|
1
|
Rubin DI, Lamb CJ. The role of electrodiagnosis in focal neuropathies. HANDBOOK OF CLINICAL NEUROLOGY 2024; 201:43-59. [PMID: 38697746 DOI: 10.1016/b978-0-323-90108-6.00010-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2024]
Abstract
Electrodiagnostic (EDX) testing plays an important role in confirming a mononeuropathy, localizing the site of nerve injury, defining the pathophysiology, and assessing the severity and prognosis. The combination of nerve conduction studies (NCS) and needle electromyography findings provides the necessary information to fully assess a nerve. The pattern of NCS abnormalities reflects the underlying pathophysiology, with focal slowing or conduction block in neuropraxic injuries and reduced amplitudes in axonotmetic injuries. Needle electromyography findings, including spontaneous activity and voluntary motor unit potential changes, complement the NCS findings and further characterize chronicity and degree of axon loss and reinnervation. EDX is used as an objective marker to follow the progression of a mononeuropathy over time.
Collapse
Affiliation(s)
- Devon I Rubin
- Department of Neurology, Mayo Clinic, Jacksonville, FL, United States.
| | | |
Collapse
|
|
2
|
Jung JW, Park YC, Lee JY, Park JH, Jang SH. Bilateral musculocutaneous neuropathy: A case report. World J Clin Cases 2021; 9:1237-1246. [PMID: 33644190 PMCID: PMC7896669 DOI: 10.12998/wjcc.v9.i5.1237] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 12/14/2020] [Accepted: 12/23/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Isolated musculocutaneous nerve injury is a rare condition. Herein, we report the first case of bilateral musculocutaneous neuropathy after vigorous stretching of both upper extremities with normal results of sensory nerve action potential. Clinicians should be aware of this rare condition that can appear bilaterally. In addition, the interpretation of the aberrant electrodiagnostic study results of this case was discussed.
CASE SUMMARY A 29-year-old male complaining of bilateral forearm tingling and upper extremity weakness visited the outpatient clinic. The symptoms began 6 mo prior, and he visited another hospital before visiting our department. The diagnosis was not made even after cervical spine magnetic resonance imaging, electrodiagnostic study, brain magnetic resonance imaging, and arteriography were conducted. The patient performed unique exercises that stretched the pectoralis minor and coracobrachialis muscles. On the follow-up electrodiagnostic study, abnormal spontaneous activities in the bilateral biceps and brachialis muscles were observed. The patient was diagnosed with bilateral musculocutaneous neuropathy. Steroid pulse therapy was administered for approximately 6 wk. After treatment, his muscle strength returned to the predisease condition.
CONCLUSION Clinicians should be aware of this condition, have adequate understanding of anatomy, and advise to correct inappropriate exercises.
Collapse
Affiliation(s)
- Ji Won Jung
- Department of Rehabilitation Medicine, Hanyang University Hospital, Seoul 04763, South Korea
| | - Yu Chan Park
- Department of Rehabilitation Medicine, Hanyang University Hospital, Seoul 04763, South Korea
| | - Jae Young Lee
- Department of Rehabilitation Medicine, Hanyang University Hospital, Seoul 04763, South Korea
| | - Jae Hyeon Park
- Department of Rehabilitation Medicine, Hanyang University Guri Hospital, Guri 11923, South Korea
| | - Seong Ho Jang
- Department of Rehabilitation Medicine, Hanyang University Guri Hospital, Guri 11923, South Korea
| |
Collapse
|
|
3
|
Abstract
This chapter covers the electrodiagnostic (EDX) evaluation of upper extremity nerves and the brachial plexus. Carpal tunnel syndrome is the most common peripheral nerve disorder of the upper extremity. A number of techniques are used but there is no gold standard approach for its diagnosis. Needle EMG aids in the differentiation of proximal and distal median neuropathies. Ulnar neuropathy at the elbow and ulnar neuropathy at or distal to the wrist can be distinguished by EDX techniques. Radial neuropathy at the spiral groove has a specific EDX pattern. EDX assessment of proximal upper extremity nerve lesions such as brachial plexopathy is a valuable tool for exploring the diagnosis and differential diagnosis of this complex disorder.
