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Meldgaard M, Kristensen RS, Z'Graggen WJ, Tan SV, Søndergaard K, Qerama E, Andersen H, Fuglsang-Frederiksen A, Tankisi H. Muscle velocity recovery cycles in myopathy. Clin Neurophysiol 2023; 151:41-49. [PMID: 37148747 DOI: 10.1016/j.clinph.2023.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 03/30/2023] [Accepted: 04/03/2023] [Indexed: 05/08/2023]
Abstract
OBJECTIVE To understand the pathophysiology of myopathies by using muscle velocity recovery cycles (MVRC) and frequency ramp (RAMP) methodologies. METHODS 42 patients with quantitative electromyography (qEMG) and biopsy or genetic verified myopathy and 42 healthy controls were examined with qEMG, MVRC and RAMP, all recorded from the anterior tibial muscle. RESULTS There were significant differences in the motor unit potential (MUP) duration, the early and late supernormalities of the MVRC and the RAMP latencies in myopathy patients compared to controls (p < 0.05 apart from muscle relatively refractory period (MRRP)). When dividing into subgroups, the above-mentioned changes in MVRC and RAMP parameters were increased for the patients with non-inflammatory myopathy, while there were no significant changes in the group of patients with inflammatory myopathy. CONCLUSIONS The MVRC and RAMP parameters can discriminate between healthy controls and myopathy patients, more significantly for non-inflammatory myopathy. MVRC differences with normal MRRP in myopathy differs from other conditions with membrane depolarisation. SIGNIFICANCE MVCR and RAMP may have a potential in understanding disease pathophysiology in myopathies. The pathogenesis in non-inflammatory myopathy does not seem to be caused by a depolarisation of the resting membrane potential but rather by the change in sodium channels of the muscle membrane.
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Affiliation(s)
- M Meldgaard
- Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark
| | - R S Kristensen
- Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark
| | - W J Z'Graggen
- Departments of Neurology and Neurosurgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - S V Tan
- Department of Neurology and Neurophysiology, Guys and St Thomas' NHS Foundation Trust, London, UK
| | - K Søndergaard
- Department of Rheumatology, Aarhus University Hospital, Aarhus, Denmark
| | - E Qerama
- Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark; Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - H Andersen
- Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark; Department of Neurology, Aarhus University Hospital, Aarhus, Denmark
| | - A Fuglsang-Frederiksen
- Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark; Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - H Tankisi
- Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark; Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark.
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Soroken C, Posfay-Barbe KM, Caflisch M, Z'Graggen WJ. Postural tachycardia syndrome among adolescents. Arch Pediatr 2022; 29:398-403. [PMID: 35523634 DOI: 10.1016/j.arcped.2022.03.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 01/20/2022] [Accepted: 03/26/2022] [Indexed: 12/01/2022]
Abstract
Postural tachycardia syndrome (PoTS) is a polymorphic clinical syndrome that is underdiagnosed, especially in adolescents. It is a form of dysautonomia, but its exact physiopathology remains elusive. Several pathologies can mimic PoTS; it is characterized by heterogeneous symptoms that accompany a disproportionate tachycardia upon the upright position. It can significantly impact the patients' quality of life. Only a Schellong test is useful for making the diagnosis. Treatment in PoTS is primarily symptomatic with the main goal being to restore the patient's condition as quickly as possible. We report here the diagnosis and management of seven adolescents, aged 11-16, who have been followed up since 2015.
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Affiliation(s)
- C Soroken
- Department of Pediatrics, Geneva University Hospitals, Willy-Donzé Street 6, 1205 Geneva, Switzerland.
| | - K M Posfay-Barbe
- Department of Pediatrics, Geneva University Hospitals, Willy-Donzé Street 6, 1205 Geneva, Switzerland
| | - M Caflisch
- Department of Pediatrics, Geneva University Hospitals, Willy-Donzé Street 6, 1205 Geneva, Switzerland
| | - W J Z'Graggen
- Departments of Neurology and Neurosurgery, Inselspital, Bern University Hospital, Freiburgstrasse 16, 3010 Bern, Switzerland
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Tankisi A, Pedersen TH, Bostock H, Z'Graggen WJ, Larsen LH, Meldgaard M, Elkmann T, Tankisi H. Early detection of evolving critical illness myopathy with muscle velocity recovery cycles. Clin Neurophysiol 2021; 132:1347-1357. [PMID: 33676846 DOI: 10.1016/j.clinph.2021.01.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 12/29/2020] [Accepted: 01/19/2021] [Indexed: 11/19/2022]
Abstract
OBJECTIVE To investigate the sensitivity of muscle velocity recovery cycles (MVRCs) for detecting altered membrane properties in critically ill patients, and to compare this to conventional nerve conduction studies (NCS) and quantitative electromyography (qEMG). METHODS Twenty-four patients with intensive care unit acquired weakness (ICUAW) and 34 healthy subjects were prospectively recruited. In addition to NCS (median, ulnar, peroneal, tibial and sural nerves) and qEMG (biceps brachii, vastus medialis and anterior tibial muscles), MVRCs with frequency ramp were recorded from anterior tibial muscle. RESULTS MVRC and frequency ramp parameters showed abnormal muscle fiber membrane properties with up to 100% sensitivity and specificity. qEMG showed myopathy in 15 patients (63%) while polyneuropathy was seen in 3 (13%). Decreased compound muscle action potential (CMAP) amplitude (up to 58%) and absent F-waves (up to 75%) were frequent, but long duration CMAPs were only seen in one patient with severe myopathy. CONCLUSIONS Altered muscle fiber membrane properties can be detected in patients with ICUAW not yet fulfilling diagnostic criteria for critical illness myopathy (CIM). MVRCs may therefore serve as a tool for early detection of evolving CIM. SIGNIFICANCE CIM is often under-recognized by intensivists, and large-scale longitudinal studies are needed to determine its incidence and pathogenesis.
