brainstem level. This study further supports the hypothesis of abnormal aging in LOET.
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Affiliation(s)
- Jos S Becktepe
- Department of Neurology, University Hospital Schleswig Holstein, 24105, Kiel, Germany
| | - Felix Gövert
- Department of Neurology, University Hospital Schleswig Holstein, 24105, Kiel, Germany
| | - Lisa Kasiske
- Department of Neurology, University Hospital Schleswig Holstein, 24105, Kiel, Germany
| | - Mevlüt Yalaz
- Department of Neurology, University Hospital Schleswig Holstein, 24105, Kiel, Germany
| | - Karsten Witt
- Department of Neurology, University Hospital Schleswig Holstein, 24105, Kiel, Germany; Department of Neurology and Research Center Neurosensory Science, Carl von Ossietzky University, 26122, Oldenburg, Germany
| | - Günther Deuschl
- Department of Neurology, University Hospital Schleswig Holstein, 24105, Kiel, Germany.
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17
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Meng Y, Solomon B, Boutet A, Llinas M, Scantlebury N, Huang Y, Hynynen K, Hamani C, Fasano A, Lozano AM, Lipsman N, Schwartz ML. Magnetic resonance-guided focused ultrasound thalamotomy for treatment of essential tremor: A 2-year outcome study. Mov Disord 2018; 33:1647-1650. [PMID: 30288794 DOI: 10.1002/mds.99] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 06/19/2018] [Accepted: 06/25/2018] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND Magnetic resonance-guided focused ultrasound is an emerging, minimally invasive thermoablation technique for medically refractory essential tremor. Beyond the initial year, data regarding efficacy and potential predictors of efficacy are still preliminary. OBJECTIVES The objective of this study was to assess the outcome at 2 years and the association between lesion volume and outcome 1 year after treatment. METHODS We reviewed data from 37 patients who underwent unilateral magnetic resonance-guided focused ultrasound thalamotomy, with primary outcome being dominant tremor subscore of the Clinical Rating Scale for Tremor. We used multivariable linear regression to model initial lesion volume with 1-year outcome, adjusting for other clinically relevant variables. RESULTS Although we detected a trend in loss of clinical benefit within the first year, the dominant tremor score at 2 years continued to be significantly improved (43.4%, 95% confidence interval 27.8%-59.0%) from baseline. Secondarily, initial lesion volume is significantly associated with 1-year outcome. CONCLUSION Our findings show that magnetic resonance-guided focused ultrasound thalamotomy results in sustained tremor reduction for medically refractory essential tremor even in the long term, and we highlight areas for improvement.
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Affiliation(s)
- Ying Meng
- Division of Neurosurgery, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
| | - Benjamin Solomon
- Division of Neurosurgery, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
| | - Alexandre Boutet
- Division of Neurosurgery, Toronto Western Hospital, Toronto, Ontario, Canada
| | - Maheleth Llinas
- Division of Neurosurgery, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.,Division of Neurosurgery, Toronto Western Hospital, Toronto, Ontario, Canada
| | - Nadia Scantlebury
- Division of Neurosurgery, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
| | - Yuexi Huang
- Sunnybrook Research Institute, Toronto, Ontario, Canada
| | | | - Clement Hamani
- Division of Neurosurgery, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.,Sunnybrook Research Institute, Toronto, Ontario, Canada
| | - Alfonso Fasano
- Edmond J. Safra Program in Parkinson's Disease, Morton and Gloria Shulman Movement Disorders Clinic, Toronto Western Hospital, University Health Network, Toronto, Ontario, Canada.,Division of Neurology, University of Toronto, Toronto, Ontario, Canada.,Krembil Research Institute, Toronto, Ontario, Canada
| | - Andres M Lozano
- Division of Neurosurgery, Toronto Western Hospital, Toronto, Ontario, Canada.,Krembil Research Institute, Toronto, Ontario, Canada
| | - Nir Lipsman
- Division of Neurosurgery, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.,Sunnybrook Research Institute, Toronto, Ontario, Canada
| | - Michael L Schwartz
- Division of Neurosurgery, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
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18
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Cao H, Wang R, Luo X, Li X, Hallett M, Thompson-Westra J, Yang J, Qu Q, Yang X. A Voxel-Based Magnetic Resonance Imaging Morphometric Study of Cerebral and Cerebellar Gray Matter in Patients Under 65 Years with Essential Tremor. Med Sci Monit 2018; 24:3127-3135. [PMID: 29754151 PMCID: PMC5973500 DOI: 10.12659/msm.906437] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2017] [Accepted: 11/02/2017] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND The aim of this study was to compare the morphological changes in cerebral and cerebellar gray matter in patients with essential tremor under 60-years-of-age, with age-matched and gender-matched normal healthy volunteer control subjects, using functional magnetic resonance imaging (fMRI) and voxel-based morphometry (VBM) analysis. MATERIAL AND METHODS A retrospective, controlled, comparative clinical study included 17 patients with essential tremor, <60 years-of-age, and 17 age-matched and gender-matched healthy volunteer control subjects, recruited between June 2010-July 2012. MRI and VBM analysis were used to compare cerebral and cerebellar gray matter density between groups. The Washington Heights-Inwood Genetic Study of Essential Tremor (WHIGET) rating scale was used to assess tremor severity in the patient group. Clinical and demographic characteristics were recorded for all study participants. RESULTS MRI and VBM analysis showed significant bilateral expansion of the cerebellum, occipital fusiform cortices, right inferior temporal gyrus, and precentral lobes in patients with essential tremor (P<0.005); reduction in gray matter was found in the left parietal lobe. The region of interest (ROI) analysis showed volume enlargement in the thalamus, midbrain, and the precuneus (P<0.005). No significant correlation between changes in gray matter and changes in clinical variables, including age, gender, tremor duration, the activity of daily living (ADL) scale, the mini-mental state examination (MMSE) scale, family history, and tremor severity were found. CONCLUSIONS Predominantly cerebellar gray matter expansion in patients less than 60 years-of-age with essential tremor might be the result of compensation for the decline in cerebellar function.
