Bulbar Onset Amyotrophic Lateral Sclerosis: The Speech/Swallowing Perspective
By: Emily Morales and Sabrina Eugene
Amyotrophic Lateral Sclerosis (also known as Lou Gehrig’s disease; pictured below) is a progressive neurodegenerative disease affecting the neurons responsible for voluntary motor movement, causing gradual weakness or stiffness in the muscles and eventual loss of motor function of various regions of the body. If a patient’s initial exhibiting symptoms of ALS are those affecting speech and swallowing, this is indicative of bulbar onset ALS. Bulbar refers to an area of the nervous system called the brainstem, which consists of the midbrain, pons, and medulla. The sensory and motor nerves that enter and exit the brainstem control the sensory and motor function of head and neck structures. While 70% of patients present with a spinal onset, most ALS patients eventually exhibit bulbar affected symptoms as the disease progresses (85%).
Motor degeneration affecting speech function manifests as a decline in speech intelligibility and speaking rate, going from an average of 160-200 words per minute (WPM) to approximately 120 WPM. Though a decline in speaking rate is considered an early clinical marker of bulbar onset ALS, it is limited in that patients with mild weakness in oral motor function can find ways to compensatefor these deficits.
Swallowing deterioration in patients with bulbar ALS can be thought of as a five-phase progression: normal eating habits, early eating problems, dietary consistency changes, needs tube feedings, and nothing per oral. Dysphagia in ALS results from deterioration of the same motor nerves that affect speech, causing dysfunction in the oral control of foods and liquids, closure of the soft palate, pharyngeal constriction, and larynx. Results can be inability to completely swallow food or liquid, and/or entrance of material into the airway (aspiration). It is important to modify and compensate for changes in motor function as the disease progresses.
Exciting research at UF
Associate professor of speech, language and hearing sciences Dr. Emily Plowman studies speech and swallowing functions in patients with ALS. Thanks to funding from the Amyotrophic Lateral Sclerosis Association (ALSA) and the National Institutes of Health (NIH), Dr. Plowman is conducting longitudinal research to delineate the natural history of speech and swallowing dysfunction in ALS, and also intervening with respiratory strength training to maintain function over time. For more information on her research, visit Dr. Plowman’s website here: http://swallowingsystemscore.org/patient-resources/
Amyotrophic Lateral Sclerosis (ALS) Fact Sheet. (n.d.). Retrieved September 19, 2017, from https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-Sheets/Amyotrophic-Lateral-Sclerosis-ALS-Fact-Sheet
Amyotrophic Lateral Sclerosis Clinical Presentation. (2017, May 22). Retrieved September 19, 2017, from http://emedicine.medscape.com/article/1170097-clinical
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