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Higashihara M, Yamazaki H, Izumi Y, Kobayashi M, Nodera H, Oishi C, Iwata A, Murayama S, Kaji R, Sonoo M. Far-field potential of the compound muscle action potential as a reliable marker in amyotrophic lateral sclerosis. Muscle Nerve 2023; 68:257-263. [PMID: 37086196 DOI: 10.1002/mus.27829] [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: 09/04/2022] [Revised: 03/29/2023] [Accepted: 03/30/2023] [Indexed: 04/23/2023]
Abstract
INTRODUCTION/AIMS Reliable neurophysiological markers in amyotrophic lateral sclerosis (ALS) are of great interest. The compound muscle action potential (CMAP) amplitude has been a conventional marker, although it is greatly influenced by the electrode position. We propose the far-field potential of the CMAP (FFP-CMAP) as a new neurophysiological marker in ALS. METHODS Patients with ALS and age-matched healthy controls were enrolled. We used a proximal reference (pref) in addition to the conventional distal reference (dref). Routine CMAP was recorded from the belly-dref lead and FFP-CMAP from the dref-pref lead for the ulnar and tibial nerves. Multiple point stimulation motor unit number estimation (MUNE) was also examined in the ulnar nerve. Inter-rater reproducibility was evaluated by two examiners, and some patients were followed up every 3 mo for 1 y. RESULTS We tested 17 patients with ALS and 10 controls. The amplitudes of routine CMAP and FFP-CMAP in the ulnar and tibial nerves, and hypothenar MUNE value in the ulnar nerve were significantly decreased in ALS compared to controls. Ulnar FFP-CMAP achieved the highest inter-rater intraclass correlation coefficient (ICC) value (0.942) when compared with routine CMAP (0.880) and MUNE (0.839). The tibial FFP-CMAP had a higher ICC value (0.986) than the routine CMAP (0.697). In this way, the FFP-CMAP showed high inter-rater reproducibility because its shape was not much influenced by the electrode position. During 1-y follow-up, decline of CMAP, FFP, and MUNE showed significant correlations with the Amyotrophic Lateral Sclerosis Functional Rating Scale - Revised (ALSFRS-R). DISCUSSION The FFP-CMAP shows promise as a reliable marker for ALS.
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Affiliation(s)
- Mana Higashihara
- Department of Neurology, Tokyo Metropolitan Geriatric Hospital, Tokyo, Japan
| | - Hiroki Yamazaki
- Department of Neurology, Tokushima University Graduate School of Biomedical Sciences, Tokushima, Japan
| | - Yuishin Izumi
- Department of Neurology, Tokushima University Graduate School of Biomedical Sciences, Tokushima, Japan
| | | | - Hiroyuki Nodera
- Department of Neurology, Tokushima University Graduate School of Biomedical Sciences, Tokushima, Japan
- Department of Neurology, Tenri Hospital, Tenri, Japan
| | - Chizuko Oishi
- Department of Neurology, Kyorin University Hospital, Mitaka, Japan
| | - Atsushi Iwata
- Department of Neurology, Tokyo Metropolitan Geriatric Hospital, Tokyo, Japan
| | - Shigeo Murayama
- Department of Neurology, Tokyo Metropolitan Geriatric Hospital, Tokyo, Japan
| | - Ryuji Kaji
- Department of Neurology, Tokushima University Graduate School of Biomedical Sciences, Tokushima, Japan
- Department of Neurology, Utano National Hospital, Kyoto, Japan
| | - Masahiro Sonoo
- Department of Neurology, Teikyo University School of Medicine, Tokyo, Japan
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Gooch CL, Doherty TJ, Chan KM, Bromberg MB, Lewis RA, Stashuk DW, Berger MJ, Andary MT, Daube JR. Motor unit number estimation: A technology and literature review. Muscle Nerve 2014; 50:884-93. [PMID: 25186553 DOI: 10.1002/mus.24442] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/27/2014] [Indexed: 12/12/2022]