Collapse
Affiliation(s)
- John C Kincaid
- Department of Neurology, Indiana University, Indianapolis, IN, United States.
| |
Collapse
|
|
4
|
Abstract
INTRODUCTION The value of needle electromyography (EMG) in thenar muscles in patients with less severe carpal tunnel syndrome is controversial. METHODS Patients referred for electrodiagnostic testing for carpal tunnel syndrome, in which nerve conduction study demonstrated median sensory nerve conduction study abnormalities and either normal median motor nerve conduction study or only prolonged median motor distal latencies (DLs) (with normal amplitudes) were prospectively studied. Patients with low-median compound muscle action potential amplitudes or any other EMG abnormality were excluded. Needle EMG of a thenar muscle was performed to assess for the presence and grade of fibrillation potentials and motor unit potential abnormalities. The frequency of abnormalities was recorded. Statistical comparison between patients with and without needle EMG abnormalities was performed. RESULTS One-hundred two patients were included (50 with normal median motor DLs and 52 with abnormal DLs). Minimal or equivocal thenar needle EMG abnormalities were found in 12% of subjects with normal DLs. In patients with abnormal DLs, 32.6% had abnormalities, 15.4% with a mild degree of fibrillation potentials, and 25.0% with mild motor unit potential abnormalities. Patients with abnormal DLs and needle EMG abnormalities had significantly lower compound muscle action potential amplitudes compared to those without needle EMG changes. CONCLUSIONS Patients with carpal tunnel syndrome with no involvement of the median motor nerve conduction study are unlikely to demonstrate prominent abnormalities on needle EMG of thenar muscles, and needle EMG of the thenar muscles is not necessary. However, in patients with carpal tunnel syndrome in which the median motor DL is prolonged but compound muscle action potential amplitudes are absolutely normal, needle EMG should be considered, as it may provide value in indicating some axonal loss despite a normal median compound muscle action potential amplitude.
Collapse
|
|
5
|
El-Emary WS, Hassan MM. Needle electromyography in carpal tunnel syndrome: is it valuable or predictable? EGYPTIAN RHEUMATOLOGY AND REHABILITATION 2016. [DOI: 10.4103/1110-161x.177426] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
|
|
6
|
Chang CW, Lee WJ, Liao YC, Chang MH. Which nerve conduction parameters can predict spontaneous electromyographic activity in carpal tunnel syndrome? Clin Neurophysiol 2013; 124:2264-8. [DOI: 10.1016/j.clinph.2013.04.338] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Revised: 04/01/2013] [Accepted: 04/05/2013] [Indexed: 11/16/2022]
|
|
7
|
Werner RA. Electrodiagnostic Evaluation of Carpal Tunnel Syndrome and Ulnar Neuropathies. PM R 2013; 5:S14-21. [DOI: 10.1016/j.pmrj.2013.03.027] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Accepted: 03/22/2013] [Indexed: 10/27/2022]
|
|
8
|
Bonfiglioli R, Botter A, Calabrese M, Mussoni P, Violante FS, Merletti R. Surface electromyography features in manual workers affected by carpal tunnel syndrome. Muscle Nerve 2012; 45:873-82. [PMID: 22581542 DOI: 10.1002/mus.23258] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
INTRODUCTION Alterations in surface electromyographic (sEMG) signals of the abductor pollicis brevis muscle were evaluated in 24 non-manual workers and 40 manual workers (25 asymptomatic and 15 reporting CTS symptoms). METHODS The initial value (IV) and the normalized rate of change (NRC) of average rectified value (ARV), mean frequency of the power spectrum (MNF), and muscle fiber conduction velocity (MFCV) were calculated during contractions at 20% and 50% of maximal voluntary contraction (MVC). Neuromuscular efficiency (NME) and kurtosis of the sEMG amplitude distribution were estimated. RESULTS With respect to controls, manual workers showed higher NME, lower ARV IV, and reduced myoelectric manifestations of fatigue (lower MNF NRC for both contraction levels, and lower MFCV NRC at 50% MVC). Kurtosis at 20% MVC showed higher values in symptomatic manual workers than in the other two groups. CONCLUSIONS Kurtosis seems to be a promising parameter for use in monitoring individuals who develop CTS.
