Capturing Key MG-symptoms Using Smartphone Recordings.

Prior treatment

• Subjects currently taking part in a clinical trial of an Investigational Medicinal Product.
• Subjects who have used an immediate release pyridostigmine-based medication in the 12 hours prior to their participation and participants on prolonged release pyridostigmine.

Other illness

• Subjects with a diagnosed neurological disease resulting in muscle weakness, other than MG.
• 1\. Limitation of upper limb mobility or speech impairment of any cause.

Other

• Not willing to be audio-recorded for the study assessments.
• Not willing to be video-recorded for the study assessments.
• Subjects have cognitive or physical limitations that, in the opinion of the investigator, limits the subject's ability to complete study procedures/
• Subjects with an upper-limb amputation or who are non-verbal.

• Age ≥ 18 years
• Ability to understand the requirements of the study and provide written informed consent.
• A clinical diagnosis of myasthenia gravis (ocular or generalized) as defined by the Dutch national guideline (category "definite" or "probable" MG).
• MGFA Clinical Classification of disease severity I-IV.
• Subjects have at least one of the symptoms of interest (namely dysarthria, dysphonia, proximal arm fatigue and/or ptosis).
• Subjects are not diagnosed with and have no clinical suspicion of MG.
• Subjects do not have a medical history of any of the symptoms of interest (namely dysarthria, dysphonia, proximal arm fatigue and/or ptosis).