Obligatory medical device diagnostics.
- Electromyography (EMG; measurement of electrical muscle activity).
- Capillary microscopy of the nail fold
- Magnetic resonance imaging (MRI; computer-assisted cross-sectional imaging method (using magnetic fields, i.e., without X-rays); particularly well suited for visualizing soft tissue lesions) – to find the right sampling site for biopsy, because the changes are detectable only in the affected muscles
- Organ diagnostics – also the muscles of the heart, lungs, esophagus (esophagus), gastrointestinal tract (gastrointestinal tract) may be affected.