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Affiliation(s)
- A Tankisi
- Department of Anaesthesiology and Intensive Care, Aarhus University Hospital, Aarhus, Denmark
| | - T H Pedersen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - H Bostock
- Institute of Neurology, University College London, Queen Square House, London, United Kingdom
| | - W J Z'Graggen
- Departments of Neurology and Neurosurgery, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - L H Larsen
- Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark
| | - M Meldgaard
- Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark
| | - T Elkmann
- Department of Anaesthesiology and Intensive Care, Aarhus University Hospital, Aarhus, Denmark
| | - H Tankisi
- Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark; Institute of Clinical Medicine, Aarhus University, Aarhus, Denmark.
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Z'Graggen WJ, Solà R, Graf NE, Serra J, Bostock H. Sensitivity to ischaemia of single sympathetic nerve fibres innervating the dorsum of the human foot. J Physiol 2017; 595:4467-4473. [PMID: 28378458 DOI: 10.1113/jp274324] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 03/30/2017] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Changes in nerve conduction velocity following an impulse (i.e. velocity recovery cycles) reflect after-potentials, and can provide an indication of altered nerve membrane properties. This study used microneurography to assess the effects of ischaemia on single human sympathetic fibres innervating the dorsum of the foot. It was found that velocity recovery cycles can distinguish whether a sympathetic nerve fibre is depolarized or not. The method may be used to detect membrane depolarization of sympathetic nerve fibres in human patients when autonomic neuropathy is suspected. ABSTRACT The aim of this study was to determine whether velocity recovery cycles (VRCs) could detect the effects of ischaemia on sympathetic nerve fibres. VRCs of human sympathetic nerve fibres of the superficial peroneal nerve innervating the dorsum of the foot were recorded by microneurography in seven healthy volunteers. Sympathetic nerve fibres were identified by studying their response to manoeuvres increasing sympathetic outflow and by measuring activity-dependent slowing at 2 Hz stimulation. VRCs were assessed at rest, during 30 min of induced limb ischaemia and during 20 min of recovery after ischaemia. From each VRC was measured the relative refractory period (RRP), the supernormality and the time to peak supernormality (SN@). During ischaemia, RRP increased from the baseline value of 37.4 ± 8.7 ms (mean ± SEM) to 67.1 ± 12.1 ms (P < 0.01) and SN@ increased from 68.6 ± 9.8 ms to 133.8 ± 11.0 ms (P < 0.005). The difference between SN@ and RRP separated ischaemic from non-ischaemic sympathetic nerve fibres. It is concluded that these sympathetic nerve fibres are sensitive to ischaemia, and that VRCs provide a method to study changes of axonal membrane potential of human sympathetic nerve fibres in vivo.
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Affiliation(s)
- W J Z'Graggen
- Department of Neurosurgery, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland.,Department of Neurology, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland
| | - R Solà
- Neuroscience Technologies, Barcelona, Spain
| | - N E Graf
- Department of Neurology, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland
| | - J Serra
- Neuroscience Technologies, Barcelona, Spain
| | - H Bostock
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, UK
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Andereggen L, Beck J, Z'Graggen WJ, Schroth G, Andres RH, Murek M, Haenggi M, Reinert M, Raabe A, Gralla J. Feasibility and Safety of Repeat Instant Endovascular Interventions in Patients with Refractory Cerebral Vasospasms. AJNR Am J Neuroradiol 2016; 38:561-567. [PMID: 27979797 DOI: 10.3174/ajnr.a5024] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 10/11/2016] [Indexed: 01/25/2023]
Abstract
BACKGROUND AND PURPOSE For patients with cerebral vasospasm refractory to medical and hemodynamic therapies, endovascular therapies often remain the last resort. Data from studies in large cohorts on the efficacy and safety of multiple immediate endovascular interventions are sparse. Our aim was to assess the feasibility and safety of multiple repeat instant endovascular interventions in patients with cerebral vasospasm refractory to medical, hemodynamic, and initial endovascular interventions. MATERIALS AND METHODS This was a single-center retrospective study of prospectively collected data on patients with cerebral vasospasm refractory to therapies requiring ≥3 endovascular interventions during the course of treatment following aneurysmal subarachnoid hemorrhage. The primary end point was functional outcome at last follow-up (mRS ≤2). The secondary end point was angiographic response to endovascular therapies and the appearance of cerebral infarctions. RESULTS During a 4-year period, 365 patients with aneurysmal subarachnoid hemorrhage were treated at our institution. Thirty-one (8.5%) met the inclusion criteria. In 52 (14%) patients, ≤2 endovascular interventions were performed as rescue therapy for refractory cerebral vasospasm. At last follow-up, a good outcome was noted in 18 (58%) patients with ≥3 interventions compared with 31 (61%) of those with ≤2 interventions (P = .82). The initial Hunt and Hess score of ≤2 was a significant independent predictor of good outcome (OR, 4.7; 95% CI, 1.2-18.5; P = .03), whereas infarcts in eloquent brain areas were significantly associated with a poor outcome (mRS 3-6; OR, 13.5; 95% CI, 2.3-81.2; P = .004). CONCLUSIONS Repeat instant endovascular intervention is an aggressive but feasible last resort treatment strategy with a favorable outcome in two-thirds of patients with refractory cerebral vasospasm and in whom endovascular treatment has already been initiated.
