Protocol for psychometric evaluation of the Amyotrophic Lateral Sclerosis - Bulbar Dysfunction Index (ALS-BDI): a prospective longitudinal study.

Introduction: Early detection and tracking of bulbar dysfunction in amyotrophic lateral sclerosis (ALS) are critical for directing management of the disease. Current clinical bulbar assessment tools are lacking, while existing physiological instrumental assessments are often inaccessible and cost-prohibitive for clinical application. The goal of our research is to develop and validate a brief and reliable, clinician-administered assessment tool-the ALS-Bulbar Dysfunction Index (ALS-BDI). This publication describes the study protocol that has been established to ascertain the tools' psychometric properties.

Methods And Analysis: The ALD-BDI's development closely follows guidelines outlined by the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN). Through the proposed study protocol, we expect to establish psychometric properties of both individual test items of the ALS-BDI as well as the final version of the entire tool, including test-retest and inter-rater reliability, construct validity using gold-standard assessment methods and responsiveness.

Ethics And Dissemination: This study has been reviewed and approved by research ethics boards at two data collection sites: Sunnybrook Health Science Centre, primary (Toronto, Canada; ID3080) and Mass General Brigham (#2013P001746, Boston, USA). Prior to participation in the study, the participants sign the informed consent in accordance with the Declaration of Helsinki. Once validated, the ALS-BDI will be disseminated to key stakeholders. Following validation, the ALS-BDI and any required training material will be implemented for clinical use in a context of a multidisciplinary ALS clinic and used as an outcome measure for clinical trials in ALS research.