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Arnold FJ, Putka AF, Raychaudhuri U, Hsu S, Bedlack RS, Bennett CL, La Spada AR. Revisiting Glutamate Excitotoxicity in Amyotrophic Lateral Sclerosis and Age-Related Neurodegeneration. Int J Mol Sci 2024; 25:5587. [PMID: 38891774 PMCID: PMC11171854 DOI: 10.3390/ijms25115587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Revised: 05/17/2024] [Accepted: 05/20/2024] [Indexed: 06/21/2024] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is the most common motor neuron disorder. While there are five FDA-approved drugs for treating this disease, each has only modest benefits. To design new and more effective therapies for ALS, particularly for sporadic ALS of unknown and diverse etiologies, we must identify key, convergent mechanisms of disease pathogenesis. This review focuses on the origin and effects of glutamate-mediated excitotoxicity in ALS (the cortical hyperexcitability hypothesis), in which increased glutamatergic signaling causes motor neurons to become hyperexcitable and eventually die. We characterize both primary and secondary contributions to excitotoxicity, referring to processes taking place at the synapse and within the cell, respectively. 'Primary pathways' include upregulation of calcium-permeable AMPA receptors, dysfunction of the EAAT2 astrocytic glutamate transporter, increased release of glutamate from the presynaptic terminal, and reduced inhibition by cortical interneurons-all of which have been observed in ALS patients and model systems. 'Secondary pathways' include changes to mitochondrial morphology and function, increased production of reactive oxygen species, and endoplasmic reticulum (ER) stress. By identifying key targets in the excitotoxicity cascade, we emphasize the importance of this pathway in the pathogenesis of ALS and suggest that intervening in this pathway could be effective for developing therapies for this disease.
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Affiliation(s)
- Frederick J. Arnold
- Department of Pathology and Laboratory Medicine, University of California Irvine, Irvine, CA 92617, USA
- Department of Neurology, Duke University School of Medicine, Durham, NC 27710, USA; (A.F.P.)
| | - Alexandra F. Putka
- Department of Neurology, Duke University School of Medicine, Durham, NC 27710, USA; (A.F.P.)
| | - Urmimala Raychaudhuri
- Department of Pathology and Laboratory Medicine, University of California Irvine, Irvine, CA 92617, USA
| | - Solomon Hsu
- Department of Pathology and Laboratory Medicine, University of California Irvine, Irvine, CA 92617, USA
| | - Richard S. Bedlack
- Department of Neurology, Duke University School of Medicine, Durham, NC 27710, USA; (A.F.P.)
| | - Craig L. Bennett
- Department of Pathology and Laboratory Medicine, University of California Irvine, Irvine, CA 92617, USA
- Department of Neurology, University of California Irvine, Irvine, CA 92617, USA
| | - Albert R. La Spada
- Department of Pathology and Laboratory Medicine, University of California Irvine, Irvine, CA 92617, USA
- Department of Neurology, Duke University School of Medicine, Durham, NC 27710, USA; (A.F.P.)
- Department of Neurology, University of California Irvine, Irvine, CA 92617, USA
- Department of Biological Chemistry, University of California Irvine, Irvine, CA 92617, USA
- Department of Neurobiology and Behavior, University of California Irvine, Irvine, CA 92697, USA
- UCI Center for Neurotherapeutics, University of California Irvine, Irvine, CA 92697, USA
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Cengiz B, Koçak ÖK, Erdoğan T, Yanık E, Pek G, Savrun Y, Evren Boran H, Reha Kuruoğlu H. Excitability of somatosensory cortex is increased in ALS: A SEP recovery function study. Clin Neurophysiol 2023; 155:58-64. [PMID: 37734132 DOI: 10.1016/j.clinph.2023.08.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 07/28/2023] [Accepted: 08/14/2023] [Indexed: 09/23/2023]
Abstract
OBJECTIVE Neuronal loss in the somatosensory, as well as the motor cortex in amyotrophic lateral sclerosis (ALS), indicative of a structural abnormality has been reported. Previously we have shown that afferent inhibition was impaired in ALS, suggestive of sensory involvement. In this study, we aimed to evaluate excitability changes in the somatosensory cortex of ALS patients. METHODS ALS patients underwent a paired pulse somatosensory evoked potential (SEP) paradigm at various interstimulus intervals (ISI). The amplitude ratio obtained by dividing the amplitude of paired pulse SEP stimulation S2 (paired pulse stimulation) to S1 (the single pulse stimulation) was considered the somatosensory cortex excitability parameter. Findings were compared to the results obtained from healthy controls. Resting motor threshold (RMT) was also assessed in the ALS group. RESULTS An increased S2/S1 ratio was found in the ALS group in every ISI examined. Additionally, the reduced inhibition correlated negatively with forced vital capacity, Medical Research Council sum score, median nerve compound muscle action potential amplitude, while there was a positive association with Penn upper motor neuron score and sural nerve conduction velocity. No correlation existed with RMT. CONCLUSIONS Our findings demonstrated increased somatosensory cortical excitability in ALS, which was associated with clinical parameters such as reduced pulmonary function and motor strength. SIGNIFICANCE Somatosensory cortical excitability is impaired in ALS. Whether this is associated with increased motor cortical excitability requires further studies.