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Affiliation(s)
- Hongmei Cao
- Department of Neurology, The First Affiliated Hospital of Medical College, Xi’an Jiaotong University, Xi’an, Shaanxi, P.R. China
| | - Rong Wang
- Department of Radiology, The First Affiliated Hospital of Medical College, Xi’an Jiaotong University, Xi’an, Shaanxi, P.R. China
| | - Xue Luo
- Department of Radiology, The First Affiliated Hospital of Medical College, Xi’an Jiaotong University, Xi’an, Shaanxi, P.R. China
- Department of Biomedical Engineering, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an, Shaanxi, P.R. China
| | - Xianjun Li
- Department of Radiology, The First Affiliated Hospital of Medical College, Xi’an Jiaotong University, Xi’an, Shaanxi, P.R. China
- Department of Biomedical Engineering, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an, Shaanxi, P.R. China
| | - Mark Hallett
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, U.S.A
| | - Johanna Thompson-Westra
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, U.S.A
| | - Jian Yang
- Department of Radiology, The First Affiliated Hospital of Medical College, Xi’an Jiaotong University, Xi’an, Shaanxi, P.R. China
- Department of Biomedical Engineering, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an, Shaanxi, P.R. China
| | - Qiumin Qu
- Department of Neurology, The First Affiliated Hospital of Medical College, Xi’an Jiaotong University, Xi’an, Shaanxi, P.R. China
| | - Xiaobo Yang
- Department of Psychology, The First Affiliated Hospital of Medical College, Xi’an Jiaotong University, Xi’an, Shaanxi, P.R. China
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19
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Geiger DW, Eggett DL, Charles SK. A method for characterizing essential tremor from the shoulder to the wrist. Clin Biomech (Bristol, Avon) 2018; 52:117-123. [PMID: 29428341 DOI: 10.1016/j.clinbiomech.2017.12.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 10/14/2017] [Accepted: 12/08/2017] [Indexed: 02/07/2023]
Abstract
BACKGROUND Despite the pervasive and devastating effect of Essential Tremor (ET), the distribution of ET throughout the upper limb is unknown. We developed a method for characterizing the distribution of ET and performed a preliminary characterization in a small number of subjects with ET. METHODS Using orientation sensors and inverse kinematics, we measured tremor in each of the seven major degrees of freedom (DOF) from the shoulder to the wrist while ten patients with mild ET assumed 16 different postures. We described the tremor in each DOF in terms of power spectral density measures and investigated how tremor varied between DOF, postures, gravitational torques, and repetitions. FINDINGS Our method successfully resulted in tremor measures in each DOF, allowing one to compare tremor between DOF and determine the distribution of tremor throughout the upper limb, including how the distribution changes with posture. In our small number of subjects, we found that the amount of power in the frequency band associated with ET (4-12Hz) was lowest in the shoulder and greatest in the wrist. Similarly, the existence and amplitude of peaks in this band increased from proximal to distal. Although the amount of tremor differed significantly between postures, we did not find any clear patterns with changes in posture or gravitational torque. INTERPRETATION This method can be used to characterize the distribution of tremor throughout the upper limb. Our preliminary characterization suggests that the amount of tremor increases in a proximal-distal manner.
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Affiliation(s)
- Daniel W Geiger
- Department of Mechanical Engineering, Brigham Young University, 435 CTB, Provo, UT 84602, United States
| | - Dennis L Eggett
- Department of Statistics, Brigham Young University, 223 TMCB, Provo, UT 84602, United States
| | - Steven K Charles
- Department of Mechanical Engineering, Brigham Young University, 435 CTB, Provo, UT 84602, United States; Neuroscience Center, Brigham Young University, S-192 ESC, Provo, UT 84602, United States.
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20
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Hopfner F, Ahlf A, Lorenz D, Klebe S, Zeuner KE, Kuhlenbäumer G, Deuschl G. Early- and late-onset essential tremor patients represent clinically distinct subgroups. Mov Disord 2017; 31:1560-1566. [PMID: 27384030 DOI: 10.1002/mds.26708] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 05/14/2016] [Accepted: 05/30/2016] [Indexed: 12/13/2022] Open
Abstract
OBJECTIVE Essential tremor is a very common disease defined by sparse clinical criteria. It is unlikely that essential tremor is an etiologically homogeneous disease. Stratifying broadly defined diseases using clinical characteristics has often aided the etiopathological understanding. Most studies of essential tremor show 2 distinct age at onset peaks: early and late. This study investigates phenotypical differences between early- and late-onset essential tremor patients. METHODS We studied a sample of 1137 tremor patients. Of these patients, 978 suffered from definite or probable essential tremor. All of the patients underwent the same standardized examination encompassing, among other items, drawing of the Archimedes spiral and assessment of the Fahn-Tolosa-Marin scale. RESULTS Two subgroups of early-onset (≤ 24 years of age, n = 317) and late-onset (≥ 46 years of age, n = 356) patients were selected based on the visual and mathematical analysis of the age-at-onset distribution. Tremor severity in both groups was comparable. Tremor progression measured as Archimedes spiral score and the Fahn-Tolosa-Marin subscales divided by the disease duration in 10-year bins was significantly faster in late-onset patients when compared with early-onset patients. Early-onset patients more frequently reported a positive family history and alcohol sensitivity of the tremor. CONCLUSIONS The age-at-onset distribution suggests a distinction between early- and late-onset tremor. Early-onset and late-onset essential tremor differ in the progression rates and the frequencies of a positive family history and history of a positive effect of alcohol on tremor. © 2016 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Franziska Hopfner
- Department of Neurology, University Hospital Schleswig Holstein, Kiel, Germany
| | - Anjuli Ahlf
- Department of Neurology, University Hospital Schleswig Holstein, Kiel, Germany
| | - Delia Lorenz
- Department of Neurology, University Hospital Schleswig Holstein, Kiel, Germany
| | - Stephan Klebe
- Department of Neurology, University Hospital of Freiburg, Freiburg, Germany
| | - Kirsten E Zeuner
- Department of Neurology, University Hospital Schleswig Holstein, Kiel, Germany
| | - Gregor Kuhlenbäumer
- Department of Neurology, University Hospital Schleswig Holstein, Kiel, Germany
| | - Günther Deuschl
- Department of Neurology, University Hospital Schleswig Holstein, Kiel, Germany.
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21
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Louis ED. The evolving definition of essential tremor: What are we dealing with? Parkinsonism Relat Disord 2017; 46 Suppl 1:S87-S91. [PMID: 28747280 DOI: 10.1016/j.parkreldis.2017.07.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 07/06/2017] [Accepted: 07/07/2017] [Indexed: 11/18/2022]
Abstract
BACKGROUND Although essential tremor (ET) is commonly encountered in clinical practice, historically, there has been considerable disagreement as how to best define it, and now with a growing sense of its clinical complexity, how to best encapsulate it. Here, I draw attention to five issues of current uncertainty. METHODS A PubMed search conducted on June 19, 2017 crossed "essential tremor" with 9 second search terms (e.g., definition, diagnosis). RESULTS There are several major issues of clinical and diagnostic uncertainty. Underlying each issue is a larger question about the nature of the underlying pathophysiology of ET. Does age of onset of ET matter? How much dystonia is acceptable in ET? How much in the way of "cerebellar signs" are acceptable? Are non-motor features due to the underlying disease or merely secondary to the clinical features? Is ET a single disease entity or something else? CONCLUSIONS We are learning more about ET and, as a by-product of these efforts, are struggling with its definition. Further understanding the nature of the underlying disease pathogenesis as well as the role the cerebellum and cerebellar relays play in this process will likely provide important clues to enable us to bring order to areas of uncertainty.
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Affiliation(s)
- Elan D Louis
- Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, USA; Department of Chronic Disease Epidemiology, Yale School of Public Health, Yale University, New Haven, CT, USA; Center for Neuroepidemiology and Clinical Neurological Research, Yale School of Medicine, Yale University, New Haven, CT, USA.
