Validation of the swallowing disturbance questionnaire in people with multiple sclerosis

The DYSPHAGIA IN MULTIPLE SCLEROSIS (DYMUS) questionnaire is the only specific tool developed to screen for dysphagia in people with Multiple Sclerosis (pwMS). However, some limitations of DYMUS could potentially be addressed by the SWALLOWING DISTURBANCE QUESTIONNAIRE (SDQ), which has not yet been validated in pwMS. The objective of this study was to translate and validate the SDQ into the Italian language for use in pwMS to detect swallowing disturbances.

We translated the SDQ into Italian and adapted it for use in Italian pwMS. PwMS aged > 18 years, assessed for disability using the Expanded Disability Status Scale (EDSS), completed the SDQ and DYMUS questionnaires and performed the 3-OUNCE WATER SWALLOW TEST (WST). Clinical and demographic data were collected for each patient. The Italian version of the SDQ was retested after 30 days.

A total of 84 pwMS were recruited for the study, consisting of 73.8 % women and 48.8 % with a relapsing-remitting form of MS. The mean age of participants was 44.5 years (SD: ±12.46), with a mean disease duration of 17 years (SD: ±10.27), and a median EDSS of 4 (range 1.5-7.5). The Cronbach's alpha for SDQ (to assess internal consistency) was 0.902, which increased to 0.908 after the elimination of item 15, resulting in the SDQ composed of 14 items. ROC analysis demonstrated good accuracy of the 14-item SDQ in pwMS (AUC: 0.811). By dividing the 14-item SDQ score into quartiles, three risk levels for dysphagia were identified: low (score 1-3), intermediate (score 4-8), and high (score ≥9). 14-item SDQ scores significantly correlated with DYMUS (r = 0.820; p<0.0001) and with EDSS (r = 0.541; p<0.0001). PwMS who reported dysphagia had a significantly higher mean 14-item SDQ score (8.27 ± SD 8.15) compared to those without swallowing problems (2.77 ± SD 4.25; p = 0.003). Additionally, pwMS with a positive WST had a significantly higher mean 14-item SDQ score (10.17 ± SD 8.96) than those with a negative WST (2.96 ± SD 3.93; p = 0.02). The Intraclass Correlation Coefficient for the retest, calculated on 48 pwMS in a stable phase of the disease, was 0.91 (95 % CI 0.84-0.95).

The 14-item SDQ has demonstrated high internal consistency, good accuracy, and reliability in pwMS, making it a readily applicable tool for investigating dysphagia in MS.