| 1. |
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| 2. |
- Barkhaus, Paul E., et al.
(författare)
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Revisiting the compound muscle action potential (CMAP)
- 2024
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Ingår i: Clinical Neurophysiology Practice. - : Elsevier. - 2467-981X. ; 9, s. 176-200
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Tidskriftsartikel (refereegranskat)abstract
- The compound muscle action potential (CMAP) is among the first recorded waveforms in clinical neurography and one of the most common in clinical use. It is derived from the summated muscle fiber action potentials recorded from a surface electrode overlying the studied muscle following stimulation of the relevant motor nerve fibres innervating the muscle. Surface recorded motor unit potentials (SMUPs) are the fundamental units comprising the CMAP. Because it is considered a basic, if not banal signal, what it represents is often underappreciated. In this review we discuss current concepts in the anatomy and physiology of the CMAP. These have evolved with advances in instrumentation and digitization of signals, affecting its quantitation and measurement. It is important to understand the basic technical and biological factors influencing the CMAP. If these influences are not recognized, then a suboptimal recording may result. The object is to obtain a high quality CMAP recording that is reproducible, whether the study is done for clinical or research purposes. The initial sections cover the relevant CMAP anatomy and physiology, followed by how these principles are applied to CMAP changes in neuromuscular disorders. The concluding section is a brief overview of CMAP research where advances in recording systems and computer-based analysis programs have opened new research applications. One such example is motor unit number estimation (MUNE) that is now being used as a surrogate marker in monitoring chronic neurogenic processes such as motor neuron diseases. CO 2024 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
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| 3. |
- Dengler, Reinhard, et al.
(författare)
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AANEM - IFCN glossary of terms in neuromuscular electrodiagnostic medicine and ultrasound
- 2020
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Ingår i: Clinical Neurophysiology. - : ELSEVIER IRELAND LTD. - 1388-2457 .- 1872-8952. ; 131:7, s. 1662-1663
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Forskningsöversikt (refereegranskat)abstract
- Modern neuromuscular electrodiagnosis (EDX) and neuromuscular ultrasound (NMUS) require a universal language for effective communication in clinical practice and research and, in particular, for teaching young colleagues. Therefore, the AANEM and the IFCN have decided to publish a joint glossary as they feel the need for an updated terminology to support educational activities in neuromuscular EDX and NMUS in all parts of the world. In addition NMUS has been rapidly progressing over the last years and is now widely used in the diagnosis of disorders of nerve and muscle in conjunction with EDX. This glossary has been developed by experts in the field of neuromuscular EDX and NMUS on behalf of the AANEM and the IFCN and has been agreed upon by electronic communication between January and November 2019. It is based on the glossaries of the AANEM from 2015 and of the IFCN from 1999. The EDX and NMUS terms and the explanatory illustrations have been updated and supplemented where necessary. The result is a comprehensive glossary of terms covering all fields of neuromuscular EDX and NMUS. It serves as a standard reference for clinical practice, education and research worldwide. (C) 2020 the American Association of Neuromuscular & Electrodiagnostic Medicine and the International Federation of Clinical Neurophysiology.
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| 4. |
- Dengler, Reinhard, et al.
(författare)
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AANEM - IFCN Glossary of Terms in Neuromuscular Electrodiagnostic Medicine and Ultrasound
- 2020
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Ingår i: Muscle and Nerve. - : WILEY. - 0148-639X .- 1097-4598. ; 62:1, s. 10-12
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Forskningsöversikt (övrigt vetenskapligt/konstnärligt)abstract
- Modern neuromuscular electrodiagnosis (EDX) and neuromuscular ultrasound (NMUS) require a universal language for effective communication in clinical practice and research and, in particular, for teaching young colleagues. Therefore, the AANEM and the IFCN have decided to publish a joint glossary as they feel the need for an updated terminology to support educational activities in neuromuscular EDX and NMUS in all parts of the world. In addition NMUS has been rapidly progressing over the last years and is now widely used in the diagnosis of disorders of nerve and muscle in conjunction with EDX. This glossary has been developed by experts in the field of neuromuscular EDX and NMUS on behalf of the AANEM and the IFCN and has been agreed upon by electronic communication between January and November 2019. It is based on the glossaries of the AANEM from 2015 and of the IFCN from 1999. The EDX and NMUS terms and the explanatory illustrations have been updated and supplemented where necessary. The result is a comprehensive glossary of terms covering all fields of neuromuscular EDX and NMUS. It serves as a standard reference for clinical practice, education and research worldwide.
