Despite how common fatigue is among patients with multiple sclerosis (MS), much remains unknown about its pathophysiological mechanism. A study examined metabolic changes in fatigue among patients with relapse-remitting MS (RRMS) using MR two‐dimensional localized correlated spectroscopy (2D L‐COSY).
The study consisted of 16 patients with RRMS and 16 healthy controls, who were assessed for fatigue impact using the Modified Fatigue Impact Scale (MFIS). The posterior cingulate cortex was used to gather MR 2D L-COSY data. Changes in creatine scaled metabolic ratios and their associations with fatigue scores were evaluated with non-parametric statistical analysis.
Patients with RRMS had much higher fatigue and lower metabolic ratios for tyrosine, glutathione, homocarnosine (GSH+Hca), fucose‐3, glutamine+glutamate (Glx), glycerophosphocholine (GPC), total choline, and N‐acetylaspartate (NAA‐2), as well as higher levels for isoleucine and glucose (P≤0.05) compared with healthy controls. The only factor positively associated with all fatigue domains was GPC (r=0.537; P≤0.05), while Glx‐upper, NAA‐2, GSH+Hca, and fucose‐3 were all negatively associated with all fatigue domains (r=–0.345 to –0.580; P≤0.05). A positive correlation was observed between tyrosine and MFIS (r=0.499; P≤0.05), but a negative correlation was observed between cognitive fatigue and total GSH (r=–0.530; P≤0.05). Lesion load and brain volumes were not associated with fatigue score.
“Our results suggest that fatigue in MS is strongly correlated with an imbalance in neurometabolites but not structural brain measurements,” the study authors concluded.