Transcutaneous Electrical Stimulation
New hope for recovery found in electrical stimulation for dysphagic BI population
By Cindy Davie, MS, CCC-SLP, and Kristin Ferris, MS, CCC-SLP
January 30, 2014
Of the CDC's estimated 750,000 Americans who annually sustain an acquired brain injury (ABI) as a result of stroke, more than half will experience dysphagia or problems swallowing normally.1 Dysphagia occurs when there is a problem with any part of the swallowing process - for instance, weak tongue or cheek muscles may make it hard to move food around in the mouth for chewing. It can also arise anywhere from the mouth to the stomach: it may be due to impaired function of the tongue, palate, pharynx, larynx, vocal folds, upper esophageal sphincter or esophagus, since all are involved in the swallowing mechanism.
Dysphagia profoundly affects quality of life for people with brain injury (BI). They often experience profound personal discomfort with symptoms that include difficulty swallowing, gagging or choking when swallowing, pocketing food, oral secretions, food spillage, watering eyes, and having food or liquids come back up through the throat or nose. People with dysphagia can develop anxiety and/or depression due to frustration and fear of eating as a result of choking and a decreased quality of life. They may also experience fatigue, weight loss and poor nutrition because they are not getting enough food or liquid.
While many people with BI do regain a safe swallow in a relatively short period of time,2 dysphagia is a potentially life-threatening condition that requires immediate therapeutic intervention to prevent choking or aspiration pneumonia, which is caused by saliva or food going down the windpipe and into the lungs and is a leading cause of death in people 65 and older.3 Traditional treatment options have included surgery, feeding tubes and medication, but advances in neuromuscular electrical stimulation (NMES) have led to promising alternative treatments for dysphagia with faster recovery times.
Speech-language pathologists (SLPs) who test for and treat swallowing disorders use a variety of tests that allow them to look at the parts of the swallowing mechanism, including a clinical bedside examination, food trials, and the gold standard diagnostic, which is the Modified Barium Swallow Study (MBSS).
A bedside swallow evaluation helps SLPs establish a possible cause for dysphagia, assess the individual's ability to protect the airway, determine the best approach to nutrition management and establish baselines to chart changes in feeding function. The bedside evaluation includes a comprehensive chart and medications review along with a patient interview to determine issues with swallowing or changes in such things as weight loss, heart burn and voice. Apart from general observations such as the patient's level of alertness or positioning, SLPs also assess the functioning of the swallow. During this assessment, patients may be asked to demonstrate tasks, such as sticking out their tongue, moving it left and right as quickly as possible, blowing a kiss, or producing successive vowel sounds. Such an assessment will provide a basis for determining possible damage to the nerves of the face, jaw, tongue and soft palate.
Observing the consumption of food, fluids or an entire meal provides information about a patient's ability to swallow, as well as allows for the identification of risk factors, such as fatigue, poor control of secretions, trouble breathing and throat clearing. In order to evaluate whether or not a patient is able to receive food orally, SLPs will present small amounts of food or water to patients and watch for signs of dysphagia and aspiration. These trials help determine the consistency of food that can be safely swallowed - thin or thick liquids, pureed or solids.
Despite the broad assessments undertaken at the bedside, the problem with this method is that it relies on findings that are subjective and clinician dependent. For these reasons, the MBSS is the gold standard follow-up assessment. It provides moving images of how the muscles in the mouth and throat work, and can detect any blockages in the esophagus as well as any material that might go into the windpipe.
Alternative Treatments with Electrical Stimulation
Neuromuscular electrical stimulation (NMES) is a relatively new treatment for the two main types of dysphagia - oropharyngeal and esophageal - that is gaining clinical popularity. SLPs at Pate Rehabilitation have seen positive outcomes using NMES, in conjunction with traditional swallowing exercises, to recruit and strengthen muscles, increase range of motion, improve voluntary motor control and increase sensory awareness. While NMES has traditionally been used by physical and occupational therapists as a non-invasive and painless rehabilitation for limbs, it has only recently been gaining attention as a treatment for dysphagia.
NMES uses electrodes, typically on the facial nerves or those surrounding the larynx to help with the elevation of the larynx. During a swallow, the larynx goes up, closes the epiglottis and allows food to go into the esophagus instead of the airway. NMES begins by introducing a low-level stimulus to elicit a sensory response. The intensity of the stimulus is then increased in order to achieve a motor response, or contraction. Over time, the treatment aims to build patient's tolerance for increased intensity of contractions. However, some questions remain in the field regarding the type of electrical current used, electrode placement and size, and the potential for decreased airway protection as a result of laryngeal depression.
VitalStim is a specific method to promote swallowing through the application of neuromuscular electrical stimulation. A small, calibrated current is delivered to the motor nerves of the patient's throat through specially designed electrodes causing the contraction of pharyngeal and laryngeal muscles, those responsible for swallowing and pushing food down the esophagus. At the same time, an SLP guides the patient through active swallowing therapy to re-educate normal swallow function. The American Speech-Language-Hearing Association4 published results of a survey into use of NMES for treatment of the disorder primarily as a result of stroke. Outcomes were generally positive and no treatment-related complications had occurred following NMES treatment. Patients were treated in three to five sessions per week, usually for a duration of one-hour and reported above-average satisfaction with treatment outcomes.
A Holistic Approach to Healing
Studies indicate that despite some remaining questions, transcutaneous electrical stimulation is superior to traditional dysphagia therapy alone.5 Used as an adjunct to traditional swallowing therapy, electrical stimulation has been found to be a safe, painless and effective for patients that speeded recovery time and helped patients achieve long-term improvements.
Cindy Davie and Kristin Ferris are licensed speech-language pathologists at Pate Rehabilitation.