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Affiliation(s)
- Bülent Cengiz
- Department of Neurology, Faculty of Medicine, Gazi University, Ankara, Turkey; Department of Neurology, Section of Clinical Neurophysiology, Faculty of Medicine, Gazi University, Ankara, Turkey; Neuroscience and Neurotechnology Center of Excellence, Ankara, Turkey.
| | - Özlem Kurtkaya Koçak
- Department of Neurology, Faculty of Medicine, Gazi University, Ankara, Turkey; Department of Neurology, Section of Clinical Neurophysiology, Faculty of Medicine, Gazi University, Ankara, Turkey
| | - Tuğba Erdoğan
- Department of Neurology, Faculty of Medicine, Gazi University, Ankara, Turkey
| | - Ece Yanık
- Department of Neurology, Faculty of Medicine, Gazi University, Ankara, Turkey
| | - Gökhan Pek
- Department of Neurology, Faculty of Medicine, Gazi University, Ankara, Turkey
| | - Yusuf Savrun
- Department of Neurology, Faculty of Medicine, Gazi University, Ankara, Turkey
| | - H Evren Boran
- Department of Neurology, Faculty of Medicine, Gazi University, Ankara, Turkey; Department of Neurology, Section of Clinical Neurophysiology, Faculty of Medicine, Gazi University, Ankara, Turkey; Neuroscience and Neurotechnology Center of Excellence, Ankara, Turkey
| | - H Reha Kuruoğlu
- Department of Neurology, Faculty of Medicine, Gazi University, Ankara, Turkey; Department of Neurology, Section of Clinical Neurophysiology, Faculty of Medicine, Gazi University, Ankara, Turkey
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Huang N, Qin W, Lin J, Dong Q, Chen H. Corticospinal fibers with different origins impair in amyotrophic lateral sclerosis: A neurite orientation dispersion and density imaging study. CNS Neurosci Ther 2023; 29:3406-3415. [PMID: 37208946 PMCID: PMC10580332 DOI: 10.1111/cns.14270] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Revised: 04/21/2023] [Accepted: 05/05/2023] [Indexed: 05/21/2023] Open
Abstract
AIMS To investigate microstructural impairments of corticospinal tracts (CSTs) with different origins in amyotrophic lateral sclerosis (ALS) using neurite orientation dispersion and density imaging (NODDI). METHODS Diffusion-weighted imaging data acquired from 39 patients with ALS and 50 controls were used to estimate NODDI and diffusion tensor imaging (DTI) models. Fine maps of CST subfibers originating from the primary motor area (M1), premotor cortex, primary sensory area, and supplementary motor area (SMA) were segmented. NODDI metrics (neurite density index [NDI] and orientation dispersion index [ODI]) and DTI metrics (fractional anisotropy [FA] and mean/axial/radial diffusivity [MD/AD/RD]) were computed. RESULTS The patients with ALS showed microstructural impairments (reflected by NDI, ODI, and FA reductions and MD, AD, and RD increases) in CST subfibers, especially in M1 fibers, which correlated with disease severity. Compared with other diffusion metrics, NDI yielded a higher effect size and detected the greatest extent of CST subfibers damage. Logistic regression analyses based on NDI in M1 subfiber yielded the best diagnostic performance compared with other subfibers and the whole CST. CONCLUSIONS Microstructural impairment of CST subfibers (especially those originating from M1) is the key feature of ALS. The combination of NODDI and CST subfibers analysis may improve diagnosing performance for ALS.