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22
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Buhmann C, Huckhagel T, Engel K, Gulberti A, Hidding U, Poetter-Nerger M, Goerendt I, Ludewig P, Braass H, Choe CU, Krajewski K, Oehlwein C, Mittmann K, Engel AK, Gerloff C, Westphal M, Köppen JA, Moll CKE, Hamel W. Adverse events in deep brain stimulation: A retrospective long-term analysis of neurological, psychiatric and other occurrences. PLoS One 2017; 12:e0178984. [PMID: 28678830 PMCID: PMC5497949 DOI: 10.1371/journal.pone.0178984] [Citation(s) in RCA: 88] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Accepted: 05/22/2017] [Indexed: 11/18/2022] Open
Abstract
Background and objective The extent to which deep brain stimulation (DBS) can improve quality of life may be perceived as a permanent trade-off between neurological improvements and complications of therapy, comorbidities, and disease progression. Patients and methods We retrospectively investigated 123 consecutive and non-preselected patients. Indications for DBS surgery were Parkinson's disease (82), dystonia (18), tremor of different etiology (21), Huntington's disease (1) and Gilles de la Tourette syndrome (1). AEs were defined as any untoward clinical occurrence, sign or patient complaint or unintended disease if related or unrelated to the surgical procedures, implanted devices or ongoing DBS therapy. Results Over a mean/median follow-up period of 4.7 years (578 patient-years) 433 AEs were recorded in 106 of 123 patients (86.2%). There was no mortality or persistent morbidity from the surgical procedure. All serious adverse events (SAEs) that occurred within 4 weeks of surgery were reversible. Neurological AEs (193 in 85 patients) and psychiatric AEs (78 in 48 patients) were documented most frequently. AEs in 4 patients (suicide under GPI stimulation, weight gain >20 kg, impairment of gait and speech, cognitive decline >2 years following surgery) were severe or worse, at least possibly related to DBS and non reversible. In PD 23.1% of the STN-stimulated patients experienced non-reversible (or unknown reversibility) AEs that were at least possibly related to DBS in the form of impaired speech or gait, depression, weight gain, cognitive disturbances or urinary incontinence (severity was mild or moderate in 15 of 18 patients). Age and Hoehn&Yahr stage of STN-simulated PD patients, but not preoperative motor impairment or response to levodopa, showed a weak correlation (r = 0.24 and 0.22, respectively) with the number of AEs. Conclusions DBS-related AEs that were severe or worse and non-reversible were only observed in PD (4 of 82 patients; 4.9%), but not in other diseases. PD patients exhibited a significant risk for non-severe AEs most of which also represented preexisting and progressive axial and non-motor symptoms of PD. Mild gait and/or speech disturbances were rather frequent complaints under VIM stimulation. GPI stimulation for dystonia could be applied with negligible DBS-related side effects.
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Affiliation(s)
- Carsten Buhmann
- Klinik für Neurologie, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Torge Huckhagel
- Klinik für Neurochirurgie, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Katja Engel
- Klinik für Neurochirurgie, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Alessandro Gulberti
- Institut für Neurophysiologie und Pathophysiologie, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Ute Hidding
- Klinik für Neurologie, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | | | - Ines Goerendt
- Klinik für Neurologie, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Peter Ludewig
- Klinik für Neurologie, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Hanna Braass
- Klinik für Neurologie, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Chi-un Choe
- Klinik für Neurologie, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Kara Krajewski
- Klinik für Neurochirurgie, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | | | | | - Andreas K. Engel
- Institut für Neurophysiologie und Pathophysiologie, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Christian Gerloff
- Klinik für Neurologie, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Manfred Westphal
- Klinik für Neurochirurgie, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Johannes A. Köppen
- Klinik für Neurochirurgie, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Christian K. E. Moll
- Institut für Neurophysiologie und Pathophysiologie, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Wolfgang Hamel
- Klinik für Neurochirurgie, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
- * E-mail:
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23
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Kuo SH, Wang J, Tate WJ, Pan MK, Kelly GC, Gutierrez J, Cortes EP, Vonsattel JPG, Louis ED, Faust PL. Cerebellar Pathology in Early Onset and Late Onset Essential Tremor. CEREBELLUM (LONDON, ENGLAND) 2017; 16:473-482. [PMID: 27726094 PMCID: PMC5336493 DOI: 10.1007/s12311-016-0826-5] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Early onset and late onset essential tremor (ET) cases differ in several respects. Whether they differ with respect to cerebellar pathologic changes remains to be determined. We quantified a broad range of postmortem features (Purkinje cell (PC) counts, PC axonal torpedoes and associated axonal changes, heterotopic PCs, and hairy basket ratings) in 30 ET cases with age of tremor onset <50 years, 30 ET cases with age of tremor onset ≥50 years, and 30 controls (total n = 90). We also used two alternative age of onset cut-points (<40 vs. ≥40 years, and <60 vs. ≥60 years) to define early onset vs. late onset ET. We found that ET cases with tremor onset <50 years and tremor onset ≥50 years had similar PC counts (8.78 ± 1.70 vs. 8.86 ± 1.24, p = 0.839), PC axonal torpedo counts (17.87 ± 18.27 [median =13.00] vs. 12.90 ± 10.60 [median =9.0], p = 0.486) and associated axonal pathology (all p values >0.05), heterotopic PC counts (9.90 ± 11.55 [median =6.00] vs. 5.40 ± 5.10 [median =3.50], p = 0.092), and hairy basket ratings (1.95 ± 0.62 [median =2.00] vs. 2.05 ± 0.92 [median =2.00], p = 0.314). When using the age of onset cut-points of 40 or 60 years, results were similar. Early onset and late onset ET cases share similar cerebellar postmortem features. These data do not support the notion that these age-of-onset related forms of ET represent distinct clinical-pathological entities.
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Affiliation(s)
- Sheng-Han Kuo
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, USA.
- Neurological Institute, Columbia University, New York, NY, 10032, USA.
| | - Jie Wang
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
- Department of Basic and Community Nursing, School of Nursing, Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - William J Tate
- Department of Pathology and Cell Biology, Columbia University Medical Center and the New York Presbyterian Hospital, New York, NY, USA
| | - Ming-Kai Pan
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
- Department of Medical Research, National Taiwan University, Taipei, Taiwan
| | - Geoffrey C Kelly
- Department of Pathology and Cell Biology, Columbia University Medical Center and the New York Presbyterian Hospital, New York, NY, USA
| | - Jesus Gutierrez
- Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Etty P Cortes
- Department of Pathology and Cell Biology, Columbia University Medical Center and the New York Presbyterian Hospital, New York, NY, USA
- Taub Institute for Research on Alzheimer's disease and the Aging Brain, Columbia University, New York, NY, USA
| | - Jean-Paul G Vonsattel
- Department of Pathology and Cell Biology, Columbia University Medical Center and the New York Presbyterian Hospital, New York, NY, USA
- Taub Institute for Research on Alzheimer's disease and the Aging Brain, Columbia University, New York, NY, USA
| | - Elan D Louis
- Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, USA
- Department of Chronic Disease Epidemiology, Yale School of Public Health, Yale University, New Haven, CT, USA
- Center for Neuroepidemiology and Clinical Neurological Research, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Phyllis L Faust
- Department of Pathology and Cell Biology, Columbia University Medical Center and the New York Presbyterian Hospital, New York, NY, USA
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Abstract
PURPOSE OF REVIEW Essential tremor has not been defined or used consistently in clinical diagnosis and research. Other monosymptomatic disorders are often referred to as essential tremor variants. RECENT FINDINGS There is now solid evidence that essential tremor, however defined, is a syndrome with multiple causes. SUMMARY A new tremor classification scheme is being developed by the International Parkinson and Movement Disorder Society Task Force on Tremor. In this scheme, tremor in the absence of other neurological signs is called isolated tremor, and tremor in combination with other signs is called combined tremor. Many isolated and combined tremor syndromes can be defined on the basis of commonly recurring or unique clinical symptoms and signs, including historical features (age at onset, family history, and temporal evolution) and tremor characteristics (body distribution, activation condition, associated features). Essential tremor, however defined, is simply a syndrome and not a specific disease. Essential tremor should be defined and used consistently, or this term should be abandoned. As essential tremor is an arbitrarily defined syndrome, it makes no sense to refer to other tremors as variants of essential tremor or essential tremor syndromes.
