title: Electrical impedance myography for the assessment of children with muscular dystrophy: a preliminary study.
abstract: Electrical impedance myography (EIM) provides a non-invasive approach for quantifying the severity of neuromuscular disease. Here we determine how well EIM data correlates to functional and ultrasound (US) measures of disease in children with Duchenne muscular dystrophy (DMD) and healthy subjects. Thirteen healthy boys, aged 2-12 years and 14 boys with DMD aged 4-12 years underwent both EIM and US measurements of deltoid, biceps, wrist flexors, quadriceps, tibialis anterior, and medial gastrocnemius. EIM measurements were performed with a custom-designed probe using a commercial multifrequency bioimpedance device. US luminosity data were quantified using a gray-scale analysis approach. Children also underwent the 6-minute walk test, timed tests and strength measurements. EIM and US data were combined across muscles. EIM 50 kHz phase was able to discriminate DMD children from healthy subjects with 98% accuracy. In the DMD patients, average EIM phase measurements also correlated well with standard functional measures. For example the 50 kHz phase correlated with the Northstar Ambulatory Assessment test (R = 0.83, p = 0.02). EIM 50 kHz phase and US correlated as well, with R = -0.79 (p < 0.001). These results show that EIM provides valuable objective measures Duchenne muscular dystrophy severity.
authors.affiliation: Department of Neurology, Beth Israel Deaconess Medical Center, and Department of Neurology, Children's Hospital Boston, Harvard Medical School, Boston, MA, USA.
authors.forename: S B
authors.initials: SB
authors.lastname: Rutkove
authors.forename: B T
authors.initials: BT
authors.lastname: Darras
references.citation: Curr Opin Neurol. 2009 Oct;22(5):532-8
references.pmid: 19745732
references.citation: Clin Investig (Lond). 2011 Sep;1(9):1217-1235
references.pmid: 22639722
references.citation: Cochrane Database Syst Rev. 2004;(2):CD003725
references.pmid: 15106215
references.citation: Muscle Nerve. 2009 Dec;40(6):936-46
references.pmid: 19768754
references.citation: Lancet Neurol. 2010 Feb;9(2):177-89
references.pmid: 19945914
references.citation: J Mol Diagn. 2005 Aug;7(3):317-26
references.pmid: 16049303
references.citation: Neuromuscul Disord. 2012 Apr;22(4):306-17
references.pmid: 22133654
references.citation: Muscle Nerve. 2012 May;45(5):642-7
references.pmid: 22499089
references.citation: Muscle Nerve. 2012 Aug;46(2):257-63
references.pmid: 22806375