Correlation of Fatigue Using Event Related Potentials

Background:  Fatigue is a common feature in people with multiple sclerosis (MS) and occurs in 80% of all cases. Unfortunately, neurological examination does not always agree with the persons’ reported outcome from the fatigue profile. On the other hand, techniques such as event-related potentials (ERPs) can help in evaluating fatigue.

Objectives: The main aim of this pilot study was to measure self-report fatigue and observe the examine the relationship between the self-report fatigue and an objective measure of brain activity before and after a fatiguing task among people with MS and healthy subjects.

Methods: Eight subjects with MS underwent the visual 0-back and 2-back task during scale encephalogram recorded using a 256-channel system. Participants also completed the Fatigue Severity Scale (FSS). Items on the FSS are scored on 7 point scale (1-7), with maximum score of 63. Preliminary analysis examines the pre and post reaction time for each subject using a paired t-test.

Results: Fatigue scores using the FSS had a median score of 40 (moderate fatigue) with scores ranging from 20-60. Overall, the mean pre-score was 543.17 (SD= 73.38) sec and mean post score was 664.33 (SD=187.82) sec. The mean difference between the reaction time for the first 50 was 121.2 seconds faster than the last 50 (p=0.02).

Conclusions: The knowledge gained from this study can be the foundation for a clinically useful tool using ERPs to recognize underpinnings of fatigue and reduce progression, and to increase the feasibility of larger longitudinal studies.