Affiliation(s)
- Clifton L. Gooch
- Department of Neurology; University of South Florida; Tampa Florida USA
| | - Timothy J. Doherty
- Department of Physical Medicine and Rehabilitation; University of Western Ontario; London Ontario Canada
- Department of Clinical Neurological Sciences; University of Western Ontario; London Ontario Canada
- Schulich School of Medicine and Dentistry; University of Western Ontario; London Ontario Canada
| | - K. Ming Chan
- Division of Physical Medicine and Rehabilitation/Centre for Neuroscience; University of Alberta; Edmonton Alberta Canada
| | - Mark B. Bromberg
- Department of Neurology; University of Utah; Salt Lake City Utah USA
| | - Richard A. Lewis
- Department of Neurology; Cedars-Sinai; Los Angeles California USA
| | - Dan W. Stashuk
- Systems Design Engineering; University of Waterloo; Waterloo Ontario Canada
| | - Michael J. Berger
- School of Kinesiology; University of Western Ontario; London Ontario Canada
- Schulich School of Medicine and Dentistry; University of Western Ontario; London Ontario Canada
| | - Michael T. Andary
- College of Osteopathic Medicine; Michigan State University; East Lansing Michigan USA
| | - Jasper R. Daube
- Department of Neurology; Mayo Clinic; Rochester Minnesota USA
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Unlusoy Acar Z, Yalinay Dikmen P, Yayla V, Başaran K, Emekli U, Öge AE. Decline of compound muscle action potentials and statistical MUNEs during Wallerian degeneration. Neurophysiol Clin 2014; 44:257-65. [PMID: 25240559 DOI: 10.1016/j.neucli.2014.04.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Revised: 01/21/2014] [Accepted: 04/12/2014] [Indexed: 12/12/2022] Open
Abstract
AIM OF THE STUDY In two previous studies, we found that the compound muscle action potential (CMAP) amplitude loss was significantly higher than the loss of estimated motor unit numbers in the course of Wallerian degeneration (WD). In order to overcome some drawbacks of the method previously used, we performed a similar CMAP vs MUNE comparison by using the statistical motor unit number estimation (MUNE) method. PATIENTS AND METHODS Initial electrophysiological studies on 6 patients were performed between 22 and 98 hours after the injuries; it was possible to make repeated examinations, four times in 1 nerve, twice in 1 nerve and three times in 4 nerves, before the eventual complete disappearance of the CMAPs. RESULTS The transected/intact (T/I) side CMAP ratios declined steeply as WD evolved. They were significantly lower than the relatively stable MUNE ratios 48 hours after the injury. CONCLUSION This study, performed with the use of statistical MUNE, strengthens our previous observation by the incremental method that might have some relevance to the pathophysiology of early WD. CMAP amplitude loss that is more than expected from the amount of axonal degeneration may indicate a considerable amount of inactive muscle fibers in the motor units innervated by the nerve fibers, which are undergoing degeneration but still retain their excitability. Although technical sources of error cannot be totally excluded, our findings could more likely be explained by the failing of neuromuscular synapses in an asynchronous order before complete unresponsiveness of the motor unit ensues.
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Affiliation(s)
- Z Unlusoy Acar
- Department of Neurology, TDV 29 May Hospital, 34091 Istanbul, Turkey
| | - P Yalinay Dikmen
- Department of Neurology, Acıbadem University School of Medicine, 34140 Istanbul, Turkey.
