Electrical impedance myography in the detection of radiculopathy

Electrical impedance myography (EIM) is a new bioimpedance‐based technique for neuromuscular disease assessment. Past work has focused on EIM in the evaluation of diffuse diseases (such as myopathy). In this study, the method's most basic form, linear‐EIM, was used for the assessment of restricted radiculopathic disease. Ten normal subjects and 10 patients with unilateral cervical or lumbosacral radiculopathy, diagnosed by electromyography and clinical criteria, were enrolled. Linear‐EIM was performed bilaterally on all individuals, and comparisons with the major outcome variable, θavg, were made. In normal subjects, side‐to‐side differences in θavg averaged 0.64% and were no greater than 15.9% in magnitude. In the 10 patients with radiculopathy, θavgwas consistently lower in the affected extremity, with a mean side‐to‐side difference of 15.3%, but ranging as low as 72.3%; there was a tendency for muscles with more prominent chronic neurogenic change to show greater relative reductions in θavg. These findings support the potential utility of EIM in assessment of localized neuromuscular disease. Muscle Nerve, 2005