Electrical impedance myography in the diagnosis of radiculopathy

Introduction: We sought to determine whether electrical impedance myography (EIM) could serve as a diagnostic procedure for evaluation of radiculopathy. Methods: Twenty-seven patients with clinically and radiologically diagnosed cervical or lumbosacral radiculopathy who met a "gold standard" definition underwent EIM and standard needle electromyography (EMG) of multiple upper or lower extremity muscles. Results: EIM reactance values revealed consistent reductions in the radiculopathy-affected myotomal muscles as compared with those on the unaffected side; the degree of asymmetry was associated strongly with the degree of EMG abnormality (P<0.001). EIM had a sensitivity of 64.5% and a specificity of 77.0%; in comparison, EMG had a sensitivity of 79.7% but a specificity of 69.7%. Conclusions: These findings support the potential for EIM to serve as a new non-invasive tool to assist in diagnosis of radiculopathy; however, further refinement of the technique is needed for this specific application.