A Bioimpedance-Based Device to Assess the Volume Conduction Properties of the Tongue in Neurological Disorders Affecting Bulbar function

IEEE Open J Eng Med Biol. 2021 Oct 6:2:278-285. doi: 10.1109/OJEMB.2021.3117871. eCollection 2021.

Abstract

Goal: Current instruments for bulbar assessment exhibit technical limitations that hinder the execution of clinical studies. The volume conduction properties (VCP) of the tongue reflect ionic content and myofiber integrity and they can serve as a new biomarker for evaluating neurological disorders with bulbar dysfunction. Methods: We designed a standalone bioimpedance measurement system that enables accurate, multi-frequency measurement of tongue anisotropic VCP including conductivity and relative permittivity. The system includes a tongue depressor with 16 non-invasive surface sensors for electrical contact with the tongue at directions 0[Formula: see text], 45[Formula: see text], 90[Formula: see text] and 150[Formula: see text]. The depressor is interfaced with the tongue electronic system with Bluetooth connectivity, and a smartphone application. De-identified patient data is sent by email. Results: We first determined the accuracy of the hardware performing phantom measurements mimicking a broad range of tongue values and determined the error to be [Formula: see text]1%. We then validated our new technology measuring a cohort of 7 healthy human subjects under Institutional Review Board approval. Conclusions: None of the subjects who participated suffered discomfort or gag reflexes. The novel technique presented for intra-oral assessment of tongue VCP provides standard, objective and quantitative data potentially sensitive to alterations in tongue internal structure and composition.

Keywords: Tongue; anisotropy; biomarker; electrodes; volume conduction properties.

Grants and funding

This work was supported in part by China Scholarship Council under Grant 201906020024 (XL), in part by the National Institutes of Health under Grant R41 NS112029-01A1 (BS), and in part by the Friends of FSH Research (BS).