Adam Pacheck1, Alex Mijailovic1, Sung Yim1, Jia Li1, Jordan R Green2, Courtney E McIlduff1, Seward B Rutkove3. 1. Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA. 2. MGH Institute of Health Professions, Boston, MA 02129, USA. 3. Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA. Electronic address: srutkove@bidmc.harvard.edu.
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.
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 ALSmouse 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.
Authors: Sanjana Shellikeri; Yana Yunusova; Jordan R Green; Gary L Pattee; James D Berry; Seward B Rutkove; Lorne Zinman Journal: Muscle Nerve Date: 2015-06-03 Impact factor: 3.217
Authors: Courtney McIlduff; Sung Yim; Adam Pacheck; Tom Geisbush; Aleksandar Mijailovic; Seward B Rutkove Journal: Clin Neurophysiol Date: 2015-07-02 Impact factor: 3.708