An improved electrical impedance myography (EIM) tongue array for use in clinical trials

Abstract

ObjectivesElectrical impedance myography (EIM) measurements of the tongue could provide valuable information about bulbar dysfunction in amyotrophic lateral sclerosis (ALS). A prototype tongue depressor EIM array produced gag reflexes. The objectives of this study were to determine the reliability, mean phase values, and tolerability of tongue EIM measurements using a smaller electrode array. MethodsTongue EIM measurements were performed in a total of 31 healthy individuals and four neuromuscular patients with lingual abnormalities. Reliability was assessed by calculating the intraclass correlation coefficient (ICC) and percent difference in addition to performing Bland–Altman analyses. Standard descriptive statistics, including results of a Mann–Whitney test, were also determined. ResultsAt the 50kHz frequency, the ICCs for intra- and inter-rater reliability were 0.76 with 5.17% difference and 0.78 with 5.34% difference respectively. The mean EIM phase values of healthy participants (11.61°±1.00°) and patients (9.87°±1.28°) were significantly different (p=0.0051). None of the participants experienced gag reflexes or discomfort. ConclusionsThe small tongue array provided good inter- and intra-rater reliability, could preliminarily distinguish between healthy and diseased muscle, and was well-tolerated. SignificanceBiomarker information about tongue health could be more comfortably obtained with a smaller EIM array.