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| 5. |
- Kouyoumdjian, Joao A., et al.
(författare)
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Concentric needle jitter in stimulated frontalis in 20 healthy subjects
- 2012
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Ingår i: Muscle and Nerve. - : Wiley. - 0148-639X .- 1097-4598. ; 45:2, s. 276-278
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Tidskriftsartikel (refereegranskat)abstract
- Normative data for jitter parameters using a disposable concentric needle have been presented in a few studies. Jitter, expressed as the mean consecutive difference (MCD), was measured in the frontalis muscle in 20 subjects by percutaneous bar stimulation of the temporal nerve branch. The mean MCD for individual studies (20) and for all potentials (600) were 16.05 +/- 2.73 mu s and 16.05 +/- 5.96 mu s, respectively. The suggested limit for mean MCD is 22 mu s and for outliers is 28 mu s.
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| 6. |
- Kouyoumdjian, Joao Aris, et al.
(författare)
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Concentric needle jitter on stimulated frontalis and extensor digitorum in 20 myasthenia gravis patients
- 2011
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Ingår i: Muscle and Nerve. - : Wiley. - 0148-639X .- 1097-4598. ; 44:6, s. 912-918
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Our objective was to study jitter parameters using a concentric needle electrode (CNE) in the extensor digitorum (ED) and frontalis (FR) muscles. Methods: Twenty myasthenia gravis (MG) patients, mean age 44.5 years, were studied. Percutaneous (FR) and intramuscular needle (ED) stimulation approaches were used. Jitter was expressed as the mean consecutive difference (MCD). The filter settings were from 1000 HZ to 10 kHZ. Results: Abnormal MCD was found in 85% for both ED and FR and in 90% when combining the two muscles. An abnormal percentage of outliers was found in 90% for ED and 85% for FR. The mean MCD did not show a difference for ED and FR, but the percentage of outliers and blocking were higher in FR. Abnormality was found in 93.7% (generalized) and in 75% (ocular) of MG cases. For ED outliers abnormality was greater than the MCD. Conclusion: CNE jitter is reliable for investigation of MG, although borderline findings should be judged with caution.
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| 7. |
- Kouyoumdjian, Joao Aris, et al.
(författare)
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Concentric needle jitter on stimulated Orbicularis Oculi in 50 healthy subjects
- 2011
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Ingår i: Clinical Neurophysiology. - : Elsevier BV. - 1388-2457 .- 1872-8952. ; 122:3, s. 617-622
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: The aim of this study was to estimate the jitter parameters in healthy controls in stimulated Orbicularis Oculi (OOc) muscle using concentric needle electrode (CNE). Methods: Fifty healthy subjects, 13 males and 37 females (21-56 years, mean age of 38 +/- 9.2 years) were studied. The zygomatic branch of facial nerve was stimulated with a bar electrode. Jitter was expressed as the mean consecutive difference (MCD). Filter settings 1000 Hz-10 kHz. Results: The mean MCD from individual studies (n = 50, Gaussian distribution) was 21.5 +/- 1.99 mu s (median = 21 mu s), ranging from 17.8 to 26 mu s (upper limit, 97.5%, 25.5 mu s). The mean and median MCD from all potentials (n = 1500, non-Gaussian distribution) were 21.6 and 21 mu s, ranging from 7.1 to 39 mu s (upper limit, 97.5%, 33.4 mu s). Conclusions: Suggested practical limits in the OOc for mean MCD was 26 mu s and for outliers 34 mu s. Significance: Stimulation jitter recordings with CNE could be used in practice but borderline findings should be judged with great caution until larger database obtained with uniform setting available.
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| 8. |
- Kouyoumdjian, Joao A., et al.
(författare)
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Concentric needle jitter on voluntary activated frontalis in 20 healthy subjects
- 2013
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Ingår i: Muscle and Nerve. - : Wiley. - 0148-639X .- 1097-4598. ; 47:3, s. 440-442
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Normative data for jitter parameters using a disposable concentric needle have been described in a few studies. Methods: Jitter, expressed as the mean consecutive difference (MCD), was measured in the frontalis muscle in 20 subjects by voluntary contraction. Results: Mean MCD for individual studies (20, Gaussian), all potentials (400, non-Gaussian), and 18th highest value (20, Gaussian) were 19.9 +/- 2.9 s, 19.9 +/- 6.6 s, and 26.9 +/- 4.4 s, respectively. Conclusion: The suggested upper normal limit for mean MCD is 26 s and for outliers is 36 s.