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Affiliation(s)
- Nao‐Xin Huang
- Department of RadiologyFujian Medical University Union HospitalFuzhouChina
| | - Wen Qin
- Department of Radiology and Tianjin Key Laboratory of Functional ImagingTianjin Medical University General HospitalTianjinChina
| | - Jia‐Hui Lin
- Department of RadiologyFujian Medical University Union HospitalFuzhouChina
| | - Qiu‐Yi Dong
- Department of RadiologyFujian Medical University Union HospitalFuzhouChina
| | - Hua‐Jun Chen
- Department of RadiologyFujian Medical University Union HospitalFuzhouChina
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Herrmann C, Schradt F, Lindner-Pfleghar B, Schuster J, Ludolph AC, Dorst J. Pharyngeal electrical stimulation in amyotrophic lateral sclerosis: a pilot study. Ther Adv Neurol Disord 2022; 15:17562864211068394. [PMID: 35154390 PMCID: PMC8832561 DOI: 10.1177/17562864211068394] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 12/03/2021] [Indexed: 12/12/2022] Open
Abstract
Background: Patients with amyotrophic lateral sclerosis (ALS) suffer from dysphagia that increases the risk for aspiration, pneumonia and weight loss. Pharyngeal electrical stimulation (PES) is a therapeutic technique that applies electric stimuli to the patient’s pharynx in order to improve swallowing based on the principle of cortical plasticity and reorganization. Previous studies have demonstrated positive effects in patients with various neurological diseases. Objective: This study was initiated to investigate the effect of PES on swallowing function in patients with ALS. Methods: In all, 20 ALS patients with severe dysphagia [characterized by a Penetration Aspiration Scale (PAS) of at least 4 in thin liquid] were randomized to receive either PES for 10 min at 3 consecutive days in addition to Standard Logopaedic Therapy (SLT) or SLT alone. Swallowing function was evaluated by Fiberoptic Endoscopic Evaluation of Swallowing (FEES) at five timepoints: at baseline, 1 day, 4 days, 3 weeks and 3 months after treatment. Primary endpoint was the severity of penetrations or aspirations as classified by PAS. Secondary endpoints were adverse events, dysphagia-related quality of life, Swallowing Quality of Life (SWAL-QOL), Dysphagia Severity Rating Scale (DSRS), residues, leaking, ALS Functional Rating Scale Revised (ALSFRS-R), and the performance in Clinical Evaluation of Swallowing (CES). The trial is registered under the name of ‘Pharyngeal Electrical Stimulation in Amyotrophic Lateral Sclerosis’ with ClinialTrials.gov, number NCT03481348 (https://clinicaltrials.gov/ct2/show/NCT03481348). Results: Both groups combined showed a significant improvement (p = 0.003) of median Total-PAS from 3.6 [interquartile range (IQR) = 2.9–5.0] at baseline to 2.3 (IQR = 1.8–4.0) 1 day after treatment. During subsequent study visits, PAS increased again but remained below baseline. PES and control group did not differ significantly 1 day after intervention (p = 0.32). Similar effects were found in the majority of secondary endpoints. Interpretation: The findings suggest that PES may not provide an additional positive effect on swallowing function in ALS. SLT seems to yield at least short-term positive effects on swallowing function and swallowing-specific life quality in ALS. Registration: ClinialTrials.gov: NCT03481348
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Affiliation(s)
| | - Falk Schradt
- Department of Neurology, University of Ulm, Ulm, Germany
| | | | | | - Albert C. Ludolph
- Department of Neurology, University of Ulm, Ulm, Germany
- German Center for Neurodegenerative Diseases (DZNE), Ulm, Germany
| | - Johannes Dorst
- Department of Neurology, University of Ulm, Oberer Eselsberg 45, D-89081 Ulm, Germany
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Zhou XY, Lu JY, Liu FT, Wu P, Zhao J, Ju ZZ, Tang YL, Shi QY, Lin HM, Wu JJ, Yen TC, Zuo CT, Sun YM, Wang J. In Vivo 18 F-APN-1607 Tau Positron Emission Tomography Imaging in MAPT Mutations: Cross-Sectional and Longitudinal Findings. Mov Disord 2021; 37:525-534. [PMID: 34842301 DOI: 10.1002/mds.28867] [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: 08/13/2021] [Accepted: 11/01/2021] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND Frontotemporal lobar degeneration with tauopathy caused by MAPT (microtubule-associated protein tau) mutations is a highly heterogenous disorder. The ability to visualize and longitudinally monitor tau deposits may be beneficial to understand disease pathophysiology and predict clinical trajectories. OBJECTIVE The aim of this study was to investigate the cross-sectional and longitudinal 18 