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Özyurt MG, Nascimento F, Brownstone RM, Beato M. On the origin of F-wave: involvement of central synaptic mechanisms. Brain 2024; 147:406-413. [PMID: 37796028 PMCID: PMC10834253 DOI: 10.1093/brain/awad342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 09/21/2023] [Accepted: 09/27/2023] [Indexed: 10/06/2023] Open
Abstract
Neurophysiological methods are used widely to gain information about motor neuron excitability and axon conduction in neurodegenerative diseases. The F-wave is a common biomarker used to test motor neuron properties in the diagnosis of neurological diseases. Although the origin of the F-wave is a subject of debate, the most widely accepted mechanism posits that the F-wave is generated by the backfiring of motor neurons stimulated antidromically from the periphery. In this study, we developed an ex vivo mouse sciatic nerve-attached spinal cord preparation with sensory axons severed. In this preparation, stimulation of the whole sciatic nerve or its tibial branch evoked responses with the electrophysiological signatures of F-waves. Manipulations of synaptic transmission by either removal of extracellular calcium or block of post-synaptic glutamate receptors abolished these responses. These results suggest that F-waves are mediated by spinal microcircuits activated by recurrent motor axon collaterals via glutamatergic synapses.
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Affiliation(s)
- M Görkem Özyurt
- Department of Neuroscience Physiology and Pharmacology (NPP), University College London, London WC1E 6BT, UK
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Filipe Nascimento
- Department of Neuroscience Physiology and Pharmacology (NPP), University College London, London WC1E 6BT, UK
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Robert M Brownstone
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Marco Beato
- Department of Neuroscience Physiology and Pharmacology (NPP), University College London, London WC1E 6BT, UK
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Miyara K, Etoh S, Kawamura K, Maruyama A, Kuronita T, Ohwatashi A, Shimodozono M. Effects of lower limb segmental muscle vibration on primary motor cortex short-latency intracortical inhibition and spinal excitability in healthy humans. Exp Brain Res 2021; 240:311-320. [PMID: 34724095 DOI: 10.1007/s00221-021-06257-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 10/23/2021] [Indexed: 12/19/2022]
Abstract
We examined the effects of lower limb segmental muscle vibration (SMV) on intracortical and spinal excitability in 13 healthy participants (mean age: 34.9 ± 7.8 years, 12 males, 1 female). SMV at 30 Hz was applied to the hamstrings, gastrocnemius, and soleus muscles for 5 min. Paired-pulse transcranial magnetic stimulation protocols were used to investigate motor-evoked potential (MEP) amplitude, short-interval intracortical inhibition (SICI) and short-interval intracortical facilitation (SICF) from the abductor hallucis muscle (AbdH). These assessments were compared to the results of a control experiment (i.e., non-vibration) in the same participants. F-waves were evaluated from the AbdH on the right (vibration side) and left (non-vibration side) sides, and we calculated the ratio of the F-wave amplitude to the M-response amplitude (F/M ratio). These assessments were obtained before, immediately after, and 10, 20, and 30 min after SMV. For SICI, there was no change immediately after SMV, but there was a decrease over time (before vs. 30 min after, p = 0.021; immediately after vs. 30 min after, p = 0.015). There were no changes in test MEP amplitude, SICF, or the F/M ratio. SMV causes a gradual decrease in SICI over time perhaps owing to long-term potentiation. The present results may have implications for the treatment of spasticity.
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Affiliation(s)
- Kodai Miyara
- Department of Rehabilitation, Kagoshima University Hospital, 8-35-1, Sakuragaoka, Kagoshima-city, Kagoshima, 890-8520, Japan. .,Doctoral Program, Graduate School of Health Sciences, Kagoshima University, Kagoshima, Japan.
| | - Seiji Etoh
- Department of Rehabilitation and Physical Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Kentaro Kawamura
- Department of Rehabilitation and Physical Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Atsuo Maruyama
- Department of Rehabilitation and Physical Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Takehiro Kuronita
- Master's Program, Department of Rehabilitation and Physical Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Akihiko Ohwatashi
- Faculty of Medicine, Course of Physical Therapy, School of Health Sciences, Kagoshima University, Kagoshima, Japan
| | - Megumi Shimodozono
- Department of Rehabilitation and Physical Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
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Mohammed NH, Hamdan FB, Al-Mahdawi AM. Evaluation of F wave and split hand index in patients with amyotrophic lateral sclerosis. THE EGYPTIAN JOURNAL OF NEUROLOGY, PSYCHIATRY AND NEUROSURGERY 2020. [DOI: 10.1186/s41983-020-00191-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Amyotrophic lateral sclerosis (ALS) is characterized by gradual disturbance of both upper and lower motor neurons (LMN). In ALS, muscle wasting favors the abductor pollicis brevis (APB) and first dorsal interosseous (FDI), with relative preservation of abductor digiti minimi (ADM).
Objectives
To interpret F wave changes in the context of upper and LMN dysfunction and the differences in dysfunction between spinal motoneurons innervating the APB and ADM.
Patients and methods
Forty-four subjects were studied (22 patients with ALS and 22 controls). F wave was elicited by 50 electrical stimuli from the median and ulnar nerves, and the split hand index (SHI) was measured.
Results
F latency mean, median, and maximum and F amplitude mean, median, and maximum F/M amplitude ratio were increased in patients with versus those without pyramidal signs. Limb-onset ALS patients showed the biggest reduction in SHI. The APB muscle of patients with no detectable wasting and upper MN (UMN) signs showed reduced F wave persistence, mean F wave latency and amplitudes, increased index repeater neuron and index F repeater, and mean F/M amplitude ratio.
Conclusion
There is enhanced segmental motoneuronal excitability following UMN dysfunctions. SHI appears to be a diagnostic biomarker for ALS. Abnormal F parameters recorded from APB muscle can distinct patients with ALS from the normal controls to a greater extent than do the APB/ADM and FDI/ADM compound muscle action potential amplitude ratios.