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| 9. |
- Kouyoumdjian, Joao Aris, et al.
(författare)
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Concentric needle single fiber electromyography : Comparative jitter on voluntary-activated and stimulated Extensor Digitorum Communis
- 2008
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Ingår i: Clinical Neurophysiology. - : Elsevier BV. - 1388-2457 .- 1872-8952. ; 119:7, s. 1614-1618
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To compare the jitter values in voluntarily activated (v-CNE) and stimulated (s-CNE) techniques for Extensor Digitorum Communis muscle using a disposable concentric needle electrode (CNE). Quantifying jitter using a CNE in conjunction with a stimulated technique has not been reported previously. Methods: Forty-one normal subjects were studied, 15 male and 26 female with a mean age of 34.1 +/- 10.7 years (19-55). The jitter values were expressed as the mean consecutive difference (MCD) of 20 analyzed potential pairs using v-CNE and 30 isolated potentials using s-CNE. Results: The mean MCD (n = 41) was 23.0 +/- 2.8 mu s for v-CNE and 18.2 +/- 2.2 mu s for s-CNE. The mean jitter of all recorded potentials was 22.9 +/- 6.7 mu s for v-CNE (n = 820) and 18.3 +/- 5.2 mu s for s-CNE (n = 1230). Upper limits for the 18th (v-CNE) and 27th highest (s-CNE) MCD were 38.9 and 30 mu s, respectively (95% confidence limit). The jitter decrease in s-CNE compared to v-CNE was 1:0.79. Conclusions: Our findings of the jitter values using CNE were similar to other published reports using the voluntarily activated technique; however, these are the first described for the stimulated technique using CNE. Significance: The present study confirms that CNE can be used for the stimulated jitter acquisition and measurement, although certain precautions must be taken regarding signal quality, e.g., observing minimal summation.
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| 10. |
- Kouyoumdjian, João Aris, et al.
(författare)
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Reference jitter values for concentric needle electrodes in voluntarily activated extensor digitorum communis and orbicularis oculi muscles.
- 2008
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Ingår i: Muscle and Nerve. - : Wiley. - 0148-639X .- 1097-4598. ; 37:6, s. 694-699
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to estimate normal jitter in voluntarily activated extensor digitorum communis (EDC) and orbicularis oculi (OOc) muscles using a disposable concentric needle electrode (CNE). The EDC of 67 normal subjects (22 males and 45 females, mean age 35.5 ± 10.2 years) and the OOc of 50 normal subjects (13 males and 37 females, mean age 37.9 ± 9.6 years) were studied. Jitter values were expressed as the mean consecutive difference (MCD) of 20 potential pairs. The mean MCD for EDC was 23.6 ± 3.1 µs (upper 95% confidence limit [CL]: 29.7 µs). The mean MCD of all potential pairs (n = 1340) was 23.5 ± 7.3 µs (95% CL: 38.2 µs). The mean MCD for the 18th highest value was 31.4 ± 4.9 µs (95% CL: 41.2 µs). The mean MCD for OOc was 24.7 ± 3.1 µs (95% CL: 31.0 µs). The mean MCD of all potential pairs (n = 1000) was 24.7 ± 7.1 µs (95% CL: 39.0 µs). The mean MCD for the 18th highest value was 32.7 ± 4.1 µs (95% CL: 40.9 µs). Our reported CNE jitter values obtained during voluntary activation represent the largest series currently available. The suggested practical limit in the EDC for mean MCD was 30 µs and for outliers was 42 µs, and in the OOc for mean MCD was 31 µs and 41 µs for outliers. The present study confirms that CNE can be used to assess jitter values, although certain precautions must be taken.
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| 11. |
- Løseth, Sissel, et al.
(författare)
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Early diabetic neuropathy : thermal thresholds and intraepidermal nerve fibre density in patients with normal nerve conduction studies.