| | - V Yayla
- Department of Neurology, Dr. Sadi Konuk Bakırköy Education and Research Hospital, 34147 Istanbul, Turkey
| | - K Başaran
- Department of Plastic and Reconstructive Surgery, Istanbul University, Istanbul Faculty of Medicine, 34390 Istanbul, Turkey
| | - U Emekli
- Department of Plastic and Reconstructive Surgery, Istanbul University, Istanbul Faculty of Medicine, 34390 Istanbul, Turkey
| | - A E Öge
- Department of Neurology, Istanbul University, Istanbul Faculty of Medicine, 34390 Istanbul, Turkey
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Asymmetry of motor unit number estimate and its rate of decline in patients with amyotrophic lateral sclerosis. J Clin Neurophysiol 2012; 28:528-32. [PMID: 21946374 DOI: 10.1097/wnp.0b013e318231c9e0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
This study was performed to investigate the asymmetry of motor unit number estimate (MUNE) and its longitudinal course in patients with amyotrophic lateral sclerosis. A modified statistical MUNE was performed at the hypothenar muscles bilaterally in a total of 135 patients, and 18 of these patients underwent a follow-up study. The degree of asymmetry varied considerably among those patients whose average MUNE of both sides was moderately reduced, whereas it tended to be low in those whose average MUNE was either severely reduced or close to normal. The rate of motor unit loss was also asymmetric, and two distinct patterns were identified. In patients whose MUNE was greater than 30 in both sides (n = 7), the rate of motor unit loss tended to be greater in the initially more affected side compared with the contralateral one, yielding the so-called lead phenomenon. In contrast, the other patients (n = 11) tended to show the opposite pattern of "catch-up," that is, MUNE declined faster in the initially less affected side compared with the contralateral one. This study shows that not only the MUNE but also the rate of motor unit loss are frequently asymmetric in amyotrophic lateral sclerosis patients.
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dl-3-n-butylphthalide extends survival by attenuating glial activation in a mouse model of amyotrophic lateral sclerosis. Neuropharmacology 2012; 62:1004-10. [DOI: 10.1016/j.neuropharm.2011.10.009] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Revised: 10/13/2011] [Accepted: 10/14/2011] [Indexed: 12/12/2022]
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Test-retest reliability of v-wave responses in the soleus and gastrocnemius medialis. J Clin Neurophysiol 2011; 28:217-21. [PMID: 21399516 DOI: 10.1097/wnp.0b013e31821215cf] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
This study was designed to assess the reliability of the first volitional (V) wave, which can be used as a measure of efferent neural drive, while also reflecting reflex excitability. Ten subjects volunteered for one familiarization session followed by an experimental test session and an identical retest session spaced 3 to 8 days apart. V-waves were evoked in the tibial nerve during plantar flexion maximal voluntary isometric contractions (MVCs). Test-retest reliability was assessed using the intraclass correlation coefficient (ICC), along with standard error of measurement and 95% confidence intervals for the following variables: MVC force, surface electromyogram activity (EMG), and the peak-to-peak V-wave amplitude in soleus (SOL) and gastrocnemius medialis (GM). The superimposed M-wave (MSUP) accompanying V-wave stimulation was also obtained for normalization purposes. Substantial reliability was documented for V/MSUP in both SOL (ICC = 0.86) and GM (0.90), as well as for the non-normalized V-wave in SOL (0.92). Moderate reliability was displayed for the non-normalized V-wave response in GM (0.78). Substantial reliability was also established for EMG/MSUP (>0.82) and MVC force (0.98). This study provides novel evidence that V-wave responses can be consistently measured in the SOL and GM, thus advocating its continued use in future research.