F-APN-1607 positron emission tomography/computed tomography (PET/CT) imaging findings in MAPT mutation carriers. METHODS Seven carriers of MAPT mutations (six within exon 10 and one outside of exon 10) and 15 healthy control subjects were included. All participants underwent 18 F-APN-1607 PET/CT at baseline. Three carriers of exon 10 mutations received follow-up 18 F-APN-1607 PET/CT scans. Standardized uptake value ratio (SUVR) maps were obtained using the cerebellar gray matter as the reference region. SUVR values observed in MAPT mutation carriers were normalized to data from healthy control subjects. A regional SUVR z score ≥ 2 was used as the criterion to define positive 18 F-APN-1607 PET/CT findings. RESULTS Although the seven study patients had heterogenous clinical phenotypes, all showed a significant 18 F-APN-1607 uptake characterized by high-contrast signals. However, the anatomical localization of tau deposits differed in patients with distinct clinical symptoms. Follow-up imaging data, which were available for three patients, demonstrated worsening trends in patterns of tau accumulation over time, which were paralleled by a significant clinical deterioration. CONCLUSIONS Our data represent a promising step in understanding the usefulness of 18 F-APN-1607 PET/CT imaging for detecting tau accumulation in MAPT mutation carriers. Our preliminary follow-up data also suggest the potential value of 18 F-APN-1607 PET/CT for monitoring the longitudinal trajectories of frontotemporal lobar degeneration caused by MAPT mutations. © 2021 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Xin-Yue Zhou
- Department of Neurology and National Research Center for Aging and Medicine & National Center for Neurological Disorders, State Key Laboratory of Medical Neurobiology, Huashan Hospital, Fudan University, Shanghai, China
| | - Jia-Ying Lu
- PET Center, Huashan Hospital, Fudan University, Shanghai, China
| | - Feng-Tao Liu
- Department of Neurology and National Research Center for Aging and Medicine & National Center for Neurological Disorders, State Key Laboratory of Medical Neurobiology, Huashan Hospital, Fudan University, Shanghai, China
| | - Ping Wu
- PET Center, Huashan Hospital, Fudan University, Shanghai, China
| | - Jue Zhao
- Department of Neurology and National Research Center for Aging and Medicine & National Center for Neurological Disorders, State Key Laboratory of Medical Neurobiology, Huashan Hospital, Fudan University, Shanghai, China
| | - Zi-Zhao Ju
- PET Center, Huashan Hospital, Fudan University, Shanghai, China
| | - Yi-Lin Tang
- Department of Neurology and National Research Center for Aging and Medicine & National Center for Neurological Disorders, State Key Laboratory of Medical Neurobiology, Huashan Hospital, Fudan University, Shanghai, China
| | - Qing-Yi Shi
- PET Center, Huashan Hospital, Fudan University, Shanghai, China
| | - Hua-Mei Lin
- PET Center, Huashan Hospital, Fudan University, Shanghai, China
| | - Jian-Jun Wu
- Department of Neurology and National Research Center for Aging and Medicine & National Center for Neurological Disorders, State Key Laboratory of Medical Neurobiology, Huashan Hospital, Fudan University, Shanghai, China
| | | | - Chuan-Tao Zuo
- PET Center, Huashan Hospital, Fudan University, Shanghai, China
| | - Yi-Min Sun
- Department of Neurology and National Research Center for Aging and Medicine & National Center for Neurological Disorders, State Key Laboratory of Medical Neurobiology, Huashan Hospital, Fudan University, Shanghai, China
| | - Jian Wang
- Department of Neurology and National Research Center for Aging and Medicine & National Center for Neurological Disorders, State Key Laboratory of Medical Neurobiology, Huashan Hospital, Fudan University, Shanghai, China
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Nash Y, Sitty M. Non-Motor Symptoms of Amyotrophic Lateral Sclerosis: A Multi-Faceted Disorder. J Neuromuscul Dis 2021; 8:699-713. [PMID: 34024773 DOI: 10.3233/jnd-210632] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Amyotrophic Lateral Sclerosis (ALS) is a fatal neurodegenerative disease characterized by progressive degeneration of motor pathways. A growing body of evidence from recent years suggests that ALS results in a wide range of non-motor symptoms as well, which can have a significant impact on patients' quality of life. These symptoms could also, in turn, provide useful information as biomarkers for disease progression, and can shed insight on ALS mechanisms. Here we aim to review a wide range of non-motor symptoms of ALS, with emphasis on their importance to research and clinical treatment of patients.
