The influence of posterior visual pathway damage on visual information processing speed in multiple sclerosis

Area of Science:

• Neuroscience
• Ophthalmology
• Radiology

Background:

• Multiple Sclerosis (MS) frequently involves visual pathway damage and altered visual processing speed (VPS).
• The direct association between posterior visual pathway integrity and VPS in MS remains largely unexplored.

Purpose of the Study:

• To investigate the relationship between the structural and functional integrity of the posterior visual pathway and VPS in patients with MS.
• To determine how specific MRI-derived measures correlate with impaired visual processing speed.

Main Methods:

• A cross-sectional study included 30 MS patients and 28 controls.
• Visual processing speed (VPS) was assessed using a composite of standardized tests.
• 3T MRI was used to evaluate visual cortex thickness, optic radiations (OR) diffusion tensor imaging (DTI) indices, and medial visual component (MVC) functional connectivity (FC).

Main Results:

• V2 atrophy, reduced OR fractional anisotropy (FA), and altered MVC functional connectivity (FC) were significantly associated with slower VPS in MS patients.
• These associations remained significant after controlling for factors like Expanded Disability Status Scale and prior optic neuritis.
• Specific findings included V2 atrophy (r²=0.210), OR FA (r²=0.243), and MVC iFC (r²=0.450) influencing VPS.

Conclusions:

• Posterior visual pathway structural integrity, specifically V2 thickness and OR FA, can explain up to 24% of VPS variability in MS.
• Functional integrity of the medial visual component (MVC FC) may account for up to 45% of VPS variability in MS patients.
• These findings highlight the importance of the posterior visual pathway in MS-related visual processing deficits.