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Ahn SW, Kim SH, Kim JE, Kim SM, Kim SH, Park KS, Sung JJ, Lee KW, Hong YH. Reproducibility of the motor unit number index (MUNIX) in normal controls and amyotrophic lateral sclerosis patients. Muscle Nerve 2010; 42:808-13. [PMID: 20976784 DOI: 10.1002/mus.21765] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Suk-Won Ahn
- Department of Neurology, Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Republic of Korea
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Blok J, van Dijk J, Drenthen J, Maathuis E, Stegeman D. Size does matter: The influence of motor unit potential size on statistical motor unit number estimates in healthy subjects. Clin Neurophysiol 2010; 121:1772-80. [DOI: 10.1016/j.clinph.2010.03.048] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Revised: 02/17/2010] [Accepted: 03/27/2010] [Indexed: 12/12/2022]
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Ahn SW, Kim SH, Oh DH, Kim SM, Park KS, Hong YH, Kwon OS, Sung JJ, Lee KW. Motor unit number estimation in evaluating disease progression in patients with amyotrophic lateral sclerosis. J Korean Med Sci 2010; 25:1359-63. [PMID: 20808681 PMCID: PMC2923797 DOI: 10.3346/jkms.2010.25.9.1359] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2009] [Accepted: 03/16/2010] [Indexed: 11/20/2022] Open
Abstract
We investigated the availability of motor unit number estimation (MUNE) as a quantitative method to assess the severity and clinical progression of amyotrophic lateral sclerosis (ALS). The 143 ALS patients were evaluated by statistical MUNE and the revised amyotrophic lateral sclerosis functional rating scale (ALSFRS-R). By using mean values of MUNE according to disease duration, regression equation between mean MUNE and disease duration was presented as a formula. The individual MUNE ratio was calculated by dividing individual MUNE value by mean MUNE value. All patients were classified into 2 groups (MUNE ratio <1 vs. MUNE ratio >or=1) according to the MUNE ratio. Comparison between the 2 groups revealed that the patients in MUNE ratio <1 group or MUNE ratio >or=1 group were respectively assigned to rapid progression or slow progression. We recommended informative mean values of MUNE and best regression equation in ALS patients according to disease duration. These values allow us to evaluate the severity and rapidity of progression in ALS.
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Affiliation(s)
- Suk-Won Ahn
- Department of Neurology, Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Korea
| | - Su-Hyun Kim
- Department of Neurology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Dong-Hoon Oh
- Department of Neurology, Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
| | - Sung-Min Kim
- Department of Neurology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Kyung Seok Park
- Department of Neurology, Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
| | - Yoon-Ho Hong
- Department of Neurology, Boramae Medical Center, Seoul National University College of Medicine, Seoul, Korea
| | - Oh-Sang Kwon
- Department of Neurology, Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Korea
| | - Jung-Joon Sung
- Department of Neurology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Kwang-Woo Lee
- Department of Neurology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
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Lehky TJ, Chen CJ, di Prospero NA, Rhodes LE, Fischbeck K, Floeter MK. Standard and modified statistical MUNE evaluations in spinal-bulbar muscular atrophy. Muscle Nerve 2009; 40:809-14. [PMID: 19670325 DOI: 10.1002/mus.21399] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Motor unit number estimation (MUNE), a technique used in amyotrophic lateral sclerosis (ALS) clinical trials to quantitatively assess motor neuron loss, should also be valuable in assessing progression in spinal bulbar muscular atrophy (SBMA), an x-linked neuronopathy. In ALS, instability of single motor units (SMUP) prompted Shefner et al.6(6) to modify the statistical MUNE method to exclude SMUPs < or = 40 microV. It is unknown if there is similar SMUP instability in the more chronic degenerative disease of SBMA. In this study the standard parameter of excluding SMUP < 10 microV was compared with the exclusion of SMUP < 40 microV in the calculation of the statistical MUNE. The mean statistical MUNE, using the standard method and the Shefner et al. method, was 60 +/- 21 to 47 +/- 23, respectively. Similar to ALS, SBMA showed an increased proportion (17%) of individual SMUPs < or = 40 microV compared to normal controls. In conclusion, excluding SMUPs < or = 40 microV from the statistical MUNE calculations is appropriate for SBMA subjects because their SMUP, characteristics are similar to ALS. Exclusion of the low-amplitude SMUPs reduces the calculated MUNE.
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Affiliation(s)
- Tanya J Lehky
- EMG Section, NINDS, NIH, Building 10/Room 7-5680, 10 Center Drive, Bethesda, Maryland 20892-1404, USA.
