Muscle fatigability : Myasthenia Gravis

Muscle fatigability can be tested for many muscles. A thorough investigation includes:

1. looking upward and sidewards for 30 seconds: ptosis and diplopia
2. looking at the feet while lying on the back for 60 seconds
3. keeping the arms stretched forward for 60 seconds
4. ten deep knee bends
5. walking 30 steps on both the toes and the heels
6. five situps, lying down and sitting up completely
7. "Peek sign": after complete initial apposition of the lid margins, they quickly (within 30 seconds) start to separate and the sclera starts to show