Evidence-based systematic review: Oropharyngeal dysphagia behavioral treatments. Part II--impact of dysphagia treatment on normal swallow function.

INTRODUCTION Swallowing dysfunction, or dysphagia, can occur in adult patients as a result of significant primary illnesses, including cerebrovascular accidents, neurodegenerative disorders, head and neck cancer, or head injury [1-3]. Treatment to improve disordered oropharyngeal deglutition has traditionally centered on behavioral interventions, with the intended purpose of facilitating safe and efficient oral feeding. These behavioral therapeutic approaches have been used clinically, primarily by speech-language pathologists trained in dysphagia management [4]. They include posturing of the head and neck, physical maneuvers altering oral and pharyngeal physiology, tactile and electrical stimulation, oral and facial exercises, and diet modifications [5]. To date, a number of published guidelines and evidence-based systematic reviews have focused on dysphagia within various populations and treatment settings [6-9]. These primarily address the need for dysphagia evaluation and dietary management with little emphasis placed on behavioral interventions. In 1972, Larsen was the first to introduce the notion of behavioral interventions to improve swallow function, describing the use of "neck-flexed postures" and "breath-holding maneuvers" to facilitate a safe, functional swallow [10]. In the 1980s, the investigation of these techniques expanded to other postural interventions and swallowing maneuvers. Currently, a body of literature exists examining the physiological effects of many of these swallowing techniques among healthy adults as well as among various patient populations [5,11]. According to a five-phase model of clinical outcomes developed by Robey [12], before the introduction of interventions as treatments for specific patient groups, it is necessary to establish the existence of an intervention effect and determine whether that effect is sufficient to warrant further testing. Establishing such an effect begins with defining the physiological changes that occur during the treatment; this identifies the ability of the treatment to modify function and establishes a knowledge base from which to formulate hypotheses regarding the potential effects of the treatment on specific types of disorders. Physiological changes can include changes in oral or pharyngeal pressures, duration and timing of swallow events, structural movement or displacement, and muscle activation. The American Speech-Language-Hearing Association's (ASHA's) National Center for Evidence-Based Practice in Communication Disorders (N-CEP), in collaboration with the Department of Veterans Affairs (VA), embarked on a series of systematic reviews to examine the current state of the evidence on behavioral swallowing treatments. The current review focuses on behavioral swallowing treatments (head and neck postures and swallowing maneuvers) with nondisordered populations (healthy adults). This body of literature examines physiological changes imposed by the treatments under examination. Subsequent reviews reported in this series focus on studies examining these same interventions in populations with neurological disorders (e.g., brain injury, stroke; see Ashford et al., this issue, Part III, p. 195) and populations with structural disorders (e.g., head and neck cancer; see McCabe et al., this issue, Part IV, p. 205). The first step in the process was to determine the clinical question addressed by studies that targeted behavioral treatments including postures and maneuvers. Postures were operationally defined as a repositioning of the body, head, and/or neck before the onset of the pharyngeal phase of the swallow, with maintenance of the position until the swallow was completed. Postures studied included side lying, chin tuck, and head rotation. Maneuvers were defined as movement of the oral, pharyngeal, or laryngeal structures that occur before or during the pharyngeal phase of the swallow and are intended to increase swallow force or alter airway protection mechanisms. …