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Affiliation(s)
- L Andereggen
- From the Department of Neurosurgery (L.A., J.B., W.J.Z., R.H.A., M.M., M.R., A.R.).,Institute for Diagnostic and Interventional Neuroradiology (L.A., G.S., J.G.)
| | - J Beck
- From the Department of Neurosurgery (L.A., J.B., W.J.Z., R.H.A., M.M., M.R., A.R.)
| | - W J Z'Graggen
- From the Department of Neurosurgery (L.A., J.B., W.J.Z., R.H.A., M.M., M.R., A.R.).,Departments of Neurology (W.J.Z.)
| | - G Schroth
- Institute for Diagnostic and Interventional Neuroradiology (L.A., G.S., J.G.)
| | - R H Andres
- From the Department of Neurosurgery (L.A., J.B., W.J.Z., R.H.A., M.M., M.R., A.R.)
| | - M Murek
- From the Department of Neurosurgery (L.A., J.B., W.J.Z., R.H.A., M.M., M.R., A.R.)
| | - M Haenggi
- Intensive Care Medicine (M.H.), Inselspital, Bern University Hospital, University of Bern, Switzerland
| | - M Reinert
- From the Department of Neurosurgery (L.A., J.B., W.J.Z., R.H.A., M.M., M.R., A.R.)
| | - A Raabe
- From the Department of Neurosurgery (L.A., J.B., W.J.Z., R.H.A., M.M., M.R., A.R.)
| | - J Gralla
- Institute for Diagnostic and Interventional Neuroradiology (L.A., G.S., J.G.)
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Humm AM, Z'Graggen WJ. Venepuncture during head-up tilt testing in patients with suspected vasovagal syncope – implications for the test protocol. Eur J Neurol 2014; 22:389-94. [PMID: 25382753 DOI: 10.1111/ene.12590] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Accepted: 09/10/2014] [Indexed: 11/28/2022]
Abstract
BACKGROUND AND PURPOSE Head-up tilt (HUT) testing is a widely used diagnostic tool in patients with suspected vasovagal syncope (VVS). However, no gold standard exists for this examination and the various protocols used have a limited sensitivity and specificity. Our aim was to determine the sensitivity of a sequential HUT testing protocol including venepuncture (VP) and sublingual nitroglycerin application. METHODS This was a retrospective analysis of the diagnostic gain of a sequential HUT testing protocol including VP applied 10 min after the start of HUT testing and sublingual application of nitroglycerin 20 min after the start of the test protocol in 106 patients with a final diagnosis of VVS. The sensitivity of the test protocol was compared between patients with positive and negative history for VP induced VVS. RESULTS Overall, pre-syncope or syncope occurred in 68 patients (64.2%). Only 17% of all patients fainted spontaneously within 10 min of passive HUT. Another 39.6% fainted within 20 min. Application of nitroglycerin after 20 min of HUT evoked syncope in another 7.5% until the end of 45 min of HUT. The sensitivity of the test protocol for evoking (pre-)syncope was 94.4% in patients with a positive history for VP associated VVS and 58% in patients with a negative history (P < 0.01**); 85.7% of patients with a positive history and 42.9% of patients with a negative history fainted within 20 min of HUT testing (P < 0.01**). CONCLUSIONS Implementation of VP in sequential HUT testing protocols allows the sensitivity of HUT testing to be increased, especially in patients with a positive history for VP associated VVS.
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Affiliation(s)
- A M Humm
- Division of Neurology, Department of Internal Medicine, HFR Fribourg - Cantonal Hospital, Fribourg, Switzerland; Department of Neurology, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland
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7
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Abstract
BACKGROUND Rapid water ingestion improves orthostatic intolerance (OI) in multiple system atrophy (MSA) and postural tachycardia syndrome (PoTS). We compared haemodynamic changes after water and clear soup intake, the latter being a common treatment strategy for OI in daily practice. METHODS Seven MSA and seven PoTS patients underwent head-up tilt (HUT) without fluid intake and 30 min after drinking 450 ml of water and clear soup, respectively. All patients suffered from moderate to severe OI because of neurogenic orthostatic hypotension (OH) and excessive orthostatic heart rate (HR) increase, respectively. Beat-to-beat cardiovascular indices were measured non-invasively. RESULTS In MSA, HUT had to be terminated prematurely in 2/7 patients after water, but in 6/7 after clear soup. At 3 min of HUT, there was an increase in blood pressure of 15.7(8.2)/8.3(2.3) mmHg after water, but a decrease of 11.6(18.9)/8.1(9.2) mmHg after clear soup (P < 0.05). In PoTS, HUT could always be completed for 10 min, but OI subjectively improved after both water and clear soup. The attenuation of excessive orthostatic HR increase did not differ significantly after water and clear soup drinking. CONCLUSIONS In MSA, clear soup cannot substitute water for eliciting a pressor effect, but even worsens OI after rapid ingestion. In PoTS, acute water and clear soup intake both result in improvement of OI. These findings cannot solely be explained by difference in osmolarity but may reflect some degree of superimposed postprandial hypotension in widespread autonomic failure in MSA compared to the mild and limited autonomic dysfunction in PoTS.
