Effects of Oropharyngeal Strengthening on Dysphagia in Patients Post-stroke

Dysphagia is estimated to occur in up to 76% of acute stroke patients1,2 and by 2030 the prevalence of stroke is estimated to rise by 21%.3 Serious health complications may result from the presence of dysphagia following stroke, including the development of aspiration pneumonia, malnutrition, and mortality.4-6 Developing pneumonia post-stroke results in a significantly increased relative risk (2.99) of death within 30 days of hospital discharge.1 Compensatory approaches to intervention, including postures or diet modification, are commonly used but do not enact lasting change in swallowing function. Early and intensive therapy approaches are suggested for attainment of optimal swallowing outcomes.7 The tongue is the primary propulsive force for movement of the bolus through the oral cavity and pharynx and into the cervical esophagus during swallowing. Patients post-stroke demonstrate lower than normal maximum isometric lingual pressures, measured as pressures produced when the tongue is pushed as hard as possible against the palate.2 Progressive resistance training for the tongue and related oropharyngeal musculature has been shown to improve swallow physiology and quality of life for patients post-stroke.8 Previous studies have examined Isometric Progressive Resistance Oropharyngeal (I-PRO) therapy facilitated by the Iowa Oral Pressure Instrument (IOPI) for lingual strengthening. The recently developed SwallowSTRONG® device consists of a customized, adjustable mouthpiece that provides pressure readings from embedded sensors allowing for consistent tongue placement, immediate knowledge of performance levels, and automatic calculation of therapeutic strengthening targets. Results from a federally-funded Department of Veterans Affairs Clinical Demonstration Program that employed use of device-facilitated (DF) I-PRO therapy showed improved swallowing-related outcomes in a group of patients with oropharyngeal dysphagia resulting from a variety of medical etiologies.9 The effects of this therapy approach on various aspects of swallowing function and health status in a group of post-stroke patients have yet to be examined. In addition, ideal treatment duration for use with stroke patients is unknown.

The long term goal of this work is to develop more effective, evidence-based treatments that improve overall health status related to swallowing-specific changes for patients with dysphagia. The preliminary group data generated will provide the basis for a line of work dedicated to determination of effective treatments for patients post-stroke.

Specific Aims include: 1) determine differences in swallowing physiology and bolus flow measures a) between a group of unilateral ischemic stroke subjects undergoing DF I-PRO therapy and a control group and b) between two durations of treatment (8 and 12 weeks); 2) examine changes in level of oral intake and swallowing quality of life in post-stroke patients undergoing I-PRO therapy as compared to a control group and as they relate to treatment duration response at 8 weeks and 12 weeks; and 3) evaluate effects of DF I-PRO therapy on overall health status reflected by the number of pneumonia diagnoses and overall hospital readmission rates in post-stroke subjects undergoing DF I-PRO therapy compared to controls.

In order to address these aims, thirty patients who have suffered unilateral ischemic stroke will be recruited. Subjects will be randomized to receive either 1) 12 weeks of DF I-PRO therapy plus compensatory treatment or 2) compensatory treatment only. Assessments will take place at baseline, 8 and 12 weeks. The primary outcome measure will be changes in maximum isometric tongue pressures. Details regarding specific outcomes most influenced by this approach and dose response effects will inform the clinical practice of Speech-Language Pathologists and facilitate strengthening regimens to become more standard for the treatment of stroke related dysphagia.

Inclusion criteria

• clinical diagnosis of unilateral ischemic strokes by attending physician (according to the National Institute of Health Stroke Scale (NIHSS))
• within 6 months of acute stroke diagnosis
• a score of 3 or higher on the Penetration-Aspiration scale OR a score of 2 on the Residue scale at any location (oral cavity, valleculae, or pharynx) that is instrumentally documented by a participating SLP during a standardized videofluoroscopic swallowing study
• between the ages of 21 and 95
• ability to perform the strengthening protocol independently or with the assistance of a caregiver
• physician approval of medical stability to participate
• decision-making capacity to provide informed consent (confirmed through discussion with the subject's primary physician)
• phone access
• ability to return to the clinic for required follow-up appointments.

Exclusion criteria

• degenerative neuromuscular disease
• prior or current diagnosis of bilateral or hemorrhagic stroke
• prior surgery to the head and neck region that would affect muscles involved in swallowing
• history of radiotherapy or chemotherapy to the head and neck
• patient unable to complete the exercise program
• taking medications that depress the central nervous system
• allergy to barium (used in videofluoroscopic swallowing assessment)
• currently pregnant.