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Wang ZL, Liu M, Cai Z, Ding Q, Hu Y, Cui L. A prospective study on split-hand index as a biomarker for the diagnosis of amyotrophic lateral sclerosis. Amyotroph Lateral Scler Frontotemporal Degener 2020; 21:574-583. [PMID: 32608275 DOI: 10.1080/21678421.2020.1779299] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
OBJECTIVE To determine the practical diagnostic utility of split-hand index (SI) values calculated from F-wave persistence (SIFP) and the F/M amplitude ratio (SIF/M) for differentiating patients with amyotrophic lateral sclerosis (ALS) from other conditions. Methods: This prospective study recruited consecutive patients from Peking Union Medical College Hospital, China, between June 2019 and December 2019. Patients 18-80 years old who had clinical neuromuscular symptoms affecting the upper limbs and required electrophysiological examinations to aid diagnosis were eligible. Compound muscle action potentials (CMAPs) and F-waves recorded from the abductor pollicis brevis (APB), first dorsal interosseous muscle (FDI), and abductor digiti minimi (ADM) were examined. SIFP and SIF/M were calculated as: SI = (APB × FDI)/ADM. The sensitivity and specificity of SIFP and SIF/M in differentiating ALS from non-ALS conditions were derived using receiver operating characteristic (ROC) curves. Results: A total of 309 participants, comprising 91 (29.4%) with ALS and 218 (70.6%) with other neuromuscular disorders, were enrolled after 54 were excluded. SIFP was significantly reduced and SIF/M increased in the ALS group compared with the non-ALS group (p < 0.001). By ROC curve analysis, an SIFP cutoff of 73.3 showed 85.7% sensitivity and 80.7% specificity for differentiating ALS from non-ALS. SIF/M and SICMAP showed lower sensitivity (67% and 75.8%, respectively, p < 0.001) than SIFP for ALS diagnosis. SIFP and SIF/M combined did not outperform SIFP alone. Conclusion: SIFP could be a sensitive, noninvasive neurophysiological diagnostic marker for ALS patients with affected upper limbs. In particular, an SIFP value of 73.3 might be the optimal cutoff for diagnosing ALS.
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Affiliation(s)
- Zhi-Li Wang
- Department of Neurology, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China, and
| | - Mingsheng Liu
- Department of Neurology, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China, and
| | - Zhengyi Cai
- Department of Neurology, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China, and
| | - Qingyun Ding
- Department of Neurology, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China, and
| | - Youfang Hu
- Department of Neurology, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China, and
| | - Liying Cui
- Department of Neurology, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China, and.,Neuroscience Center, Chinese Academy of Medical Sciences, Beijing, China
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Simonet C, Schrag A, Lees AJ, Noyce AJ. The motor prodromes of parkinson's disease: from bedside observation to large-scale application. J Neurol 2019; 268:2099-2108. [PMID: 31802219 PMCID: PMC8179909 DOI: 10.1007/s00415-019-09642-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 11/13/2019] [Accepted: 11/14/2019] [Indexed: 12/12/2022]
Abstract
There is sufficient evidence that the pathological process that causes Parkinson's disease begins years before the clinical diagnosis is made. Over the last 15 years, there has been much interest in the existence of a prodrome in some patients, with a particular focus on non-motor symptoms such as reduced sense of smell, REM-sleep disorder, depression, and constipation. Given that the diagnostic criteria for Parkinson's disease depends on the presence of bradykinesia, it is somewhat surprising that there has been much less research into the possibility of subtle motor dysfunction as a pre-diagnostic pointer. This review will focus on early motor features and provide some advice on how to detect and measure them.
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Affiliation(s)
- C Simonet
- Preventive Neurology Unit, Wolfson Institute of Preventive Medicine, Queen Mary University of London, London, UK
| | - A Schrag
- Department of Clinical and Movement Neurosciences, Institute of Neurology, University College London, London, UK
| | - A J Lees
- Reta Lila Weston Institute of Neurological Studies, University College London, London, UK
| | - A J Noyce
- Preventive Neurology Unit, Wolfson Institute of Preventive Medicine, Queen Mary University of London, London, UK. .,Department of Clinical and Movement Neurosciences, Institute of Neurology, University College London, London, UK.
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Oguz Akarsu E, Sirin NG, Kocasoy Orhan E, Erbas B, Dede HO, Baslo MB, Idrisoglu HA, Oge AE. Repeater F-waves in amyotrophic lateral sclerosis: Electrophysiologic indicators of upper or lower motor neuron involvement? Clin Neurophysiol 2019; 131:96-105. [PMID: 31760213 DOI: 10.1016/j.clinph.2019.09.030] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Revised: 09/08/2019] [Accepted: 09/25/2019] [Indexed: 12/11/2022]
Abstract
OBJECTIVE To extract insight about the mechanism of repeater F-waves (Frep) by exploring their correlation with electrophysiologic markers of upper and lower motor neuron dysfunction in amyotrophic lateral sclerosis (ALS). METHODS The correlations of Frep parameters with clinical scores and the results of neurophysiological index (NI), MScanfit MUNE, F/M amplitude ratio (F/M%), single and paired-pulse transcranial magnetic stimulation (TMS), and triple stimulation technique (TST) studies, recorded from abductor digiti minimi (ADM) and abductor pollicis brevis (APB) muscles of 35 patients with ALS were investigated. RESULTS Frep parameters were correlated with NI and MScanfit MUNE in ADM muscle and F/M% in both muscles. None of the Frep parameters were correlated with clinical scores or TST and TMS measures. While the CMAP amplitudes were similar in the two recording muscles, there was a more pronounced decrease of F-wave persistence in APB, probably heralding the subsequent split hand phenomenon. CONCLUSION Our findings suggest that the presence and density of Freps are primarily related to the degree of lower motor neuron loss and show no correlation with any of the relatively extensive set of parameters for upper motor neuron dysfunction. SIGNIFICANCE Freps are primarily related to lower motor neuron loss in ALS.