Collapse
Affiliation(s)
- Roberta Bonfiglioli
- Department of Internal Medicine, Geriatrics, and Nephrology, Alma Mater Studiorum, University of Bologna, Bologna, Italy.
| | | | | | | | | | | |
Collapse
|
|
9
|
Sohn MK, Jee SJ, Hwang SL, Kim YJ, Shin HD. Motor unit number estimation and motor unit action potential analysis in carpal tunnel syndrome. Ann Rehabil Med 2011; 35:816-25. [PMID: 22506210 PMCID: PMC3309374 DOI: 10.5535/arm.2011.35.6.816] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Accepted: 10/09/2011] [Indexed: 12/12/2022] Open
Abstract
Objective To evaluate the clinical significance of motor unit number estimation (MUNE) and quantitative analysis of motor unit action potential (MUAP) in carpal tunnel syndrome (CTS) according to electrophysiologic severity, ultrasonographic measurement and clinical symptoms. Method We evaluated 78 wrists of 45 patients, who had been diagnosed with CTS and 42 wrists of 21 healthy controls. Median nerve conduction studies, amplitude and duration of MUAP, and the MUNE of the abductor pollicis brevis were measured. The cross sectional area (CSA) of the median nerve at the pisiform and distal radioulnar joint level was determined by high resolution ultrasonography. Clinical symptom of CTS was assessed using the Boston Carpal Tunnel Questionnaire (BCTQ). Results The MUNE, the amplitude and the duration of MUAP of the CTS group were significantly different from those found in the control group. The area under the ROC curve was 0.944 for MUNE, 0.923 for MUAP amplitude and 0.953 for MUAP duration. MUNE had a negative correlation with electrophysiologic stage of CTS, amplitude and duration of MUAP, CSA at pisiform level, and the score of BCTQ. The amplitude and duration of MUAP had a positive correlation with the score of BCTQ. The electrophysiologic stage was correlated with amplitude but not with the duration of MUAP. Conclusion MUNE, amplitude and duration of MUAP are useful tests for diagnosis of CTS. In addition, the MUNE serves as a good indicator of CTS severity.
Collapse
Affiliation(s)
- Min Kyun Sohn
- Department of Rehabilitation Medicine, School of Medicine, Chungnam National University, Daejeon 301-172, Korea
| | | | | | | | | |
Collapse
|
|
10
|
Abstract
Carpal tunnel syndrome (CTS) is the most common nerve entrapment. Electrodiagnostic (EDX) studies are a valid and reliable means of confirming the diagnosis. This monograph addresses the various EDX techniques used to evaluate the median nerve at the wrist. It also demonstrates the limitations of EDX studies with a focus on the sensitivity and specificity of EDX testing for CTS. The need to use reference values for populations such as diabetics and active workers, where normative values differ from conventional cutoffs used to confirm suspected CTS, is presented. The value of needle electromyography (EMG) is examined.