- 2008
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Ingår i: Journal of Neurology. - : Springer Science and Business Media LLC. - 0340-5354 .- 1432-1459. ; 255:8, s. 1197-1202
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES To determine whether neuropathy in diabetic patients with normal nerve conduction studies could be detected by measurements of thermal thresholds and quantification of intraepidermal nerve fibre (IENF) density, and to evaluate differences in parameters between patients with and without neuropathic symptoms. METHODS A total of 22 patients with and 37 patients without sensory symptoms suggesting distal neuropathy were included. Measurements of warm and cold perception thresholds and skin biopsy for quantification of IENFs were performed distally on the leg. Reference data were used to normalize test results for age and height or gender of individual patients by calculating the Z-scores. RESULTS IENF density was significantly reduced in both symptomatic and asymptomatic patients compared to controls (p < 0.001), and in patients with symptoms compared to those without (p = 0.01). Thermal thresholds were significantly elevated (more abnormal) in patients with symptoms compared to controls (p < 0.01), but only for cold perception threshold (CPT) (p < 0.001) in the asymptomatic group. When comparing symptomatic and asymptomatic patients, there was no statistically significant difference in thermal thresholds. Depletion of IENFs in skin biopsy was the most frequent abnormal finding in the subgroup of patients with neuropathic symptoms (36 %) followed by abnormal CPT (27 %). CONCLUSION Patients with diabetes and normal nerve conduction studies had significantly lower IENF density and higher CPT than controls, whether they had symptoms of polyneuropathy or not. In patients with neuropathic symptoms, abnormal IENF density predominated and seemed thus to be the most sensitive tool of detecting small diameter nerve fibre involvement.
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| 12. |
- Løseth, Sissel, et al.
(författare)
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Small and large fiber neuropathy in those with type 1 and type 2 diabetes : a 5-year follow-up study
- 2016
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Ingår i: Journal of the peripheral nervous system. - : Wiley. - 1085-9489 .- 1529-8027. ; 21:1, s. 15-21
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to evaluate progression of diabetic polyneuropathy and differences in the spectrum and evolution of large- and small-fiber involvement in patients with diabetes type 1 and 2 over 5 years. Fifty-nine patients (35 type 1 and 24 type 2) were included. Nerve conduction studies (NCS), quantitative sensory testing, skin biopsy for quantification of intraepidermal nerve fiber density (IENFD), symptom scoring and clinical evaluations were performed. Z-scores were calculated to adjust for the physiologic effects of age and height/gender. Neuropathic symptoms were not significantly more frequent in type 2 than in type 1 diabetic patients at follow-up (54% vs. 37%). The overall mean NCS Z-score remained within the normal range, but there was a small significant decline after 5 years in both groups: type 1 (p = 0.004) and type 2 (p = 0.02). Mean IENFD Z-scores changed from normal to abnormal in both groups, but only significantly in those with type 2 diabetes (reduction from 7.9 +/- 4.8 to 4.3 +/- 2.8 fibers/mm, p = 0.006). Cold perception threshold became more abnormal only in those with type 2 diabetes (p = 0.049). There was a minimal progression of large fiber neuropathy in both groups. Reduction of small fibers predominated and progressed more rapidly in those with type 2 diabetes.
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| 13. |
- Marrero, Humberto Gonzalez, et al.
(författare)
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Optimizing testing methods and collection of reference data for differentiating critical illness polyneuropathy from critical illness myopathy.
- 2016
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Ingår i: Muscle and Nerve. - : Wiley. - 0148-639X .- 1097-4598. ; 53:4, s. 555-563
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: In severe acute quadriplegic myopathy in intensive care unit (ICU) patients, muscle fibers are electrically inexcitable; in critical illness polyneuropathy the excitability remains normal. Conventional electrodiagnostic methods do not provide the means to adequately differentiate between them.OBJECTIVE: To further optimize methodology for the study of critically ill ICU patients and to create a reference database in healthy controls.METHODS: Different electrophysiologic protocols were tested to find sufficiently robust and reproducible techniques for clinical diagnostic applications.RESULTS: Many parameters show large test-retest variability within the same healthy subject. Reference values have been collected and described as a basis for studies of weakness in critical illness.DISCUSSION: Using the ratio of neCMAP/dmCMAP (response from nerve and direct muscle stimulation), refractory period, and stimulus-response curves may optimize the electrodiagnostic differentiation of patients with critical illness myopathy from those with critical illness polyneuropathy.
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| 14. |
- Nandedkar, Sanjeev D., et al.
