Abstract
Electrical impedance myography (EIM) is a noninvasive technique for neuromuscular assessment, wherein a low-intensity alternating current is applied to a muscle, and the consequent surface voltage patterns are evaluated. Commercial wet electrodes are most commonly used for EIM. However, these electrodes are not suitable for use on small muscles, as they do not effectively solve the problem of high electrode-skin contact impedance (ESCI) that negatively influences the quality of recorded biopotentials. To address this problem, we fabricated a novel microneedle electrode array (MEA) that consists of 124-µm-long microneedles. Compared to wet electrodes, the MEA could pierce through the outer skin surface in a painless and micro-invasive manner, and could thus effectively reduce ESCI. The MEA has excellent test–retest reproducibility, with intraclass correlation coefficients exceeding 0.920. When used in combination with EIM, the MEA differentiated the affected muscles from the unaffected muscles in patients with neurogenic myopathy, by using EIM parameters of reactance and phase (p = 0.023 and 0.008, respectively). Thus, the novel MEA is a practical and reusable device for EIM assessment in cases of neurogenic myopathy. However, further refinement of the electrode is needed to enhance the clinical application of the system.
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Abbreviations
- EIM:
-
Electrical impedance myography
- ESCI:
-
Electrode-skin contact impedance
- MEA:
-
Microneedle electrode array
- EMG:
-
Electromyography
- SC:
-
Stratum corneum
- DRIE:
-
Deep reactive ion etching
- SEM:
-
Scanning electron microscope
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Acknowledgments
This study was supported by the National Natural Science Foundation of China (Grant No. 61376072; 61334008). The authors acknowledge the support of the Department of Neurology of the Peking Union Medical College Hospital.
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Associate Editor Tingrui Pan oversaw the review of this article.
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Li, Z., Li, Y., Liu, M. et al. Microneedle Electrode Array for Electrical Impedance Myography to Characterize Neurogenic Myopathy. Ann Biomed Eng 44, 1566–1575 (2016). https://doi.org/10.1007/s10439-015-1466-5
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DOI: https://doi.org/10.1007/s10439-015-1466-5