Tongue electrical impedance in amyotrophic lateral sclerosis modeled using the finite element method

Abstract

Objective Electrical impedance myography (EIM) of the tongue has demonstrated alterations in patients with amyotrophic lateral sclerosis (ALS) compared to normal subjects. Whether these differences are due to reduced tongue size or diseased-associated alterations in the electrical characteristics of intrinsic tongue muscles is uncertain. Methods We employed computer simulations using the finite element method, inputting data from healthy and ALS mouse muscle, to help answer that question, comparing our modeled results to human data. Results The models revealed that much of the electrical current flows superficially in the tongue and that tongue thickness only begins to have a major impact on the measured impedance when substantial atrophy is present. Modeled values paralleled the human tongue data. Conclusions These findings suggest that the observed changes in tongue impedance in ALS are mainly due to alterations in the electrical properties of the tongue and are not a mere consequence of tongue volume loss. Significance Further development of EIM for evaluation of bulbar dysfunction in ALS may provide useful information on drug efficacy and could serve as a biomarker in future clinical trials.

Multi-dimensional electrical impedance myography of the tongue as a potential biomarker for amyotrophic lateral sclerosis

“…The modelling work of Pacheck et al, indicates tongue volume has little impact on impedance data and we were recording in the midline of the tongue blade and hence not near the muscle edge. (Pacheck et al , 2016). We therefore consider that it is unlikely that our results are explained by differences in tongue volume.…”

Use of Electrical Impedance Spectroscopy for Intraoperative Tissue Differentiation During Thyroid and Parathyroid Surgery

“…EIS can detect changes in the shape and structure of the cells within the tissue [1][2][3]. This property has been used to aid the early detection of cervical cancer [1,2,4] and is being explored in the oral cavity to detect oral cancer and its potential use in detection of multiple sclerosis [5][6][7]. Other early studies have investigated its ability to identify cancer in prostate, bladder and breast tissues [8][9][10][11][12][13][14].…”

Electrical Impedance Myography to Detect the Effects of Electrical Muscle Stimulation in Wild Type and Mdx Mice

“…We have previously observed this effect in rats, in which we witnessed reductions in reactance and resistance as young animals matured, despite their having larger myofiber cross sectional area [ 27 ]. More recently, we have modeled this effect in the human tongue and similarly observed that increasing muscle size alone, keeping all other parameters identical, causes reductions in the measured resistance and reactance [ 28 ]. This also is due to a lower current density in the region of the voltage electrodes.…”