Abstract
BACKGROUND AND OBJECTIVES: Telemedicine has become a mainstay of ALS clinical care, but there is currently no standardized approach for assessing and tracking changes to the neurologic examination in this format. The goal of this study was to create a standardized telemedicine-based motor examination scale to objectively and reliably track ALS progression and use Rasch methodology to validate the scale and improve its psychometric properties. METHODS: A draft telemedicine examination scale with 25 items assessing movement in the bulbar muscles, neck, trunk, and extremities was created by an ALS expert panel, incorporating input from patient advisors. This prospective, observational study was approved by the Emory IRB, and participants provided informed consent. Adults with a diagnosis of ALS who were able to undergo a video telemedicine evaluation by an Emory clinician were eligible for participation. Rasch analyses were performed to determine the final item responses and optimize the scoring structure. Test-retest reliability was assessed in a subset of participants through 2 separate examinations by 2 different examiners within a 7-day period. Construct validity was assessed by calculating correlations with simultaneously administered Rasch-built Overall ALS Disability Scale (ROADS) and revised ALS Functional Rating Scale (ALSFRS-R). RESULTS: The ALS Motor Observational Telemedicine Objective Rasch-built assessment was administered to a total of 258 PALS representing the full spectrum of a typical ALS clinic population. After performing Rasch analyses, 3 items were removed and item response categories were consolidated for 8 items. The final 22-item ALS MOTOR scale conformed to Rasch model criteria. The inter-rater reliability was 95%. The ALS MOTOR had a 0.78 (95% CI 0.72-0.83) correlation with ALSFRS-R and 0.81 (95% CI 0.76-0.85) correlation with ROADS. DISCUSSION: The ALS MOTOR is a novel, accessible tool for remotely and objectively tracking ALS progression for both clinical care and research studies. Use of Rasch methodology for scale validation allowed for optimization of scale psychometric properties, which is particularly important when using the sum score as an overall outcome measure. Longitudinal and external validation studies are ongoing.