Final answer:
The damage to the myelin sheath in MS causes slower signal propagation.
Step-by-step explanation:
When the myelin sheath of neurons is damaged in Multiple Sclerosis (MS), it impairs signal propagation.
The myelin sheath acts as an insulator, preventing current leakage and increasing the speed of action potential conduction. However, when the myelin sheath is compromised, current leaks from previously insulated axon areas, slowing down the conduction of action potentials.
Therefore, the problem caused by the damage to the myelin sheath in MS is that signal propagation is slower.