It's the muscles controlling the eyelids that are usually affected first causing them to droop and creating the appearance of looking tired. Those controlling eye movements are also commonly involved causing double-vision. Next the facial muscles may be weak such that any facial expression appears as a grimace. If the jaw and muscles of the gullet are affected then eating and swallowing becomes difficult. In severe cases people find themselves unable to speak, lift their arms, walk, and have difficulty breathing.
Rest helps Most people find that rest and a good night's sleep relieves their symptoms initially.
Symptoms may become worse as the day progresses and the muscles are used. Any stress worsens the muscle weakness and women often find that their symptoms are more severe during their periods. If an injection of a drug that increases the levels of chemical neurotransmitters causes a temporary improvement in symptoms, then this confirms the diagnosis. Other tests that may be performed are blood tests looking for the damaging antibodies and electrical muscle function tests. A CT scan of the chest may also be performed looking for an abnormality of the thymus gland.