Scintigraphic Evaluation of Mild to Moderate Dysphagia in Motor Neuron Disease

Approximately 30% of patients with motor neuron disease (MND) present swallowing difficulties even in early disease stages. The aim of this study was to examine the usefulness of esophageal scintigraphy in detecting early stage of dysphagia in MND.

Esophageal scintigraphy (ES) including mean transit time (MTT) estimation was performed in 121 MND patients presenting various levels of upper (UMN) and lower motor neuron (LMN) degeneration.

ES detected dysphagia in more than 80% of MND patients who had referenced swallowing difficulties. In MND patients with ES-confirmed dysphagia, the MTT was increased approximately 2-fold without significant differences between the clinical phenotypes. The MTT was significantly longer in patients with bulbar-pseudobulbar syndrome in comparison to patients with isolated pseudobulbar syndrome, which indicates a higher involvement of the LMN deficiency in developing dysphagia in MND. The esophageal passage in MND was not dependent on age, sex, disease duration, or diagnosis delay. Interestingly, ES was also able to detect dysphagia in almost 70% of MND individuals who had no swallowing complaints (subclinical dysphagia). A more benign disease course and a higher percentage of male patients characterized this group.

Esophageal scintigraphy is a helpful screening tool in determining early swallowing impairment in a high percent of patients with MND of various clinical phenotypes.