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Affiliation(s)
- Emel Oguz Akarsu
- Istanbul University, Istanbul Faculty of Medicine, Department of Neurology, Istanbul, Turkey.
| | - Nermin Gorkem Sirin
- Istanbul University, Istanbul Faculty of Medicine, Department of Neurology, Istanbul, Turkey
| | - Elif Kocasoy Orhan
- Istanbul University, Istanbul Faculty of Medicine, Department of Neurology, Istanbul, Turkey
| | - Bahar Erbas
- Istanbul University, Istanbul Faculty of Medicine, Department of Neurology, Istanbul, Turkey; Demiroglu Bilim University, Faculty of Medicine, Department of Pharmacology, Istanbul, Turkey
| | - Hava Ozlem Dede
- Istanbul University, Istanbul Faculty of Medicine, Department of Neurology, Istanbul, Turkey
| | - Mehmet Baris Baslo
- Istanbul University, Istanbul Faculty of Medicine, Department of Neurology, Istanbul, Turkey
| | - Halil Atilla Idrisoglu
- Istanbul University, Istanbul Faculty of Medicine, Department of Neurology, Istanbul, Turkey
| | - Ali Emre Oge
- Istanbul University, Istanbul Faculty of Medicine, Department of Neurology, Istanbul, Turkey
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Ginanneschi F, Mondelli M, Aretini A, Rossi A. Reappraisal of the F/M amplitude ratio in carpal tunnel syndrome. FUNCTIONAL NEUROLOGY 2017; 32:23-27. [PMID: 28380320 DOI: 10.11138/fneur/2017.32.1.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The F-wave/M-wave amplitude (F/M-amp) ratio has been shown to be increased in peripheral neuropathies, provided the maximum M-wave is relatively preserved. Reduced M-wave amplitudes and central facilitation of antidromically-induced reactivation of the anterior horn cells' axon hillocks (F-wave) are believed to contribute to higher F/M-amp ratios. The present study was undertaken to re-evaluate mechanisms responsible for higher F/M-amp ratios in carpal tunnel syndrome (CTS). We enrolled 232 cases affected by CTS and 108 controls. Fand M-wave amplitudes and F-wave chronodispersion were analyzed for the median and ulnar nerves. The F/M-amp ratio of the median nerve in CTS subjects with moderate-severe nerve damage was significantly higher than that of mild CTS subjects and controls. Chronodispersion of the median nerve F-wave increased with increasing CTS severity. We conclude that the relative preservation of the median nerve F-wave is due to damage to the large diameter muscle afferent fibers responsible for the monosynaptic response. Absence of the monosynaptic response makes the small motoneurons, usually inaccessible to the antidromic volley because of its collision with the orthodromic reflex volley, able to fire in the F-wave.
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8
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Assessment of the upper motor neuron in amyotrophic lateral sclerosis. Clin Neurophysiol 2016; 127:2643-60. [PMID: 27291884 DOI: 10.1016/j.clinph.2016.04.025] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2015] [Revised: 04/22/2016] [Accepted: 04/27/2016] [Indexed: 02/07/2023]
Abstract
Clinical signs of upper motor neuron (UMN) involvement are an important component in supporting the diagnosis of amyotrophic lateral sclerosis (ALS), but are often not easily appreciated in a limb that is concurrently affected by muscle wasting and lower motor neuron degeneration, particularly in the early symptomatic stages of ALS. Whilst recent criteria have been proposed to facilitate improved detection of lower motor neuron impairment through electrophysiological features that have improved diagnostic sensitivity, assessment of upper motor neuron involvement remains essentially clinical. As a result, there is often a significant diagnostic delay that in turn may impact institution of disease-modifying therapy and access to other optimal patient management. Biomarkers of pathological UMN involvement are also required to ensure patients with suspected ALS have timely access to appropriate therapeutic trials. The present review provides an analysis of current and recently developed assessment techniques, including novel imaging and electrophysiological approaches used to study corticomotoneuronal pathology in ALS.
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Karakoyun A, Boyraz İ, Gunduz R, Karamercan A, Ozgirgin N. Electrophysiological and clinical evaluation of the effects of transcutaneous electrical nerve stimulation on the spasticity in the hemiplegic stroke patients. J Phys Ther Sci 2015; 27:3407-11. [PMID: 26696708 PMCID: PMC4681915 DOI: 10.1589/jpts.27.3407] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Accepted: 08/05/2015] [Indexed: 01/28/2023] Open
Abstract
To investigate whether transcutaneous electrical nerve stimulation (TENS) mitigates the spasticity of hemiplegic stroke patients, as assessed by electrophysiological variables, and the effects, if any, on the clinical appearance of spasticity. [Subjects and Methods] Twenty-seven subjects who had acute hemiplegia and 24 healthy people as the control group, were enrolled in this study. Some of the acute cerebrovascular disease patients could walk. Subjects who did not have spasticity, who were taking antispasticity medicine, or had a previous episode of cerebrovascular disease were excluded. The walking speed of the patients was recorded before and after TENS. EMG examinations were performed on the healthy controls and in the affected side of the patients. A 30-minute single session of TENS was applied to lower extremity. At 10 minutes after TENS, the EMG examinations were repeated. [Results] A statistically significant decrease in the spasticity variables, and increased walking speed were found post-TENS. The lower M amplitude and higher H reflex amplitude, H/M maximum amplitude ratio, H slope, and H slope/M slope ratio on the spastic side were found to be statistically significant. [Conclusion] TENS application for hemiplegic patients with spastic lower extremities due to cerebrovascular disease resulted in marked improvement in clinical scales of spasticity and significant changes in the electrophysiological variables.
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Affiliation(s)
- Ahmet Karakoyun
- Department of Physical Therapy and Rehabilitation, Aksaray State Hospital, Turkey
| | - İsmail Boyraz
- Department of Physical Therapy and Rehabilitation, School of Medicine, Abant Izzet Baysal University, Turkey
| | - Ramazan Gunduz
- Department of Physical Therapy and Rehabilitation, School of Medicine, Karabuk University, Turkey
| | | | - Nese Ozgirgin
- Ankara Physical Therapy and Rehabilitation Training and Research Hospital, Turkey
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10
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Abstract
ABSTRACT:The purpose of this investigation was to compare three methods of assessing the excitability of lower motoneurones—TA-reflex, H-reflex and F-wave—in 120 patients with spastic hemiparesis following a stroke. The H-reflex was recorded from the soleus muscle after submaximal electrostimulation of the tibial nerve. The T-Achilles (TA) reflex was recorded from the soleus muscle after percussion of the Achilles tendon. The F-wave was recorded in the distal limb muscles after supramaximal electrostimulation of the median, ulnar, fibular and tibial nerves. The patient’s healthy side was used as a control. The TA-reflex, H-reflex and F-wave showed increased amplitudes on the spastic side. All amplitude ratios: TA/M, H/M, Fmax/M and Fmean/M were increased. The H-reflex thresholds were decreased. The F-wave duration, persistence and number of phases were also increased on the spastic side. Despite clinically decreased muscle tone, there were no changes in TA or H-reflex parameters after treatment. On the other hand, F-wave parameters tended to normalize after treatment in all groups. In conclusion, the F-wave is a more sensitive method than the TA and H-reflexes in assessing the excitability of the lower motoneurone.