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Louis ED, Michalec M. Reduced body mass index in essential tremor: a study of 382 cases and 392 matched controls. Eur J Neurol 2015; 22:384-8. [PMID: 25367457 PMCID: PMC4289439 DOI: 10.1111/ene.12589] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 08/29/2014] [Indexed: 11/27/2022]
Abstract
BACKGROUND AND PURPOSE There is mounting evidence that essential tremor (ET) is a neurodegenerative disease. Reduced body mass index (BMI) is a clinical feature of many neurodegenerative diseases, yet there has been little documentation of BMI in patients with ET. METHODS Essential tremor cases and controls were enrolled in a study of the environmental epidemiology of ET at Columbia University Medical Center. Weight and height were measured using a standard protocol; BMI was weight (kg) divided by height (m(2)). Daily calorie count (kcal) was calculated using the Willett Semi-Quantitative Food Frequency Questionnaire. Tremor severity was assessed with a clinical rating scale (total tremor score, range 0-36). RESULTS The 382 ET cases and 392 controls were similar with respect to age, gender and other demographic variables. BMI was lower in ET cases than controls [26.7 ± 5.0 (median = 26.2) vs. 27.7 ± 5.6 (median = 26.7), P = 0.03] despite the fact that the daily caloric intake was marginally higher in ET cases than controls (P = 0.09). In ET cases, BMI was not associated with tremor severity (Spearman's r = -0.02, P = 0.66) but, among younger onset ET cases, longer tremor duration was associated with lower BMI (Spearman's r = -0.14, P = 0.049). CONCLUSIONS The observed lower BMI in ET is consistent with the neurodegenerative hypothesis of ET. The data also suggest that some mechanism other than decreased daily caloric intake or an involuntary movement-related increased burning of calories is likely to account for this case-control difference.
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Affiliation(s)
- E D Louis
- GH Sergievsky Center, College of Physicians and Surgeons, Columbia University, New York, NY, USA; Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, USA; Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, NY, USA; Taub Institute for Research on Alzheimer's Disease and the Aging Brain, College of Physicians and Surgeons, Columbia University, New York, NY, USA
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Klaming R, Annese J. Functional anatomy of essential tremor: lessons from neuroimaging. AJNR Am J Neuroradiol 2014; 35:1450-7. [PMID: 23620075 DOI: 10.3174/ajnr.a3586] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The neuropathogenetic processes underlying essential tremor appear to cause subtle morphologic changes in neural networks that include multiple brain structures, primarily the cerebellum, brain stem, frontal lobes, and thalamus. One of the main challenges of neuroimaging in essential tremor is differentiating disease-specific markers from the spectrum of structural changes that occur due to aging. This review discusses recent neuroimaging studies in the light of current knowledge of the neuropsychology and pathology of the disease. We suggest that the application of multiple macroscopic and microscopic neuroimaging modalities, combined with personalized information relative to cognitive and behavioral symptoms, is the prerequisite for a comprehensive classification and correct diagnosis of essential tremor.
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Affiliation(s)
- R Klaming
- From The Brain Observatory, San Diego, California; and Department of Radiology, University of California, San Diego, San Diego, California
| | - J Annese
- From The Brain Observatory, San Diego, California; and Department of Radiology, University of California, San Diego, San Diego, California.
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Benito-León J. Essential tremor: a neurodegenerative disease? TREMOR AND OTHER HYPERKINETIC MOVEMENTS (NEW YORK, N.Y.) 2014; 4:252. [PMID: 25120943 PMCID: PMC4107287 DOI: 10.7916/d8765cg0] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 06/29/2014] [Indexed: 12/01/2022]
Abstract
Background Essential tremor (ET) is one of the most common neurological disorders among adults, and is the most common of the many tremor disorders. It has classically been viewed as a benign monosymptomatic condition, yet over the past decade, a growing body of evidence indicates that ET is a progressive condition that is clinically heterogeneous, as it may be associated with a spectrum of clinical features, with both motor and non-motor elements. In this review, I will describe the most significant emerging milestones in research which, when taken together, suggest that ET is a neurodegenerative condition. Methods A PubMed search conducted in June 2014 crossing the terms “essential tremor” (ET) and “neurodegenerative” yielded 122 entries, 20 of which included the term “neurodegenerative” in the article title. This was supplemented by articles in the author's files that pertained to this topic. Results/Discussion There is an open and active dialogue in the medical community as to whether ET is a neurodegenerative disease, with considerable evidence in favor of this. Specifically, ET is a progressive disorder of aging associated with neuronal loss (reduction in Purkinje cells) as well as other post-mortem changes that occur in traditional neurodegenerative disorders. Along with this, advanced neuroimaging techniques are now demonstrating distinct structural changes, several of which are consistent with neuronal loss, in patients with ET. However, further longitudinal clinical and neuroimaging longitudinal studies to assess progression are required.
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Affiliation(s)
- 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
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Louis ED. 'Essential tremor' or 'the essential tremors': is this one disease or a family of diseases? Neuroepidemiology 2013; 42:81-9. [PMID: 24335621 DOI: 10.1159/000356351] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 10/10/2013] [Indexed: 12/14/2022] Open
Abstract
There is accumulating evidence that the entity referred to as 'essential tremor' (ET) is not a single disease. It may be a family of diseases better referred to as 'the ETs'. This review will summarize the following evidence: (1) the presence of etiological heterogeneity; (2) the heterogeneity of findings in postmortem studies, thus suggesting several diseases; (3) the recent discussion that age of onset may be an important marker of disease heterogeneity; (4) the clinical expansion of the concept of ET in recent years to include a broader range of tremor phenomenology, other motor features (gait ataxia), other involuntary movements (dystonia), and nonmotor features (cognitive problems, psychiatric problems), some of which could be primary; (5) the heterogeneity of pharmacological response profiles and clinical progression, and (6) the association of ET with Parkinson's disease, Alzheimer's disease, and possibly progressive supranuclear palsy, with the possibility that some ET patients are more predisposed to develop one of these. © 2013 S. Karger AG, Basel.
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Affiliation(s)
- Elan D Louis
- GH Sergievsky Center, College of Physicians and Surgeons, Columbia University, New York, N.Y., USA
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Abstract
Classic essential tremor is a clinical syndrome of action tremor in the upper limbs (at least 95 % of patients) and less commonly the head, face/jaw, voice, tongue, trunk, and lower limbs, in the absence of other neurologic signs. However, the longstanding notion that essential tremor is a monosymptomatic tremor disorder is being challenged by a growing literature describing associated disturbances of tandem walking, personality, mood, hearing, and cognition. There is also epidemiologic, pathologic, and genetic evidence that essential tremor is pathophysiologically heterogeneous. Misdiagnosis of essential tremor is common because clinicians frequently overlook other neurologic signs and because action tremor in the hands is caused by many conditions, including dystonia, Parkinson disease, and drug-induced tremor. Thus, essential tremor is nothing more than a syndrome of idiopathic tremulousness, and the challenge for researchers and clinicians is to find specific etiologies of this syndrome.
