Treatment with ac pulsed electromagnetic fields normalizes the latency of the visual evoked response in a multiple sclerosis patient with optic atrophy

Abstract

Visual evoked response (VER) studies have been utilized as supportive information for the diagnosis of multiple sclerosis (MS) and may be useful in objectively monitoring the effects of various therapeutic modalities. Delayed latency of the VER, which reflects slowed impulse transmission in the optic pathways, is the most characteristic abnormality associated with the disease. Brief transcranial applications of AC pulsed electromagnetic fields (EMFs) in the picotesla flux density are efficacious in the symptomatic treatment of MS and may also reestablish impulse transmission in the optic pathways. A 36 year old man developed an attack of right sided optic neuritis at the age of 30. On presentation he had blurring of vision with reduced acuity on the right and fundoscopic examination revealed pallor of the optic disc. A checkerboard pattern reversal VER showed a delayed latency to right eye stimulation (P100 = 132 ms; normal range: 95-115 ms). After he received two successive applications of AC pulsed EMFs of 7.5 picotesla flux density each of 20 minutes duration administered transcra-nially, there was a dramatic improvement in vision and the VER latency reverted to normal (P100 = 107 ms). The rapid improvement in vision coupled with the normalization of the VER latency despite the presence of optic atrophy, which reflects chronic demyelination of the optic nerve, cannot be explained on the basis of partial or full reformation of myelin. It is proposed that in MS synaptic neurotransmitter deficiency is associated with the visual impairment and delayed VER latency following optic neuritis and that the recovery of the VER latency by treatment with pulsed EMFs is related to enhancement of synaptic neurotransmitter functions in the retina and central optic pathways. Recovery of the VER latency in MS patients may have important implications with respect to the treatment of visual impairment and prevention of visual loss. Specifically, repeated pulsed applications of EMFs may maintain impulse transmission in the optic nerve and thus potentially sustain its viability.