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11
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Fang J, Cui LY, Liu MS, Guan YZ, Li XG, Cui B, Ding QY. F Wave Study in Amyotrophic Lateral Sclerosis: Assessment of Segmental Motoneuronal Dysfunction. Chin Med J (Engl) 2015; 128:1738-42. [PMID: 26112713 PMCID: PMC4733717 DOI: 10.4103/0366-6999.159346] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Background: Dysfunctional spinal circuit may play a role in the pathophysiology of amyotrophic lateral sclerosis (ALS). The purpose of this study was to use F waves for assessment of segmental motoneuronal excitability following upper motor neuron (UMN) dysfunctions in ALS. Methods: We studied the F waves of 152 ulnar nerves recorded from abductor digiti minimi in 82 patients with ALS. Two groups of hands were defined based on the presence or absence of pyramidal signs in the same upper limb. The group with pyramidal signs in the upper limbs was designated as the P group, and the group without pyramidal signs in the upper limbs was designated as the NP group. Results: The mean (P < 0.001), median (P < 0.001) and maximum (P = 0.035) F wave amplitudes, mean (P < 0.001), median (P < 0.001) and maximum (P = 0.003) F/M amplitude ratio, index repeating neuron (P < 0.001) and index repeater F waves (P < 0.001) of the P group were significantly increased compared with the NP group. No significant differences were identified for F wave chronodispersion (P = 0.628), mean F wave latency (P = 0.151), minimum F wave latency (P = 0.211), maximum F wave latency (P = 0.199), F wave persistence (P = 0.738), F wave duration (P = 0.152), F wave conduction velocity (P = 0.813) and number of giant F waves (P = 0.072) between the two groups. Conclusions: In this study, increased F wave amplitude, F/M amplitude ratio and number of repeater F waves reflected enhanced segmental motoneuronal excitability following UMN dysfunctions in ALS.
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Affiliation(s)
| | - Li-Ying Cui
- Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
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Abstract
Multiple studies have demonstrated alterations in excitability in the central nervous system after peripheral nerve injury. However, there are few reports on changes in the central nervous system after peripheral facial nerve injury. Our objective was to determine the excitability changes that occur in the facial nucleus after facial nerve impairment. The excitability changes in the facial nucleus were investigated by assessing two types of compound muscle action potentials (M and F waves) in the orbicularis oculi muscles, evoked by electrical stimulation of the zygomatic branch of the facial nerve. In rats, M and F waves were measured in the orbicularis oculi muscles before and every week up to 8 weeks after the application of nerve compression under anesthesia. M and F waves disappeared after nerve compression, only to reappear 2 weeks later, although M-wave amplitude was decreased and the latencies of both waves were delayed. Thereafter, these waves recovered gradually. During the recovery period, the F/M wave amplitude ratio, which is an indicator of facial nucleus excitability, significantly increased on the impaired side but not on the intact side. This increase was most prominent within 3 weeks; thereafter, the ratio gradually decreased and reached the levels recorded before facial nerve impairment by 7 weeks. Facial nerve impairment leads to hyperexcitability of the facial nucleus during the recovery period.
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13
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Sahin N, Ugurlu H, Albayrak I. The efficacy of electrical stimulation in reducing the post-stroke spasticity: a randomized controlled study. Disabil Rehabil 2011; 34:151-6. [DOI: 10.3109/09638288.2011.593679] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Orhan EK, Yayla V, Cebeci Z, Baslo MB, Ovalı T, Öge AE. Excitability changes at brainstem and cortical levels in blind subjects. Clin Neurophysiol 2011; 122:1827-33. [DOI: 10.1016/j.clinph.2011.02.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2010] [Revised: 02/02/2011] [Accepted: 02/14/2011] [Indexed: 11/17/2022]
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15
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Chen SC, Chen YL, Chen CJ, Lai CH, Chiang WH, Chen WL. Effects of surface electrical stimulation on the muscle–tendon junction of spastic gastrocnemius in stroke patients. Disabil Rehabil 2009; 27:105-10. [PMID: 15823991 DOI: 10.1080/09638280400009022] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
PURPOSE The purpose of this study was to explore the effects of spasticity suppression by surface electrical stimulation (ES) o the muscle-tendon junction of spastic gastrocnemius muscles in stroke. METHODS Twenty-four neurologically stable stroke patients (aged 41-69 years, 12-35 months post-stroke), with spasticity graded 2 or 3 on the modified Ashworth scale, were recruited and divided into two groups. In the ES group, each patient received 20 min of surface ES once daily, 6 days per week for 1 month. In the control groups, ES was used with stimulation intensity kept at zero. To evaluate the therapeutic effect, the modified Ashworth scale, Fmax/Mmax ratio, H-reflex latency, H-reflex recovery curve, and the 10-m walking time were tested before and after the 1-month of treatment. RESULTS In the ES group, the modified Ashworth scale showed a trend toward reduced spasticity after 1 month of treatment. The Fmax/Mmax ratio decreased from 8.10% +/- 4.84% to 4.00% +/- 1.36%; the H-reflex latency increased from 28.87 +/- 2.45 ms to 29.40 +/- 2.57 ms; the H-reflex recovery curves indicated a downward shift; and the 10-metre walking time significantly decreased after ES. In the control group, none of the measures showed a statistically significant change. CONCLUSIONS In this study, we demonstrated a way to suppress spasticity at a metameric site and to increase walking speed effectively by applying surface ES on the muscle-tendon junction of spastic gastrocnemius muscles.