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Affiliation(s)
- Yuval Nash
- Tel Aviv Youth University, The Jaime and Joan Constantiner School of Education, Tel Aviv University, Tel Aviv, Israel
| | - Michal Sitty
- Clalit Health Services, Kiryat Ono, Israel.,Department of Family Medicine, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
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Ranieri F, Mariotto S, Dubbioso R, Di Lazzaro V. Brain Stimulation as a Therapeutic Tool in Amyotrophic Lateral Sclerosis: Current Status and Interaction With Mechanisms of Altered Cortical Excitability. Front Neurol 2021; 11:605335. [PMID: 33613416 PMCID: PMC7892772 DOI: 10.3389/fneur.2020.605335] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 12/22/2020] [Indexed: 12/14/2022] Open
Abstract
In the last 20 years, several modalities of neuromodulation, mainly based on non-invasive brain stimulation (NIBS) techniques, have been tested as a non-pharmacological therapeutic approach to slow disease progression in amyotrophic lateral sclerosis (ALS). In both sporadic and familial ALS cases, neurophysiological studies point to motor cortical hyperexcitability as a possible priming factor in neurodegeneration, likely related to dysfunction of both excitatory and inhibitory mechanisms. A trans-synaptic anterograde mechanism of excitotoxicity is thus postulated, causing upper and lower motor neuron degeneration. Specifically, motor neuron hyperexcitability and hyperactivity are attributed to intrinsic cell abnormalities related to altered ion homeostasis and to impaired glutamate and gamma aminobutyric acid gamma-aminobutyric acid (GABA) signaling. Several neuropathological mechanisms support excitatory and synaptic dysfunction in ALS; additionally, hyperexcitability seems to drive DNA-binding protein 43-kDA (TDP-43) pathology, through the upregulation of unusual isoforms directly contributing to ASL pathophysiology. Corticospinal excitability can be suppressed or enhanced using NIBS techniques, namely, repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS), as well as invasive brain and spinal stimulation. Experimental evidence supports the hypothesis that the after-effects of NIBS are mediated by long-term potentiation (LTP)-/long-term depression (LTD)-like mechanisms of modulation of synaptic activity, with different biological and physiological mechanisms underlying the effects of tDCS and rTMS and, possibly, of different rTMS protocols. This potential has led to several small trials testing different stimulation interventions to antagonize excitotoxicity in ALS. Overall, these studies suggest a possible efficacy of neuromodulation in determining a slight reduction of disease progression, related to the type, duration, and frequency of treatment, but current evidence remains preliminary. Main limitations are the small number and heterogeneity of recruited patients, the limited "dosage" of brain stimulation that can be delivered in the hospital setting, the lack of a sufficient knowledge on the excitatory and inhibitory mechanisms targeted by specific stimulation interventions, and the persistent uncertainty on the key pathophysiological processes leading to motor neuron loss. The present review article provides an update on the state of the art of neuromodulation in ALS and a critical appraisal of the rationale for the application/optimization of brain stimulation interventions, in the light of their interaction with ALS pathophysiological mechanisms.
