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Yang Y, Zheng C, Chen B, Hernandez NC, Faust PL, Cai Z, Louis ED, Matuskey D. Decreased Synaptic Vesicle Glycoprotein 2A Binding in the Human Postmortem Essential Tremor Cerebellum: Evidence of Reduction in Synaptic Density. CEREBELLUM (LONDON, ENGLAND) 2024; 23:1053-1060. [PMID: 37783917 DOI: 10.1007/s12311-023-01611-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 09/27/2023] [Indexed: 10/04/2023]
Abstract
OBJECTIVE Despite being one of the most prevalent neurological diseases, the pathophysiology of essential tremor (ET) is not fully understood. Neuropathological studies have identified numerous degenerative changes in the cerebellum of ET patients, however. These data align with considerable clinical and neurophysiological data linking ET to the cerebellum. While neuroimaging studies have variably shown mild atrophy in the cerebellum, marked atrophy is not a clear feature of the cerebellum in ET and a search for a more suitable neuroimaging signature of neurodegeneration is in order. Postmortem studies in ET have examined different neuropathological alterations in the cerebellum, but as of yet have not focused on measures of generalized synaptic markers. This pilot study focuses on synaptic vesicle glycoprotein 2A (SV2A), a protein expressed in practically all synapses in the brain, as a measure of synaptic density in postmortem ET cases. METHODS The current study utilized autoradiography with the SV2A radioligand [18F]SDM-16 to assess synaptic density in the cerebellar cortex and dentate nucleus in three ET cases and three age-matched controls. RESULTS Using [18F]SDM-16, SV2A was 53% and 46% lower in the cerebellar cortex and dentate nucleus, respectively, in ET cases compared to age-matched controls. CONCLUSION In this pilot study, using in vitro SV2A autoradiography, we have observed significantly lower synaptic density in the cerebellar cortex and dentate nucleus of ET cases. Future research could expand on our sample size and focus on in vivo imaging in ET to explore whether SV2A imaging could serve as a much-needed disease biomarker.
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Affiliation(s)
- Yanghong Yang
- Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, USA
| | - Chao Zheng
- Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, USA
| | - Baosheng Chen
- Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, USA
| | - Nora C Hernandez
- Department of Neurology, University of Texas Southwestern School of Medicine, Dallas, TX, USA
| | - Phyllis L Faust
- Department of Pathology and Cell Biology, Columbia University Vagelos College of Physicians and Surgeons and the New York Presbyterian Hospital, New York, NY, USA
| | - Zhengxin Cai
- Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, USA
| | - Elan D Louis
- Department of Neurology, University of Texas Southwestern School of Medicine, Dallas, TX, USA
| | - David Matuskey
- Department of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, USA.
- Department of Neurology, Yale School of Medicine, New Haven, CT, USA.
- Department of Psychiatry, Yale School of Medicine, New Haven, CT, USA.
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Panyakaew P, Phuenpathom W, Bhidayasiri R, Hallett M. Bedside clinical assessment of patients with common upper limb tremor and algorithmic approach. ASIAN BIOMED 2024; 18:37-52. [PMID: 38708334 PMCID: PMC11063083 DOI: 10.2478/abm-2024-0008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/07/2024]
Abstract
The diagnostic approach for patients with tremor is challenging due to the complex and overlapping phenotypes among tremor syndromes. The first step in the evaluation of tremor is to identify the tremulous movement and exclude the tremor mimics. The second step is to classify the tremor syndrome based on the characteristics of tremor from historical clues and focused examination (Axis 1). Comprehensive tremor examinations involve the assessment of tremor in different conditions (rest, action or mixed, position or task-specific), distribution of tremor (upper limb, lower limb, head, jaw), positive signs for functional tremor (FT) if suspected (distractibility, entrainment, co-contraction), and associated neurological signs including parkinsonism, dystonic posture, cerebellar/brainstem signs, neuropathy, and cognitive impairment. A pivotal feature in this step is to determine any distinct feature of a specific isolated or combined tremor syndrome. In this review, we propose an algorithm to assess upper limb tremors. Ancillary testing should be performed if clinical evaluation is unclear. The choice of investigation depends on the types of tremors considered to narrow down the spectrum of etiology (Axis 2). Laboratory blood tests are considered for acute onset and acute worsening of tremors, while structural neuroimaging is indicated in unilateral tremors with acute onset, nonclassical presentations, and a combination of neurological symptoms. Neurophysiological study is an important tool that aids in distinguishing between tremor and myoclonus, etiology of tremor and document specific signs of FT. Treatment is mainly symptomatic based depending on the etiology of the tremor and the patient's disabilities.