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Affiliation(s)
- S-C Chen
- Department of Physical Medicine and Rehabilitation, Taipei Medical University and Hospital, Taiwan
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Yayla V, Oge AE, Deymeer F, Gurvit H, Akca-Kalem S, Parman Y, Oflazer P. Cortical excitability in Duchenne muscular dystrophy. Clin Neurophysiol 2007; 119:459-65. [PMID: 18053763 DOI: 10.1016/j.clinph.2007.09.125] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2007] [Revised: 09/14/2007] [Accepted: 09/23/2007] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To investigate the probable cortical excitability changes in DMD by electrophysiological means. METHODS Sixteen cases with DMD, 10 age-matched control children (CC) and 10 healthy adult volunteers (AC) were studied with a transcranial magnetic stimulation (TMS) test battery composed of central conduction time, cortical silent period and paired TMS paradigm. RESULTS There were no significant differences between DMD and CC groups except for lower amplitude motor responses in DMD cases. These two groups showed a similar pattern of excitability with less short interval intracortical inhibitions and shorter silent period durations as compared to the AC subjects. CONCLUSIONS The electrophysiological tests performed in our DMD patients did not reveal abnormalities caused particularly by the disorder. SIGNIFICANCE TMS excitability studies performed in DMD boys may not provide findings other than those related to the developmental age.
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Affiliation(s)
- V Yayla
- Department of Neurology, Istanbul University Istanbul Faculty of Medicine, Capa 34390, Istanbul, Turkey.
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Oge AE, Yayla V, Demir GA, Eraksoy M. Excitability of facial nucleus and related brain-stem reflexes in hemifacial spasm, post-facial palsy synkinesis and facial myokymia. Clin Neurophysiol 2005; 116:1542-54. [PMID: 15953558 DOI: 10.1016/j.clinph.2005.02.021] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2004] [Revised: 02/09/2005] [Accepted: 02/21/2005] [Indexed: 10/25/2022]
Abstract
OBJECTIVE To compare the electrophysiological excitability characteristics of the facial nucleus and related structures in hemifacial spasm (HFS), post-facial palsy synkinesis (PFPS) and facial myokymia (FM). METHODS Facial F-waves, blink reflex recoveries and magnetically elicited silent periods (SP) were prospectively studied in 17 HFS, 17 PFPS, 8 FM cases and in 13 controls. Earlier unpublished observations on abnormal impulse transmission in 36 HFS and 29 PFPS cases were also included. RESULTS Enhanced F-waves were recorded on the symptomatic side in PFPS and HFS cases with a tendency to be more pronounced in PFPS. HFS and PFPS groups both showed an earlier blink reflex recovery, more prominent in PFPS patients, when stimulated and/or recorded on the symptomatic side. Unelicitable SPs were encountered after 24/39 stimulations in 5 patients with PFPS and rarely in HFS cases. Duration of elicitable SPs did not change remarkably. FM group had similar characteristics as normal controls in the 3 electrophysiological tests. Latencies of the lateral and synkinetic spread responses were significantly prolonged in the earlier PFPS group as compared to HFS. In two-point stimulation, both groups showed a greater latency shift in late responses, again more pronounced in PFPS. CONCLUSIONS PFPS and HFS cases had similar enhanced excitability patterns at the facial nucleus and related brain-stem structures, more marked on the symptomatic side and more obvious in the PFPS group. Findings elicited in the FM group were thought to be caused by asynchronous hyperactivity of facial motoneurons. SIGNIFICANCE In this comparative electrophysiological study, similar excitability patterns were found in HFS and PFPS groups, albeit with different intensities.
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Affiliation(s)
- A Emre Oge
- Department of Neurology, Istanbul University, Istanbul Faculty of Medicine, Capa 34390, Istanbul, Turkey.
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Mesrati F, Vecchierini MF. F-waves: neurophysiology and clinical value. Neurophysiol Clin 2004; 34:217-43. [PMID: 15639131 DOI: 10.1016/j.neucli.2004.09.005] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2004] [Accepted: 09/06/2004] [Indexed: 10/26/2022] Open
Abstract
This review deals with F responses, which are late responses obtained by supramaximal stimulation of virtually all the motor and mixed peripheral nerves. They are recorded over a muscle innervated by the stimulated nerve. The first description of F-waves was published in the fifties. Their neurophysiological mechanisms have been abundantly discussed in the literature leading to a current consensus, whereby F-waves are considered as antidromic responses produced by a pool of motoneurons activated by peripheral nerve stimulation. In the first part of this review, the neurophysiological mechanisms of F-waves as well as the distinction between these and H reflexes are described from a historical point of view. Other late responses are intentionally not reported; nevertheless A-waves are discussed since they are frequently ill-described in a number of conditions. Stimulation and recording procedures as well as F-wave parameters analysis are detailed, with emphasis on measures most useful for clinical purposes. A rigorous F-wave recording method is mandatory for reliable and meaningful analyses. Physiological factors, which influence F-waves such as ageing, drugs and sleep, must be known and their effects discussed. Also, as maturation is an important factor in clinical neurophysiology, data on F-wave ontogenesis are reviewed and discussed. Finally, the different F-wave alterations described so far in the literature, in either peripheral or central disorders, are listed and commented. It is emphasised that F-waves are particularly useful for the diagnosis of polyneuropathies at a very early stage and for the diagnosis of proximal nerve lesions. F-wave recording is indeed one of the rare methods in routine examination allowing at the same time the functional assessment of motor fibres on their proximal segment, and contributing to the evaluation of motoneuronal excitability.
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Affiliation(s)
- F Mesrati
- Service de physiologie, Laboratoire d'explorations fonctionnelles, Groupe hospitalier Bichat-Claude-Bernard, 46, rue Henri-Huchard, 75877 Paris cedex 18, France
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Elovic EP, Simone LK, Zafonte R. Outcome Assessment for Spasticity Management in the Patient With Traumatic Brain Injury. J Head Trauma Rehabil 2004; 19:155-77. [PMID: 15247825 DOI: 10.1097/00001199-200403000-00007] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The objective of this article was to (1) review the engineering and medical literature to structure the available information concerning the assessment of spasticity in the neurological population; (2) to discuss the strengths and weaknesses of the different methods currently in use in spasticity assessment; and (3) make recommendations for future efforts in spasticity outcome assessment. Spasticity textbooks, Web sites, and OVID, IEEE, and Medline searches from 1966 through 2003 of spasticity, quantitative measure, or outcome assessment in the rehabilitation population were used as data sources. Over 500 articles were reviewed. Articles that discussed outcome measures used to assess interventions and evaluation of spasticity were included. Authors reviewed the articles looking at inclusion criteria, data collection, methodology, assessment methods, and conclusions for validity and relevance to this article. Issues such as clinical relevance, real-world function and lack of objectivity, and time consumed during performance are important issues for spasticity assessment. Some measures such as the Ashworth Scale remain in common use secondary to ease of use despite their obvious functional limitations. More functional outcome goals are plagued by being more time consuming and a general inability to demonstrate changes after an intervention. This may be secondary to the other factors that combine with spasticity to cause dysfunction at that level. Quantitative metrics can provide more objective measurements but their clinical relevance is sometimes problematic. The assessment of spasticity outcome is still somewhat problematic. Further work is necessary to develop measures that have real-world functional significance to both the individuals being treated and the clinicians. A lack of objectivity is still a problem. In the future it is important for clinicians and the engineers to work together in the development of better outcome measures.
