Cortical activation during swallowing rehabilitation maneuvers: a functional MRI study of healthy controls.

Objective/Hypothesis: We hypothesize that the central response during swallowing rehabilitation is critical and may be exploited to maximize the therapeutic benefit. We seek to provide preliminary data regarding the neural networks associated with commonly employed rehabilitation strategies to increase our understanding of the neural bases underlying these maneuvers. Study Design: Case series. Methods: Ten healthy adults (five males, five females), ranging in age from 20 to 30 years (mean age = 25 years, SD = 2.5 years) with no previous history of neurologic illness or swallowing complaint were subjected to a single-trial functional magnetic resonance imaging (fMRI) paradigm. The experimental tasks consisted of three swallow maneuvers, dry swallow, Effortful swallow, and the Mendelsohn maneuver. Results: Multiple regions including the cingulate gyrus, inferior frontal gyrus, insula, pre- and postcentral gyrus, inferior parietal lobe, superior frontal gyrus, supramarginal gyrus thalamus, were detected. The Effortful swallow, when compared to the dry swallow, elicited significant differential activation in the left superior temporal gyrus, left insula, left inferior parietal lobe, bilateral medial frontal gyrus, and right anterior cingulate. The Mendelsohn maneuver, when compared to the dry swallow, elicited significant activation in the bilateral postcentral gyrus, bilateral precentral gyrus, bilateral cingulate gyrus, bilateral medial frontal gyrus, left inferior parietal lobe, left supramarginal gyrus, and right insula. Conclusions: Our findings suggest that a single-trial design is sensitive to delineate a widespread neural network of activation in both hemispheres associated with rehabilitation tasks. Both the Effortful swallow and Mendelsohn maneuvers elicited significantly higher responses in regions related to swallowing, suggestive of enhanced cortical activation during these tasks.