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Affiliation(s)
- Pattamon Panyakaew
- Chulalongkorn Centre of Excellence for Parkinson’s Disease and Related Disorders, Department of Medicine, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok10330, Thailand
- Division of Neurology, Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok10330, Thailand
| | - Warongporn Phuenpathom
- Chulalongkorn Centre of Excellence for Parkinson’s Disease and Related Disorders, Department of Medicine, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok10330, Thailand
| | - Roongroj Bhidayasiri
- Chulalongkorn Centre of Excellence for Parkinson’s Disease and Related Disorders, Department of Medicine, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok10330, Thailand
- Division of Neurology, Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok10330, Thailand
- The Academy of Science, The Royal Society of Thailand, Bangkok10330, Thailand
| | - Mark Hallett
- Human Motor Control Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892-1428, USA
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Pandey S, Dinesh S, Rawat CS, Thelma BK. The Spectrum of Non-Parkinsonian Tremor: A Registry at a Tertiary Care Teaching Institute. Tremor Other Hyperkinet Mov (N Y) 2023; 13:48. [PMID: 38145280 PMCID: PMC10742104 DOI: 10.5334/tohm.828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 12/09/2023] [Indexed: 12/26/2023] Open
Abstract
Background Tremors other than those associated with Parkinson's disease (non-parkinsonian tremor) are commonly observed in clinical settings. However, their frequency and clinical characteristics have rarely been reported. Objectives To classify non-parkinsonian tremors based on the consensus statement on the classification of tremors, from the task force of the International Parkinson and Movement Disorder Society published in 2018. Methods A prospective registry at a tertiary care teaching institute. Results A total of 475 patients with non-parkinsonian tremors were recruited for the study. 67.57% (n = 321) of our patients were male and a family history of tremor was present in 20.84% (n = 99) of patients. Dystonic tremor (DT) was the most common non-parkinsonian tremor (33.26%). 27.78% of patients fulfilled the new classification criteria for essential tremor, with 13.47% classified as pure ET (ET) and 14.31% exhibiting neurological soft signs, leading to the classification of ET plus (ETP). Patients with ETP had more family history (57.35%) [vs DT (26.48%, p = 0.00004) and ET (10.93%, p = 0.00003], longer duration of disease [mean ± standard deviation (SD) = 9.53 ± 8.64 years] [vs DT (5.60 ± 5.93, p = 0.0003) and ET (6.38 ± 5.97, p = 0.01) years], and more severe tremor as measured by the essential tremor rating assessment scale total score [mean ± SD = 27.42 ± 11.70] [vs DT (23.50 ± 8.62, p = 0.007) and ET (22.12 ± 8.19, p = 0.007)] compared with patients with DT and ET. Conclusions DT was the most common cause of non-parkinsonian tremor in our registry followed by essential tremor syndrome. ETP was more common than ET.
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Affiliation(s)
- Sanjay Pandey
- Department of Neurology, Govind Ballabh Pant Institute of Postgraduate medical education and Research, New Delhi, India
- Department of Neurology and Stroke Medicine, Amrita Hospital, Mata Amritanandamayi Marg Sector 88, Faridabad, Delhi National Capital Region, India
| | - Shreya Dinesh
- Department of Neurology, Govind Ballabh Pant Institute of Postgraduate medical education and Research, New Delhi, India
- Department of Microbiology and Bioinformatics, Aravind Medical Research Foundation, Madurai, Tamil Nadu, India
| | - Chandra Shekhar Rawat
- Department of Neurology, Govind Ballabh Pant Institute of Postgraduate medical education and Research, New Delhi, India
| | - B K Thelma
- Department of Genetics, University of Delhi South Campus, New Delhi, India
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Lenka A, Louis ED. Developing a Staging Scheme for Essential Tremor: A Discussion of Organizing Principles. Tremor Other Hyperkinet Mov (N Y) 2023; 13:43. [PMID: 37954035 PMCID: PMC10637291 DOI: 10.5334/tohm.812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 10/26/2023] [Indexed: 11/14/2023] Open
Abstract
Essential tremor (ET) is a chronic, progressive neurological disease that may negatively affect patients' lives. While there has been considerable progress in ET research, some fundamental issues remain unaddressed. One such issue is disease staging. Staging schemes have inherent value and are part of the dialogue that clinicians have with other movement disorders patients. We highlight the value of and challenges with developing a staging system for ET and organize a discussion around the potential steps in developing such a system. Diseases for which there are staging schemes generally have a number of shared characteristics. ET has numerous features that would lend themselves to a staging scheme: emerging evidence supporting the existence of a premotor phase of disease, insidious onset, progressive worsening of arm tremor, spread of tremor to other body regions, the observation that patients seem to be at increased risk for other conditions within the same organ (i.e., emergence of Parkinson's disease and Alzheimer's disease in excessive numbers of ET patients), pathological changes in the cerebellum whose evolution can be ordered from (i) those that compromise the physical integrity and physiological function of Purkinje cells, (ii) subsequent changes that are reparative and regenerative, and (iii) eventual cell death. Challenges to formulating a staging scheme are the absence of both a biological marker and an "end stage" of disease. The sum of combined evidence suggests that a staging scheme would be of value. We provide initial thoughts as to how to begin to structure such a staging scheme.