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Affiliation(s)
- Elie P Elovic
- Kessler Medical Rehabilitation Research and Education Corp., 1199 Pleasant Valley Way, West Orange, NJ 07052, USA.
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20
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de Carvalho M, Turkman A, Swash M. Motor responses evoked by transcranial magnetic stimulation and peripheral nerve stimulation in the ulnar innervation in amyotrophic lateral sclerosis: the effect of upper and lower motor neuron lesion. J Neurol Sci 2003; 210:83-90. [PMID: 12736094 DOI: 10.1016/s0022-510x(03)00024-8] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
We studied the upper (UMN) and lower motor neuron (LMN) innervations of 159 hands from 81 patients with amyotrophic lateral sclerosis (ALS). Eleven patients with various chronic LMN disorders causing weakness in the abductor digiti minimi (ADM) muscle served as LMN controls. Thirty healthy subjects served as normal controls. Cortical motor threshold, central conduction time (CMCT), and motor-evoked response amplitude (MEP) after transcranial magnetic stimulation (TMS) were studied, and the MEP/M wave ratio was calculated. The data was analyzed in the ALS subjects in groups defined by ADM muscle strength and by the presence or absence of clinical signs of UMN involvement. CMCT was not increased in the ALS or LMN disease groups. The threshold was higher in limbs with both weak ADM muscles and UMN signs. The MEP/M wave amplitude ratio was increased in weak muscles in the ALS patients, notably in limbs with no UMN signs, and also in weak muscles in patients with other chronic LMN disorders. It was frequently decreased in strong muscles. There was no difference between bulbar-onset and limb-onset ALS groups, and there was no correlation between threshold and disease duration. We suggest that expressing the data as an index and utilising the MEP/M wave amplitude ratio as a variable is a sensitive method for detecting UMN abnormality in ALS in particular in early affected muscles.
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Affiliation(s)
- Mamede de Carvalho
- EMG Laboratory of Centro de Estudos Egas Moniz, Department of Neurology, Hospital de Santa Maria, Lisbon, Portugal
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21
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Abstract
H reflexes and F waves have become integral parts of the electrodiagnostic examination in general, and nerve conduction studies in particular. They supplement the sensory and motor conduction studies by assessing the entire nerve segments including proximal portions of the motor and sensory axons. H reflexes and F waves have their own advantages and limitations, similarities and differences. These "late" responses are useful in patients with radiculopathies, plexopathies, and peripheral polyneuropathies, including the Guillain-Barre syndrome. They are also helpful in spinal cord disorders.
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Affiliation(s)
- Morris A Fisher
- Department of Neurology, Loyola University Stritch School of Medicine, Maywood, IL 60153, USA.
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22
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Abstract
This study was performed to create a normative database for median nerve F-wave responses for a large subject population so normal ranges could be created for subsets of the general population and the effect of various physical characteristics on F-wave results could be determined. One hundred ninety-five asymptomatic subjects without risk factors for neuropathy were recruited. Ten consecutive supramaximal stimuli were applied to the wrists of each arm to obtain median nerve F-wave results. The shortest F-wave latency (Fmin), mean latency (Fmean), range of latencies (Frange), and number of stimuli that resulted in F-wave recordings (Fpersist) were recorded. An analysis of variance revealed that age, gender, and height were associated with different results for Fmin and Fmean. For all subjects taken together, the mean Fmin was 26.8 +/- 2.4 ms. The mean Fmean was 28.3 +/- 2.6 ms, and the mean Frange was 3.4 +/- 1.9 ms. Five or more F-waves were elicited in 94% of the subjects. The mean side-to-side difference in Fmin was 0.2 +/- 1.2 ms. Additional findings are presented in the article.
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Abstract
This study was performed to create a large database of normal values for the ulnar F-wave study and to investigate the effect of various demographic factors on F-wave results. The study was designed to incorporate a standard distance measure and temperature control, which are lacking in some previous studies. One hundred ninety-three asymptomatic volunteers without risk factors for neuropathy were recruited and had ten F-waves performed on each arm. Data were collected for the shortest F-wave (Fmin), mean F-wave (Fmean), the number of F-waves present out of ten stimuli (Fpersist), and the range of latencies (Frange). An analysis of variance statistical procedure was applied, and the Fmin and Fmean were found to correlate with age, gender, and height, although the gender effect was relatively weak. For all subjects taken together, the mean Fmin was 26.5 +/- 2.5 ms. The Fmean was 27.7 +/- 2.5 ms, and the mean Frange was 2.6 +/- 1.2 ms. Ninety-seven percent of subjects had an Fpersist of five or more. Mean side-to-side difference for Fmin was 0.2 +/- 1.1 ms.
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24
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Abstract
This study was performed to create a large database of normal peroneal F-wave latencies. A total of 180 subjects were tested bilaterally and had their shortest (Fmin), mean (Fmean), and latency range (Frange) of F-waves recorded. The number of F-waves present out of ten stimuli (Fpersist) was also recorded. Demographic characteristics were noted and an analysis of variance was performed to determine whether any of these characteristics were associated with different results for the F-wave measures. Age and height, and, to a lesser extent, gender correlated with differences in Fmin, and Fmean, but not Frange. Race and body mass index (weight divided by height squared) were not associated with any differences in results. The mean Fmin was 50.2 +/- 5.5 ms. Mean Fmean was 52.0 +/- 5.6 ms and mean Frange was 4.9 +/- 2.3 ms. Median Fpersist was between 5 and 6. Mean side-to-side difference for Fmin was 0.7 +/- 2.4 ms. All other results are provided in the article. This article presents a database for normal values and the upper limits of normal for Fmin, Fmean, Frange, and side-to-side differences. A low Fpersist does not seem particularly clinically useful for the peroneal nerve, although a high Fpersist seems to be a sign of normality.