(författare)
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Cumulative Motor Index : An Index to Study Progression of Amyotrophic Lateral Sclerosis
- 2015
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Ingår i: Journal of clinical neurophysiology. - 0736-0258 .- 1537-1603. ; 32:1, s. 79-85
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Tidskriftsartikel (refereegranskat)abstract
- Purpose:To study disease progression in patients with amyotrophic lateral sclerosis (ALS), we have developed the cumulative motor index (CMI) using the compound muscle action potential amplitude recorded in multiple upper and lower limb muscles.Methods:To study its reproducibility, CMI was measured by 2 operators in 10 healthy subjects on 2 occasions. In 15 patients with ALS, CMI and ALS functional rating score (revised) were measured at 3- to 6-month interval for 12 months or longer.Results:The CMI had good reproducibility in healthy subjects. In one patient with ALS, CMI and ALS functional rating score (revised) remained relatively unchanged. In all remaining 14 patients with disease progression, CMI decreased in a relatively monotonic manner. At 1 year after baseline study, CMI was reduced more than ALS functional rating score (revised) in 10 patients. CMI measurements were possible for longer time period, than analysis from a single distal muscle recording.Conclusions:The CMI can be measured using standard equipment and software available in most electrodiagnostic laboratories. This may be a simple measurement that can be used for clinical studies of ALS progression over longer time periods.
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| 15. |
- Nandedkar, Sanjeev D., et al.
(författare)
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Experiment for teaching virtual cathode in nerve conduction studies
- 2021
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Ingår i: Muscle and Nerve. - : John Wiley & Sons. - 0148-639X .- 1097-4598. ; 64:1, s. 86-89
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Tidskriftsartikel (refereegranskat)abstract
- Introduction/AimsThe virtual cathode (VC) is a site near the anode where the nerve can be stimulated. Costimulation of neighboring nerves via the VC can affect recording and interpretation of responses. Hence, it is important to teach trainees the concept of the VC. The VC has been demonstrated previously with subtle changes in response latency, amplitude, and shape. Herein we describe an experiment that simply demonstrates a VC with its effects recognizable by gross changes in waveforms.MethodsCompound muscle action potentials of the abductor pollicis brevis were recorded using various placements of the cathode and anode at different stimulus intensity levels. Studies were performed in nine healthy subjects.ResultsThree patterns were observed that demonstrated no stimulation, partial stimulation, and complete nerve stimulation by the VC. Partial stimulation yielded responses with long duration and low amplitude. Response patterns also depended on stimulus strength and proximity of the nerve from the skin surface.DiscussionThis experiment demonstrates that nerve stimulation can occur near the anode when high-intensity stimulus is used. It also illustrates collision of action potentials. This exercise can help trainees understand potential pitfalls in nerve conduction studies, especially at very proximal stimulation sites or when high stimulus intensity is used.
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| 16. |
- Nandedkar, Sanjeev D., et al.
(författare)
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MeRef : Multivariable extrapolated reference values in motor nerve conduction studies
- 2021
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Ingår i: Muscle and Nerve. - : John Wiley & Sons. - 0148-639X .- 1097-4598. ; 63:5, s. 737-744
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: In this study we describe a method called "multivariable extrapolated reference values" (MeRef) that derives reference values (RVs) using patient data and includes the dependence of these variables on multiple patient demographic variables, such as age and height. Methods: Computer simulations were used to generate "normal" and "patient" nerve conduction data. Median, ulnar, and tibial motor nerve conduction data from 500 patients studied were tabulated. Data were analyzed using the MeRef method. Results: The simulations showed great similarity between RVs obtained from MeRef of "patient" data and traditional analysis of "normal" data. In the real patient data, MeRef gave RVs as regression equations based on patient age and/or height. Discussion: MeRef can provide RVs by including patient demographic data and does not require subject grouping. It provides parameters of multivariable linear regression and standard deviation, and requires a few hundred patient studies to define reference values.
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| 17. |
- Nandedkar, Sanjeev D., et al.
(författare)
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Motor unit number index (MUNIX) : principle, method, and findings in healthy subjects and in patients with motor neuron disease
- 2010
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Ingår i: Muscle and Nerve. - : Wiley. - 0148-639X .- 1097-4598. ; 42:5, s. 798-807
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Tidskriftsartikel (refereegranskat)abstract
- The motor unit number index (MUNIX) is a method for assessment of number and size (MUSIX) of motor units (MUs) using the compound muscle action potential (CMAP) and surface electromyographic interference pattern (SIP). This method was used to study the hypothenar muscle in 34 healthy subjects to define normal range, and to study reproducibility. Four healthy subjects and 13 patients with amyotrophic lateral sclerosis (ALS) were studied serially over a 1-year period. In healthy subjects, MUNIX showed good reproducibility. In serial studies, healthy subjects showed no change in the CMAP amplitude and MUNIX. ALS patients with minimal change in CMAP amplitude had a significant drop in MUNIX and increase in MUSIX, indicating MU loss compensated by reinnervation. When the CMAP changed significantly (>30%) in 1 year, the CMAP and MUNIX decreased in parallel. MUNIX would be useful to study MU loss in degenerative diseases of motor neurons.
