Impact of Medical Diagnosis on Swallow Function
Dysphagia is not a disease but rather a symptom of a disease. While there is great variability across dysphagia profiles, there are some commonalities within a medical diagnosis. This section provides a brief summary of some common clinical and instrumental signs of dysphagia by medical diagnosis.
Stroke
Oropharyngeal dysphagia is a common sequela for individuals who have suffered a stroke (a.k.a.,cerebral vascular accident). In fact, more than half of the individuals who suffer a stroke will have some reduction in swallow efficiency or safety (Crary, Carnaby, Sia, Khanna, & Waters, 2013; Falsetti et al., 2009). While there are some consistencies in the swallow deficits noted post stroke, there is much variability across individuals. As the incidence of stroke is increased with age and poor cardiovascular health, the variability in swallow disorders post stroke is related not only to the type, location and size of the stroke, but also the age of the individual and the presence of comorbidities. Therefore, it is a complex task to define a classic dysphagia profile for individuals post stroke. However, some swallow deficits are more characteristic of this population.
Swallow deficits commonly observed in patient’s status post acute stroke may be related to the location of the stroke. Recall that the swallow central pattern generator is located in the medulla. Damage to this area can have a devastating impact on swallow function. However, cortical strokes can also alter swallow efficiency and safety. Strokes that unilaterally involve the primary motor cortex can alter bolus management, particularly on the side with motor weakness (contralateral to the cortical damage). Strokes that involve the primary sensory cortex can alter bolus awareness and response time to the bolus. Neglect, which may occur with right hemisphere strokes, can result in a reduced ability to manage mealtimes due to inattention to food and liquid on the left side of the plate or food tray.
Common clinical predictors of dysphagia in this population may include a weak spontaneous cough or abnormal volitional cough, abnormal gag reflex, dysphonia or vocal quality changes related to oral intake, and dysarthria. The presence of two or more of these signs is linked to an increased risk of aspiration pneumonia (McCullogh et al., 2001; Daniels, Ballo, Mahoney, & Foundas, 2000). Instrumental evaluations may reveal unilateral reductions in bolus flow resulting in protracted transit times and a slow response time, with an increased potential for residue, particularly on the effected side. While delayed pharyngeal swallow trigger is not a significant finding in elderly individuals, the length of the delay should be considered, as well as its imposition on the safety of the swallow. Aspiration, with or without a response, may be present before or after the swallow.
Clinical Note
Common swallow deficits in stroke include poor bolus formation and control, slowed transit times, increased risk of premature spillage, oral and pharyngeal pocketing on the weaker side, and increased risk of aspiration including silent aspiration.
Traumatic Brain Injury
The incidence of oropharyngeal dysphagia in individuals who suffered a traumatic brain injury is approximately 30% (Field & Weiss, 1989; Winstein, 1983) and may be linked to cognitive status (Winstein, 1983; Mackay, Morgan & Bernstein, 1999). In fact, the cognitive status may also dictate the ability to assess and treat the swallow deficit(s). As with other disease categories, the types of swallow deficits are largely related to the neurologic subsystems involved in the injury. For traumatic brain injury, a category that encompasses all regions and types of brain injury, the possible list of deficits is comprehensive and inclusive across all oropharyngeal swallow deficits. That said, studies that have evaluated dysphagia in patient’s status post head injury have noted some common clinical presentations including coughing with oral intake, changes in vocal quality associated with oral intake, and impaired gag reflex, (Terre & Martin, 2007; Lazarus & Logemann, 1987; Lazarus, 1989). Although instrumental evaluation yielded positive findings in 90% of patients with closed head injury (Terre & Mearin, 2007), no classic pattern of deficits emerged. Swallow deficits with the highest incidence included delayed or absent swallow trigger, pharyngeal residue, and aspiration (Terre & Mearin, 2007).
Clinical Note
Cuff inflation does not protect against aspiration and may increase the incidence of aspiration pneumonia if food is trapped atop of the inflated cuff and allowed to breakdown and later (upon cuff deflation) fall into the airway.
Tracheostomy Tube
A tracheostomy or a surgical hole in the neck, anterior to the trachea is used to insert a curved tube to establish an artificial airway. Patients with tracheostomy tubes may be at an increased risk of swallowing disorders (Cameron, Reynolds, & Zuidema, 1973, Abel, Ruf & Spahn, 2004). This can occur for a variety of reasons including the illness or condition that resulted in the need for the tracheostomy tube, or the result of the presence of the tracheostomy tube (TT). When a tracheostomy (with or without a tube) is present, this may impact swallow physiology due to altered pressure and mechanics, as well as the impact of the open system on receptor behavior. However, inconsistent reports and limited level 1 evidence makes it difficult to develop a clear hypothesis on the effects of tracheostomy on swallow function.
Swallow is a pressure-driven event. Theoretically, a leak in the system may change pressure gradients, which can result in a misdirection of bolus flow. Further, the tracheostomy may reduce the ability of the system to build up subglottal pressure, rendering the glottal closure vulnerable to any misdirected bolus flow. This hypothesis is supported by the observation that a one way speaking valve, which can be applied to the hub of the tracheostomy tube to reduce leak, improves subglottal pressure gradients and results in reduced incidence of aspiration (Gross, Atwood, Grayhack, & Shaiman ,2003; Suiter, McCullough & Powell, 2003; Stackler, Hamlet, Choi & Fleming, 1996).
