Muscular Dystrophy Specialized Care Needed For Speech, Swallowing
Specialized Care Needed For Speech, Swallowing
By Abigail Shoemaker
Approximately a quarter of a million people in the United States have any one of the nine different types of muscular dystrophy (MD), according to the Muscular Dystrophy Association, which is based in Tucson, AZ. The progressive genetic disorders affect connective tissue, bone and muscle.
The various types of MD are myotonic dystrophy (Steinert's disease), Duchenne (pseudohypertrophic), Becker, limb-girdle, oculopharyngeal, facioscapulohumeral, Landouzy-Dejerine, congenital, distal and Emery-Dreifuss.
In particular, oculopharyngeal and myotonic MD can result in severe swallowing and speech disorders.
"What is affected depends a great deal on the type and severity of muscular dystrophy," said Jeri Logemann, PhD, CCC-SLP, chair of the Department of Communication Sciences and Disorders at Northwestern University in Evanston, IL.
Oculopharyngeal MD, Dr. Logemann explained, can profoundly affect the pharynx in terms of muscle contractions of the pharyngeal wall and the lifting of the larynx. This disorder also causes ptosis, a drooping of the eyelids, and a progressive weakness of the palate.
Recent research has revealed that the oculopharyngeal MD gene resides on chromosome 14 and may result in the phenomenon of genetic anticipation, in which the disease worsens with each generation.
For example, a male patient seen at the Center for Craniofacial Disorders, Montefiore Medical Center at Albert Einstein College of Medicine, Bronx, NY, was diagnosed with oculopharyngeal MD on the basis of family history, reported Rosalie Goldberg, MS, CGC, a board-certified genetic counselor. The patient's mother and other relatives had a similar but less severe presentation of the disease. Therefore, there is a 50 percent chance that he could pass the disease on to his offspring.
Myotonic MD also affects the pharynx, particularly the cricopharyngeal and mastication muscles, Dr. Logemann said. Persons with this form of MD often present with systemic abnormalities and nervous system dysfunction. In addition to swallowing and speech difficulties, they may have cataracts and cardiopulmonary disorders.
Speech-language pathologists experience some limitations when treating swallowing and speech disorders in patients with MD, she noted. A patient's difficulty with muscle control can create problems in positioning during testing, such as radiographic studies, and treatment procedures.
For patients with poor chewing and swallowing function, speech-language pathologists should evaluate the patient, usually radiographically, and implement compensatory strategies and exercises to maintain tongue motion and other aspects of the swallow, Dr. Logemann recommended. If that approach is ineffective, a change in diet may be needed.
Patients who experience difficulty in laryngeal elevation may need to have their posture modified in order to protect their airway. One example is the "chin-down" position, which narrows and protects the airway. Surgery to cut the cricopharyngeal muscle may be necessary to facilitate swallowing in patients with myotonic MD.
Dr. Logemann recommends counseling for families of patients who are newly diagnosed with MD to alert them to potential swallowing disorders. Warning signs include coughing, difficulty in managing saliva, or a "gurgly" voice during or after eating. If these signs appear, families should seek an immediate evaluation, which may involve a radiographic or videofluoroscopic study.
"Usually there is good motivation on the part of the patient and the family," the dysphagia expert said.
Dr. Logemann stressed the importance of monitoring individuals with MD at least every six months to identify any problems or changes in swallowing that may occur as the disease progresses.
Speech disorders resulting from the various forms of MD include hypernasality and oral resonance dysfunction from weakness in the velopharyngeal region, according to Etoile LeBlanc, MS, CCC-SLP, assistant director of the Center for Craniofacial Disorders at the Albert Einstein College of Medicine. These weaknesses prevent a seal between the nasal and oral cavities.
