Does focal inflammation have an impact on cognition in multiple sclerosis? An MRI study

Area of Science:

• Neuroscience
• Radiology
• Cognitive Science

Background:

• Cognitive impairment affects a significant portion of multiple sclerosis (MS) patients.
• Asymptomatic gadolinium (Gd)-enhancing lesions on MRI have been previously associated with transient cognitive changes in MS.
• Understanding the impact of these lesions on cognitive function is crucial for patient management.

Purpose of the Study:

• To evaluate changes in cognitive function in relapsing MS patients before and after the appearance of asymptomatic MRI Gd-enhancing lesions.
• To compare cognitive performance in MS patients with and without Gd-enhancing lesions to healthy controls.

Main Methods:

• Neuropsychological evaluations were conducted on 84 relapsing-remitting MS patients and 40 healthy controls before and after brain MRI with Gd administration.
• Patients were categorized as Gd positive (presence of enhancing lesions) or Gd negative (absence of enhancing lesions).
• Cognitive performance was assessed using the Symbol Digit Modality Test and other neuropsychological evaluations.

Main Results:

• 16.7% of MS patients exhibited asymptomatic Gd-enhancing lesions.
• No significant overall cognitive performance variation was noted between baseline and follow-up in MS patients with or without enhancing lesions.
• A significant increase in Symbol Digit Modality Test scores was observed from baseline to follow-up, but this improvement was notably lower in Gd-positive MS patients compared to Gd-negative patients and healthy controls.

Conclusions:

• The absence of a practice effect in Gd-positive MS patients suggests that focal inflammation may negatively influence cognitive function.
• Asymptomatic Gd-enhancing lesions could play a role in cognitive deficits observed in MS.
• Further research is warranted to explore the relationship between subclinical inflammation and cognitive decline in MS.