Collapse
Affiliation(s)
- Robert A Werner
- University of Michigan Health System, Ann Arbor Veterans Health System, Ann Arbor, Michigan, USA.
| | | |
Collapse
|
|
11
|
Shen H, Choe W. Spontaneous high-frequency action potential. SCIENCE CHINA-LIFE SCIENCES 2011; 54:311-35. [PMID: 21509656 DOI: 10.1007/s11427-011-4157-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2010] [Accepted: 12/27/2010] [Indexed: 11/24/2022]
Abstract
Action potential, which is the foundation of physiology and electrophysiology, is most vital in physiological research. This work starts by detecting cardiac electrophysiology (tachyarrhythmias), combined with all spontaneous discharge phenomena in vivo such as wound currents and spontaneous neuropathic pain, elaborates from generation, induction, initiation, to all of the features of spontaneous high-frequency action potential-SSL action potential mechanism, i.e., connecting-end hyperpolarization initiates spontaneous depolarization and action potential in somatic membrane. This work resolves the conundrums of in vivo spontaneous discharge in tachyarrhythmias, wounds, denervation supersensitivity, neurogenic pain (hyperalgesia and allodynia), epileptic discharge and diabetic pain in pathophysiological and clinical researches that have puzzled people for a hundred years.
Collapse
Affiliation(s)
- Haiying Shen
- Department of Biochemistry and Molecular Biology, Medical Research Center and Biomedical Science Institute, School of Medicine, Kyung Hee University, Seoul 130-701, Republic of Korea
| | | |
Collapse
|
|
12
|
Rozmaryn LM, Bartko JJ, Isler MLD. The Ab-Adductometer: a new device for measuring the muscle strength and function of the thumb. J Hand Ther 2008; 20:311-24; quiz 325. [PMID: 17954352 DOI: 10.1197/j.jht.2007.07.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The purpose of this study was to present normative values for thumb abduction and adduction and also to present measures of reliability of the measuring system arising from the use of the Ab-Adductometer. With the Ab-Adductometer, we obtained abductor and adductor measurements of intrinsic muscle strength of the healthy hand thumb in 600 volunteers. Handgrip strength values were obtained with the Jamar dynamometer. Age and male-female specific reference ranges for the Ab-Adductometer and the Jamar dynamometer are presented. This study, with a very large number of volunteer subjects, 600, presents reference ranges for pure palmar adduction and abduction of the thumb. The results indicate that the Ab-Adductometer is a clinically useful device for the purpose of quantitatively measuring thumb adduction and abduction strength at various starting angles of thumb abduction relative to the plane of the palm. The device may be especially helpful in the evaluation of compressive neuropathies of the median or ulnar nerves such as carpal tunnel syndrome or cubital tunnel syndrome as well as for primary disease of the peripheral nerves that affect intrinsic muscles and for thumb function in proximal conditions such as tetraplegia and brachial plexopathy.
Collapse
|
|
13
|
Jung SH, Han TR. Some controversies in carpal tunnel syndrome. SUPPLEMENTS TO CLINICAL NEUROPHYSIOLOGY 2006; 59:321-6. [PMID: 16893128 DOI: 10.1016/s1567-424x(09)70047-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Affiliation(s)
- Se Hee Jung
- Department of Rehabilitation Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
| | | |
Collapse
|
|
14
|
Ilkhani M, Jahanbakhsh SM, Eghtesadi-Araghi P, Moayyeri A. Accuracy of somatosensory evoked potentials in diagnosis of mild idiopathic carpal tunnel syndrome. Clin Neurol Neurosurg 2005; 108:40-4. [PMID: 16311144 DOI: 10.1016/j.clineuro.2005.02.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2004] [Revised: 02/01/2005] [Accepted: 02/08/2005] [Indexed: 10/25/2022]
Abstract
OBJECTIVE Concerning prevalence of carpal tunnel syndrome (CTS) and the difficulties with electromyography (EMG) and nerve conduction studies (NCS), this study was designed to evaluate the power of somatosensory evoked potential (SSEP) in CTS diagnosis among Iranian patients. PATIENTS AND METHODS SSEP was performed on 100 asymptomatic hands of 50 healthy participants (40 female, age range 38-59 years) and on 61 hands of 46 patients (39 female, age range 34-58 years). Mean difference between N(20) latency of the middle finger and the wrist (median nerve innervation) as well as N(20) latency of the third finger and the fifth finger (ulnar nerve innervation) were measured. Using receiver operating characteristic (ROC) curve analysis, the upper limits of these variables were defined as 6.0 and 1.5 ms, respectively. Higher amounts in either of these variables were considered as positive SSEP for diagnosis of CTS. Measures of accuracy for SSEP were measured getting clinical diagnosis by two separate neurologists as the reference standard. In the patients' group who underwent both techniques of SSEP and EMG-NCS, kappa statistic as the agreement coefficient between two procedures was calculated. RESULTS Sensitivity, specificity, and likelihood ratios for positive and negative results of SSEP in diagnosis of CTS were 70.4%, 91.0%, 7.83 and 0.32, respectively. Sensitivity of EMG-NCS in diagnosis of CTS was measured as 81.9%. Measure of agreement between two procedures (kappa) was calculated as 0.42. CONCLUSION This study showed that positive results of SSEP might have a role in diagnosis of CTS. However, larger studies to demonstrate diagnostic power of SSEP in comparison with EMG-NCS seem necessary.
