During the last year we completed a study examining the central nervous system for swallowing using functional neuroimaging. Volitional swallowing invokes activity in widely distributed regions of the cerebral cortex, basal ganglia and cerebellum.
We aim ed to determine what portions of this network are elicited either by sensory stimulation alone, or swallowing planning without movement feedback from swallowing. We compared brain activation during volitional swallowing with that produced with sensory stimulation of the faucial pillars, during covert swallowing without execution, and during volitional swallowing of saliva. Very similar patterns of activation were elicited in all three tasks demonstrating the significant role of sensory facilitation in volitional swallowing and that motor planning can also invoke a similar pattern of brain activation. We are also comparing the degree to which different sensory stimuli can increase swallowing behavior as well as the urge to swallow in healthy volunteers in order to develop more potent sensory triggers for reinstituting swallowing following dysphagia after brain injury.? ? We completed our third study of the effects of surface electrical stimulation on vocal tract kinematics. Using nasolaryngoscopy during surface electrical stimulation we demonstrated that neither vocal fold adduction nor abduction occurred with stimulation showing that this technique is not efficacious for airway protection during swallowing. ? ? We aim to determine how sensory facilitation or motor augmentation of volitional swallowing can enhance swallowing in patients with chronic pharyngeal dysphagia secondary to neurological diseases or disorders. Two phase II trials are ongoing in chronic pharyngeal dysphagia. The first study is examining neuroplasticity following 2 weeks of swallowing training in different conditions using biofeedback swallowing training while providing sensory facilitation and/or cortical direct current stimulation. The second is a two year trial comparing an implanted neuroprosthesis for augmenting hyo-laryngeal elevation during swallowing with sensory facilitation when both are used during volitional retraining by the patient.
