The Neurological Fatigue Index for people with multiple sclerosis (NFI-MS) and the performance fatigability measures evaluated in a recent study are easy to administer, according to researchers. Therefore, they encourage wider use of these measures in clinical and research settings for comprehensive assessment of MS-related fatigue. 52 participants (mean ± SD age, 46.8 ± 10.1 years) completed the study. 3 measures of performance fatigability were used: percent change in meters walked from first to last minute of the 6-Minute Walk Test, percent change in force exerted from first to last trial on a repetitive maximal hand grip test, and response speed variability on the Continuous Performance Test. Perceived physical and cognitive fatigue were measured using the NFI-MS. The state level of fatigue was examined immediately before and after performing the fatigability measures using a 1-item visual analog fatigue scale. They found:

• Of the 3 performance fatigability measures, only the attentional task (response speed variability) was significantly associated with NFI-MS physical and cognitive domain scores.
• Participants demonstrated significantly higher state levels of fatigue after performing all performance fatigability measures.