Volitional Swallowing in Stroke Patients With Chronic Dysphagia
Condition: Stroke; Dysphagia
MeSH terms: Deglutition Disorders; Stroke
Study type: Interventional
Phase: Phase 2

Summary: 
      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.
    

Detailed description: 
      Objectives:

      Chronic pharyngeal dysphagia is a life threatening disorder following brain injury. Repeated
      occurrences of aspiration pneumonia result in expensive hospital stays and reduced survival.
      The purpose of this investigation is to compare two novel training methods: 1) training to
      initiate swallowing while pressing a switch; 2) training to initiate swallowing while
      pressing a switch with coincident peripheral vibrotactile stimulation.

      Some preliminary studies will be conducted in healthy volunteers to determine the feasibility
      of using near infrared spectroscopy (fNIRS) for measuring change in brain activation for
      swallowing before and after treatment and to determine the physiological effects of direct
      current stimulation on brain activation for swallowing, during sensory stimulation and at
      rest.

      Patients will be randomly assigned to one of two training groups and the results of 12
      training sessions will be contrasted using blinded assessment. The hypothesis being tested is
      that training methods involving simultaneous peripheral-sensory stimulation will reduce the
      risk of aspiration or penetration during swallowing in patients with chronic pharyngeal
      dysphagia post brain injury.

      Two additional questions address the neural mechanisms involved in the training effects. To
      determine whether changes occur in cortical control of the hyo-laryngeal musculature involved
      in swallowing, patients will also be studied before and after training using transcranial
      magnetic stimulation to assess muscle responses to cortical stimulation. Finally, to
      determine if training effects are related to changes in cortical neuroplasticity, we will use
      near infrared spectroscopy to measure functional change in brain activation in M1, for
      swallowing to determine if cortical control is enhanced in the different training groups.

      Study Population:

      Healthy volunteers and patients with chronic pharyngeal dysphagia following brain injury will
      be studied.

      Design:

      Healthy control subjects will be assessed first in three studies:

        1. A study comparing the effects of air puff versus vibrotactile stimulation on inducing
           swallowing

        2. A study of the transcranial magnetic stimulation to elicit responses from pharyngeal and
           submental muscles

        3. A study using near infrared spectroscopy to examine brain activation responses to
           sensory stimulation, brain laterality for swallowing and the effects of transcranial
           direct current stimulation (tDCS) on brain responses to sensory stimulation and brain
           activation for swallowing.

      Patients with chronic pharyngeal dysphagia following brain injury will participate in a
      clinical trial evaluating swallowing motor retraining with and without sensory stimulation.
      This study will be a randomized, blinded Phase 2 clinical trial in which patients will be
      assigned to two training conditions: training with sham sensory stimulation and training with
      vibrotactile sensory stimulation.

      A non-invasive, external vibrotactile stimulator on the throat will provide external sensory
      stimulation. Pre-training testing, training sessions, and post-training testing will be
      provided in up to 20 visits for each subject.

      Outcome Measures:

      The primary outcome variables will be measures of swallowing function before and after
      training and at 3 and 6 months post training. These will include the NIH Swallowing Safety
      Scale scored from masked videofluoroscopy recordings and the Water Test, a non-invasive
      assessment of swallowing. Both will be scored by speech pathologists blinded to patient
      training group identity or condition before or after training.

      To assess the relationship of improvements in training with changes in neuronal function,
      transcranial magnetic stimulation with surface electromyography recordings will be used to
      assess changes in corticobulbar conduction following training.

      To assess whether functional activation within the brain (particularly in the region of M1)
      is related to improvement in swallowing following each type of training, near infrared
      spectroscopy NIRS will be used to examine blood oxygenation level dependent changes in brain
      function for swallowing following training. All outcome measures will be scored without
      knowledge of training group or condition (pre vs. post training or training group).
    

Intervention name(s): Swallowing Training
Intervention type(s): Procedure
Intervention description(s): Swallowing Training with press of button
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Treatment
Keywords: Training; Cortical Stimulation; Sensory Stimulation; Brain Imaging; Transcranial Magnetic Stimulation (TMS); Swallowing; Dysphagia; Stroke; CVA; Cerebral Vascular Accident; Healthy Volunteer; HV