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25
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Abstract
Single thenar motor unit F waves (FMUPs) were collected from 23 healthy volunteers (age range 21-91 years, mean 46 +/- 20 SD). In each subject, 10 distinct FMUPs were recorded, using surface stimulating and recording electrodes, and the conduction velocity (CV) of each motor unit was calculated. The distribution of CVs (overall range 42-66 m/s; individual FMUP CV dispersion range 6-27% of the maximal FMUP CV) was close to those previously reported whatever the technique used. With age, a progressive CV reduction was observed, and maximal FMUP CV was significantly correlated with age (r = -0.58, P < 0.01), whereas no statistically significant correlation was found between minimal FMUP CV and age (r = -0.27, ns). Individual FMUP CV dispersion presented a statistically significant decrease with age (r = -0.46, P < 0.05). Furthermore, thenar motor unit number (MUNE), estimated by the adapted multiple point stimulation method, decreased progressively with age and was statistically correlated with maximal FMUP CV (r = 0.59, P < 0.01), whereas there was no correlation with minimal FMUP CV (r = 0.34, ns). Thus, we propose that motor unit loss is progressive with age throughout life, affecting particularly the largest and fastest conducting motor units. Preferential involvement of these fibers could be responsible for the age-related changes in motor nerve CV.
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Affiliation(s)
- F C Wang
- University Department of Neurology, Hôpital de la Citadelle, Bld du 12 ème de Ligne 1, B-4000 Liège, Belgium
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26
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Manconi FM, Syed NA, Floeter MK. Mechanisms underlying spinal motor neuron excitability during the cutaneous silent period in humans. Muscle Nerve 1998; 21:1256-64. [PMID: 9736053 DOI: 10.1002/(sici)1097-4598(199810)21:10<1256::aid-mus3>3.0.co;2-a] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The transient suppression of muscle contraction during the cutaneous silent period (CSP) could be produced either through postsynaptic inhibition of motoneurons or through presynaptic inhibition of the excitatory inputs to motoneurons that sustain voluntary contraction. We sought to delineate the mechanisms underlying the CSP in hand muscles by measuring changes in H-reflexes and motor-evoked potentials (MEPs) produced by transcranial magnetic stimulation (TMS) during the CSP in 10 healthy volunteers. H-reflexes and MEPs both measure the excitability of the motoneuron pool and activate similar subpopulations of motoneurons through different pathways. Inhibition of H-reflexes and MEPs of similar size was maximal at the midpoint of the CSP and gradually returned to baseline. The similar time course of recovery suggests that the H-reflex and MEP are affected by inhibition at a common site, most likely postsynaptic inhibition of the motoneurons.
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Affiliation(s)
- F M Manconi
- Electromyography Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892-1404, USA
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27
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Affiliation(s)
- M A Fisher
- Department of Neurology, Loyola University Medical Center, Maywood, Illinois, USA
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Doherty TJ, Komori T, Stashuk DW, Kassam A, Brown WF. Physiological properties of single thenar motor units in the F-response of younger and older adults. Muscle Nerve 1994; 17:860-72. [PMID: 8041393 DOI: 10.1002/mus.880170805] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The purpose of this study was to characterize the properties of single thenar motor units in the F-response of healthy younger (n = 15; age 33 +/- 11 years) and older subjects (n = 15; age 68 +/- 3 years). Trains of 300 stimuli at intensities evoking M-potentials 10%, 20%, and 30% of the peak-to-peak amplitude of the maximum M-potential, were delivered to the median nerve. In the young, observed firing probabilities of surface-detected motor unit action potentials (S-MUAPs) extracted from the F-response ranged from less than 1-10%, the S-MUAPs varied in size from 0.015% to 5.3% of the maximum M-potential negative peak area, and they were similar in size to the population of S-MUAPs collected by multiple point stimulation of the median nerve. The percentage difference between the slowest and fastest conducting fibers for individual subjects ranged from 8% to 20%, which translated to conduction velocities (CVs) of 48-68 m.s-1 (mean 59 +/- 4). The preceding were all independent of stimulus intensity. The S-MUAP sizes were significantly larger in older subjects (39%), and the range and distribution of motor unit CVs (38-61 m.s-1; mean 52 +/- 3) were markedly shifted to reflect a slower population of motor fibers. These findings suggest that age-related axonal slowing may uniformly affect all median motor fibers.
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Affiliation(s)
- T J Doherty
- Faculty of Kinesiology, University of Western Ontario, London, Canada
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29
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Abstract
This investigation estimated the mechanisms of tizanidine action on spasticity using a battery of neurophysiological methods. Thirty patients with old post-stroke spastic hemiparesis took part in the investigation. They were treated with tizanidine-mean daily dose 15.8 +/- 5.6 mg for a mean of 23.3 +/- 4.8 days. A questionnaire for assessment of subjective improvement after treatment used a 5-point scale. For standardization of the neurological examination 5-point scales were used to assess muscle tone, muscle force and tendon reflexes. A battery of neurophysiological methods was used to analyze different mechanisms of spasticity: for alpha motoneuron excitability--the F wave parameters; for presynaptic inhibition--the ratio of H reflex amplitudes before and after vibration of the achilles tendon (Hvibr/Hmax); for common interneuron activity--the flexor reflex parameters. Our results revealed that tizanidine reduces spastically increased muscle tone, but has no influence on muscle force, tendon reflexes, Babinski sign and ankle clonus. Tizanidine is supposed to act by increasing the presynaptic inhibition and decreasing of alpha motoneuron excitability. When spasticity has decreased presynaptic inhibition and increased motoneuron excitability, it is better to treat with tizanidine.
