A friend of mine with Parkinson’s disease, recently sent me a copy of an advertisement that was in their local newspaper. The advertisement, sponsored by a local rehabilitation facility was promoting neuromuscular electrical stimulation (NMES) as a treatment for swallowing problems related to a host of conditions including: trouble taking pills, trouble with certain food consistencies, swallowing difficulties after surgery, head and neck cancer treatment, stroke, and so on. The promise of almost “magical” treatment for this host of symptoms, prompted my friend to ask my advice re: NMES as treatment for swallowing problems, specifically associated with Parkinsons’s and related diseases.
In responding to her question, I tried to address some of the issues common to all swallowing problems, and then more specifically discuss the research that is specific to Parkinson’s disease, and finally comment on NMES. Since swallowing disorders can be caused by many different diseases and diagnosis, and symptoms can occur at any phase of the swallow from the mouth to the stomach, a thorough evaluation by a speech-language pathologist (swallowing or dysphagia therapist) has to be the starting point for management decisions. Once this evaluation has been completed and the cause or causes of the swallowing problem identified, treatment can be recommended, which may include some regimen of exercise.
It is known that problems occurring in the oral stage of swallowing, and primarily due to tongue strength and coordination may benefit from tongue strengthening exercises. Multiple studies investigating oral-motor exercise programs (Kays et al., 2004; Logemann et al., 1997; Robbins et al., 2007; Sullivan et al., 2001) have found the exercise is effective in increasing tongue strength and improving swallowing, including patients with swallowing symptoms related to Parkinson’s.
Some reports indicate that patients completing the Lee Silverman Voice Treatment (LSVT®) program, also demonstrate improvements in swallowing, and this may be due to the emphasis on high effort voicing tasks.
For swallowing problems primarily associated with airway protection, expiratory muscle strength training (EMST) is a promising treatment approach that is supported by research led by Dr. Christine Sapienza and colleagues at the University of Florida. * Expiratory muscle strength training (EMST) is accomplished by using a handheld device with variable resistance (think weight training for your breathing muscles). Patients exhale by blowing into the device, which in turn activates the muscles of exhalation (primarily abdominal muscles) which helps to strengthen cough effort. Strengthening the muscles of exhalation may also help strengthen the lung’s natural mechanism for clearing any foreign bodies that have entered the lungs during eating or drinking, and safeguard against aspiration pneumonia. In addition, when patients have been observed performing EMST training during a video-swallow study (x-ray of swallowing), increased activation of the muscle group responsible for hyoid elevation has been observed. This is an important observation, because the movement of the hyoid bone during swallowing helps close off the respiratory airway protecting it from foreign material traveling the wrong way, and helping to open the sphincter of the esophagus (stomach tube) which then allows food to enter the stomach.
*Impact of Expiratory Muscle Strength Training on Voluntary Cough and Swallow Function in Parkinson Disease Sapienza, et al CHEST May 2009 vol. 135 no. 5 1301-1308
The coordination of breathing and swallowing in Parkinson’s disease is also the focus of research by Dr Roxann Diez Gross from Pittsburgh.** Dr Gross is investigating lung volume differences and swallowing in healthy adults and individuals with Parkinson’s and states: “accurate coordination between breathing and swallowing could be the key to safety in Parkinson’s Disease.” Individuals with Parkinson’s disease may need to swallow at higher lung volumes to maximize activation of swallowing sensory stimulators below the vocal folds. Training patients to generate high lung volumes at the onset of swallowing may counter some of the changes in the respiratory and swallowing system that have occurred from PD.
**The Coordination of Breathing and Swallowing in Parkinson’s Disease. Roxann Diez Gross. Dysphagia Vol 23. Number 2. June 2008
So, now we come to neuromuscular electrical stimulation (NMES). NMES has been used by physical and occupational therapists for a number of years, but it is a relatively recent addition to swallowing (dysphagia) treatment by speech-language pathologist. Its addition to treatment protocols has raised interest as well as concern among researchers regarding efficacy (benefit) and safety. For example, depending on the placement of the electrodes on the patient’s throat, some researchers found a lowering of the hyoid to take place (Humbert et al 2008, Ludlow, 2008). Lowering of the hyoid bone is opposite the normal upward direction of hyoid movement, and may actually increase the aspiration risk for some patients. This may be especially true for individuals with Parkinson’s disease, who have slowness and stiffness of motor function as a feature of the disease, and may not be able to overcome the muscle resistance.
Clearly, many more studies which look at the role of NMES and swallowing in general, and then specific to various disease states, are warranted before recommending its routine use in swallowing treatment. If recommended as a part of swallowing treatment, NMES should be considered cautiously and only if evidence on a video-swallow study demonstrates more benefit than risk.
In summary, my recommendations to any individual exploring treatment for swallowing problems related to Parkinson’s:
- PREVENTION is always best, through implementing a general exercise program, oral hygiene, and specific swallow exercises if indicated.
- Expiratory muscle strength training (EMST) for improving pulmonary hygiene and, cough effort which must be preserved in individuals with Parkinson’s.
- Breath support and swallowing exercises and strategies which improve coordination of respiration and swallowing may also provide defense against aspiration pneumonia in the later stages of Parkinson’s.
Expiratory muscle strength training is a device driven therapy that has shown to have positive effects on breathing, swallow function and cough function in persons with Parkinson’s disease. Dr. Sapienza’s research group at the University of Florida has numerous research studies to support these outcomes. Please email Dr. Sapienza at sapienza@ufl.edu for more information .
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