From the Guidelines
Visual Evoked Potentials (VEP) should be used as a diagnostic tool in patients presenting with acute CNS demyelination of putative autoimmune etiology, particularly in those with radiological or electrophysiological findings compatible with CNS demyelination, as recommended by the 2018 international guidelines on MOG-IgG testing 1.
Key Points to Consider
- VEP can provide additional support for diagnosis, particularly in situations where MRI abnormalities are few or have lesser specificity, such as in patients with primary progressive MS with progressive myelopathy or in older individuals with risk factors for microvascular ischemic disease 1.
- The 2018 guidelines recommend VEP testing in patients with monophasic or relapsing acute optic neuritis, myelitis, brainstem encephalitis, encephalitis, or any combination thereof, and at least one of the specified findings, including radiological or electrophysiological findings compatible with CNS demyelination 1.
- VEP testing can help identify patients with MOG-IgG-related disorders, which may have distinct clinical and radiological features compared to multiple sclerosis (MS) 1.
- The use of VEP in diagnosis should be considered in conjunction with other diagnostic tools, including MRI, CSF analysis, and clinical evaluation, to provide a comprehensive assessment of the patient's condition 1.
Clinical Implications
- Early diagnosis and treatment of MOG-IgG-related disorders can improve patient outcomes and reduce the risk of recurrent attacks and long-term disability 1.
- VEP testing can help guide treatment decisions, particularly in patients with MOG-IgG-related disorders, who may require different treatment approaches compared to patients with MS 1.
- Clinicians should be aware of the potential benefits and limitations of VEP testing in the diagnosis of CNS demyelination and use this tool in conjunction with other diagnostic modalities to provide optimal patient care 1.
From the Research
Visual Evoked Potentials (VEP)
- VEP is a useful tool in assessing the extent of demyelination along the optic nerve in patients with multiple sclerosis (MS) and optic neuritis (ON) 2.
- VEP testing can be used to predict the extent of recovery after ON and capture disabling effects of clinical and subclinical demyelination events in the afferent visual pathway 2.
- Multifocal visual evoked potentials (mfVEP) are useful in detecting abnormality in patients with ON/MS and monitoring the progression of lesions (remyelination, atrophy) 3.
- mfVEP has good correlation with conventional visual evoked potential (VEP), standard automated perimetry, optical coherence tomography, and magnetic resonance imaging 3.
Diagnostic Value of VEP
- VEP may help distinguish resolved MS-related ON from resolved NMOSD-related ON 4.
- mfVEP is a sensitive and specific tool for detecting optic neuritis, with a sensitivity and specificity of 100% in detecting patients with ON due to MS when compared with normal patients 5.
- mfVEP provides direct topographical information of specific lesions and facilitates investigations on structural-functional correlations, thus providing new methods for exploring the interplay between demyelination, atrophy, and remyelination in MS 6.
Comparison of VEP in Different Conditions
- ON-MS eyes showed significantly delayed N75 and P100 latencies, while ON-NMOSD eyes showed significantly lower N75/P100 amplitudes and P100/N135 amplitudes 4.
- mfVEP latency z-scores had a significant difference among all ON groups, with a bimodal distribution in the possible MS group 5.
- Abnormal mfVEP responses in the fellow, non-ON afflicted eye may predict MS risk in ON patients 6.