Further development of a patient-reported outcome measure to assess the impact of oral secretion problems in people living with MND.

Objective

Oral secretion problems are common yet poorly managed in people living with MND (plwMND). A validated patient-reported outcome for measuring saliva symptoms in this patient group would facilitate better monitoring of individuals. This study aimed to assess the validity, reliability and sensitivity to change of a revised version of the clinical saliva score for MND (CSS-MNDr).

Methods

Data were collected as part of a longitudinal, observational saliva management study. The CSS-MNDr, ALS Functional Rating Scale, a Global Rating of Change questionnaire and saliva-specific modified Likert scale were completed at each study visit, each of which probed the severity of saliva symptoms. Construct validity, test-retest reliability and sensitivity of the CSS-MNDr were assessed and the minimal important difference of the instrument was estimated.

Results

The CSS-MNDr showed excellent test-retest reliability (intraclass correlation coefficient >0.9). Construct validity showed the CSS-MNDr performed as expected, with bulbar-onset participants scoring significantly higher than those who reported limb-onset across all visits (group mean scores). Strong correlation of total scores with the ALSFRS-R saliva question was demonstrated (-0.8), with the thick subscore correlating less well (-0.5). A minimal important difference in the range of -2.5 to -3.6 over 3 months was estimated for worsening symptoms.

Conclusions

The CSS-MNDr has been validated as a reliable patient reported outcome for measuring saliva problems in plwMND. With separate scores for thick and thin secretion problems, the CSS-MNDr is the most comprehensive tool for assessing salivary problems in plwMND reported to date.