Introduction
Acquired brain injury (ABI) can occur from a traumatic (i.e., falls, assaults, injuries, motor vehicle accidents) or non-traumatic (tumors, congenital defects, aneurysm, etc.) etiology (1, 2). Traditionally, ischemic or hemorrhagic strokes have not been included in the definition of ABI given their unique pathophysiology and outcomes. Following an ABI, patients may present with a number of impairments including dysphagia, a common and challenging problem affecting the rehabilitation process. Dysphagia or oropharyngeal dysphagia is characterized by abnormal function or structural deficit of the oral cavity, pharynx, larynx, or esophagus as a result of damage to motor and sensory coordinating pathways (3). Delayed pharyngeal movement and failure to coordinate the passage of food into the esophagus, while also protecting the airway or trachea, can result in aspiration of food and liquids. While many patients with dysphagia do not aspirate, the risk of aspiration rises with the severity of the dysphagia.
Severity of dysphagia is typically related to the severity of the underlying brain lesion. Moderate and severe ABIs result in high rates of dysphagia (4, 5); dysphagia is rare in those with mild ABI (6). Overall, prevalence rates of dysphagia range 27-30% in patients with traumatic brain injury (TBI) (7). Dysphagia can cause severe and sometimes life-threatening problems largely due to airway obstruction, aspiration, and the risk of pneumonia and sepsis (8). Additionally, poor nutritional intake with resultant malnutrition and dehydration can present later (3). Nutritional status is important after ABI as it impacts both short and long-term recovery. Malnutrition and dehydration have been shown to significantly extend a patient’s acute care hospital stay, 1.6 times longer compared to non-malnourished, and impact functional independence during rehabilitation (9-11). The consequences of dysphagia can be mitigated if this condition is diagnosed and managed promptly (12). Generally, Speech Language Pathologists assess and apply interventions to reduce the risk of aspiration and improve swallowing function (6). While the most common interventions are dietary-related (food texture modification), compensatory and rehabilitative strategies are also used.
Controversy remains regarding the effectiveness of dysphagia interventions in neurological populations. Research often focuses on either a single intervention type or on a specific research question, not reflecting the significant heterogeneity of data (13). The majority of dysphagia studies examine the stroke population, or a mixed populations with little attention to the underlying etiology (14, 15). Since deficits are similar between ABI and stroke (16), often ABI rehabilitation therapists “borrow” strategies from the stroke rehabilitation literature. Unfortunately, differences in underlying pathophysiology of ABI may warrant the use of distinct approaches (17). While stroke leads to focal brain damage, TBI lesions may be a complex mixture of focal injury and diffuse axonal injury (18). In fact, there is a paucity of ABI-specific literature for dysphagia interventions. Reviewing ABI-specific studies are necessary to better address the rehabilitation needs of these patients. To investigate the available literature and identify existing interventions for dysphagia rehabilitation, we sought to conduct scoping review of individuals with moderate to severe ABI during the acute and chronic phases of recovery.