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Affiliation(s)
- W J Z'Graggen
- Department of Neurology, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland
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8
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Z'Graggen WJ, Brander L, Tuchscherer D, Scheidegger O, Takala J, Bostock H. Muscle membrane dysfunction in critical illness myopathy assessed by velocity recovery cycles. Clin Neurophysiol 2010; 122:834-41. [PMID: 21044861 DOI: 10.1016/j.clinph.2010.09.024] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2010] [Revised: 09/08/2010] [Accepted: 09/23/2010] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To test the hypothesis that muscle fibers are depolarized in patients with critical illness myopathy by measuring velocity recovery cycles (VRCs) of muscle action potentials. METHODS VRCs were recorded from brachioradialis muscle by direct muscle stimulation in 10 patients in intensive care with evidence of critical illness myopathy (CIM). Two sets of recordings were made, mean 3.9 d apart, and compared with those from 10 age-matched controls. RESULTS Muscle supernormality was reduced in the patients by 50% compared with controls (P<0.002) and relative refractory period was increased by 59% (P<0.01). Supernormality was correlated with plasma potassium levels (R=-0.753, P<0.001), and the slope of this relationship was much steeper than previously reported for non-critically ill patients with renal failure (P<0.01). CONCLUSIONS The abnormal excitability properties indicate that the muscle fibers in CIM were depolarized, and/or that sodium channel inactivation was increased. The heightened sensitivity to potassium is consistent with the hypothesis that an endotoxin reduces sodium channel availability in depolarized muscle fibers. SIGNIFICANCE VRCs provide a practicable means to monitor muscle membrane changes in intensive care and to investigate the pathogenesis of CIM.
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Affiliation(s)
- W J Z'Graggen
- Department of Neurology, Inselspital, Bern University Hospital and University of Bern, Switzerland
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9
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Z'Graggen WJ, Aregger F, Farese S, Humm AM, Baumann C, Uehlinger DE, Bostock H. Velocity recovery cycles of human muscle action potentials in chronic renal failure. Clin Neurophysiol 2010; 121:874-81. [PMID: 20181515 DOI: 10.1016/j.clinph.2010.01.024] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2009] [Revised: 12/20/2009] [Accepted: 01/08/2010] [Indexed: 11/19/2022]
Abstract
OBJECTIVE To test the hypothesis that muscle fibers are depolarized in patients with chronic renal failure, by measuring velocity recovery cycles of muscle action potentials as indicators of muscle membrane potential. METHODS Velocity recovery cycles were recorded from brachioradialis muscle by direct muscle stimulation in 13 patients, before, immediately after, and 1h after haemodialysis, and compared with those from 10 age-matched controls. RESULTS In the patients, supernormality was reduced by 47%, and relative refractory period increased by 60.5% compared with controls (both P<0.001). Dialysis normalized the supernormality, but an hour later it was again reduced. These changes in supernormality were strongly correlated with the changes in serum potassium levels (P<0.0001). A late component of supernormality, attributed to potassium accumulation in the t-tubule system, was also reduced in the patients but remained abnormally low after dialysis. CONCLUSIONS Muscle membranes in the patients were chronically depolarized by hyperkalemia. Whereas dialysis transiently normalized muscle membrane potential, it was not adequate to normalize t-tubule function. SIGNIFICANCE Chronic muscle membrane depolarization by hyperkalemia may account for some of the functional deficits in uremic myopathy. Consistent normalization of membrane potential by avoiding hyperkalemia may therefore reduce symptoms of 'uremic myopathy'.
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Affiliation(s)
- W J Z'Graggen
- Department of Neurology, Inselspital, Bern University Hospital and University of Bern, Switzerland
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10
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Schroeder R, Ackermann KA, Tuchscherer D, Djafarzadeh S, Z'Graggen WJ, Sinderby C, Jakob SM, Takala J, Brander L. Twenty-four-hour neurally adjusted ventilatory assist and volume cycled ventilation have similar effects on respiratory neuromuscular function in a porcine model of fecal peritonitis. Crit Care 2010. [PMCID: PMC2934209 DOI: 10.1186/cc8438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Z'Graggen WJ, Conforto AB, Wiest R, Remonda L, Hess CW, Kaelin-Lang A. Mapping of direction and muscle representation in the human primary motor cortex controlling thumb movements. J Physiol 2009; 587:1977-87. [PMID: 19289547 DOI: 10.1113/jphysiol.2009.171066] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Larger body parts are somatotopically represented in the primary motor cortex (M1), while smaller body parts, such as the fingers, have partially overlapping representations. The principles that govern the overlapping organization of M1 remain unclear. We used transcranial magnetic stimulation (TMS) to examine the cortical encoding of thumb movements in M1 of healthy humans. We performed M1 mapping of the probability of inducing a thumb movement in a particular direction and used low intensity TMS to disturb a voluntary thumb movement in the same direction during a reaction time task. With both techniques we found spatially segregated representations of the direction of TMS-induced thumb movements, thumb flexion and extension being best separated. Furthermore, the cortical regions corresponding to activation of a thumb muscle differ, depending on whether the muscle functions as agonist or as antagonist for flexion or extension. In addition, we found in the reaction time experiment that the direction of a movement is processed in M1 before the muscles participating in it are activated. It thus appears that one of the organizing principles for the human corticospinal motor system is based on a spatially segregated representation of movement directions and that the representation of individual somatic structures, such as the hand muscles, overlap.