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Affiliation(s)
- Abhishek Lenka
- Department of Neurology, Baylor College of Medicine, Houston, TX, USA
| | - Elan D Louis
- Department of Neurology, University of Texas Southwestern, Dallas, TX, USA
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Yang Y, Zheng C, Chen B, Hernandez NC, Faust PL, Cai Z, Louis ED, Matuskey D. Decreased Synaptic Vesicle Glycoprotein 2A Binding in the Human Postmortem Essential Tremor Cerebellum: Evidence of Reduction in Synaptic Density. RESEARCH SQUARE 2023:rs.3.rs-2838184. [PMID: 37205584 PMCID: PMC10187382 DOI: 10.21203/rs.3.rs-2838184/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Objective Despite being one of the most prevalent neurological diseases, the pathophysiology of essential tremor (ET) is not fully understood. Neuropathological studies have identified numerous degenerative changes in the cerebellum of ET patients, however. These data align with considerable clinical and neurophysiological data linking ET to the cerebellum. While neuroimaging studies have variably shown mild atrophy in the cerebellum, marked atrophy is not a clear feature of the cerebellum in ET and that a search for a more suitable neuroimaging signature of neurodegeneration is in order. Postmortem studies in ET have examined different neuropathological alterations in the cerebellum, but as of yet have not focused on measures of generalized synaptic markers. This pilot study focuses on synaptic vesicle glycoprotein 2A (SV2A), a protein expressed in practically all synapses in the brain, as a measure of synaptic density in postmortem ET cases. Methods The current study utilized autoradiography with the SV2A radioligand [ 18 F]SDM-16 to assess synaptic density in the cerebellar cortex and dentate nucleus in three ET cases and three age-matched controls. Results Using [ 18 F]SDM-16, SV2A was 53% and 46% lower in the cerebellar cortex and dentate nucleus, respectively, in ET cases compared to age-matched controls. Conclusion For the first time, using in vitro SV2A autoradiography, we have observed significantly lower synaptic density in the cerebellar cortex and dentate nucleus of ET cases. Future research could focus on in vivo imaging in ET to explore whether SV2A imaging could serve as a much-needed disease biomarker.
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Affiliation(s)
| | | | | | | | - Phyllis L Faust
- Columbia University Vagelos College of Physicians and Surgeons and the New York Presbyterian Hospital
| | | | - Elan D Louis
- University of Texas Southwestern School of Medicine
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Bologna M, Espay AJ, Fasano A, Paparella G, Hallett M, Berardelli A. Redefining Bradykinesia. Mov Disord 2023; 38:551-557. [PMID: 36847357 PMCID: PMC10387192 DOI: 10.1002/mds.29362] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 01/31/2023] [Accepted: 02/06/2023] [Indexed: 03/01/2023] Open
Affiliation(s)
- Matteo Bologna
- Department of Human Neurosciences, Sapienza University of Rome, Rome, Italy
- IRCCS Neuromed, Pozzilli, Italy
| | - Alberto J. Espay
- Gardner Family Center for Parkinson’s Disease and Movement Disorders, Department of Neurology, University of Cincinnati, Cincinnati, Ohio, USA
| | - Alfonso Fasano
- Edmond J. Safra Program in Parkinson’s Disease, Morton and Gloria Shulman Movement Disorders Clinic, Toronto Western Hospital, UHN, Toronto, Ontario, Canada
- Division of Neurology, University of Toronto, Toronto, Ontario, Canada
- Krembil Brain Institute, Toronto, Ontario, Canada
| | | | - Mark Hallett
- Human Motor Control Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Alfredo Berardelli
- Department of Human Neurosciences, Sapienza University of Rome, Rome, Italy
- IRCCS Neuromed, Pozzilli, Italy
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