Effect of Transorbital Electrical STIMulation of Optic Nerve on Remyelination After an Acute Optic Neuritis

Overview

In light of experimental models showing that neuronal electrical activity is crucial for the remyelination process, we hypothesize that maintenance of electrical axonal activity in the early stages of optic neuritis may promote myelin repair, limiting thereby axonal degeneration. In humans, electrical stimulation of the optic nerve has been tested mainly in ischemic neuropathy and retinitis pigmentosa, which are both associated with severe axonal/retinal pathology and poor visual prognosis. In contrast, the inflammation of the optic nerve in optic neuritis is generally transient, with less severe axonal damage at the acute phase, which would allow for better efficacy of electrical stimulation as a strategy to promote remyelination and neuroprotection.In light of experimental models showing that neuronal electrical activity is crucial for the remyelination process, we hypothesize that maintenance of electrical axonal activity in the early stages of optic neuritis may promote myelin repair, limiting thereby axonal degeneration. In humans, electrical stimulation of the optic nerve has been tested mainly in ischemic neuropathy and retinitis pigmentosa, which are both associated with severe axonal/retinal pathology and poor visual prognosis. In contrast, the inflammation of the optic nerve in optic neuritis is generally transient, with less severe axonal damage at the acute phase, which would allow for better efficacy of electrical stimulation as a strategy to promote remyelination and neuroprotection.

This is a randomized, controlled, prospective, interventional, blinded trial which aims to evaluate the safety and efficacy of transorbital electrical nerve stimulation on remyelination and neuroprotection after an acute episode of retrobulbar optic neuritis in patients with multiple sclerosis (MS). Expected Explorations: The study is composed of 14 visits: a screening/inclusion visit with neurological and ophthalmological evaluation, electrophysiology, MRI and Magnetoencephalography (MEG), 10 transorbital electrical stimulation or sham stimulation visits and finally 3 follow-up visits and evaluations (neurological and ophthalmological). Patient's participation will last 49 weeks (inclusion visit and 48 weeks of follow-up). Participation of healthy volunteers will last one day. MS patients diagnosed with an optic neuritis will be randomized either in the active arm (transorbital electrical stimulation of the optic nerve - 10 sessions during 2 consecutive weeks) or in the placebo arm (sham stimulation - 10 sessions during 2 consecutive weeks) Expected benefits: Electrical stimulation of the optic nerve after an acute episode of retrobulbar optic neuritis may promote remyelination in the optic nerve and a better long-term visual outcome.