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Barkhaus PE, Nandedkar SD, de Carvalho M, Swash M, Stålberg EV. Revisiting the compound muscle action potential (CMAP). Clin Neurophysiol Pract 2024; 9:176-200. [PMID: 38807704 PMCID: PMC11131082 DOI: 10.1016/j.cnp.2024.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 04/15/2024] [Accepted: 04/21/2024] [Indexed: 05/30/2024] Open
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.
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Affiliation(s)
- Paul E. Barkhaus
- Department of Neurology, Medical College of Wisconsin, Milwaukee, WI USA
| | - Sanjeev D. Nandedkar
- Department of Neurology, Medical College of Wisconsin, Milwaukee, WI USA
- Natus Medical Inc., Hopewell Junction, NY, USA
| | - Mamede de Carvalho
- Instituto de Medicina Molecular and Institute of Physiology, Centro de Estudos Egas Moniz, Faculty of Medicine, University of Lisbon, Portugal
- Department of Neurosciences and Mental Health, CHULN-Hospital de Santa Maria, Lisbon, Portugal
| | - Michael Swash
- Barts and the London School of Medicine, Queen Mary University of London, London UK
| | - Erik V. Stålberg
- Department of Medical Sciences, Uppsala University, Uppsala, Sweden
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Al-Mazidi SH, ALRouq F, Alsabty AS, Alhajlah A, AlYahya A, Alsabih A, Al-Taweraqi R, Alahmari AS, Al-Dakhil L, Habib S. Relationship Between Clinical Outcomes and Nerve Conduction Studies Before and After Viral Infections in Healthy Individuals: Case Series. Cureus 2023; 15:e48980. [PMID: 38111436 PMCID: PMC10726065 DOI: 10.7759/cureus.48980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/17/2023] [Indexed: 12/20/2023] Open
Abstract
BACKGROUND The neurological effect of viral respiratory infections has been acknowledged in many studies. However, patients who recovered from this infection show neurological manifestations and are not being routinely transferred for electrodiagnostic evaluation. AIM This study aimed to examine the neurological effect of viral respiratory infections on the nerve function using electrophysiology in patients fully recovered from viral respiratory infections. METHODS To limit bias in the results, the authors decided to choose patients who recovered from one virus in all participants (coronavirus). Medical records were screened for patients who performed nerve conduction studies (NCSs) before the coronavirus pandemic. Thirty patients met our inclusion criteria, and only 10 showed up to perform NCS. Data of the NCS was compared before and after the coronavirus infection for motor and sensory NCS parameters. RESULTS An increase in both the median and ulnar sensory nerve latencies and a decrease in the sensory nerve amplitude was observed. Also, there was a decrease in the motor conduction velocity (MCV) of the ulnar nerves and motor amplitude in the median nerve. In the lower limbs, there was a decrease in the sural nerve latency, increased MCV in the tibial nerves, and decreased MCV in the peroneal nerves. The proximal amplitudes of the tibial and peroneal nerves were increased, but the distal amplitude was increased only in the peroneal nerves and decreased in the tibial nerves. CONCLUSION There is a significant impact of viral infections on the peripheral nerves. Large-scale prospective studies are required to investigate the pathogenesis of the neuropathy and myopathy after viral infections.
