The Myasthenia Gravis Activities of Daily Living (MG-ADL) is an 8-item scale that assesses MG symptoms and their effects on daily activities. The 8 items are rated by the participant on a scale of 0 to 3. The total score can range from 0 to 24, with higher total scores indicating more impairment.

The Patient-Reported Outcomes Measurement Information System Global Health Scale (PROMIS-GHS) is a quality-of-life questionnaire that comprises questions on overall physical health, physical function, pain, and fatigue (GPH); and quality of life, mental health, satisfaction with social activities, and emotional problems (GMH). The participant marks their response on a 5-point Likert scale, with lower scores indicating poorer health

The Patient-Reported Outcomes Measurement Information System Dyspnea Functional Limitations (PROMIS-DFL) is a questionnaire that evaluates the impact of dyspnea on the ability to perform daily activities within the last 7 days. The participant marks their response on a 4-point scale (0 to 3), with lower values indicating less functional impairment.

The EQ-5D-5L questionnaire is a standardized test recognized by many health authorities as a generic measure of health status for clinical and economic appraisal. The descriptive system comprises 5 dimensions: mobility, self-care, usual activities, pain/discomfort, anxiety/depression. Participants mark their health status from 0 (the worst health you can imagine) to 100 (the best health you can imagine).

The Triple Timed Up and Go (3TUG) is an objective measure of mobility requiring 3 repetitions (laps) to assess lower extremity weakness and fatigability.

The Quality of Life in Neurological Disorders (Neuro-QoL) Fatigue questionnaire will be completed by participants aged ≥18 years. The Neuro-QoL Pediatric Fatigue questionnaire will be completed by pediatric participants aged ≥12 to <18 years. Participants aged <8 years will be evaluated using the proxy version of the questionnaire.