Background and purpose: Many patients with multiple sclerosis (MS) present swallowing difficulties. Dysphagia is associated with significant morbidity and mortality, has a profound impact on the quality of life but is under-reported by patients. The objective was to investigate the psychometric properties of the Dysphagia in Multiple Sclerosis (DYMUS) questionnaire and examine whether item reduction improves them.
Methods: The participants, 153 patients with MS and 104 healthy controls, completed the DYMUS and the Eating Assessment Tool 10 (EAT-10). The study consisted of factor, reliability and validity analysis of DYMUS, and item reduction, reliability, validity analysis and normative data generation for the modified DYMUS (mod-DYMUS).
Results: The internal consistency of DYMUS was excellent (Cronbach's alpha 0.886). Test-retest reliability was good for all the items. Factor and reliability analysis, along with other psychometric features, supported item reduction. The mod-DYMUS (consisting of items 1 and 3-7) showed improved internal consistency (Cronbach's alpha 0.903) and inter-item correlation coefficients (0.558-0.657), good test-retest reliability, excellent criterion validity and improved convergent validity. Patients had significantly higher mean mod-DYMUS score than controls (P < 0.001), and dysphagic patients (EAT-10 ≥ 3) had significantly higher mod-DYMUS than non-dysphagic patients (P < 0.001). A strong positive and significant correlation was noted between the mod-DYMUS and the EAT-10 (P < 0.001). A mod-DYMUS score of 1 or higher indicates dysphagia.
Conclusions: Item reduction improves the psychometric properties of DYMUS. The mod-DYMUS is a valid, reliable, low-burden, screening tool for the detection of dysphagia in MS, which can enhance personalized assessment and guide management decisions that better respond to individual patients' needs.
Keywords: dysphagia; multiple sclerosis; normative data; questionnaire; reliability; swallowing; validity.
© 2020 European Academy of Neurology.