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Affiliation(s)
- W J Z'Graggen
- Department of Neurology, Inselspital, Bern University Hospital and University of Bern, Bern, Switzerland
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12
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Scheidegger O, Slotboom J, Z'Graggen WJ, Jung S, Luginbuehl M, Nirkko AC. Failure of muscular blood flow regulation in immune neuropathies. KLIN NEUROPHYSIOL 2009. [DOI: 10.1055/s-0029-1216105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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13
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Bostock H, Z'Graggen WJ. Muscle velocity recovery cycles: a tool to study muscle membrane properties in vivo. KLIN NEUROPHYSIOL 2009. [DOI: 10.1055/s-0029-1216103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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14
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Z'Graggen WJ, Brander L, Tuchscherer D, Brunello A, Passath C, Takala J, Jakob SM, Bostock H. Assessment of muscle membrane properties using muscle velocity recovery cycles in patients with critical illness polyneuromyopathy. Crit Care 2009. [PMCID: PMC4083997 DOI: 10.1186/cc7275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Abstract
Patients who are recovering from critical illness may be weak and difficult to wean from ventilatory support as a complication of their underlying disorder, intercurrent events or treatment given during prolonged intensive care. These patients are difficult to assess because of the severity of their weakness and any accompanying encephalopathy. It is essential to undertake a meticulous review, including assessment of any septic, hypoxic or metabolic derangements and a detailed look at the dosage and duration of medication including antibiotics, neuromuscular junction blocking agents and sedation. If a primary underlying neurological cause or an intercurrent event have been excluded, the likeliest cause of weakness is one of the neuromuscular complications of critical care such as: critical care polyneuropathy, an acute axonal neuropathy which develops in patients with preceding sepsis or multi-organ failure; the use of neuromuscular junction blocking agents or steroids; and critical illness myopathy, which is the most common cause of critical care related weakness.
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Affiliation(s)
- R S Howard
- National Hospital for Neurology and Neurosurgery, London, UK.
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16
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Abstract
Patients in intensive care units frequently suffer muscle weakness and atrophy due to critical illness polyneuropathy (CIP), an axonal neuropathy associated with systemic inflammatory response syndrome and multiple organ failure. CIP is a frequent and serious complication of intensive care that delays weaning from mechanical ventilation and increases mortality. The pathogenesis of CIP is not well understood and no specific therapy is available. The aim of this project was to use nerve excitability testing to investigate the changes in axonal membrane properties occurring in CIP. Ten patients (aged 37-76 years; 7 males, 3 females) were studied with electrophysiologically proven CIP. The median nerve was stimulated at the wrist and compound action potentials were recorded from abductor pollicis brevis muscle. Strength-duration time constant, threshold electrotonus, current-threshold relationship and recovery cycle (refractoriness, superexcitability and late subexcitability) were recorded using a recently described protocol. In eight patients a follow-up investigation was performed. All patients underwent clinical examination and laboratory investigations. Compared with age-matched normal controls (20 subjects; aged 38-79 years; 7 males, 13 females), CIP patients exhibited reduced superexcitability at 7 ms, from -22.3 +/- 1.6% to -7.6 +/- 3.1% (mean +/- SE, P approximately 0.0001) and increased accommodation to depolarizing (P < 0.01) and hyperpolarizing currents (P < 0.01), indicating membrane depolarization. Superexcitability was reduced both in patients with renal failure and without renal failure. In the former, superexcitability correlated with serum potassium (R = 0.88), and late subexcitability was also reduced (as also occurs owing to hyperkalaemia in patients with chronic renal failure). In patients without renal failure, late subexcitability was normal, and the signs of membrane depolarization correlated with raised serum bicarbonate and base excess, indicating compensated respiratory acidosis. It is inferred that motor axons in these CIP patients are depolarized, in part because of raised extracellular potassium, and in part because of hypoperfusion. The chronic membrane depolarization may contribute to the development of neuropathy.
