Induction of Volitional Swallowing in Chronic Dysphagia Post Stroke: A Novel Mechanism-Based Intervention

This study will compare several techniques designed to improve the ability to swallow in stroke patients with chronic dysphagia (difficulty swallowing).

Healthy volunteers 20 to 60 years of age and people 20 to 90 years of age who have had a stroke resulting in swallowing problems may be eligible for this study. Volunteers are screened with a medical history, physical examination, and urine test for women to rule out pregnancy. Stroke patients are screened additionally with a chest x-ray, physical examination, cognitive screening, swallowing questionnaires, nasoendoscopy (examination of the nasal passages in the back of the throat using a lighted telescopic instrument) and FEESST (passage of a thin, flexible telescope through the nose to the voice box), videofluoroscopy (x-ray of the head and neck during swallowing) and button press training (learning how to press a button on a table in coordination with swallowing).

All participants undergo the following procedures:

• Transcranial magnetic stimulation (TMS): A metal coil is placed on the head and sends a pulse of energy to the brain through the scalp. The muscle response to the pulse is recorded from the muscles in the throat that are associated with swallowing.
• Electromyography: A needle is used to insert tiny wires in specific muscles of the throat to record the muscle response to the TMS pulses.
• Magnetic resonance imaging (MRI): During brain MRI scanning, subjects lie quietly and images of the brain are taken.

In addition to the above tests, stroke patients undergo the following:

• Water test: The subject swallows a small amount of water and the number of times required to clear the throat or cough is counted. This test is repeated five times.

• Experimental training. Subjects have a total of 12 60-minute training sessions, one session a day for up to 5 sessions a week.

• Button press training: The subject swallows small amounts of water. A device placed on the throat senses when swallowing occurs. The subject learns how to coordinate pressing a button on a table in coordination with swallowing.

• Vibrotactile stimulator training: A device that uses a buzzing vibration is placed on the throat at times during the swallowing training.

• Transcranial direct current stimulation (tDCS): Wires attached to sponge electrodes are placed on the scalp and over the eye. Small electric currents are delivered to areas of the brain involved with swallowing. This is done at times during the swallowing training.

Participants may receive one of several combinations of training approaches; all receive the volitional (button-press) training. Within 5 days of completing training, subjects repeat the tests. TMS, MRI, MEG and x-ray study of swallowing function are also repeated to see if any changes have occurred in the brain or in the ability to swallow after training. Patients are contacted by telephone and in writing 3 and 6 months after training for follow-up on their swallowing status and oral intake.