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Affiliation(s)
| | - Fawzia ALRouq
- Physiology, King Saud University, College of Medicine, Riyadh, SAU
| | - Areej S Alsabty
- College of Medicine, Imam Mohammad Ibn Saud Islamic University, Riyadh, SAU
| | - Abdullah Alhajlah
- College of Medicine, Imam Mohammad Ibn Saud Islamic University, Riyadh, SAU
| | - Asma AlYahya
- Physiology, King Saud University, College of Medicine, Riyadh, SAU
| | - Ahmed Alsabih
- Physiology, King Saud University, College of Medicine, Riyadh, SAU
| | | | | | - Lina Al-Dakhil
- Research, King Saud Medical City, Research Center, Riyadh, SAU
| | - Syed Habib
- Physiology, King Saud University, Riyadh, SAU
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Oh BM. Refined Diagnostic Protocol for Diabetic Polyneuropathy: Paving the Way for Timely Detection. Ann Rehabil Med 2023; 47:234-236. [PMID: 37644713 PMCID: PMC10475809 DOI: 10.5535/arm.23122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 08/16/2023] [Indexed: 08/31/2023] Open
Affiliation(s)
- Byung-Mo Oh
- Editor-in-Chief, Department of Rehabilitation Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
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Lee GY, Cho S, Baik HJ, Lee JW, Woo JH, Lee HJ, Yoo SH. Reliability of submaximal stimulation for the train-of-four test using acceleromyography and electromyography with individualized stimulation currents. J Clin Monit Comput 2023; 37:431-436. [PMID: 36264451 DOI: 10.1007/s10877-022-00920-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 08/10/2022] [Accepted: 09/18/2022] [Indexed: 10/24/2022]
Abstract
PURPOSE The supramaximal stimulation (SMS) of the TOF test causes uncomfortable sensations in patients. We aimed to determine whether the submaximal stimulation would be reliable in TOF tests with reduced painful sensation. METHODS The accelomyography (AMG) and electromyography (EMG) monitor was applied at each arm and general anesthesia was induced and maintained by total intravenous anesthesia. At extubation, we conducted TOF test three times at each of four different currents: SMS, 70% SMS, 50% SMS, and 30% SMS. The same procedure was performed in the postanesthesia care unit (PACU) only with EMG, and the pain scores on the numerical rating scale (NRS) during the tests were recorded. RESULTS A total of 36 patients were enrolled. At extubation, TOF ratios with SMS in AMG and EMG were 112.0 ± 13.1% and 93.7 ± 8.9%, respectively. There were no significant differences in TOF ratios between the SMS and lower stimulation intensities. However, 30% and 50% SMS showed significantly higher rates of the unmeasurable results of tests in the PACU. In terms of the stimulation pain, NRS showed a downward pattern as the current decreased and was significantly lower at 50% and 30% SMS than the NRS at SMS. CONCLUSION The TOF test with submaximal stimulation is still reliable and can reduce stimulation pain. Considering the importance of the TOF results in determining extubation, the authors suggest the minimal current for the TOF test as 70% SMS.
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Affiliation(s)
- Gi Year Lee
- Department of Anesthesiology and Pain Medicine, Ewha Womans University Medical Center Mokdong Hospital, Seoul, Republic of Korea
| | - Sooyoung Cho
- Department of Anesthesiology and Pain Medicine, Ewha Womans University Medical Center Mokdong Hospital, Seoul, Republic of Korea.
- Department of Anesthesiology and Pain Medicine, College of Medicine, Ewha Womans University, Seoul, Republic of Korea.