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Affiliation(s)
- W J Z'Graggen
- Sobell Department of Neurophysiology, Institute of Neurology, London, UK
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17
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Humm AM, Z'Graggen WJ, Bühler R, Magistris MR, Rösler KM. Quantification of central motor conduction deficits in multiple sclerosis patients before and after treatment of acute exacerbation by methylprednisolone. J Neurol Neurosurg Psychiatry 2006; 77:345-50. [PMID: 16174651 PMCID: PMC2077708 DOI: 10.1136/jnnp.2005.065284] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVE To compare the effects of intravenous methylprednisolone (IVMP) in patients with relapsing-remitting (RR-MS), secondary progressive (SP-MS), and primary progressive multiple sclerosis (PP-MS). METHODS Clinical and neurophysiological follow up was undertaken in 24 RR-MS, eight SP-MS, and nine PP-MS patients receiving Solu-Medrol 500 mg/d over five days for exacerbations involving the motor system. Motor evoked potentials (MEPs) were used to measure central motor conduction time (CMCT) and the triple stimulation technique (TST) was applied to assess conduction deficits. The TST allows accurate quantification of the number of conducting central motor neurones, expressed by the TST amplitude ratio. RESULTS There was a significant increase in TST amplitude ratio in RR-MS (p<0.001) and SP-MS patients (p<0.02) at day 5, paralleling an increase in muscle force. TST amplitude ratio and muscle force remained stable at two months. In PP-MS, TST amplitude ratio and muscle force did not change. CMCT did not change significantly in any of the three groups. CONCLUSIONS In RR-MS and SP-MS, IVMP is followed by a prompt increase in conducting central motor neurones paralleled by improvement in muscle force, which most probably reflects partial resolution of central conduction block. The lack of similar clinical and neurophysiological changes in PP-MS corroborates previous clinical reports on limited IVMP efficacy in this patient group and points to pathophysiological differences underlying exacerbations in PP-MS.
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MESH Headings
- Adult
- Dose-Response Relationship, Drug
- Evoked Potentials, Motor/drug effects
- Evoked Potentials, Motor/physiology
- Female
- Humans
- Infusions, Intravenous
- Isometric Contraction/drug effects
- Isometric Contraction/physiology
- Male
- Methylprednisolone/adverse effects
- Methylprednisolone/therapeutic use
- Middle Aged
- Motor Neuron Disease/drug therapy
- Motor Neuron Disease/physiopathology
- Multiple Sclerosis, Chronic Progressive/diagnosis
- Multiple Sclerosis, Chronic Progressive/drug therapy
- Multiple Sclerosis, Chronic Progressive/physiopathology
- Multiple Sclerosis, Relapsing-Remitting/diagnosis
- Multiple Sclerosis, Relapsing-Remitting/drug therapy
- Multiple Sclerosis, Relapsing-Remitting/physiopathology
- Muscle, Skeletal/innervation
- Neural Conduction/drug effects
- Neural Conduction/physiology
- Optic Neuritis/drug therapy
- Optic Neuritis/physiopathology
- Pyramidal Tracts/drug effects
- Pyramidal Tracts/physiopathology
- Treatment Outcome
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Affiliation(s)
- A M Humm
- Department of Neurology, University of Berne, Switzerland
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18
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Z'Graggen WJ, Humm AM, Durisch N, Magistris MR, Rösler KM. Repetitive spinal motor neuron discharges following single transcranial magnetic stimuli: a quantitative study. Clin Neurophysiol 2005; 116:1628-37. [PMID: 15908271 DOI: 10.1016/j.clinph.2005.03.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2005] [Revised: 03/01/2005] [Accepted: 03/25/2005] [Indexed: 10/25/2022]
Abstract
OBJECTIVE To quantify repetitive discharges of spinal motor neurons (repMNDs) in response to single transcranial magnetic stimuli (TMS). To assess their contribution to the size of motor evoked potentials (MEPs). METHODS We combined the triple stimulation technique (TST) with an additional nerve stimulus in the periphery (= quadruple stimulation; QuadS). The QuadS eliminates the first action potential descending on each axon after TMS, and eliminates effects on response size induced by desynchronization of these discharges, thereby allowing a quantification of motor neurons (MNs) discharging twice. In some instances, a quintuple stimulation (QuintS) was used, to quantify the number of MNs discharging three times. Recordings were from the abductor digiti minimi of 14 healthy subjects, using two different stimulation intensities and three different levels of facilitatory muscle pre-contractions. RESULTS The threshold to obtain repMNDs was high. Their maximal size differed markedly between subjects, ranging from 8 to 52% of all MNs. Stimulation intensity and facilitatory muscle contraction, but not resting motor threshold, correlated with the amount of repMNDs. QuintS never yielded discernible responses, hence all observed repMNDs were double discharges. RepMNDs contributed to the MEP areas, but did not influence MEP amplitudes. CONCLUSIONS QuadS and QuintS allow precise quantification of repMNDs. The threshold of repMNDs is high and varies considerably between subjects. SIGNIFICANCE repMNDs have to be considered when MEP areas are measured. Their analysis may be of interest in neurological disorders, but standardized stimulation parameters appear essential.
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Affiliation(s)
- W J Z'Graggen
- Department of Neurology, Inselspital, University of Berne, Freiburgstrasse, CH-3010 Bern, Switzerland
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19
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Abstract
An immunocompetent patient recovering from gallstone-induced pancreatitis had to be readmitted due to abdominal pain, fever, and rapid deterioration. Computed tomography guided needle aspiration established the diagnosis of pancreatic necrosis infection; microbiological investigations revealed monoinfection with Lactobacillus paracasei subspecies tolerans. To our knowledge, this is the first description of a pancreatic necrosis infection due to L. paracasei in an immunocompetent patient without any known risk factors for Lactobacillus infections.
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Affiliation(s)
- W J Z'Graggen
- Department of Internal Medicine, Kantonsspital Aarau, Aarau, Switzerland.