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| 18. |
- Nandedkar, Sanjeev D., et al.
(författare)
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Motor unit recruitment and firing rate at low force of contraction
- 2022
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Ingår i: Muscle and Nerve. - : John Wiley & Sons. - 0148-639X .- 1097-4598. ; 66:6, s. 750-756
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Tidskriftsartikel (refereegranskat)abstract
- Introduction/Aims: A prevailing concept of motor unit (MU) recruitment used for calculating recruitment ratio (RR) suggests a progressive linear increase in firing rate (FR). The objective of this study is to assess its validity. Methods: Concentric needle electromyography (EMG) recordings were made in normal muscle and abnormal muscle of patients with neurogenic findings. Signals recorded at low force were visually decomposed to study MU FR at onset, recruitment of a second MU, and recruitment of more MUs with further increases in force. Results: We observed one to six MUs discharging at a rate < 15 Hz in normal muscles at low force. The MU FR was 5-8 Hz at onset. With increasing force, FR increased by 3-5 Hz and then idled at <15 Hz while other MUs were recruited. The recruitment frequency (RF) and RR had low sensitivity and were abnormal mainly in moderately to severely weak muscles. Discussion: Our data are consistent with FR analysis results described by other investigators. It does not support a progressive linear increase in MU FR with recruitment. A revised model for MU recruitment at low effort during gradual increase in force is presented. On subjective assessment, the FR of the fastest firing MU can help detect MU loss in neurogenic processes.
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| 19. |
- Nandedkar, Sanjeev D., et al.
(författare)
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Quantitative measurements and analysis in electrodiagnostic studies : present and future
- 2008
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Ingår i: Future neurology. - : Future Medicine Ltd. - 1748-6971 .- 1479-6708. ; 3:6, s. 745-764
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Tidskriftsartikel (refereegranskat)abstract
- Electrodiagnostic studies (nerve conduction and needle electromyography) are powerful methods to study diseases of nerves and muscles. Conduction studies are performed to assess the continuity, anatomic course, excitability, number of axons and their synaptic connections, while needle electromyography examination is performed to assess the ‘electrical stability’ of the muscle fiber membrane, and the study of motor units (architecture, activation and number). We have reviewed the relationship between the quantitative measurements and the generators of the recorded potentials. Based on these relationships, the expected patterns of abnormalities for different pathologies are tabulated. This gives us a better appreciation of the sensitivity, specificity and usefulness of different tests when planning and conducting an electrodiagnostic examination. The limitations of current methods are indicated to suggest the need for future development.
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| 20. |
- Nandedkar, Sanjeev D., et al.
(författare)
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Reproducibility of munix in patients with amyotrophic lateral sclerosis
- 2011
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Ingår i: Muscle and Nerve. - : Wiley. - 0148-639X .- 1097-4598. ; 44:6, s. 919-922
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: In this study we investigated the reproducibility of motor unit number index (MUNIX) in patients with amyotrophic lateral sclerosis (ALS). Methods: MUNIX was recorded in patients with ALS. Studies were performed in 18 thenar and 18 hypothenar muscles by two operators. The reproducibility was assessed using mean MUNIX values, linear regression, correlation coefficient, and coefficient of variation (COV) in individual studies. Results: The mean values showed no significant difference. The linear regression showed a strong correlation. Most patients had low COV. A high COV was seen when MUNIX was very low. The COV was higher in thenar than in hypothenar muscles. Conclusions: MUNIX has very good reproducibility in ALS patients. COV may exaggerate interoperator variation when MUNIX is very low. The higher variability in the thenar muscle is also due to variability in compound muscle action potential amplitude. Although both muscles show good reproducibility, the hypothenar is better suited for serial studies in individual patients.
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| 21. |
- Nebuchennykh, M., et al.
