Objectives
Electrical 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.
Methods
Tongue 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.
Results
At the 50 kHz 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.
Conclusions
The small tongue array provided good inter- and intra-rater reliability, could preliminarily distinguish between healthy and diseased muscle, and was well-tolerated.
Significance
Biomarker information about tongue health could be more comfortably obtained with a smaller EIM array.