Which symptom improves with rest in patients with Myasthenia Gravis?

In Myasthenia Gravis, a condition characterized by weakness and rapid fatigue of voluntary muscles, the symptom that notably improves with rest is general weakness. This improvement occurs because patients often experience increased muscle strength after brief periods of inactivity, a hallmark feature of this neuromuscular disorder. The fatigue is primarily due to the impaired transmission of signals at the neuromuscular junction, which can lead to significant muscle weakness, particularly after activity.

Rest allows the neuromuscular junctions to recover somewhat, thereby temporarily alleviating the weakness. As for the other symptoms listed, muscle spasms are not a typical presentation of Myasthenia Gravis; they are more indicative of other conditions, such as muscle or nerve disorders. Loss of balance may occur due to weakness of the muscles that control posture and movement, but it does not specifically improve with rest in the same manner as general weakness. Hyperactivity is not relevant to Myasthenia Gravis, as the condition is associated with fatigue and weakness, rather than an increase in activity levels. Therefore, the correct answer is that general weakness improves with rest.