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Louis ED, Ottman R. Is there a one-way street from essential tremor to Parkinson's disease? Possible biological ramifications. Eur J Neurol 2013; 20:1440-4. [PMID: 24033795 DOI: 10.1111/ene.12256] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 07/26/2013] [Indexed: 11/28/2022]
Abstract
There is considerable evidence for an association between essential tremor (ET) and Parkinson's disease (PD), although the topic remains somewhat controversial. An important issue, not previously addressed, is what seems to be the unidirectional nature of the relationship (ET→ET + PD and not PD→PD + ET). The aims of this review are (i) to discuss the evidence for and against a unidirectional relationship and (ii) to discuss the implications of such a unidirectional relationship, if it exists, for disease mechanisms. Evidence 'for' a unidirectional relationship includes (i) abundant clinical anecdotal observation and (ii) clinical and epidemiological studies. Evidence 'against' is theoretical rather than empirical. Overall, the evidence 'for' is stronger, although additional studies are needed in order to be certain; for the time being, it might be best to leave this as an open question. The biological ramifications/extensions of such a unidirectional relationship include (i) that the association is causal (i.e., some aspect of ET pathophysiology predisposes an individual to develop PD) and (ii) that some ET cases may have a circumscribed form of Lewy body disease, and the secondary development of PD may represent a spread of those Lewy bodies in the brainstem. The presence and nature of the links between ET and PD are controversial. Further primary data (epidemiological and pathological) are needed to improve understanding of the relationship and its implications for the pathogenesis of both disorders.
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Affiliation(s)
- E D Louis
- GH Sergievsky Center, College of Physicians and Surgeons, Columbia University, New York, NY, USA; Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, USA; Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, NY, USA
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Babij R, Lee M, Cortés E, Vonsattel JPG, Faust PL, Louis ED. Purkinje cell axonal anatomy: quantifying morphometric changes in essential tremor versus control brains. ACTA ACUST UNITED AC 2013; 136:3051-61. [PMID: 24030953 DOI: 10.1093/brain/awt238] [Citation(s) in RCA: 126] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Growing clinical, neuro-imaging and post-mortem data have implicated the cerebellum as playing an important role in the pathogenesis of essential tremor. Aside from a modest reduction of Purkinje cells in some post-mortem studies, Purkinje cell axonal swellings (torpedoes) are present to a greater degree in essential tremor cases than controls. Yet a detailed study of more subtle morphometric changes in the Purkinje cell axonal compartment has not been undertaken. We performed a detailed morphological analysis of the Purkinje cell axonal compartment in 49 essential tremor and 39 control brains, using calbindin D28k immunohistochemistry on 100-µm cerebellar cortical vibratome tissue sections. Changes in axonal shape [thickened axonal profiles (P = 0.006), torpedoes (P = 0.038)] and changes in axonal connectivity [axonal recurrent collaterals (P < 0.001), axonal branching (P < 0.001), terminal axonal sprouting (P < 0.001)] were all present to an increased degree in essential tremor cases versus controls. The changes in shape and connectivity were significantly correlated [e.g. correlation between thickened axonal profiles and recurrent collaterals (r = 0.405, P < 0.001)] and were correlated with tremor duration among essential tremor cases with age of onset >40 years. In essential tremor cases, thickened axonal profiles, axonal recurrent collaterals and branched axons were 3- to 5-fold more frequently seen on the axons of Purkinje cells with torpedoes versus Purkinje cells without torpedoes. We document a range of changes in the Purkinje cell axonal compartment in essential tremor. Several of these are likely to be compensatory changes in response to Purkinje cell injury, thus illustrating an important feature of Purkinje cells, which is that they are relatively resistant to damage and capable of mobilizing a broad range of axonal responses to injury. The extent to which this plasticity of the Purkinje cell axon is partially neuroprotective or ultimately ineffective at slowing further cellular changes and cell death deserves further study in essential tremor.
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Affiliation(s)
- Rachel Babij
- 1 GH Sergievsky Centre, College of Physicians and Surgeons, Columbia University, New York, NY, USA
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Fang W, Lv F, Luo T, Cheng O, Liao W, Sheng K, Wang X, Wu F, Hu Y, Luo J, Yang QX, Zhang H. Abnormal regional homogeneity in patients with essential tremor revealed by resting-state functional MRI. PLoS One 2013; 8:e69199. [PMID: 23869236 PMCID: PMC3711903 DOI: 10.1371/journal.pone.0069199] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Accepted: 06/06/2013] [Indexed: 01/23/2023] Open
Abstract
Essential tremor (ET) is one of the most common movement disorders in human adults. It can be characterized as a progressive neurological disorder of which the most recognizable feature is a tremor of the arms or hands that is apparent during voluntary movements such as eating and writing. The pathology of ET remains unclear. Resting-state fMRI (RS-fMRI), as a non-invasive imaging technique, was employed to investigate abnormalities of functional connectivity in ET in the brain. Regional homogeneity (ReHo) was used as a metric of RS-fMRI to assess the local functional connectivity abnormality in ET with 20 ET patients and 20 age- and gender-matched healthy controls (HC). The ET group showed decreased ReHo in the anterior and posterior bilateral cerebellar lobes, the bilateral thalamus and the insular lobe, and increased ReHo in the bilateral prefrontal and parietal cortices, the left primary motor cortex and left supplementary motor area. The abnormal ReHo value of ET patients in the bilateral anterior cerebellar lobes and the right posterior cerebellar lobe were negatively correlated with the tremor severity score, while positively correlated with that in the left primary motor cortex. These findings suggest that the abnormality in cerebello-thalamo-cortical motor pathway is involved in tremor generation and propagation, which may be related to motor-related symptoms in ET patients. Meanwhile, the abnormality in the prefrontal and parietal regions may be associated with non-motor symptoms in ET. These findings suggest that the ReHo could be utilized for investigations of functional-pathological mechanism of ET.