At the annual joint meeting of the American Pediatric Society and the Society for Pediatric Research, held earlier this year in Washington, DC, LeBlanc and center colleagues presented a retrospective review of diagnoses for 30 patients seen at the center between 1984 and 1996. The patients, ages 2-29, represented seven primary muscle diseases: Duchenne, amyotonic, congenital, facioscapulohumeral and oculopharyngeal MD; myotonia congenita; and nemaline myopathy.
LeBlanc, an associate in the Department of Plastic and Reconstructive Surgery at Albert Einstein, said 67 percent of the patients presented with hypernasality and 71 percent made speech errors that affected intelligibility. Twenty-nine percent had age-appropriate sound production.
Thirty-nine percent showed compensatory errors that were typically produced in the glottic, supraglottic and hypopharyngeal regions instead of the anterior oral cavity.
LeBlanc said compensatory articulation errors--such as glottal stops, pharyngeal fricative substitution errors--may occur in patients with MD and other neurological disorders who have velopharyngeal insufficiency.
Patients also experience speech disorders related to dental and skeletal abnormalities, which increase during the progression of MD, she explained. Changes in their craniofacial growth and development--such as excessive mandibular growth, temporoman-dibular joint dysfunction, and anterior and lateral open bites--often result in obligatory articulation errors.
Many speech-language pathologists fail to consider the changes in facial and dental growth and medical conditions that affect speech in patients with MD, LeBlanc commented. A highly specialized, interdisciplinary treatment is essential for optimum success.
Assessment and management of hypernasality and other speech disorders in children with MD follow a specific protocol at the Center for Craniofacial Disorders. They undergo a diagnostic protocol that involves a craniofacial pediatrician, pediatric neurologist, speech-language pathologist and speech physiologist.
"It definitely involves a team approach at the diagnostic, therapeutic and maintenance levels," she said.
Craniofacial specialists may per-form a nasopharyngoscopy, a diagnostic procedure to assess the velopharyngeal mechanism during speech, on patients who are at least 4 years old. This provides information on the etiology of hypernasality, its relation to articulation skills, and the treatment procedure that may be most effective.
If a child experiences hypernasality and has a significant articulation disorder, the speech-language pathologist may suggest articulation therapy be provided first. Treatment for imprecise articulation is "difficult and arduous because of persistent neuromuscular dysfunction," LeBlanc said.
The Center for Craniofacial Disorders has four goals for articulation therapy: anterior oral sound production, adequate articulatory strength of contact, adequate place and manner of articulation, and development of adaptive articulatory compensations.
As a child's articulation improves with therapy, the clinician may recommend prosthetic management to complement intensive therapy. For example, a speech bulb appliance closes off the nose from the mouth.
"It acts as a complete seal between the mouth and the nose," LeBlanc said of the acrylic ball.
The speech bulb often serves as a "test run" to predict whether surgical procedures to correct hypernasality will be successful.
There has been some controversy as to whether pharyngeal flap surgery should be performed to alleviate hypernasality because of the number of possible complications, LeBlanc said. Pre- and post-operative complications include restrictive pulmonary disease, malignant hypothermia and obstructive apnea.
However, LeBlanc pointed out that Albert Einstein has had a zero percent complication rate for pharyngeal flap surgery since 1985, when it developed and implemented its current diagnostic and treatment protocol.
For More Information
Rosalie Goldberg, Albert Einstein College of Medicine, Department of Molecular Genetics, Human Genetics Program, 300 Morris Park Ave., Bronx, NY 10461; (718) 430-2568
Etoile LeBlanc, Albert Einstein College of Medicine, Center for Craniofacial Disorders, Montefiore Medical Center, 111 E. 210th St., Bronx, NY 10461; (718) 920-4781
Jeri Logemann, PhD, Department of Communication Sciences and Disorders, Northwestern University, 2299 N. Sheridan Rd., Evanston, IL 60208; (847) 491-3066
Muscular Dystrophy Association, 3300 E. Sunrise Dr., Tucson, AZ 85718-3208; (520) 529-2000