(författare)
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Quantitative sensory testing in patients with polyneuropathy and healthy individuals
- 2008
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Ingår i: Acta Neurologica Scandinavica, Supplementum. - : Hindawi Limited. - 0065-1427 .- 1600-5449 .- 0001-6314 .- 1600-0404. ; 117:188, s. 56-61
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Tidskriftsartikel (refereegranskat)abstract
- AIMS Elderly individuals and patients with polyneuropathy often feel heat pain or burning sensation on quantitative sensory testing (QST) of warm perception distally in the lower limbs. We therefore studied heat pain threshold (HPT), warm perception threshold (WPT) and the difference between heat pain and warm perception thresholds in 48 patients with symptoms and signs of polyneuropathy matched according to age and gender with 48 healthy persons. METHODS QST (using method of limits) was performed on the distal calf and the dorsal foot. RESULTS Particularly in the neuropathy group several individuals (58%) had an unpleasant feeling, often burning, when the thresholds according to the WPT algorithm were recorded. Difference between heat pain and warm perception thresholds in the lower calf of the patients was 3.9 +/- 3.5 and 5.8 +/- 3.4 degrees C in the controls (P = 0.012), and on the foot 3.8 +/- 2.8 vs 5.3 +/- 3.6 degrees C (P = 0.02). CONCLUSIONS When performing QST it is important to assess also quality features of warm perception, such as burning and heat pain sensation.
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| 22. |
- Rostedt Punga, Anna, et al.
(författare)
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Electrophysiological signs and the prevalence of adverse effects of acetylcholinesterase inhibitors in patients with myasthenia gravis
- 2007
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Ingår i: Muscle and Nerve. - : Wiley. - 0148-639X .- 1097-4598. ; 37:3, s. 300-307
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this prospective study was to assess whether extra discharges (EDs), sometimes following the compound muscle action potential, could be used as a neurophysiological indicator of overdose of acetylcholinesterase inhibitors (AChEIs) in patients with myasthenia gravis (MG). The characteristics and frequency of EDs were explored and the correlation of EDs with cholinergic side effects was also determined. Twenty-two MG patients (14 women, 8 men; 61 ± 16 years of age) with daily AChEI treatment were examined. The mean disease duration was 10 years (range 2-62 years) and all patients had been treated with AChEI since MG onset. Both single and repetitive stimulation of the ulnar and accessory nerves were performed before and 60 min after oral pyridostigmine bromide (PB) administration and after additional edrophonium injection. Fatigue, side effects, and AChE activity in blood were assessed before and 60 min after PB intake. The daily dose of PB ranged from 150 to 900 mg/day. Fourteen patients (64%) experienced daily cholinergic adverse effects, and muscarinic side effects correlated with AChE activity. Eleven patients (50%) developed EDs after oral PB. Among the eight patients with daily nicotinic side effects, EDs were significantly (P < 0.05) more common. Additionally, older patients were more prone to develop cholinergic side effects and EDs. Thus, when EDs are found, patients should be asked about daily muscular symptoms, which may be related to AChEI treatment and not solely to MG. Muscle Nerve, 2007
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| 23. |
- Rostedt Punga, Anna, et al.
(författare)
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Monozygous twins with neuromuscular transmission defects at opposite sides of the motor endplate
- 2009
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Ingår i: Acta Neurologica Scandinavica. - : Hindawi Limited. - 0001-6314 .- 1600-0404. ; 119:3, s. 207-211
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Tidskriftsartikel (refereegranskat)abstract
- Disorders affecting the postsynaptic side of the neuromuscular junction include autoimmune myasthenia gravis (MG) as well as some of the congenital myasthenic syndromes (CMS). Lambert-Eaton myasthenic syndrome (LEMS) is an acquired autoimmune neuromuscular disorder in which autoantibodies are directed against the presynaptic calcium channels. Here we describe two monozygous twin brothers: case 1 was diagnosed with an indeterminate form of acquired postsynaptic neuromuscular junction defect at age 32 and case 2 with LEMS at age 47. Case 1 presented clinically with mild generalized myasthenic weakness, neurophysiological examination revealed disturbed neuromuscular transmission along with probable myositis and serum analysis regarding antibodies against the acetylcholine receptor and muscle-specific tyrosine kinase was negative. Case 2 presented with proximal muscle fatigue accompanied by areflexia at rest and antibodies against the P/Q-type voltage-gated calcium channels were present. Neurophysiologically, case 2 had reduced baseline compound motor action potential amplitudes on neurography, decrement on low-frequency repetitive nerve stimulation (RNS) and pathological increment on high frequency RNS. To our knowledge this is the first case report of its kind and adds an intriguing contrast to the more common diagnosis of CMS in monozygous twins.
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| 24. |
- Sanders, Donald B., et al.
