title: 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.
  
  
  CONCLUSIONS
  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.affiliation: Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
authors.forename: Adam
authors.initials: A
authors.lastname: Pacheck
authors.affiliation: Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
authors.forename: Alex
authors.initials: A
authors.lastname: Mijailovic
authors.affiliation: Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
authors.forename: Sung
authors.initials: S
authors.lastname: Yim
authors.affiliation: Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
authors.forename: Jia
authors.initials: J
authors.lastname: Li
authors.affiliation: MGH Institute of Health Professions, Boston, MA 02129, USA.
authors.forename: Jordan R
authors.initials: JR
authors.lastname: Green
authors.affiliation: Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
authors.forename: Courtney E
authors.initials: CE
authors.lastname: McIlduff
authors.affiliation: Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA. Electronic address: srutkove@bidmc.harvard.edu.
authors.forename: Seward B
authors.initials: SB
authors.lastname: Rutkove
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000690:Amyotrophic Lateral Sclerosis / Q000175:diagnosis* / Q000503:physiopathology*; D000818:Animals; D017097:Electric Impedance; D005260:Female; D020342:Finite Element Analysis; D006801:Humans; D008297:Male; D051379:Mice; D008875:Middle Aged; D008954:Models, Biological; D014059:Tongue / Q000502:physiology*; D055815:Young Adult
keywords: Amyotrophic lateral sclerosis; Atrophy; Electrical impedance; Modeling; Tongue