Alterations in Localized Electrical Impedance Myography of Biceps Brachii Muscles Paralyzed by Spinal Cord Injury

Frontiers in Neurology, 2017 · DOI: 10.3389/fneur.2017.00253 · Published: June 20, 2017

Simple Explanation

This study assessed electrical impedance myography (EIM) changes after spinal cord injury (SCI) with a localized multifrequency technology. The EIM measurement was performed on the biceps brachii muscle at rest condition of 17 cervical SCI subjects, and 23 neurologically intact subjects as control group. Since EIM requires no patient effort and is quick and convenient to conduct, it may provide a useful tool for examination of paralyzed muscle changes after SCI.

Study Duration

Not specified

Participants

17 cervical SCI subjects and 23 neurologically intact subjects

Evidence Level

Not specified

Key Findings

1
The results showed that there was a significant decrease in muscle reactance (X) and phase angle (θ) at selected frequencies (i.e., 50 and 100 kHz) in SCI compared to control.
2
The anisotropy examination revealed that SCI group had a decreased anisotropy ratio in resistance.
3
In addition, the multifrequency spectrum analysis showed a decreased slope of the log(freq)-resistance regression in SCI group when compared to healthy control.

Research Summary

We have demonstrated that, in SCI, multifrequency EIM patterns differ substantially from those in healthy control subjects at biceps brachii, especially the reactance and phase angle. Our results revealed reductions in reactance and phase angle in SCI group compared to healthy control which might be related to the changes in muscle inherent and structural property alterations after injury. In addition, we also observed that the AR of resistance was smaller which might be related to loss of muscle fibers and fat infiltration.

Practical Implications

Diagnostic Tool

EIM may provide a useful tool for examination of paralyzed muscle changes after SCI.

Monitoring Disease Progression

EIM changes could be used to document the muscle cell membrane property changes after SCI as demonstrated in other populations.

Therapeutic Interventions

Rehabilitation interventions used to improve cellular membrane integrity or increase muscle myocyte size and number could be evaluated by EIM techniques.

Study Limitations

1
The optimal electrode distance between injecting current and measuring voltage to use is likely dependent on details of the skin–subcutaneous fat layer thickness of measured muscle
2
the changes in EIM alone do not fully explain the mechanism of complex neuromuscular changes after SCI.
3
It may be better to have body mass index of SCI subjects in the future to correlate with EIM that can further verify the body size or limb girth effects.

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