Brain activation during oral exercises used for dysphagia rehabilitation in healthy human subjects: A functional magnetic resonance imaging study

Oral exercises, including tongue, lip, and jaw movements, are commonly used in clinical practice as training to improve oral and pharyngeal swallowing in dysphagia patients. These rehabilitation exercises are believed to affect the peripheral and central nervous system at various levels. However, few studies have examined healthy subjects' brain activity while performing oral exercises used in dysphagia rehabilitation. The current study sought to measure brain activation during oral exercises in healthy subjects using functional magnetic resonance imaging (fMRI). Lip-pursing and lip-stretching, tongue protrusion, lateral tongue movement, and oral ballrolling were selected as tongue and lip exercise tasks. The tasks were performed by eight healthy subjects, and the fMRI data were submitted to conjunction analyses. The results confirmed that head movements during all tasks exhibited translation of<1.0 mm and rotation of<1.0° in x, y, and z coordinates. We found several clear regions of increased brain activity during all four oral exercises. Commonly activated regions during tongue and lip exercises included the precentral gyrus and cerebellum. Brain activation during ball-rolling was more extensive and stronger compared to the other three oral exercises.