A Technique for Performing Electrical Impedance Myography in the Mouse Hind Limb: Data in Normal and ALS SOD1 G93A Animals

OBJECTIVE To test a method for performing electrical impedance myography (EIM) in the mouse hind limb for the assessment of disease status in neuromuscular disease models. METHODS An impedance measuring device consisting of a frame with electrodes embedded within an acrylic head was developed. The head was rotatable such that data longitudinal and transverse to the major muscle fiber direction could be obtained. EIM measurements were made with this device on 16 healthy mice and 14 amyotrophic lateral sclerosis (ALS) animals. Repeatability was assessed in both groups. RESULTS The technique was easy to perform and provided good repeatability in both healthy and ALS animals, with intra-session repeatability (mean ± SEM) of 5% ± 1% and 12% ± 2%, respectively. Significant differences between healthy and ALS animals were also identified (e.g., longitudinal mean 50 kHz phase was 18 ± 0.6° for the healthy animals and 14 ± 1.0° for the ALS animals, p=0.0025). CONCLUSIONS With this simple device, the EIM data obtained is highly repeatable and can differentiate healthy from ALS animals. SIGNIFICANCE EIM can now be applied to mouse models of neuromuscular disease to assess disease status and the effects of therapy.