The diagnostic accuracy of the Dutch DYMUS, a 10-item questionnaire to assess dysphagia in multiple sclerosis.

The reported incidence of dysphagia in multiple sclerosis (MS) varies between
33% and 90% and is higher in more disabled patients. Dysphagia is associated
with an increased risk of aspiration pneumonia, increase in health-care cost
and increase in mortality. Patients with oropharyngeal swallowing problems are
commonly referred to a speech-therapist for further assessment and treatment.
In the assessment of dysphagia, fiberoptic endoscopy (FEES) or videofluoroscopy
(VFSS) of the swallowing act are considered to be the gold standard. However,
these diagnostic instruments have their limitations, because they are invasive,
time consuming and not directly available.
In 2008 a 10-item questionnaire to assess DYsphagia for liquids and solid foods
in patients with Multiple Sclerosis (DYMUS) was developed. Although it showed a
very good internal consistency, it has not yet been validated against a gold
standard to determine its diagnostic value and the reproducibility has not yet
been tested.

Primairy objective:
To estimate the diagnostic accuracy of the DYMUS against a gold standard.

Secundairy objectives:
- To determine the reproducibility of the DYMUS.
- To compare the diagnostic accuracy of the DYMUS with different swallowing
tests (i.e. the Volume-Viscosity Swallowing Test (V-VST) and the yes/no
question (*Do you have difficulty swallowing?*).
- To study whether the presence of cognitive impairment (based on the Symbol
Digit Modalities Test (SDMT)) influences the DYMUS results.

A prospective study of diagnostic accuracy that complies with the STAndards for
Reporting of Diagnostic Accuracy (STARD criteria). The DYMUS will be assessed
by a nurse with an interval of one week. FEES will be used as the reference
test. The FEES assessments, that are videotaped, will take place within 72
hours of the second DYMUS assessment by a speech-therapist. Two
speech-therapists will independently rate the FEES video. All raters are
blinded to the results of the DYMUS. Sensitivity and specificity and the 95%
confidence intervals will be calculated. Reproducibility will be assessed with
the smallest real difference. A 2x2 classification table with the McNemar test
will be used to compare the diagnostic accuracy of the different swallowing
tests. Differences in DYMUS scores between cognitively preserved and
cognitively impaired patients will be evaluated with the Fisher Exact test.

Burden:
All examinations take place within clinical staff rooms and departments of
Nieuw Unicum.

The participants will have 3 contact moments to complete the entire
examanition. The total duration of the study is approximately 2 weeks.
Time investment: 3 sessions of 20 + 30 + 30 = 80 minutes in total.

Risks:
Despite of the various advantages of FEES, this diagnostic procedure is not
without risks. The most probable consequences are discomfort, gagging and/or
vomiting, vasovagal syncope, epistaxis, mucosal perforation and laryngospasm.
Those consequences do not appear frequently. Langmore et al. (1995) reported 2
incidences of laryngospasmen (0.03%), 4 vasovagal episodes (0.06%) and 20
incidences of epistaxis (0.3%) in 6000 FEES examinations. The risk
classification for this study is 'moderate', due to the vulnerable participant
group (people with advanced MS).