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Affiliation(s)
- Weidong Fang
- Department of Radiology, the First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Fajin Lv
- Department of Radiology, the First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Tianyou Luo
- Department of Radiology, the First Affiliated Hospital of Chongqing Medical University, Chongqing, China
- * E-mail: (TL); (HZ)
| | - Oumei Cheng
- Department of Neurology, the First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Wei Liao
- Center for Cognition and Brain Disorders, Hangzhou Normal University, Hangzhou, China
- Zhejiang Key Laboratory for Research in Assessment of Cognitive Impairments, Hangzhou, China
| | - Ke Sheng
- Department of Neurology, the First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Xuefeng Wang
- Department of Neurology, the First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Fei Wu
- Department of Radiology, the First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Yida Hu
- Department of Neurology, the First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Jing Luo
- Department of Neurology, the First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Qing X. Yang
- Center for NMR Research, Department of Radiology, Penn State College of Medicine, Hershey, Pennsylvania, United States of America
| | - Han Zhang
- Center for Cognition and Brain Disorders, Hangzhou Normal University, Hangzhou, China
- Zhejiang Key Laboratory for Research in Assessment of Cognitive Impairments, Hangzhou, China
- * E-mail: (TL); (HZ)
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Barbosa MT, Caramelli P, Cunningham MCQ, Maia DP, Lima-Costa MFF, Cardoso F. Prevalence and clinical classification of tremor in elderly--a community-based survey in Brazil. Mov Disord 2013; 28:640-6. [PMID: 23450620 DOI: 10.1002/mds.25355] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Revised: 11/25/2012] [Accepted: 12/09/2012] [Indexed: 11/11/2022] Open
Abstract
Prevalence data on different types of tremor among the elderly population are very scarce. The objective of this study was to study the prevalence of tremor in a community-dwelling elderly population in the town of Bambuí, Brazil. The authors studied 1186 inhabitants aged≥64 years. This was a 2-phase study in which all participants who screened positive in a questionnaire for tremor and parkinsonism or who used drugs capable of causing/suppressing tremor were examined. In this population, the prevalence rate was 17.4% for tremor, 7.4% for essential tremor, 5.6% for parkinsonian tremor, 2.8% for enhanced physiological tremor, and 1.6% for other causes. There were no gender differences in prevalence rates for all types. Patients who had Parkinson's disease with tremor were older than those who had essential tremor, whereas patients who had enhanced physiological tremor were significantly younger. The age-specific prevalence of tremor increased with advancing age for both men and women. The prevalence of tremor in the studied population was high and increased with advancing age. Essential tremor, parkinsonian tremor, and enhanced physiological tremor were the most commonly identified causes. © 2013 Movement Disorder Society.
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Affiliation(s)
- Maira Tonidandel Barbosa
- Department of Internal Medicine, Faculty of Medicine, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
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Cohort study of prevalence and phenomenology of tremor in dementia with Lewy bodies. J Neurol 2013; 260:1731-42. [PMID: 23400498 PMCID: PMC3705145 DOI: 10.1007/s00415-013-6853-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 01/21/2013] [Accepted: 01/22/2013] [Indexed: 10/27/2022]
Abstract
To study prevalence, specific patterns and response to treatment of tremor in dementia with Lewy bodies (DLB), in comparison with other tremulous disorders prevalence, qualitative and quantitative features of tremor were studied in an incident cohort of 67 dopaminergic treatment naive DLB, 111 Parkinson's Disease (PD) and 34 Essential Tremor (ET) patients. Tremulous DLB patients (tDLB) were compared with tremulous PD (tPD) and ET patients and followed for 2 years. Double blind placebo-controlled acute drug challenge with L-Dopa and alcohol was performed in all ET, 24 tDLB and 27 tPD. Effects of dopaminergic chronic treatment in all tDLB and tPD patients and primidone in 8 tDLB were also assessed. Tremor occurred in 44.76 % of DLB patients. The tDLB patients presented a complex pattern of mixed tremors, characterized by rest and postural/action tremor, including walking tremor and standing overflow in 50 % tDLB. Standing tremor with overflow was characteristic of tDLB (p < 0.001). Head tremor was more frequent in tDLB than tPD and ET (p = 0.001). The tDLB tremors were reduced by acute and chronic dopaminergic treatments (p < 0.01) but not by alcohol or primidone. Tremor occurs commonly in DLB patients with a complex mixed tremor pattern which shows a significant response to acute and chronic dopaminergic treatments. Recognizing that there is a clinical category of tremulous DLB may help the differential diagnosis of tremors.
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Favilla CG, Topiol DD, Zesiewicz TA, Wagle Shukla A, Foote KD, Jacobson CE, Okun MS. Impact of discontinuing tremor suppressing medications following thalamic deep brain stimulation. Parkinsonism Relat Disord 2013; 19:171-5. [DOI: 10.1016/j.parkreldis.2012.09.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Revised: 08/28/2012] [Accepted: 09/10/2012] [Indexed: 10/27/2022]
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Louis ED, Hernandez N, Ionita-Laza I, Ottman R, Clark LN. Does rate of progression run in essential tremor families? Slower vs. faster progressors. Parkinsonism Relat Disord 2012; 19:363-6. [PMID: 23121728 DOI: 10.1016/j.parkreldis.2012.10.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Revised: 09/25/2012] [Accepted: 10/05/2012] [Indexed: 10/27/2022]
Abstract
BACKGROUND Essential tremor (ET) is a progressive disorder, worsening gradually with time in most patients. Yet there are few data on the factors that influence rate of progression. ET is a highly familial disorder, and physicians often care for patients who have other affected family members. Do ET families differ from one another with respect to rate of progression? Are some families slower progressors and other families faster progressors? We are unaware of published data. METHODS ET probands and relatives were enrolled in a cross-sectional genetic study at Columbia University. Rate of progression was calculated as total tremor score ÷ log disease duration. RESULTS There were 100 enrollees (28 probands, 72 relatives). Data from 78 enrollees (23 probands, 55 relatives) were selected for final analysis. The mean familial rate of progression ranged from as little as 8.4 to as much as 34.3, a > 4-fold difference. In an analysis of variance, we found significant evidence of heterogeneity in the log rate of progression across families (p < 0.001), with more than one-half (i.e., 55.4%) of the total variance in the log rate of progression explained by the family grouping. CONCLUSIONS Familial factors seem to affect rate of tremor progression in ET. There was a 4-fold difference across families in observed mean rate of progression; thus, some families seemed to be more rapid progressors than others. We hope these data may be used by clinicians to provide basic prognostic and family guidance information to their patients and families with ET.
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Affiliation(s)
- Elan D Louis
- GH Sergievsky Center, College of Physicians and Surgeons, Columbia University, New York, NY, USA.
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Benito-León J. 'When did my tremor start?': can essential tremor patients pinpoint their disease onset? Neuroepidemiology 2012; 40:99-100. [PMID: 23095676 DOI: 10.1159/000342312] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Affiliation(s)
- Julián Benito-León
- Department of Neurology, University Hospital 12 de Octubre, Madrid, Spain.
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Bareš M, Husárová I, Lungu OV. Essential tremor, the cerebellum, and motor timing: towards integrating them into one complex entity. Tremor Other Hyperkinet Mov (N Y) 2012; 2:tre-02-93-653-1. [PMID: 23439925 PMCID: PMC3572554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Accepted: 05/26/2012] [Indexed: 10/27/2022] Open
Abstract
Essential tremor (ET) is the most common movement disorder in humans. It is characterized by a postural and kinetic tremor most commonly affecting the forearms and hands. Isolated head tremor has been found in 1-10% of patients, suggesting that ET may be a composite of several phenotypes. The exact pathophysiology of ET is still unknown. ET has been repeatedly shown as a disorder of mild cerebellar degeneration, particularly in postmortem studies. Clinical observations, electrophysiological, volumetric and functional imaging studies all reinforce the fact that the cerebellum is involved in the generation of ET. However, crucial debate exists as to whether ET is a neurodegenerative disease. Data suggesting that it is neurodegenerative include postmortem findings of pathological abnormalities in the brainstem and cerebellum, white matter changes on diffusion tensor imaging, and clinical studies demonstrating an association with cognitive and gait changes. There is also conflicting evidence against ET as a neurodegenerative disease: the improvement of gait abnormalities with ethanol administration, lack of gray matter volume loss on voxel-based morphometry, failure to confirm the prominent presence of Lewy bodies in the locus ceruleus, and other pathological findings. To clarify this issue, future research is needed to describe the mechanism of cellular changes in the ET brain and to understand the order in which they occur. The cerebellum has been shown to be involved in the timing of movement and sensation, acting as an internal timing system that provides the temporal representation of salient events spanning hundreds of milliseconds. It has been reported that cerebellar timing function is altered in patients with ET, showing an increased variability of rhythmic hand movements as well as diminished performance during predictive motor timing task. Based on current knowledge and observations, we argue that ET is essentially linked with cerebellar degeneration, or at least cerebellar dysfunction, together with disturbance of motor timing. We explain the context of our current understanding on this topic, highlighting possible clinical consequences for patients suffering from ET and future research directions.
