Tests & scales

DOSS (Dysphagia Outcome and Severity Scale)

Also written as DOSS, Dysphagia Outcome and Severity Scale, DOSS level, DOSS score, Dysphagia Outcome Severity Scale, O'Neil DOSS.

The DOSS is a seven-point scale clinicians use to summarize how severe a swallowing problem looked on a swallow study, where 7 is normal and 1 is severe.

Dysphagia is the medical word for trouble swallowing. The DOSS, short for the Dysphagia Outcome and Severity Scale, is one tool a speech-language pathologist may use to put a single number on what a swallow study showed. It has seven levels. A 1 sits at the severe end and a 7 means the swallow looked normal, so the number climbs as the picture gets closer to typical. It was published in 1999 by O'Neil, Purdy, Falk and Gallo in the journal Dysphagia, and it was built using modified barium swallow studies, the moving X-ray exam of swallowing.

The number is not based on one single thing. The clinicians who built the scale looked at how the mouth moved food and liquid back toward the throat, at how much was left sitting in the throat after the swallow, and at how well the airway was protected. Clinicians call the ball of food or liquid a bolus, so you may see that first part described as bolus transfer. The scale also takes in more everyday details: how wide a range of food and drink was recommended, whether extra strategies were suggested at mealtimes, how much help a person needed to eat, and whether nutrition was being taken by mouth. A lower number generally reflects that more support was recommended.

A DOSS level is a summary, not the whole report. It compresses a long exam into one number so a team can track change over time and describe that change to each other in the same words. It reflects one study, on one day, with the foods and liquids that were tried that day. The scale was developed and validated on X-ray swallow studies, and researchers have since looked at how it performs when it is used to rate FEES, the camera exam passed through the nose. The number sits alongside the rest of the report rather than standing in for it.

An SLP uses the DOSS to record swallowing severity in a consistent way, so a change between one study and the next can be seen, and so clinicians in different settings mean the same thing by the same number. It was designed to be quick and repeatable, and the original 1999 paper reported high agreement both between different raters and within the same rater. What it is not is an explanation. A level in a report is shorthand written by the clinician who watched the study, and reading a definition of the scale does not tell you what your own number means, or what was recommended because of it. Only the SLP who did the study can answer that.