What is the rate of Visual Evoked Potential (VEP) abnormalities in Multiple Sclerosis (MS)?

From the Guidelines

VEP abnormalities are a common finding in Multiple Sclerosis (MS) patients, occurring in approximately 60-90% of cases, and are a valuable tool for detecting subclinical lesions and providing objective evidence of previous optic nerve involvement. VEP testing measures the electrical activity in the brain's visual pathways in response to visual stimuli, and the most typical finding is increased P100 latency (delayed conduction), which reflects demyelination of the optic nerve fibers 1. This delay occurs because demyelination slows nerve impulse transmission along the visual pathways. Some key points to consider when interpreting VEP results in MS patients include:

• VEP abnormalities often persist even after clinical recovery from optic neuritis, making them a useful marker for previous optic nerve involvement 1
• VEP testing is particularly useful in diagnosing MS when combined with other diagnostic criteria, especially in patients with unclear clinical presentations or when trying to establish dissemination in space 1
• The high sensitivity of VEP testing for detecting optic pathway demyelination makes it an important tool in MS evaluation rather than a rare finding It's worth noting that while other studies have discussed the use of MRI in MS evaluation, such as the 2015 study on evidence-based guidelines for the use of MRI in MS 1, this information is not directly relevant to the question of VEP abnormalities in MS. Therefore, the focus should remain on the diagnostic value of VEP testing in MS patients.

From the Research

VEP Abnormalities Rate in MS

• The rate of VEP abnormalities in MS patients can vary depending on the study and the specific population being examined.
• A study published in 2007 found that approximately 60.4% of patients with a definite diagnosis of multiple sclerosis presented abnormalities in pattern-reversal VEP 2.
• Another study published in 2014 found that VEP was abnormal in 11 out of 14 patients (78.57%) with clinically definite MS, while OCT (RNFL thickness) was abnormal in 5 out of 14 patients (35.71%) 3.
• A review published in 2021 highlighted the usefulness of multifocal visual evoked potentials (mfVEP) in detecting abnormality in patients with optic neuritis (ON) and/or multiple sclerosis (MS), and monitoring the progression of lesions 4.

Comparison of VEP and Other Tests

• The study published in 2014 compared the utility of optical coherence tomography (OCT) versus visual evoked potentials (VEP) in detecting visual impairment in patients with MS, and found that OCT is less sensitive than VEP in detecting visual subclinical impairment 3.
• The review published in 2021 found that mfVEP has good correlation with conventional visual evoked potential (VEP), standard automated perimetry, optical coherence tomography, and magnetic resonance imaging 4.

Clinical Significance of VEP Abnormalities

• The study published in 2007 found that the correlation between P100 latency and visual acuity was statistically significant, suggesting that VEP abnormalities can be a useful indicator of visual impairment in MS patients 2.
• The study published in 2016 found that successive VEP monitoring can bring valuable information by highlighting infraclinical lesions and monitoring the evolution of the disease 5.