(författare)
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Single fiber electromyography and measuring jitter with concentric needle electrodes
- 2022
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Ingår i: Muscle and Nerve. - : John Wiley & Sons. - 0148-639X .- 1097-4598. ; 66:2, s. 118-130
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Tidskriftsartikel (refereegranskat)abstract
- This monograph contains descriptions of the single fiber electromyography (SFEMG) method and of the more recently implemented method of recording jitter with concentric needle electrodes (CNEs). SFEMG records action potentials from single muscle fibers (SFAPs), which permits measuring fiber density (FD), a sensitive measure of reinnervation, and jitter, a sensitive measure of abnormal neuromuscular transmission (NMT). With voluntary activation, jitter is measured between two SFAPs with acceptable amplitude and rise time. With activation by axon stimulation, jitter is measured between the stimulus and individual SFAPs. Pitfalls due to unstable triggers and inconstant firing rates during voluntary activation and subliminal stimulation during axon stimulation should be identified and avoided. In CNE recordings, spikes with shoulders or rising phases that are not parallel are produced by summation of SFAPS; these should be excluded and reference values for CNE jitter should be used. CNE and SFEMG have similar and very high sensitivity in detecting increased jitter, as in myasthenia gravis and other myasthenic conditions. However, jitter is also seen in ongoing reinnervation and some myopathic conditions. With SFEMG, these can be identified by increased FD; however, FD cannot be measured with CNE, and conventional electromyography should be performed in muscles with increased jitter to detect neurogenic or myogenic abnormalities. Jitter is abnormal after injections of botulinum toxin, even in muscles remote from the injection site, and can persist for 6 mo or more. This can complicate the detection or exclusion of abnormal NMT.
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| 25. |
- Schreurs, Annabel, et al.
(författare)
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Indication of peripheral nerve hyperexcitability in adult-onset subacute sclerosing panencephalitis (SSPE)
- 2008
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Ingår i: Neurological Sciences. - : Springer Science and Business Media LLC. - 1590-1874 .- 1590-3478. ; 29:2, s. 121-124
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Tidskriftsartikel (refereegranskat)abstract
- Subacute sclerosing panencephalitis (SSPE) is a rare chronic, progressive encephalitis that affects primarily children and young adults, caused by a persistent infection of immune-resistant measles virus. Diagnostic hallmarks include widespread cortical dysfunction on EEG, myoclonus, white matter abnormalities on neuroradiological examination and the presence of IgG antimeasles antibodies in the cerebrospinal fluid. We present the first case of SSPE with signs of peripheral nerve hyperexcitability, observed as extra discharges following the compound motor action potential at motor nerve stimulation. In addition we demonstrate the importance of SSPE in the differential diagnosis of adult patients with psychiatric and neurological symptoms.
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| 26. |
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| 27. |
- Stålberg, Erik, et al.
(författare)
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High order accurate solution of flow past a circular cylinder
- 2006
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Ingår i: Journal of Scientific Computing. - : Springer Science and Business Media LLC. - 0885-7474 .- 1573-7691. ; 27:03-jan, s. 431-441
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Tidskriftsartikel (refereegranskat)abstract
- A high order method is applied to time-dependent incompressible flow around a circular cylinder geometry. The space discretization employs compact fourth-order difference operators. In time we discretize with a second-order semi-implicit scheme. A large linear system of equations is solved in each time step by a combination of outer and inner iterations. An approximate block factorization of the system matrix is used for preconditioning. Well posed boundary conditions are obtained by an integral formulation of boundary data including a condition on the pressure. Two-dimensional flow around a circular cylinder is studied for Reynolds numbers in the range 7 <= R <= 180. The results agree very well with the data known from numerical and experimental studies in the literature.
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| 28. |
- Stålberg, Erik V., et al.
(författare)
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Jitter recordings with concentric needle electrodes
- 2009
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Ingår i: Muscle and Nerve. - : Wiley. - 0148-639X .- 1097-4598. ; 40:3, s. 331-339
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Forskningsöversikt (refereegranskat)abstract
- Neuromuscular jitter is generally recorded with a single fiber (SF) electromyography (EMG) electrode. Due to concern about using reusable needle electrodes, an acceptable alternative for the SF electrode has been sought. This is a review of the issues involved in using disposable concentric needle (CN) electrodes to measure jitter. Signals recorded with CN electrodes frequently represent the summation of many single fiber action potentials, which will decrease the apparent jitter. The influence of these artifacts on the final result also depends on the analysis method. Reference values obtained with CN electrodes correlate with SF EMG values, but they are a few microseconds lower. Overall results show that the CN method is a good alternative to SFEMG and will facilitate the use of jitter analysis. The results must be interpreted with caution, particularly in borderline cases, but they may be acceptable for clinical use when SF electrodes cannot be used.
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| 29. |
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