Exploration of Bulbar Symptoms in Motor Neuron Disease

Abstract

Motivated by the need to establish non-invasive objective tools for evaluation of bulbar motor dysfunction, this study investigated the sensitivity of tongue electrical impedance spectroscopy (EIS) and tongue in strength in differentiation between patients with motor neuron disease (MND) and healthy controls. Seventy-one participants were evaluated (patients =41 and controls=30). EIS and tongue strength were significantly different between patients and controls and between patients with normal bulbar examination and patients with tongue atrophy. In addition, the study assessed the severity of salivation using the amended Clinical Saliva Scale for MND (CSS-MND). The study examined the correlations of EIS, tongue strength and the CSS-MND to the ALSFRS-R and clinical signs of bulbar lower motor neuron dysfunction in patients with MND, as well as their sensitivity to progression. The measures correlated significantly with the bulbar functional/ symptomatic scales and clinical signs of bulbar lower motor neuron dysfunction. EIS and tongue strength displayed modest progression, compared to the ALSFRS-R and the CSS-MND. The ability of EIS to differentiate between patients and controls was promising. Correlation to objective measures sensitive to reinnervation is needed. The CSS-MND was a sensitive tool to progression. Its sensitivity to intervention needs to be assessed.