A NEW study has shown that long sustained-attention tasks are more effective than short cognitive tests in detecting measurable fatigue in people with multiple sclerosis. The findings demonstrate that prolonged continuous performance tasks provide stronger behavioural indicators of fatigue than brief symbol-digit tests that are often favoured for convenience in clinical settings.
Fatigue is one of the most debilitating symptoms experienced by people with multiple sclerosis and affects daily functioning, work ability, and overall quality of life. While fatigue is commonly assessed using self-report questionnaires, these measures depend heavily on memory and personal interpretation. As a result, researchers have sought objective behavioural methods that can more reliably capture fatigue-related changes in performance over time.
In this study, twenty individuals with clinically confirmed multiple sclerosis and twenty age-matched individuals without neurological conditions completed two computer-based cognitive tasks. The first was a brief, five-minute symbol-digit task designed to measure changes in performance within a short time frame. The second was a prolonged attention task lasting up to thirty minutes for participants with multiple sclerosis and up to sixty minutes for participants without neurological conditions.
Although accuracy was generally high across tasks, only the long attention task revealed clear differences between groups. Individuals without neurological conditions became faster as the task progressed, whereas people with multiple sclerosis did not show this improvement. Statistical models demonstrated that measures derived from the long task, particularly reaction time and variability in responses, were strong predictors of fatigue status. In contrast, the short symbol-digit task showed limited ability to distinguish between fatigued and non-fatigued individuals.
Clinical Implications for Multiple Sclerosis Fatigue Testing
The researchers noted that short cognitive tasks are easier for patients to complete and more practical for routine use, but they may fail to capture gradual performance decline that reflects genuine cognitive fatigue. The findings suggest that long sustained-attention tasks remain important for objective fatigue assessment and that creating brief yet sensitive alternatives continue to be challenging.
Reference
Linnhoff S et al. Fatigue prediction needs time: comparing the diagnostic value of short vs. prolonged cognitive load. J Neurol. 2025; DOI:10.1007/s00415-025-13510-5.
