Reference Values for Videofluoroscopic Measures of Swallowing: An Update.

Eighty people consented, but videofluoroscopy data were unavailable for two participants under age 60, so the analyzed sample was 78. The age range was broad, but ages were not sampled in a representative way, so the study did not create age-specific reference intervals. The analyzed sample was half male and half female, but sex was not used to partition the reference intervals because the scatter plots did not show obvious separation. The sample was not large enough for the preferred nonparametric confidence intervals around reference limits, so the authors used a robust method instead. Reference values apply only to xanthan-gum thickened liquids and to the specific protocol used here, including 20% w/v E-Z-PAQUE barium, room temperature serving, self-administered sips or teaspoon boluses, and ascending consistency order. Moderately and extremely thick liquids were served by teaspoon, so their smaller bolus volume may confound consistency effects. The proposed clinical decision limits are not established for diagnosing dysphagia, detecting risk, or measuring treatment outcomes. Some pixel-based measures had lower preconsensus agreement, and hyoid measures were not rated in duplicate. Order effects cannot be ruled out because consistencies were presented in ascending thickness. Generalizability to other barium products, bolus volumes, cued swallows, or iodine-based contrast is unknown.

Funding came from a National Institute of Deafness and Other Communication Disorders operating grant to the first author. The article does not state other conflicts of interest.

Do not treat a single value outside these tables as proof of dysphagia. The limits are preliminary, the study was done in adults without swallowing symptoms, and the paper states that up to one quarter of healthy adults may fall beyond one proposed limit.