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Affiliation(s)
- I Milanov
- University Hospital, IV kilometer, III Neurological Clinic, Sofia, Bulgaria
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30
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Taniguchi MH, Hayes J, Rodriguez AA. Reliability Determination of F Mean Response Latency. Arch Phys Med Rehabil 1993. [DOI: 10.1016/s0003-9993(23)00003-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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31
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Zappia M, Valentino P, Marchello LP, Paniccia M, Montagna P. F-wave normative studies in different nerves of healthy subjects. ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 1993; 89:67-72. [PMID: 7679633 DOI: 10.1016/0168-5597(93)90087-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
F-wave main characteristics were investigated following stimulation of 8 different nerves (facial, axillary, radial, median, ulnar, femoral, deep peroneal, posterior tibial) in a population of normal healthy subjects. Additional studies compared different stimulation and recording techniques (stimulus intensity, stimulus duration, number of consecutive stimuli, facilitating maneuvers, type of recording electrodes). F-wave persistency varied markedly among the different nerves. Mean latencies were correlated to subjects' height, whereas conduction velocity was related to age. The optimal stimulation and recording parameters to obtain reliable information on F-wave studies were: stimulation duration of 0.2 msec with a strength adjusted 30% supramaximal to the direct M-response; administration of a train composed of 10 consecutive stimuli at rest and recording by concentric needle electrodes.
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Affiliation(s)
- M Zappia
- Institute of Neurology, University of Bologna, Italy
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32
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Fisher MA. AAEM Minimonograph #13: H reflexes and F waves: physiology and clinical indications. Muscle Nerve 1992; 15:1223-33. [PMID: 1488060 DOI: 10.1002/mus.880151102] [Citation(s) in RCA: 202] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Motoneurons can be activated both reflexly and antidromically following electrical stimulation of peripheral nerves. These H reflexes and F waves are clinically useful responses which interface at the level of the peripheral nerves and the spinal cord. Because these responses are commonly employed in the electrodiagnostic evaluation of patients, an understanding of their physiology and clinical applications is important. These are reviewed. Reasoning from the physiology, both the value and limitations of H-reflex and F-wave studies are considered for disorders of peripheral nerves, roots, and the central nervous system. Theoretical concepts about the physiology and pathophysiology of the nervous system based on H-reflex and F-wave data are also discussed.
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Affiliation(s)
- M A Fisher
- Department of Neurology, Loyola University Medical Center, Hines VA Hospital, IL 60141
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Uozumi T, Ito Y, Tsuji S, Murai Y. Inhibitory period following motor potentials evoked by magnetic cortical stimulation. ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 1992; 85:273-9. [PMID: 1380915 DOI: 10.1016/0168-5597(92)90116-s] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Following motor potentials evoked (MEPs) by magnetic cortical stimulation, there is a transient suppression of muscle action potentials (inhibitory period). We recorded MEPs, the inhibitory period, V1 waves and F waves from the abductor pollicis brevis muscle in 20 normal subjects and in 17 patients with spastic hyperreflexia due to cerebral infarction. The duration of the inhibitory period increased in correspondence with increasing stimulus intensity and did not necessarily depend on the amplitude of the MEPs. The duration of the inhibitory period elicited by a twin coil, which can stimulate the motor cortex locally, was shorter than by a single coil. The mean duration of the inhibitory period was significantly shorter in patients with spastic hyperreflexia than in normal subjects, and it correlated with the amplitude of F waves. The effects of the inhibitory period on V1 waves were different from its effects on F waves in one patient with large V1 and F waves. The amplitudes of V1 waves recorded during the inhibitory period were approximately 30-50% of the maximal amplitude of V1 waves, but F waves were not smaller. The inhibitory period is probably caused primarily by central inhibitory mechanisms.
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Affiliation(s)
- T Uozumi
- Department of Neurology, University of Occupational and Environmental Health, School of Medicine, Fukuoka, Japan
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Abstract
This investigation estimated the mechanisms of baclofen action on spasticity using a battery of electromyographic methods. Thirty patients with old post-stroke spastic hemiparesis took part in the investigation. They were treated with baclofen-mean daily dose 54.3 alpha 11.6 mg for a mean of 26.3 alpha 4.9 days. A questionnaire for assessment of subjective improvement after treatment used a 5-point scale. For standardization of the neurological examination 5-point scales were used to assess muscle tone, muscle force and tendon reflexes. A battery of electromyographic methods was used to analyse different mechanisms of spasticity: for alpha motoneurone activity--the F wave parameters; for gamma motoneurone activity--the T/H reflex amplitude ratio; for presynaptic inhibition--the ratio of H reflex amplitudes before and after vibration on the achilles tendon (Hvibr./Hmax); for common interneurone activity--the flexor reflex parameters. Our results revealed that baclofen reduces spastically increased muscle tone and Babinski sign. It has no influence on muscle force, tendon reflexes and ankle clonus. Baclofen acts by normalizing the altered interneurone activity and decreasing of alpha motoneurone activity. When spasticity has altered interneurone activity and increased motoneurone activity, it is better to treat with baclofen.
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Affiliation(s)
- I G Milanov
- Institute of Neurology, Psychiatry & Neurosurgery, IIIrd Neurological Clinic, Sofia, Bulgaria
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36
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Tanenbaum DI, Jabre JF. New method for expressing F-wave data as conduction velocity. J Electromyogr Kinesiol 1991; 1:68-74. [DOI: 10.1016/1050-6411(91)90028-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/13/1990] [Indexed: 10/26/2022] Open
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37
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Uncini A, Cutarella R, Di Muzio A, Assetta M, Lugaresi A, Gambi D. F response in vascular and degenerative upper motor neuron lesions. Neurophysiol Clin 1990; 20:259-68. [PMID: 2290410 DOI: 10.1016/s0987-7053(05)80116-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The F response represents the recurrent discharge of a small percentage of the motoneuron pool activated antidromically by any single impulse delivered to the nerve. We studied F waves from median nerve stimulation in 22 controls, in 30 patients with spasticity after cerebrovascular accident (CVA), and in 4 patients with familial spastic paraplegia (FSP). The following parameters were analyzed: median nerve conduction velocity, median nerve M response amplitude (M), average amplitude of 16 F responses (F16); persistence of F response (Fp) defined as the percentage of measurable responses to 16 stimuli, average amplitude of F response expressed as percentage of maximal M amplitude: (F16/M%). Results showed that Fp, F16 and F16/M% values were significantly increased on the spastic side of CVA patients and in FSP. Our findings indicate that after upper motor neuron lesions (whatever etiology and course) a change in the frequency of recurrent discharge and/or in the total number of lower motor neurons capable of backfiring occurs. Therefore, F response reflects the hyperexcitability state of the lower motor neurons in spasticity.
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Affiliation(s)
- A Uncini
- Institute of Clinical Neurology and Sciences of Behavior, University of Chieti, Italy
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