Factors in Optic Nerve Conduction - VEP Analysis

An alteration or arrest of conduction through zones of demyelination is assumed to account for the temporary signs and symptoms in patients with multiple sclerosis. In some instances these transient deficits are reportedly influenced by factors extrinsic to the nervous system, i.e. temperature, exercise, hyperventilation, anxiety and menstruation. By comparison of visual evoked potentials (VEP) following separate stimulation of each eye, an opportunity is provided to determine the effect of these physiologic variables on optic nerve conduction. An investigation employing normal subjects and patients with multiple sclerosis may lend insight into the nature of a conduction defect. Is conduction uniformly slower, dispersed temporally or blocked? If conduction is reversible by alteration of physiologic variables, is perturbed conduction amenable to therapeutic maneuvers? Would physiologic alterations permit provocations of VEP with greater diagnostic potential? The following VEP study on the effects of temperature , exercise and hyperventilation was undertaken with these questions in mind.