| | - Hee Jung Baik
- Department of Anesthesiology and Pain Medicine, Ewha Womans University Medical Center Mokdong Hospital, Seoul, Republic of Korea
- Department of Anesthesiology and Pain Medicine, College of Medicine, Ewha Womans University, Seoul, Republic of Korea
| | - Jong Wha Lee
- Department of Anesthesiology and Pain Medicine, Ewha Womans University Medical Center Mokdong Hospital, Seoul, Republic of Korea
- Department of Anesthesiology and Pain Medicine, College of Medicine, Ewha Womans University, Seoul, Republic of Korea
| | - Jae Hee Woo
- Department of Anesthesiology and Pain Medicine, College of Medicine, Ewha Womans University, Seoul, Republic of Korea
- Department of Anesthesiology and Pain Medicine, Ewha Womans University Medical Center Seoul Hospital, Seoul, Republic of Korea
| | - Hyun Jung Lee
- Department of Anesthesiology and Pain Medicine, College of Medicine, Ewha Womans University, Seoul, Republic of Korea
- Department of Anesthesiology and Pain Medicine, Ewha Womans University Medical Center Seoul Hospital, Seoul, Republic of Korea
| | - Seung Hee Yoo
- Department of Anesthesiology and Pain Medicine, Ewha Womans University Medical Center Mokdong Hospital, Seoul, Republic of Korea
- Department of Anesthesiology and Pain Medicine, College of Medicine, Ewha Womans University, Seoul, Republic of Korea
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Shelly S, Ramon-Gonen R, Paul P, Klein CJ, Klang E, Rahman N, Nikitin V, Ben David M, Dori A. Nerve Conduction Differences in a Large Clinical Population: The Role of Age and Sex. J Neuromuscul Dis 2023; 10:925-935. [PMID: 37545257 PMCID: PMC10578272 DOI: 10.3233/jnd-230052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/18/2023] [Indexed: 08/08/2023]
Abstract
BACKGROUND The normal limits of nerve conduction studies are commonly determined by testing healthy subjects. However, in comprehensive real-life nerve conduction electrodiagnostic (EDX) evaluations, multiple nerves are tested, including normal nerves, for purposes of comparison with abnormal ones. OBJECTIVE This study aims to evaluate the average values of normal nerve conduction studies in a large population and examined the influence of age and sex. METHODS EDX parameters were extracted from an electronic database of studies performed from May 2016 to February 2022. Established normal values were used to determine the classification of a nerve study as normal. RESULTS We identified 10,648 EDX reports with 5077 normally interpreted nerve conduction studies (47.6%) of which 57% (n = 2890) were for females. The median age of studies with no abnormalities was 45.1 years (range < 1 to 92) overall and 42.5 years (range: 0.16 -89.5 years) for males and 47.5 years (range:<1 -91.7) for females. Correlations between age and amplitude, latency, and velocity (p < 0.001) were observed in most nerves. Amplitude correlated negatively with age in adults in all nerves with a mean of -0.44 (range: -0.24 to -0.62). However, in the pediatric population (age < 18 years), amplitude as well as velocity increased significantly with age. In the adult cohort, sex differences were noted, where females had higher mean sensory nerve action potentials in ulnar, median, and radial evaluations (p < 0.001). In older patients (aged > 70 years) with normally interpreted EDX studies (845 records of 528 patients), sural responses were present in 97%. CONCLUSIONS This real-life study confirms that advanced aging is associated with decreased nerve conduction amplitudes, increased latency, and the slowing of conduction velocity. The findings also indicate higher sensory amplitudes and conduction velocities in females. Sural nerve responses were identified in most adults over age 70.
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Affiliation(s)
- Shahar Shelly
- Department of Neurology, Rambam Medical Center, Haifa, Israel
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Department of Neurology, Mayo Clinic, Rochester, MN, USA
| | - Roni Ramon-Gonen
- The Graduate School of Business Administration, Bar-Ilan University, Ramat-Gan, Israel
| | - Pritikanta Paul
- Department of Neurology and Rehabilitation, University of Illinois at Chicago, Chicago, IL, USA
| | | | - Eyal Klang
- Department of diagnostic imaging, Sheba Medical Center, Sackler Faculty Institute, Tel Aviv, Israel
- The Sami Sagol AI Hub, ARC Innovation Center, Sheba Medical Center, Tel Hashomer, Israel
| | - Nisim Rahman
- The Sami Sagol AI Hub, ARC Innovation Center, Sheba Medical Center, Tel Hashomer, Israel
| | - Vera Nikitin
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Department of Neurology, Sheba Medical Center, Ramat Gan, Israel
| | - Merav Ben David
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Department of Neurology, Sheba Medical Center, Ramat Gan, Israel
| | - Amir Dori
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Department of Neurology, Sheba Medical Center, Ramat Gan, Israel
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