 The most prevalent types of pain are thought to be headaches (43%), dysesthetic limb pain (26%), back pain (20%), painful spasms (15%), painful Lhermitte's phenomenon (16%) and Trigeminal Neuralgia (3%).These authors did not however find enough data to quantify the prevalence of painful optic neuritis.Acute pain is mainly due to optic neuritis, trigeminal neuralgia, Lhermitte's sign or dysesthesias.