Fatigability-related oscillatory brain activity changes in people with MS

Area of Science:

• Neuroscience
• Clinical Neurophysiology
• Rehabilitation Medicine

Background:

• Cognitive fatigue is a prevalent and challenging symptom in people with multiple sclerosis (pwMS), often resistant to treatment.
• Current diagnosis of cognitive fatigue relies on subjective reporting due to a lack of objective measures.
• Brain wave activity monitoring is a potential strategy for assessing cognitive fatigue.

Purpose of the Study:

• To investigate changes in oscillatory brain activity associated with cognitive fatigability in pwMS.
• To explore the relationship between objective measures of fatigability and subjective fatigue ratings in pwMS.

Main Methods:

• 21 pwMS and 21 healthy controls (HC) performed a 30-minute sustained attention task.
• Electroencephalography (EEG) recorded brain activity before and after the task.
• Objective measures included reaction time variability and EEG power (theta, alpha); subjective measures included mental fitness, exhaustion, and mind wandering ratings.

Main Results:

• PwMS exhibited objectively measurable, stronger fatigability development compared to HC, indicated by increased reaction time variability.
• A significant increase in occipital alpha power during the task was more pronounced in pwMS.
• Time-on-task-induced changes in brain activity were not associated with subjective fatigue ratings.

Conclusions:

• Cognitive fatigability in pwMS is associated with distinct neural mechanisms, particularly in upper alpha power.
• Objective EEG measures may complement subjective assessments for diagnosing and monitoring fatigue in pwMS.
• Further research is needed to bridge the gap between objective neural changes and subjective fatigue experiences.