Measuring the speed of signals sent to the brain by nerves in the eye could help assess if remyelination is taking place, a study in cats suggests.
Such measurements could be useful in evaluating multiple sclerosis (MS) treatments aiming to repair myelin in clinical trials — of particular interest to people with progressive MS, who have few therapy options, its researchers said.
The study, “Evoked potentials as a biomarker of remyelination,” was published in the journal PNAS.
Myelin is a protein that surrounds neurons like a protective sheath, allowing them to send electrical signals faster and more efficiently. In MS, the immune system attacks myelin, ultimately leading to disease symptoms.
Interest is growing in therapies that might promote remyelination — the recovery of myelin. But confirming the presence of myelin in the central nervous system, important in evaluating potential treatments, requires taking samples of nerve tissue. That’s too invasive and damaging to be a feasible approach for patients.
Researchers at the University of Wisconsin-Madison demonstrated that remyelination could be assessed using a non-invasive test called visual evoked potential (VEP).
VEP is a measurement of the electrical signal recorded through the visual pathway in response to a light stimulus. It involves giving a person a flash of light to the eye, which triggers an electrical signal that travels from the eye’s retina through the optic nerve until it reaches the brain. Using electrodes on the person’s scalp, it is possible to measure the specific brain activity resulting from the flash of light stimulus.
The time lag between the light flash and the brain activity is called latency.