Electrical Impedance Myography For The Evaluation Of The Tongue Musculature In Amyotrophic Lateral Sclerosis. (P4.103)

Abstract

OBJECTIVE:(1) Compare tongue electrical impedance myography (EIM) 50 kHz phase values in patients with amyotrophic lateral sclerosis (ALS) to those of age-matched healthy controls; (2) correlate these values with measures of bulbar function. BACKGROUND:The majority of individuals diagnosed with ALS show signs of bulbar impairment at the onset of disease or as disease progresses. Considering the diagnostic challenges in ALS, a measure that is highly sensitive to disease onset and progression would be of significant clinical importance, assisting with early diagnosis and serving as a biomarker of bulbar health in clinical trials. The recently developed technique of EIM provides quantitative data on muscle health by measuring localized tissue impedance. EIM has been evaluated as a biomarker of muscle abnormalities in limb musculature in ALS, showing a reduction in phase as disease progresses. However, EIM of the tongue has not been studied in patients with ALS. DESIGN/METHODS:Nineteen subjects with ALS and 16 healthy age-matched controls participated. All participants with ALS showed signs of bulbar impairment (e.g., tongue fasciculations, atrophy, weakness). EIM of tongue was performed using a novel tongue depressor electrode array. Severity of disease (e.g., ALS Functional Rating Scale-R, bulbar subscore, speaking rate during a reading task) and tongue function (maximum strength and endurance) were correlated with EIM values. RESULTS:Independent-samples t-tests revealed significantly smaller phase values (p < 0.001) (mean±standard deviation) for ALS participants (10.7±3.7°) than for controls (16.4±1.8°). Correlations between EIM values and most measures of bulbar function were non-significant; however, a correlation between phase and tongue endurance was identified in participants with ALS (r = 0.48, p=0.045). CONCLUSIONS:EIM of the tongue can distinguish patients with ALS from healthy controls and correlates with one measure of tongue function. Further refinement, validation and study of this biomarker for the evaluation of bulbar dysfunction are warranted.

Disclosure: Dr. Rutkove has received personal compensation for activities with Skulpt, Inc. as a consultant. Dr. Rutkove has received royalty payments from UpToDate, and Springer, Inc. Dr. Rutkove has received compensation for serving on the board of directors of Skulpt, Inc. Dr. Rutkove holds stock and/or stock options in Skulpt, Inc. Dr. Shellikeri has nothing to disclose. Dr. Yunusova has nothing to disclose. Dr. Green has nothing to disclose. Dr. Zinman has nothing to disclose.