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Affiliation(s)
- Martin Bareš
- Central European Institute of Technology, CEITEC MU, Behavioral and Social Neuroscience Research Group, Masaryk University, Brno, Czech Republic
- First Department of Neurology, Faculty of Medicine Masaryk University and St. Anne's Teaching Hospital, Brno, Czech Republic
| | - Ivica Husárová
- First Department of Neurology, Faculty of Medicine Masaryk University and St. Anne's Teaching Hospital, Brno, Czech Republic
| | - Ovidiu V. Lungu
- Psychiatry Department, Université de Montréal, Montréal, Québec, Canada
- Functional Neuroimaging Unit, Research Center of the Geriatric Institute affiliated with the Université de Montréal, Montréal, Québec, Canada
- Research Department, Donald Berman Maimonides Geriatric Centre, Montréal, Québec, Canada
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Essential tremor is a neurodegenerative disease. J Neural Transm (Vienna) 2012; 119:1383-7; discussion 1373. [DOI: 10.1007/s00702-012-0878-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2011] [Accepted: 07/25/2012] [Indexed: 10/28/2022]
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Favilla CG, Ullman D, Wagle Shukla A, Foote KD, Jacobson CE, Okun MS. Worsening essential tremor following deep brain stimulation: disease progression versus tolerance. Brain 2012; 135:1455-62. [PMID: 22344584 DOI: 10.1093/brain/aws026] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
A major concern regarding ventralis intermedius nucleus deep brain stimulation for essential tremor has been the loss of surgical efficacy over time in a minority of patients. Some experts have ascribed the worsening tremor to tolerance, while other evidence has suggested that disease progression may play a role. Suboptimal lead placement has also been reported to be a factor in worsening tremor following deep-brain stimulation; however, most authors consider this phenomenon to manifest within a few months of the actual surgery. We aimed to dissect the tolerance versus disease progression issue by analysing preoperative versus long-term post-surgical Fahn-Tolosa-Marin Tremor Rating Scale scores both on and off stimulation among 28 patients who underwent ventralis intermedius nucleus deep brain stimulation and 21 age-matched controls. Of the 28 patients in the treatment arm of the cohort, seven (25%) demonstrated evidence of tremor progression, and had a 34% increase in the tremor score off stimulation at the 36 month follow-up compared with a 32% increase among controls (P = 0.67). In one of the seven patients there was evidence of suboptimal lead placement given the lateral position of the lead, and the motor side effects during threshold testing. This patient demonstrated a loss of stimulation benefit between 24 and 36 months, which may have been more indicative of tolerance. The other six subjects (86%) maintained stimulation benefit throughout the follow-up period, despite worsening tremor off stimulation (at a comparable rate to that of controls), making disease progression the most likely explanation. The data suggest that deep brain stimulation tolerance may be over-reported in the literature, and that a tolerance versus disease progression work-up should include: examining the trend in off stimulation scores, accounting for image based lead locations, and during programming sessions checking for thresholds which may elicit clinical benefits and side effects.
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Affiliation(s)
- Christopher G Favilla
- Department of Neurology, Centre for Movement Disorders and Neurorestoration, University of Florida College of Medicine, 100 S Newell Drive, Gainesville, FL 32610, USA
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Saini J, Bagepally BS, Bhatt MD, Chandran V, Bharath RD, Prasad C, Yadav R, Pal PK. Diffusion tensor imaging: tract based spatial statistics study in essential tremor. Parkinsonism Relat Disord 2012; 18:477-82. [PMID: 22297126 DOI: 10.1016/j.parkreldis.2012.01.006] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Revised: 01/02/2012] [Accepted: 01/08/2012] [Indexed: 11/15/2022]
Abstract
INTRODUCTION Essential tremor (ET) is a common movement disorder with motor and non-motor symptoms. We aimed to investigate the neurodegenerative changes in the brain white matter of patients with ET using Diffusion Tensor Imaging (DTI). METHODS Clinical and MRI data from 20 patients (5 women and 15 men; age-38.2 ± 16.5 yrs) with ET and 17 controls (3 women and 14 men; age-40.7 ± 16.5 yrs) were collected prospectively. The DTI data were analyzed using tract based spatial statistics (TBSS) software for tract wise analysis. Further region of interest (ROI) analysis was carried out in the genu of corpus callosum, anterior limb of internal capsule (ALIC), corticospinal tract (CS), and cerebellar peduncles. Effect of tremor severity, disease duration and age of onset on DTI metrics was also studied. RESULTS Patients with ET in comparison to controls showed significant (P(corrected) < 0.05) increase of mean diffusivity and radial diffusivity in right frontoparietal white matter. Axial diffusivity increase was seen in bilateral cerebral hemispheres, thalamus, brainstem and cerebellar hemisphere white matter. No significant change in fractional anisotropy of the white matter was seen. ROI analysis also revealed abnormalities in the ALIC and cerebellar peduncles. There was no correlation between the severity of white matter changes and clinical tremor severity score as well as disease duration. CONCLUSIONS This study provides in vivo evidence for axonal disintegration of the cerebral and cerebellar white matter fibres in patients with ET.
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Affiliation(s)
- Jitender Saini
- Department of Neuroimaging and Interventional Radiology, National Institute of Mental Health & Neurosciences, Hosur Road, Bangalore-560029, Karnataka, India
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Louis ED, Agnew A, Gillman A, Gerbin M, Viner AS. Estimating annual rate of decline: prospective, longitudinal data on arm tremor severity in two groups of essential tremor cases. J Neurol Neurosurg Psychiatry 2011; 82:761-5. [PMID: 21436230 PMCID: PMC3696191 DOI: 10.1136/jnnp.2010.229740] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
BACKGROUND Despite its high prevalence, there are surprisingly few prospective, longitudinal data on the clinical course of essential tremor (ET). Patients themselves often want to know from their treating physician whether and by how much their tremor is expected to worsen over time. METHODS As part of two research protocols, prospective, longitudinal data were collected on tremor severity in two samples of ET cases (44+39 cases, combined n=83). At a baseline and one follow-up evaluation, a detailed clinical assessment was performed and action tremor in the arms was rated by a senior movement disorders neurologist using a standardised clinical rating scale (Total Tremor Score (TTS), range 0-36). RESULTS In the first case sample, TTS increased annually by 0.32 ± 0.89 points (ie, an annual increase of 5.3 ± 17.1% (median 1.8%) from the mean baseline score). TTS increased by ≥ 0.5 points in 23/24 (95.8%) cases followed for ≥ 5 years. In the second sample, TTS score increased annually by 0.64 ± 1.49 points (annual increase of 3.1 ± 8.1% (median 2.0%) from the mean baseline score). TTS increased by ≥ 0.5 points in 11/15 (73.3%) cases followed for ≥ 5 years. No baseline factors were identified that predicted annual change in TTS. CONCLUSIONS Most ET cases exhibited a progressive worsening in tremor scores with time such that the average annual increase in tremor severity from baseline was estimated to be between 3.1% and 5.3% and the median annual increase from baseline was between 1.8% and 2.0%. These published estimates will hopefully be a useful prognostic guide for clinicians and their patients.