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20
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Humm AM, Z'Graggen WJ, von Hornstein NE, Magistris MR, Rösler KM. Assessment of central motor conduction to intrinsic hand muscles using the triple stimulation technique: normal values and repeatability. Clin Neurophysiol 2004; 115:2558-66. [PMID: 15465445 DOI: 10.1016/j.clinph.2004.06.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/08/2004] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To establish the triple stimulation technique (TST) for recordings from the first dorsal interosseus (FDI) and the abductor pollicis brevis muscles (APB), and to analyse the test-retest repeatability of the TST measurements in APB. METHODS The recently developed TST was slightly modified for recordings from small hand muscles to account for volume conducted activity from surrounding muscles. The TST combines transcranial magnetic stimulation (TMS) with a peripheral collision technique [Magistris et al. Brain 121 (1998) 437]. In contrast to conventional motor-evoked potentials (MEPs), it quantifies the number of conducting central motor neurons (expressed by the TST amplitude ratio, TST-AR). MEPs and TST were performed in 30 sides of 25 healthy subjects (target muscle FDI), and in 29 sides of 21 healthy subjects (target muscle APB). All APB recordings were repeated after 25+/-5.9 days. RESULTS The TST-AR averaged 97.4+/-2.5% in FDI and 95.9+/-4.7% in APB. There was a mean difference of the TST-AR ratio of 2.9+/-3.1% between the repeated APB recordings (95% limits of agreement+/-6.3%). CONCLUSIONS TMS allows activation of virtually all motor neurons supplying FDI and APB, when effects of volume conduction are eliminated. Its test-retest repeatability is excellent. SIGNIFICANCE The TST is well suited for follow-up examinations of central motor conduction failures. The greater number of established target muscles widens its clinical applicability.
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Affiliation(s)
- A M Humm
- Department of Neurology, University of Berne, Inselspital, CH-3010 Berne, Switzerland.
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21
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Affiliation(s)
- A M Humm
- Department of Neurology, University of Berne, Berne, Switzerland.
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22
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Humm AM, Z'Graggen WJ, Remonda L, Rösler KM. Bilaterale axonale Läsion des N. facialis nach sagittaler Splitosteotomie: Eine Patientenbeschreibung. KLIN NEUROPHYSIOL 2003. [DOI: 10.1055/s-2003-816454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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23
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Z'Graggen WJ, Humm AM, Carruzzo A, Arnold M, Rösler KM. Elektrophysiologische Untersuchung des N. ulnaris im Bereich der Handwurzel. KLIN NEUROPHYSIOL 2003. [DOI: 10.1055/s-2003-816565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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24
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Rösler KM, Z'Graggen WJ, Humm AM. Desynchronisation von Motoneuronentladungen nach transkranieller Magnetstimulation: Eine quantitative Analyse. KLIN NEUROPHYSIOL 2003. [DOI: 10.1055/s-2003-816522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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25
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Z'Graggen WJ, Bregenzer T, Fankhauser H, Arnoux A, Laeng H, Itin PH. Primary cutaneous nocardiosis in an immune-competent patient. Eur J Dermatol 2001; 11:569-71. [PMID: 11701411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
We present a patient who was hospitalized due to a purulent skin lesion with a surrounding erythematous area in the region of the right paranasal crease accompanied by a swelling of the right eyelid. Initially the diagnosis of a carbuncle caused by an infection with Staphylococcus aureus was supposed. A surgical debridement was performed and an antibiotic therapy was started. Only special microbial investigations requested by the clinician led to the diagnosis of a cutaneous infection with Nocardia brasiliensis. The presented case is remarkable because the nocardia infection was in an immune-competent patient and the patient showed a primary cutaneous nocardiosis without dissemination.
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Affiliation(s)
- W J Z'Graggen
- Department of Internal Medicine, Hospital Cantonal Aarau, Switzerland
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26
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Z'Graggen WJ, Wehrli C, Gautschi K, Alex V, Conen D. [Differential diagnostic considerations in CK-MB level increase]. Praxis (Bern 1994) 2000; 89:1864-1867. [PMID: 11109924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We present two patients who were hospitalized due to thrombo-embolic disease. Both patients had an increase in total creatine kinase activity with the creatine kinase MB fraction value exceeding the total creatine kinase activity. We determined that the high values for creatine kinase MB fraction in the immunoinhibition assay were due to the existence of macro creatine kinase type I in one patient and a highly elevated creatinine kinase BB fraction in the other patient. The patient with macro CK type I had ulcerative colitis and the other patient with elevated CK BB fraction was diagnosed with prostatic carcinoma.
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27
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Z'Graggen WJ, Fouad K, Raineteau O, Metz GA, Schwab ME, Kartje GL. Compensatory sprouting and impulse rerouting after unilateral pyramidal tract lesion in neonatal rats. J Neurosci 2000; 20:6561-9. [PMID: 10964961 PMCID: PMC6772991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023] Open
Abstract
After lesions of the developing mammalian CNS, structural plasticity and functional recovery are much more pronounced than in the mature CNS. We investigated the anatomical reorganization of the corticofugal projections rostral to a unilateral lesion of the corticospinal tract at the level of the medullary pyramid (pyramidotomy) and the contribution of this reorganization and other descending systems to functional recovery. Two-day-old (P2) and adult rats underwent a unilateral pyramidotomy. Three months later the corticofugal projections to the red nucleus and the pons were analyzed; a relatively large number of corticorubral and corticopontine fibers from the lesioned side had crossed the midline and established an additional contralateral innervation of the red nucleus and the pons. Such anatomical changes were not seen after adult lesions. Intracortical microstimulation of the primary motor cortex with EMG recordings of the elbow flexor muscles were used to investigate possible new functional connections from the motor cortex of the pyramidotomy side to the periphery. In rats lesioned as adults, stimulation of the motor cortex ipsilateral to the pyramidotomy never elicited EMG activity. In contrast, in P2 lesioned rats bilateral forelimb EMGs were found. EMG latencies were comparable for the ipsilateral and contralateral responses but were significantly longer than in unlesioned animals. Transient inactivation of both red nuclei with the GABA receptor agonist muscimol led to a complete loss of these bilateral movements. Movements and EMGs reappeared after wash-out of the drug. These results suggest an important role of the red nucleus in the reconnection of the cortex to the periphery after pyramidotomy.