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Affiliation(s)
- Federico Ranieri
- Neurology Unit, Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Sara Mariotto
- Neurology Unit, Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Raffaele Dubbioso
- Department of Neurosciences, Reproductive Sciences and Odontostomatology, University of Naples “Federico II”, Naples, Italy
| | - Vincenzo Di Lazzaro
- Unit of Neurology, Neurophysiology, Neurobiology, Department of Medicine, Campus Bio-Medico University, Rome, Italy
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Štětkářová I, Ehler E. Diagnostics of Amyotrophic Lateral Sclerosis: Up to Date. Diagnostics (Basel) 2021; 11:231. [PMID: 33546386 PMCID: PMC7913557 DOI: 10.3390/diagnostics11020231] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 01/27/2021] [Accepted: 01/29/2021] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease characterized by gradual loss of upper and lower motor neurons and their pathways, usually without affecting the extraocular and sphincter muscles. The cause of the disease is not yet known. It is a chain of subsequent events, ending in programmed cell death in selective neuronal subpopulations. The prognosis for survival is rather short with a median of 2 to 4 years. Survival may be prolonged based on prompt diagnosis, ALS subtype and proper management with supportive treatment (tracheostomy, gastrostomy, etc.). According to the clinical picture, the typical form of ALS with upper and lower motoneuron involvement and progressive bulbar paralysis with bulbar muscle involvement is observed. The ALS form with progressive muscle atrophy, where only the lower motoneuron is affected, and primary lateral sclerosis with only upper motoneuron damage are rare. Familiar forms of ALS (FALS) associated with specific genes (the most common is C9orf72) have been discovered. FALS is usually associated with dementia (frontotemporal lobar dementia, FTLD), behavioral disorders, cognitive dysfunction and impairment of executive functions. The diagnosis of ALS is determined by excluding other conditions and utilizing clinical examinations, laboratory and genetic tests and nerve conduction/needle electromyography studies (EMG). Needle EMG records abnormal activities at rest and looks for neurogenic patterns during muscle contraction. Motor evoked potentials after transcranial magnetic stimulation remain the test of choice to identify impairment of upper motor neurons. New biochemical, neurophysiological and morphological biomarkers are extensively studied as early diagnostic and prognostic factors and have implications for clinical trials, research and drug development.
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Affiliation(s)
- Ivana Štětkářová
- Department of Neurology, Third Faculty of Medicine, Charles University and Faculty Hospital Královské Vinohrady, 100 34 Prague, Czech Republic
| | - Edvard Ehler
- Neurological Department, Faculty of Health Studies, Pardubice University and Pardubice Regional Hospital, 530 03 Pardubice, Czech Republic;
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Transcutaneous spinal direct current stimulation shows no effect on paired stimulation suppression of the somatosensory cortex. Sci Rep 2020; 10:22010. [PMID: 33319846 PMCID: PMC7738485 DOI: 10.1038/s41598-020-79131-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 12/03/2020] [Indexed: 11/08/2022] Open
Abstract
Transcutaneous spinal direct current stimulation (tsDCS) is a safe and convenient method of neuromodulation. It has been proven to alter sensory processing at cervicomedullary level by amplitude changes of the P30 response of tibial nerve somatosensory evoked potentials (TN SEPs). With knowledge that tsDCS affects cortical circuits, we hypothesized that tsDCS may also affect intracortical excitability of the somatosensory cortex assessed by paired stimulation suppression (PSS). Fourteen healthy men were included in this prospective, single-blinded, placebo-controlled crossover study. Single (SS) and paired stimulation (PS) TN SEPs were recorded over the scalp before, immediately as well as 30 and 60 min after applying 15 min of tsDCS over the twelfth thoracic vertebra. Each volunteer underwent three independent and randomized sessions of either cathodal, anodal or sham stimulation. tsDCS showed no effect on peak-to-peak amplitudes or latencies of cortical P40-N50 response after SS. Furthermore, tsDCS failed to induce significant changes on amplitude ratios of PSS, thus showing no impact on intracortical excitability of the somatosensory cortex in healthy subjects. Further research is required to reveal the different mechanisms and to strengthen clinical use of this promising technique.
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Nardone R, Golaszewski S, Thomschewski A, Sebastianelli L, Versace V, Brigo F, Orioli A, Saltuari L, Höller Y, Trinka E. Disinhibition of sensory cortex in patients with amyotrophic lateral sclerosis. Neurosci Lett 2020; 722:134860. [DOI: 10.1016/j.neulet.2020.134860] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 02/05/2020] [Accepted: 02/21/2020] [Indexed: 12/11/2022]
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