JCPSLP Vol 14 No 1 2012

function, with studies demonstrating its applications for specific populations such as those suffering from neurological disorders such as stroke (Seidl, Nusser- Muller-Busch, Westhofen, & Ernst, 2008; Warnecke et al., 2009a; Warnecke et al., 2009b), severe brain injury (Brady, Pape, Darragh, & Escobar, 2009), neurodegenerative and neuromuscular disorders (Coscarelli, Verrecchia, & Coscarelli, 2007; Warnecke, Duning et al., 2010; Warnecke, Oelenberg et al., 2010; Warnecke et al., 2008), recurrent laryngeal nerve paralysis (Perie, Roubeau, & Lacau St Guily, 2003), and tracheostomy (Hales, Drinnan, & Wilson, 2008). Different fields of view The fields of view obtained via FEES and VFSS are very different. Figure 1 shows a side-by-side comparison of the typical field of view for VFSS and FEES.

reasonable amount of contrast needs to be swallowed for these observations to be made. This may pose significant risk to patients where secretion management is an issue.

Figure 2. Endoscopic view showing secretions throughout the pharynx and larynx

Radiographic imaging via VFSS provides information about how atypical submucosal structures such as cervical osteophytes impact on swallowing function (Langmore, 2001). FEES provides a direct view of the surface anatomy of the pharynx and larynx (Rugiu, 2007). This view enables the impact of abnormal surface anatomy such as oedema, mucositis, as well the effect of the presence or reduction in oral secretions on swallowing function, to be examined. Reduced saliva production, xerostomia, and inflammatory processes has been found to be associated with an increased incidence of pain and discomfort associated with swallowing (Ku et al., 2006; Logemann et al., 2001; Wu, Hsiao, Ko, & Hsu, 2000) and to negatively affect the ability to satisfy nutritional requirements orally (Scully, Epstein, & Sonis, 2003; Worthington et al., 2010). Judgments regarding pharyngeal residue, or penetration and aspiration can be influenced by the type of instrumental swallowing examination used (Kelly, Drinnan, & Leslie, 2007; Kelly, Leslie, Beale, Payten, & Drinnan, 2006). Researchers have shown that observers rate pharyngeal residue, penetration, and aspiration as more impaired when evaluating swallowing via FEES compared to ratings made via VFSS (Kelly et al., 2007; Kelly et al., 2006). These differences are likely to be associated with the indirect versus direct nature of the images provided by VFSS and FEES, respectively. Radiographic imaging provides indirect views of the food/fluid bolus being swallowed, and indirect information about the anatomy and physiology of swallowing functions (Rugiu, 2007). In contrast, FEES provides direct views of food/fluid bolus and residue within the hypopharynx (Rugiu, 2007). Figure 3 attempts to illustrate how the source of the visual images can affect the judgements made about pharyngeal residue (Rugiu, 2007). Although these images have not been taken from the same patient, they still provide a useful comparison. The image on the left is taken from a VFSS. This picture shows post swallow residue localised mainly to the valleculae, with a lesser amount in the pyriform fossae. The image on the right is taken from a FEES. Similarly, it shows post swallow residue localised mainly in the valleculae with a lesser amount in the pyriform fossae.

Figure 1. Radiographic image taken in the lateral plane during VFSS (left). Endoscopic image taken with endoscope positioned in the oropharynx during FEES (right) As shown, the field of view obtained via FEES enables the surface anatomy of the pharyngeal and laryngeal structures to be visualised. In this position, the movement of these structures in response to swallowing can be evaluated. There is a brief moment at the height of the swallow when the visual image is interrupted due to contact made between the objective lens of the endoscope and surrounding tissue (Langmore, 2001; Leder & Murray, 2008). Although many may argue that this is a critical moment in a swallowing evaluation, and that aspiration during the swallow cannot therefore be observed, researchers have identified that aspiration during the swallow occurs much less frequently than aspiration before or after the swallow (Smith, Logemann, Colangela, Rademaker, & Pauloski, 1999). Through the use of ionising radiation, VFSS enables the submucosal structures of the entire upper aerodigestive tract to be visualised while a patient swallows a radio-opaque bolus. These views enable the oral, pharyngeal, and upper oesophageal phases of swallowing to be observed, including the dynamic interplay between the various anatomical structures of this region (Martin-Harris & Jones, 2008). These views enable the movement of the bolus to be observed as it moves from the oral cavity through the upper oesophageal sphincter. FEES enables secretions to be directly visualised and the management of these secretions to be evaluated without the patient being required to ingest food/fluids, as shown in Figure 2. Significant predictive relationships have been identified between the presence of pharyngeal secretions and aspiration (Donzelli, Brady, Wesling, & Craney, 2003; Langmore et al., 1998; Linden, Kuhlmeier, & Patterson, 1993; Murray, Langmore, Ginsberg, & Dostie, 1996). Accumulation of pharyngeal secretions can sometimes be inferred with VFSS, when the ingested contrast- laden material adheres to these secretions. However, a

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JCPSLP Volume 14, Number 1 2012

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