To assess whether the order of test diets influences the results of swallowing studies with regard to their accuracy and safety.

Subjects with suspected dysphagia underwent a videofluoroscopic swallowing study (VFSS) and/or a fiberoptic endoscopic evaluation of swallowing (FEES) and repeated the study on the same day or within a week. The order of test diets comprised of two different sets: trial 1 with the fluid first and trial 2 with the semi-solid food first. Main outcome measurements were the modified penetration-aspiration scale (mPAS) and the pharyngeal residue severity scale (PRSS) for the vallecula and the pyriform sinus.

Sixty-six patients (44 men and 22 women, aged 65.0±15.0 years) were enrolled in this study. Forty-three subjects were evaluated with VFSS only and 23 with both VFSS and FEES. As a result of the swallowing studies, there was no significant difference in each chosen diet sequence regarding mPAS and PRSS. Furthermore, there was no difference regarding the duration of studies, rate of premature study termination, rate of abnormal findings in post-study chest X-ray, and rate of fever or pneumonia post-study.

The accuracy and safety of the swallowing studies do not rely on the order of test diets.