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Affiliation(s)
- Elan D Louis
- GH Sergievsky Center, College of Physicians and Surgeons, Columbia University, New York, New York, USA.
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Louis ED, Rios E, Rao AK. Tandem gait performance in essential tremor: clinical correlates and association with midline tremors. Mov Disord 2010; 25:1633-8. [PMID: 20629168 DOI: 10.1002/mds.23144] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Gait difficulty has been reported in essential tremor (ET) although it has been the subject of a limited number of studies. We broadly assessed these clinical correlates, including the association of gait difficulty with a variety of midline tremors (jaw, voice, neck). Tandem gait (10 steps) was assessed in 122 ET cases. Cranial tremor score (0-3) was the number of locations (neck, jaw, voice) in which tremor was present. Number of tandem mis-steps positively correlated with age (P < 0.001), age of tremor onset (P = 0.001), and presence of neck (P < 0.001), jaw (P = 0.001), and voice tremors (P = 0.047). Number of tandem mis-steps increased markedly with cranial tremor score: 0 (0.8 +/- 1.2), 1 (1.1 +/- 1.6), 2 (2.3 +/- 3.0), 3 (3.7 +/- 1.6) (P < 0.001). It was not correlated with severity of arm or leg tremors. ET patients with cranial tremors (neck, jaw, voice), those with older age of onset, and those of current older age are more likely to manifest tandem gait difficulty. Tandem gait difficulty was not correlated with severity of limb tremors. Tandem gait difficulty and cranial tremors in ET may both be symptomatic of the same underlying pathophysiology, a disturbance of cerebellar regulation of the midline, which is distinct from its regulation of the limbs.
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Affiliation(s)
- Elan D Louis
- GH Sergievsky Center, College of Physicians and Surgeons, Columbia University, New York, New York, USA.
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Abstract
Cerebellar Purkinje cells (PCs), the sole output neurons in the cerebellar cortex, play an important role in the cerebellar circuit. PCs appear to be rather sensitive to aging, exhibiting significant changes in both morphology and function during senescence. This article reviews such changes during the normal aging process, including a decrease in the quantity of cells, atrophy in the soma, retraction in the dendritic arborizations, degeneration in the subcellular organelles, a decline in synapse density, disorder in the neurotransmitter system, and alterations in electrophysiological properties. Although these deteriorative changes occur during aging, compensatory mechanisms exist to counteract the impairments in the aging PCs. The possible neural mechanisms underlying these changes and potential preventive treatments are discussed.
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Essential tremor: evolving clinicopathological concepts in an era of intensive post-mortem enquiry. Lancet Neurol 2010; 9:613-22. [PMID: 20451458 DOI: 10.1016/s1474-4422(10)70090-9] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Essential tremor (ET) is one of the most common neurological disorders. In recent years, as a result of systematic post-mortem examinations, our knowledge of the pathophysiology of this disease has grown substantially. Clearly identifiable structural changes (ie, Purkinje cell loss, Lewy bodies) have been observed in the brains of individuals with ET. These changes are not uniform and seem to follow several patterns, localising to the cerebellum itself or to a collection of brainstem neurons that synapse directly with Purkinje cells. Furthermore, these changes are similar to those seen in degenerative diseases. A wealth of clinical, epidemiological, and now post-mortem data indicate that this disease, or perhaps this family of diseases, is likely to be neurodegenerative. The molecular mechanisms that underlie these structural changes in ET are unknown. However, with more controlled, tissue-based studies being done, it is hoped that these mechanisms will be elucidated, thereby laying the foundation for the development of more targeted, effective pharmacotherapeutic interventions.
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"Hairy baskets" associated with degenerative Purkinje cell changes in essential tremor. J Neuropathol Exp Neurol 2010; 69:262-71. [PMID: 20142764 DOI: 10.1097/nen.0b013e3181d1ad04] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Essential tremor (ET) is one of the most common neurologic diseases. Increased numbers of torpedoes and Purkinje cell (PC) loss have been documented in the brains of patients with ET. We recently observed a dense and tangled appearance ("hairiness") of the basket cell axonal plexuses that surround PC soma in Bielschowsky preparations of cerebellar cortex in ET brains. Here, we assessed basket cell "hairiness" in 37 ET (32 cerebellar ET; 5 Lewy body variant ET), 21 nondisease control, and 48 disease control brains using a semiquantitative scale. In 8 cerebellar ET cases (25%), there were high basket scores (rating = 3), whereas no Lewy body variant ET, 1 nondisease control (4.8%), and 2 diseased controls (4.2%) had high basket scores (p = 0.001). The hairy basket scores correlated with numbers of torpedoes (p < 0.001) and inversely with numbers of PCs (p = 0.06). Axonal plexus density obtained by image analysis of basket cell processes traced from digitized images was higher in ET than in nondiseased control cases (p = 0.016). Closely spaced sites of synaptic contact between basket cell processes and PCs were identified by electron microscopy in ET cases. These data indicate that structural changes are not restricted to PCs in ET, and that other neurons within their functional network may be involved in its pathogenesis.
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Animal models of human cerebellar ataxias: a cornerstone for the therapies of the twenty-first century. THE CEREBELLUM 2009; 8:137-54. [PMID: 19669387 DOI: 10.1007/s12311-009-0127-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Cerebellar ataxias represent a group of disabling neurological disorders. Our understanding of the pathogenesis of cerebellar ataxias is continuously expanding. A considerable number of laboratory animals with neurological mutations have been reported and numerous relevant animal models mimicking the phenotype of cerebellar ataxias are becoming available. These models greatly help dissecting the numerous mechanisms of cerebellar dysfunction, a major step for the assessment of therapeutics targeting a given deleterious pathway and for the screening of old or newly synthesized chemical compounds. Nevertheless, differences between animal models and human disorders should not be overlooked and difficulties in terms of characterization should not be occulted. The identification of the mutations of many hereditary ataxias, the development of valuable animal models, and the recent identifications of the molecular mechanisms underlying cerebellar disorders represent a combination of key factors for the development of anti-ataxic innovative therapies. It is anticipated that the twenty-first century will be the century of effective therapies in the field of cerebellar ataxias. The animal models are a cornerstone to reach this goal.
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Bares M, Lungu OV, Husárová I, Gescheidt T. Predictive Motor Timing Performance Dissociates Between Early Diseases of the Cerebellum and Parkinson's Disease. THE CEREBELLUM 2009; 9:124-35. [PMID: 19851820 DOI: 10.1007/s12311-009-0133-5] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Martin Bares
- Department of Neurology, St. Anne's Hospital Medical Faculty Masaryk University Brno, Pekarská 53, Brno, Czech Republic.
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