During the last year we completed a study examining the use of two different types of sensory stimulation, a continuous vibratory stimulus to the larynx and an intermittent air pressure pulse to the oral cavity. We evaluated the effects of these two conditions on spontaneous swallowing in normal volunteers. The rates of stimulation varied in each of the two stimulation sets. Overall a higher rate of stimulation using the air pressure pulse at 4 Hz increased spontaneous swallowing in the normal volunteers. No effects were found with the vibratory stimulus on spontaneous swallowing in healthy volunteers. Further experiments are planned aimed at determining which types of stimuli enhance swallowing and increase blood flow responses in the sensori-motor cortex to enhance swallowing control first in healthy volunteers and then in patients with dysphagia.? ? 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. We have found that fMRI cannot be conducted in the majority of these patients because of metal devices or an adversion to the scanning environment and are now exploring other approaches for examining neuroplasticity as a result of swallowing rehabilitation in persons with chronic pharyngeal dysphagia. ? ? The second is a 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. Patient recruitment is continuing and thus far most patients are showing gains in their swallowing with retraining. Recently acute studies have shown that at least some patients with chronic progressive dysphagia following radiation/chemoradiation for the treatment of head and cancer respond to intramuscular stimulation with similar patterns of hyo-laryngeal elevation occurring with hooked wire electrode stimulation indicating that some of these patients might be candidates for an implanted neuroprosthesis. This will undergo examination in the upcoming year.