Collapse
Affiliation(s)
- Manuchehr Ilkhani
- Department of Neurology, Loghman Hospital Complex, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | | | | | | |
Collapse
|
|
15
|
Sylvain JR, Andary MT. Disability Issues with Carpal Tunnel Syndrome: A Case Discussion. Phys Med Rehabil Clin N Am 2001. [DOI: 10.1016/s1047-9651(18)30061-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
|
16
|
Conway RR. The role of needle electromyography in the evaluation of patients with carpal tunnel syndrome: Needle EMG is often unnecessary. Muscle Nerve 1999. [DOI: 10.1002/(sici)1097-4598(199902)22:2<284::aid-mus20>3.0.co;2-a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
|
17
|
Choi SJ, Ahn DS. Correlation of clinical history and electrodiagnostic abnormalities with outcome after surgery for carpal tunnel syndrome. Plast Reconstr Surg 1998; 102:2374-80. [PMID: 9858172 DOI: 10.1097/00006534-199812000-00016] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
A retrospective study on 294 wrists in 154 patients who had been diagnosed with carpal tunnel syndrome and subsequently had surgery performed was undertaken; both clinical and electrodiagnostic findings were correlated. The cases were divided into three groups based on electromyographic severity (mild, moderate, severe), and recovery from symptoms was evaluated after 1 week, 3 months, and 1 year. The cases were also divided into five groups based on symptom duration, and the same investigations were performed. All operations were conducted by applying the open release method with the limited-palmar incision technique. Operative outcomes showed no association between recovery from symptoms and the severity of electromyographic findings or the duration of symptoms, although the group that had the shortest duration of symptoms recovered faster than the long-duration groups statistically. Postoperative results after 1 year were also successful for those patients who had had symptoms of long duration. Of the 294 wrist operations studied, good to excellent postoperative outcomes were recorded in 242 cases (82 percent), fair outcomes in 39 cases (13 percent), and poor outcomes in 13 cases (4 percent). Patients whose electromyogram revealed double crush syndrome still showed improvement, with good-to-excellent results in 11 out of 15 cases (73 percent). Patients with diabetes mellitus also showed improvement, with good-to-excellent results in 14 out of 19 patients (74 percent). This study showed that postoperative results were satisfactory within 1 year, regardless of the degree of electromyographic severity, symptom duration, presence of diabetes mellitus, or double crush syndrome.