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Xiong GX, Guan Y, Hong Y, Zhang JW, Guan H. Motor unit number estimation may be a useful method to evaluate motor function recovery after spinal cord transection in rats. Spinal Cord 2009; 48:363-6. [PMID: 19884895 DOI: 10.1038/sc.2009.141] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
STUDY DESIGN Experimental rat study. OBJECTIVE To investigate changes in motor unit number estimation (MUNE) value of the medial gastrocnemius (MG) muscle after thoracic spinal cord transection in rats and to correlate the MUNE with hindlimb motor function recovery. SETTING China Rehabilitation Research Center, Beijing, China. METHODS Twelve rats were subjected to spinal cord transection or sham surgery and then evaluated by MUNE and the Basso, Beattie and Bresnahan (BBB) behavioral scale 56 days after the surgery. RESULTS The MUNE values of the MG muscle were significantly decreased from baseline at 14-49 days after surgery. However, they returned to near pre-injury levels after 56 days. Rats recovered progressively from the severely impaired hindlimb motor function induced by spinal cord injury, as indicated by a gradual increase in BBB score during days 3-49 after surgery. However, this behavioral recovery was only partial and reached a plateau on day 49. Finally, there was a U-shape-like correlation between changes in MUNE values and BBB scores after thoracic spinal cord transection. CONCLUSIONS Time-dependent changes in the functional motor unit number may occur in spinal segments caudal to the transection level, and MUNE could be a useful method to evaluate motor function recovery.
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Affiliation(s)
- G-X Xiong
- Department of Rehabilitation, School of Public Health and Family Medicine, Capital Medical University, Beijing, China.
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Xiong GX, Zhang JW, Hong Y, Guan Y, Guan H. Motor unit number estimation of the tibialis anterior muscle in spinal cord injury. Spinal Cord 2008; 46:696-702. [DOI: 10.1038/sc.2008.7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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van Dijk JP, Blok JH, Lapatki BG, van Schaik IN, Zwarts MJ, Stegeman DF. Motor unit number estimation using high-density surface electromyography. Clin Neurophysiol 2008; 119:33-42. [PMID: 18037342 DOI: 10.1016/j.clinph.2007.09.133] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2007] [Revised: 09/13/2007] [Accepted: 09/23/2007] [Indexed: 10/22/2022]
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Daube JR. Motor unit number estimates: A Holy Grail? Clin Neurophysiol 2007; 118:2542-3. [PMID: 17910936 DOI: 10.1016/j.clinph.2007.08.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2007] [Revised: 08/11/2007] [Accepted: 08/18/2007] [Indexed: 11/18/2022]
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Hong YH, Sung JJ, Park KS, Kwon O, Min JH, Lee KW. Statistical MUNE: a comparison of two methods of setting recording windows in healthy subjects and ALS patients. Clin Neurophysiol 2007; 118:2605-11. [PMID: 17911043 DOI: 10.1016/j.clinph.2007.05.073] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2006] [Revised: 04/18/2007] [Accepted: 05/06/2007] [Indexed: 10/22/2022]
Abstract
OBJECTIVE To address the issue as to how best to perform statistical MUNE, we applied two different approaches and compared results in healthy subjects and ALS patients. METHODS Twelve normal subjects (women 8, mean age 52years) and 11 ALS patients (women 4, mean age 54years) underwent two consecutive MUNE studies, which differed in terms of setting and modifying the recording window. These are referred to as the 'expansion' and 'narrowing' methods, respectively. Size-weighted average (Av) SMUP and MUNE values were obtained using the two methods, and compared in control and patient groups. RESULTS Expansion method-derived Av SMUP sizes and MUNE values differed only slightly from those obtained using the narrowing method in healthy subjects, whereas the narrowing method resulted in significantly larger Av SMUP sizes and smaller MUNE values than the expansion method in ALS patients (Wilcoxon signed ranks test, p=0.003). The sizes of tested areas (mean+/-SD) were significantly larger for the narrowing method than the expansion method in both subject groups with much greater difference in ALS patients; 9.6+/-3.1% vs. 7.9+/-1.7% in healthy subjects and 16.1+/-5.1% vs. 11.2+/-3.0% in ALS patients (Student t-test, p<0.01). CONCLUSIONS The present study shows, unlike that found in normal subjects, that the results of statistical MUNE in ALS patients are heavily dependent on the approach used to set and modify recording windows. SIGNIFICANCE The expansion method using a 10%-sized window is likely to suffer from systemic errors due to the ceiling effect and the sampling of artifactually small motor units in ALS patients. The authors recommend that the narrowing method be considered as an alternative that avoids these problems.
