Pattern and flash evoked responses in disseminated and selective optic pathway damage.

Area of Science:

• Neuroscience
• Ophthalmology

Background:

• Multiple sclerosis (MS) diagnosis often relies on clinical symptoms and established biomarkers.
• Visual evoked responses (VER) are a key electrophysiological tool for assessing the visual pathway's integrity.

Purpose of the Study:

• To investigate the earliest electrophysiological changes in visual evoked responses (VER) in multiple sclerosis (MS) patients.
• To compare the diagnostic utility of flash and pattern VER in detecting subclinical MS-related visual pathway alterations.

Main Methods:

• Utilized both flash and pattern stimulation to record visual evoked responses (VER).
• Analyzed wave-shape, amplitude, and latency of VER in MS patients, including those without subjective visual symptoms.
• Compared VER findings with other diagnostic markers like oligoclonal gammaglobulin fractionation.

Main Results:

• Lowered amplitude and altered wave-shape were observed in 100% of MS patients when combining flash and pattern VER.
• Increased latency was found in 77% of MS patients.
• These VER changes were also noted in conditions like sectoral ischemic neuropathy and open-angle glaucoma, indicating axonal damage.

Conclusions:

• Combined flash and pattern VER testing reveals consistent early changes in amplitude and wave-shape in MS, preceding latency increases.
• VER, particularly its initial components, serves as a sensitive indicator of axonal damage in the visual pathway.
• The study recommends comprehensive electro-oculographic investigation for subclinical MS cases.