Dysphagia is a serious clinical problem that can decrease the quality of life and lead to lethal conditions, such as aspiration pneumonia.[1–3] Although few clinical bedside tests are used universally, the videofluoroscopic swallowing study (VFSS) has been commonly accepted as the gold standard in assessing dysphagia.[4] The VFSS can detect aspiration and penetration in addition to various abnormalities in the oral, pharyngeal, and esophageal phases.[5] Therefore, it provides some guidance in determining which swallowing therapy should be applied and what type of diet should be adequate.
Among numerous methods to predict and quantify the prognosis of dysphagia, the Functional Dysphagia Scale is a useful tool that correlates well with the American Speech-Language-Hearing Association National Outcomes Measurement System.[6, 7] However, despite its value in interpreting the severity of dysphagia, it does not predict the long-term prognosis, which is important because of the close relationship among prolonged dysphagia, high mortality, and a low respiratory tract infection rate.[8]
The Videofluoroscopic Dysphagia Scale (VDS) is used to predict the long-term prognosis of dysphagia in patients with stroke.[8, 9] Han et al. used the VDS to assess the long-term prognosis of dysphagia based on the development of any aspiration or penetration episode after 6 months from the onset of dysphagia.[10] The VDS consists of 14 categories and shows good correlation with an aspiration or a penetration symptom that occurs 6 months after the initial onset of dysphagia. [10] The 14 items of the VDS (Table 1) represent oral functions (lip closure, mastication, bolus formation, premature bolus loss, apraxia, and oral transit time) and pharyngeal functions (pharyngeal triggering, laryngeal elevation and epiglottic closure, pharyngeal transit time, pharyngeal coating, vallecular and pyriform sinus residues, and aspiration) that can be observed from the VFSS video.[10]
Table 1
Videofluoroscopic Dysphagia Scale
parameter | score |
lip closure | intact | 0 | 4 |
inadequate | 2 |
none | 4 |
bolus formation | intact | 0 | 6 |
inadequate | 3 |
none | 6 |
mastication | intact | 0 | 8 |
inadequate | 4 |
none | 8 |
apraxia | none | 0 | 4.5 |
mild | 1.5 |
moderate | 3 |
severe | 4.5 |
tongue-to-palate contact | intact | 0 | 10 |
inadequate | 5 |
none | 10 |
premature bolus loss | none | 0 | 4.5 |
< 10% | 1.5 |
10–50% | 3 |
> 50% | 4.5 |
oral transit time | ≤ 1.5 seconds | 0 | 3 |
> 1.5 seconds | 3 |
triggering of pharyngeal swallow | normal | 0 | |
delayed | 4.5 |
vallecular residue | none | 0 | 6 |
< 10% | 2 |
10–50% | 4 |
> 50% | 6 |
laryngeal elevation | normal | 0 | 9 |
impaired | 9 |
pyriform sinus residue | none | 0 | 13.5 |
< 10% | 4.5 |
10–50% | 9 |
> 50% | 13.5 |
coating of pharyngeal wall | no | 0 | 9 |
yes | 9 |
pharyngeal transit time | ≤ 1.0 second | 0 | 6 |
> 1.0 second | 6 |
aspiration | none | 0 | 12 |
supraglottic penetration | 6 |
subglottic aspiration | 12 |
total score | | | 100 |
The VDS can also quantify the severity of dysphagia in total scores, but limitations regarding the subjectivity of the results have been noted in previous studies. Kim et al. reported the inter-rater reliability results of the VDS among 10 physiatrists.[11] In their study, the inter-rater reliability of the VDS showed a low rate of agreement (κ < 0.20), especially in bolus formation (κ = 0.153), mastication (κ = 0.123), apraxia (κ = 0.099), tongue to palate contact (κ = 0.153), premature bolus loss (κ = 0.060), and pharyngeal transit time (κ = 0.165).[11] Other parameters showed a fair rate of agreement (κ > 0.2, κ < 0.4).[11] Such results suggest that the VDS can be subjective according to interpreters, especially for several parameters, such as apraxia, tongue to palate contact, premature bolus loss, or bolus formation. Subjectivity is also possible because of the ambiguous criterion of several parameters of the VDS.
Therefore, to overcome the mentioned limitations of the VDS, some parameters of the VDS were modified in the present study. Furthermore, the modified version of the VDS (mVDS) was clinically applied to evaluate its usefulness in choosing the feeding method for stroke patients with dysphagia.