Collapse
Affiliation(s)
- S J Choi
- Division of Plastic and Reconstructive Surgery at Korea University, Seoul
| | | |
Collapse
|
|
18
|
|
|
19
|
Balbierz JM, Cottrell AC, Cottrell WD. Is needle examination always necessary in evaluation of carpal tunnel syndrome? Arch Phys Med Rehabil 1998; 79:514-6. [PMID: 9596390 DOI: 10.1016/s0003-9993(98)90064-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE To investigate whether needle evaluation added any important clinical information to normal nerve conduction studies in the evaluation of carpal tunnel syndromes. DESIGN Retrospective review of electromyography (EMG) done with the referring diagnosis of possible carpal tunnel syndrome. SETTING Outpatients seen for EMG evaluation at one university hospital by a single electromyographer. PATIENTS Consecutive sample of possible carpal tunnel syndrome patients. INTERVENTIONS None. MAIN OUTCOME MEASURE We determined whether needle examination was abnormal when nerve conduction studies were normal. RESULTS In patients in whom only carpal tunnel syndrome was suspected, normal nerve conduction studies predicted that EMG would be normal 89.8% of the time (p = .0494). Testing based on a larger sample size might increase the predictive value. CONCLUSIONS There may be a subpopulation of patients referred for carpal tunnel syndrome who may be adequately evaluated by nerve conduction studies alone. Additional studies will help evaluate whether this is so.
Collapse
Affiliation(s)
- J M Balbierz
- Division of Physical Medicine and Rehabilitation, University of Utah, Salt Lake City, USA
| | | | | |
Collapse
|
|
20
|
Vennix MJ, Hirsh DD, Chiou-Tan FY, Rossi CD. Predicting acute denervation in carpal tunnel syndrome. Arch Phys Med Rehabil 1998; 79:306-12. [PMID: 9523783 DOI: 10.1016/s0003-9993(98)90011-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVE To determine which nerve conduction parameters can predict the presence of acute denervation in carpal tunnel syndrome. SETTING The electrodiagnostic laboratories of a hospital and a county hospital district. DESIGN A retrospective review. PATIENTS A total of 1,590 consecutive cases from January 1992 to June 1996, diagnosed as having median neuropathy at the wrist. MAIN OUTCOME MEASURES Evidence of acute denervation on needle electromyography of the abductor pollicis brevis and its relationship to patient age, gender, and parameters obtained from nerve conduction studies, including median sensory latency and amplitude, and median motor latency and amplitude. RESULTS Logistic regression analysis identified gender, median motor latency, and median motor amplitude (all p < or = .008) as contributing to the prediction of denervation. Needle examination of the cases with a median motor amplitude <7 mV detected 95.3% (141/148) of all cases with denervation and could have spared 52% (708/1,362) of the population from a needle examination of the abductor pollicis brevis. CONCLUSION The median motor amplitude can predict the presence of acute denervation in the thenar muscles in median neuropathy at the wrist and possibly eliminate a painful needle examination of the median-innervated thenar muscles in over 50% of the cases.
Collapse
Affiliation(s)
- M J Vennix
- Department of Physical Medicine and Rehabilitation, Baylor College of Medicine, Houston, TX 77030, USA
| | | | | | | |
Collapse
|
|
21
|
Stevens JC. AAEM minimonograph #26: the electrodiagnosis of carpal tunnel syndrome. American Association of Electrodiagnostic Medicine. Muscle Nerve 1997; 20:1477-86. [PMID: 9390659 DOI: 10.1002/(sici)1097-4598(199712)20:12<1477::aid-mus1>3.0.co;2-5] [Citation(s) in RCA: 346] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The electrodiagnosis of carpal tunnel syndrome (CTS) is reviewed, including discussions of old and new techniques of motor and sensory nerve conduction, anomalous innervation, and needle electrode examination. A variety of sensitive nerve conduction studies (NCSs) are available for the evaluation of a patient with suspected CTS. For any particular patient, the NCS method chosen by the clinical neurophysiologist may vary for a number of reasons, including the severity of the deficit and the presence of superimposed conditions.
Collapse
Affiliation(s)
- J C Stevens
- Department of Neurology, Mayo Clinic Scottsdale, Arizona 85259, USA
| |
Collapse
|
|
22
|
|