Which of the following is true regarding weakness in myasthenia gravis?

Myasthenia gravis (MG) is a neuromuscular junction (NMJ) disorder characterized by weakness and fatigability of skeletal muscles. The underlying defect is a decrease in the number of available acetylcholine receptors (AChRs) at NMJs due to an antibody-mediated autoimmune attack. If weakness remains restricted to the EOMs for 3 years, it is likely that it will not become generalized, and these patients are said to have ocular MG. The limb weakness in MG is often proximal and may be asymmetric. Despite the muscle weakness, deep tendon reflexes are preserved. If ventilatory weakness becomes requires respiratory assistance, the patient is said to be in crisis. The diagnosis is suspected on the basis of weakness and fatigability in the typical distribution described above, without loss of reflexes or impairment of sensation or other neurologic function. Ref harrison 20th edition page 3232, 3233