MScanFit motor unit number estimation of abductor pollicis brevis: Findings from different experimental parameters

Ya Zong; Zhiyuan Lu; Peipei Xu; Maoqi Chen; Lianfu Deng; Sheng Li; Yingchun Zhang; Qing Xie; Ping Zhou

doi:10.3389/fnagi.2022.953173

MScanFit motor unit number estimation of abductor pollicis brevis: Findings from different experimental parameters

Front Aging Neurosci. 2022 Oct 17:14:953173. doi: 10.3389/fnagi.2022.953173. eCollection 2022.

Authors

Ya Zong¹, Zhiyuan Lu², Peipei Xu¹, Maoqi Chen², Lianfu Deng³, Sheng Li⁴, Yingchun Zhang⁵, Qing Xie¹, Ping Zhou²

Affiliations

¹ Department of Rehabilitation Sciences, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
² School of Rehabilitation Science and Engineering, University of Health and Rehabilitation Sciences, Qingdao, China.
³ Shanghai Key Laboratory for Prevention and Treatment of Bone and Joint Diseases, Department of Orthopaedics, Ruijin Hospital, Shanghai Institute of Traumatology and Orthopaedics, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
⁴ Department of Physical Medicine and Rehabilitation, University of Texas Health Science Center at Houston, and TIRR Memorial Herman Hospital, Houston, TX, United States.
⁵ Department of Biomedical Engineering, University of Houston, Houston, TX, United States.

Abstract

MScanFit motor unit number estimation (MUNE) based on the recording of the compound muscle action potential (CMAP) scan has wide applications. This study evaluated the effect of different CMAP scan settings on MScanFit MUNE. CMAP scan of the abductor pollicis brevis (APB) muscle was performed in 10 healthy subjects at a United States (US) research center using different stimulus pulse widths (0.1, 0.2 ms) and total number of stimuli or steps (500, 1,000), and in 12 healthy subjects at a China research center using a 0.1 ms pulse width and 500 steps. MScanFit MUNE was derived using the default model parameters. A significantly higher MUNE was obtained using the shorter than longer pulse width; 84.70 ± 21.56 (500 steps) and 77.90 ± 27.62 (1,000 steps) at a pulse width of 0.1 ms vs. 67.60 ± 18.72 (500 steps) and 62.20 ± 15.82 (1,000 steps) at a pulse width of 0.2 ms (p < 0.05). However, MUNE was unrelated to the number of steps (500 vs. 1,000, p > 0.1). MUNE was significantly higher in persons studied in the China center (136.42 ± 32.46) than the US center (84.70 ± 21.56) despite each center using the same pulse widths and steps (p < 0.001). After excluding the ethnicity, age and experimenter factors, this significant difference is speculated to be partly related to different electrode size used in the two centers. The findings suggest that CMAP scan experimental parameters should remain consistent, so the MScanFit MUNE will not be compromised by non-physiological factors.

Keywords: CMAP scan; MScanFit; abductor pollicis brevis (APB); compound muscle action potential (CMAP); motor unit number estimation (MUNE).