The presence of the tracheotomy tube may alter the biomechanics of swallowing. That is, the actual tube may weight or anchor the larynx, limiting its swallow-related trajectory. The extent of the mechanical impact may be dependent on the orientation of the surgical incision (between tracheal rings or across tracheal rings), or the presence of an inflated cuff. When the tracheostomy is created the surgeon may use a vertical or horizontal incision. While a horizontal incision may prove to have better cosmetic outcome after decanulation, it is more likely to provide greater anchoring of the larynx during the swallow. Recall that the anterior and superior hyo-laryngeal trajectory aids in airway protection, epiglottic inversion, and UES opening. If the tracheostomy tube in fixed between tracheal rings, as is the case in a horizontal incision, then hyo-laryngeal trajectory may be limited due to the anchoring effect of the tube placement. Greater anchoring may also result from an inflated cuff (Ding & Logemann, 2005; Suiter et al., 2003), particularly when over-inflation occurs.
Clinical Note
An over-inflated cuff may impinge on the function of the upper esophageal body.
Head & Neck Cancer
Head and neck cancer may be treated with surgery, chemotherapy, and/or radiation therapy. The resulting swallow deficits depend on the location and extent of the cancer, as well as the medical approach(es) used to treat the cancer. Head and neck cancer staging provides a terminology to quantify the extent of the cancer by noting the size of the tumor (T), the number of positive regional nodes (N), and the presence or absence of metastatic disease (M). These variables are combined to give a tumor stage ranging from 0 to IV. Severity of swallow deficits is linked to cancer stage and location where a higher staged cancer will yield a greater impact on swallow function. Oropharyngeal cancers will have a greater impact on swallow function than laryngeal cancers.
Medical treatment of head and neck cancer plays a role in the impact on swallow function. Surgical removal of a tumor and surrounding structures, may have a predictable impact on swallow function that is linked directly to the role of the removed structures and the closing procedure. Individuals who receive radiation as part of their medical treatment will experience immediate and late deficits that impact swallow function. During or immediately after the radiation treatment, individuals may experience xerostomia (dry mouth), dysgeusia (altered taste sensation), and skin irritation and pain (odynophagia) (Rosenthal, Lewin, & Eisbruch, 2006), all of which can reduce mealtime desirability and swallow efficiency. As time progresses, fibrosis of the irradiated oropharyngeal region can result in atrophy of the tongue, velopharyngeal incompetence, reduced glottal valving, and poor pharyngeal constriction (Lazarus et al., 2007; Wu, Ko, Hsiao, & Hsu, 2000). The physiological implication of these effects may include reductions in tongue base retraction, hyo-laryngeal elevation, and laryngeal vestibule closure, as well as altered timing and coordination of events. The end result, if oral intake is still possible, is reduced swallow efficiency yielding increased residue and risk of penetration and/or aspiration after the swallow. When chemotherapy is added to the medical treatment, the effects on swallow function are enhanced by the reduced appetite which increases the risk of malnutrition (Russi et al., 2012).
Clinical Note
There is a current movement away from the TNM staging to a more personal staging approach. In this new approach, TNM staging is combined with positive prognostic factors, personal survival outcomes relative to the patient, and data extracted from clinical trials.
Developmental Disability
Developmental disability (DD) refers to a list of diagnoses that can occur in an individual of any age who is born with, or acquired early in life, a condition with a chronic mental and/or physical disability. Common diagnoses include cerebral palsy, intellectual disability, Down’s syndrome, or autism. According to the CDC, developmental disabilities occur in about 14% of the population. Approximately 85% of these individuals will have a feeding or swallowing problem at some point in their lifetime (Sheppard, Hochman & Baer, 2014), and approximately 40% of these individuals will have lasting feeding or swallowing problems (Reilly et al., 1996; Benfer et al., 2015). The feeding and swallowing deficits are varied in type and severity depending on the degree of mental or physical disability. In fact, in a cohort of kids with cerebral palsy, the number of noted signs of oropharyngeal dysphagia was related to the degree of the gross motor disability (Benfer et al., 2015).
Often, individuals with DD are dependent on caregivers to provide consistent and safe oral intake. Therefore, for a thorough understanding of feeding and swallow deficits, mealtime observation and caregiver interviews are warranted. However, when choosing a caregiver to interview, the caregiver should have long-term experience with a particular individual as it is possible for unfamiliar caregivers to underestimate the level of dysphagia (Crawford, Leslie & Drinnan, 2007).
Common signs and symptoms in this diverse population include coughing during mealtimes, multiple swallows per bolus, a wet gurgly vocal quality, a rattley sound in the chest or respirations (fremitus), gagging, drooling, and regurgitation or rumination (bringing up of food back to the mouth). Some individuals with DD with refuse oral intake or a subset of consistencies. Swallow deficits noted in instrumental exam are varied and may include reductions in oral bolus control, and aspiration with or without reaction (Weir. McMahon, Taylor, & Chang, 2011; Arvedson, 2008). It should be noted that this population is known for idiosyncratic feeding and swallowing patterns that may appear atypical to the dysphagia clinician. For example, a facial grimace or jaw protrusion during oral bolus preparation may be typical of a specific individual and may not be indicative of dysphagia. Therefore, accurate assessment may be limited when only clinical approaches are employed. When multiple clinical signs and symptoms are observed and there is no report of recent change in feeding or swallow patterns, the dysphagia clinical should consider the medical status. That is, has the individual suffered multiple bouts of unexplained respiratory illness, or are nutritional needs not being met.