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Affiliation(s)
- Yoon-Ho Hong
- Department of Neurology, Seoul National University College of Medicine, Boramae Hospital, Seoul, Republic of Korea
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Clark BC, Cook SB, Ploutz-Snyder LL. Reliability of techniques to assess human neuromuscular function in vivo. J Electromyogr Kinesiol 2007; 17:90-101. [PMID: 16427317 DOI: 10.1016/j.jelekin.2005.11.008] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2005] [Revised: 11/21/2005] [Accepted: 11/28/2005] [Indexed: 11/20/2022] Open
Abstract
The purpose of this study was to comprehensively evaluate the reliability of a large number of commonly utilized experimental tests of in vivo human neuromuscular function separated by 4-weeks. Numerous electrophysiological parameters (i.e., voluntary and evoked electromyogram [EMG] signals), contractile properties (i.e., evoked forces and rates of force development and relaxation), muscle morphology (i.e., MRI-derived cross-sectional area [CSA]) and performance tasks (i.e., steadiness and time to task failure) were assessed from the plantarflexor muscle group in 17 subjects before and following 4-weeks where they maintained their normal lifestyle. The reliability of the measured variables had wide-ranging levels of consistency, with coefficient of variations (CV) ranging from approximately 2% to 20%, and intraclass correlation coefficients (ICC) between 0.53 and 0.99. Overall, we observed moderate to high-levels of reliability in the vast majority of the variables we assessed (24 out of the 29 had ICC>0.70 and CV<15%). The variables demonstrating the highest reliability were: CSA (ICC=0.93-0.98), strength (ICC=0.97), an index of nerve conduction velocity (ICC=0.95), and H-reflex amplitude (ICC=0.93). Conversely, the variables demonstrating the lowest reliability were: the amplitude of voluntary EMG signal (ICC=0.53-0.88), and the time to task failure of a sustained submaximal contraction (ICC=0.64). Additionally, relatively little systematic bias (calculated through the limits of agreement) was observed in these measures over the repeat sessions. In conclusion, while the reliability differed between the various measures, in general it was rather high even when the testing sessions are separated by a relatively long duration of time.
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Affiliation(s)
- Brian C Clark
- Musculoskeletal Research Laboratory, Department of Exercise Science, Syracuse University, 820 Comstock Avenue, Room 201, Syracuse, NY 13244, USA.
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Sorenson EJ, Daube JR, Windebank AJ. Motor unit number estimates correlate with strength in polio survivors. Muscle Nerve 2006; 34:608-13. [PMID: 16929544 DOI: 10.1002/mus.20632] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Motor unit number estimation (MUNE) has been proposed as an outcome measure in clinical trials for the motor neuron diseases. One major criticism of MUNE is that it may not represent a clinically meaningful endpoint. We prospectively studied a cohort of polio survivors over a period of 15 years with respect to MUNE and strength. We identified a significant association between thenar MUNE and arm strength, extensor digitorum brevis MUNE and leg strength, and the summated MUNE and global strength of the polio survivors. These findings confirm the clinical relevance of MUNE as an outcome measure in the motor neuron diseases and provide further validation for its use in clinical trial research.
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Affiliation(s)
- Eric J Sorenson
- Department of Neurology, Mayo Clinic, Rochester, Minnesota 55905, USA.
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