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Affiliation(s)
- W J Z'Graggen
- Brain Research Institute, University of Zurich and Swiss Federal Institute of Technology Zurich, CH-8057 Zurich, Switzerland.
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28
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Z'Graggen WJ, Itin PH, Conen D. [Progressive, small spotted, confluent erythema with bullae formation and general symptoms. Acute Lyell syndrome]. Praxis (Bern 1994) 2000; 89:1022-1024. [PMID: 10909325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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29
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Raineteau O, Z'Graggen WJ, Thallmair M, Schwab ME. Sprouting and regeneration after pyramidotomy and blockade of the myelin-associated neurite growth inhibitors NI 35/250 in adult rats. Eur J Neurosci 1999; 11:1486-90. [PMID: 10103143 DOI: 10.1046/j.1460-9568.1999.00560.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
After a selective unilateral lesion of the corticospinal tract (CST) at the level of the brainstem (pyramidotomy) and neutralization of the myelin associated neurite growth inhibitors NI-35/250 with the monoclonal antibody (mAb) IN-1, we had previously observed a strong behavioural recovery in parallel with an enhanced structural plasticity of the lesioned as well as the unlesioned CST. The present study focuses on the regenerative response of the cut CST axons at the lesion site in these adult rats. The results show a strong enhancement of regenerative sprouting of CST fibres by treatment with the mAb IN-1. Successful elongation of these sprouts through the pyramidal decussation and into the cervical spinal cord was also dependent on the presence of this antibody. In the spinal cord, regenerating fibres were rarely found in the position of the former CST; most of the fibres were distributed seemingly randomly over the entire lateral extent of the spinal cord.
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Affiliation(s)
- O Raineteau
- Brain Research Institute, University of Zürich, Switzerland.
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30
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Z'Graggen WJ, Metz GA, Kartje GL, Thallmair M, Schwab ME. Functional recovery and enhanced corticofugal plasticity after unilateral pyramidal tract lesion and blockade of myelin-associated neurite growth inhibitors in adult rats. J Neurosci 1998; 18:4744-57. [PMID: 9614248 PMCID: PMC6792708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
After a lesion of the mature CNS, structural plasticity and functional recovery are very limited, in contrast to the developing CNS. The postnatal decrease in plasticity is correlated in time with the formation of myelin. To investigate the possible role of an important myelin-associated neurite growth inhibitor (NI-250; IN-1 antigen), one pyramidal tract of adult Lewis rats was lesioned (pyramidotomy), and the rats were treated with the antibody IN-1, a control antibody, or no antibody. Functional recovery was studied from postoperative day 14 until day 42 using a food pellet reaching task, rope climbing, and a grid walk paradigm. The corticofugal projections to the red nucleus and basilar pontine nuclei were analyzed after survival times of 2 and 16 weeks. Treatment with the monoclonal antibody IN-1 resulted in almost complete restoration of skilled forelimb use, whereas all the control groups showed severe and chronic impairments. This functional recovery was paralleled by sprouting of the corticorubral and the corticopontine fibers across the midline, thus establishing a bilateral, anatomically specific projection.
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Affiliation(s)
- W J Z'Graggen
- Brain Research Institute, University of Zurich and Swiss Federal Institute of Technology Zurich, CH-8029 Zurich, Switzerland
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31
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Thallmair M, Metz GA, Z'Graggen WJ, Raineteau O, Kartje GL, Schwab ME. Neurite growth inhibitors restrict plasticity and functional recovery following corticospinal tract lesions. Nat Neurosci 1998; 1:124-31. [PMID: 10195127 DOI: 10.1038/373] [Citation(s) in RCA: 323] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Anatomical plasticity and functional recovery after lesions of the rodent corticospinal tract (CST) decrease postnatally in parallel with myelin formation. Myelin-associated neurite growth inhibitory proteins prevent regenerative fiber growth, but whether they also prevent reactive sprouting of unlesioned fibers is less clear. Here we show that after unilateral CST lesion in the adult rat brainstem, both intact and lesioned tracts show topographically appropriate sprouting after treatment with a monoclonal antibody that neutralizes these inhibitory proteins. Antibody-treated animals showed full recovery in motor and sensory tests, whereas untreated lesioned rats exhibited persistent severe deficits. Neutralization of myelin-associated neurite growth inhibitors thus restores in adults the structural plasticity and functional recovery normally found only at perinatal ages.
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Affiliation(s)
- M Thallmair
- Brain Research Institute, University of Zürich, Switzerland.
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