Fatigue and processing speed are related in multiple sclerosis

Area of Science:

• Neuroscience
• Clinical Neurology
• Cognitive Psychology

Background:

• Fatigue is a prevalent symptom in multiple sclerosis (MS).
• MS-related brain alterations may impair processing speed, contributing to fatigue.
• Understanding this relationship is crucial for managing MS symptoms.

Purpose of the Study:

• To investigate the association between processing speed and fatigue in relapsing-remitting MS patients.
• To compare processing speed in fatigued versus non-fatigued MS patients and healthy controls.

Main Methods:

• Patients were classified as fatigued (Fatigue Severity Scale [FSS] score ≥5.0) or non-fatigued (FSS score ≤4.0), with EDSS score ≤3.5.
• Fatigued patients were further categorized as primary or secondary fatigued.
• Cognitive function was assessed using a battery from Wechsler's Adult Intelligence Scale-III/Wechsler's Memory Scale-III.

Main Results:

• Processing speed, measured by Digit Symbol Coding, was significantly lower in all MS patient groups compared to healthy controls.
• Fatigued MS patients exhibited slower processing speed than non-fatigued MS patients.
• A significant inverse relationship was found between processing speed and fatigue severity in the combined fatigued MS patient group (r = -0.35; P < 0.05).

Conclusions:

• Processing speed impairment is demonstrably related to the degree of fatigue experienced by MS patients.
• Further longitudinal research is recommended to elucidate the causal relationship and mutual dependency between processing speed and fatigue in MS.