Faculty Bibliography

BACKGROUND:The association between subjective cognitive fatigue and objective cognitive dysfunction in patients with multiple sclerosis (PwMS) has been studied, with conflicting results. OBJECTIVE:To explore the impact of fatigue on cognitive function, while controlling for the influence of depression, disability, comorbidities, and psychotropic medications. METHODS:PwMS completed a computerized cognitive testing battery with age- and education-adjusted cognitive domain scores. Disability (Expanded Disability Status Scale (EDSS)), cognitive fatigue, and depression were concurrently evaluated. RESULTS:In all, 699 PwMS were included. Both cognitive fatigue and depression were significantly and negatively correlated with the same cognitive domains: information processing speed, executive function, attention, motor function, and memory (-0.15 ⩽ r ⩽ -0.14 for cognitive fatigue; -0.24 ⩽ r ⩽ -0.19 for depression). Multivariate analysis revealed significant but small independent correlations only between depression and neuropsychological test results, while cognitive fatigue had no independent correlation with objective cognitive function except for a trend toward impaired motor function in highly fatigued PwMS. Depression and cognitive fatigue accounted for no more than 6% of the variance in objective cognitive domain scores. CONCLUSION:Cognitive fatigue is not independently related to objective cognitive impairment. Depression may influence cognitive function of PwMS primarily when it is severe. Cognitive impairment in PwMS should not be ascribed to fatigue or mild depression.

An Online First version of this article was made available online at http://link.springer.com/journal/40263/onlineFirst/page/1 on 24 August 2018. An error was subsequently identified in the article, and the following correction should be noted.

BACKGROUND:Cognitive impairment affects many patients with multiple sclerosis (MS). NeuroTrax, a computerized cognitive screen that can be administered during routine clinical care, provides a consistent, validated, objective cognitive profile measure with a global cognitive score (GCS) and seven individual domain scores. Natalizumab is an efficacious therapy for relapsing MS, demonstrating reductions in disability worsening and MS disease activity measured by magnetic resonance imaging. OBJECTIVE:The aim of this study was to assess cognitive function as measured by NeuroTrax in MS patients treated with natalizumab for ≥ 2 years. METHODS:This retrospective observational study included adult MS patients in the United States who received 300 mg intravenous natalizumab every 4 weeks for ≥ 2 years. NeuroTrax data were evaluated at baseline and yearly thereafter. Changes in GCS and the seven individual cognitive domain scores from baseline to after 24 infusions of natalizumab were analyzed. RESULTS:In the study population at baseline (N = 52), 22 patients (42.3%) had disease duration of 0-5 years; 12 patients (23.1%) were treatment naive. GCS score improved significantly from baseline [mean 95.5, standard deviation (SD) 12.9] to year 2 (mean 98.9, SD 13.2; change from baseline 3.4; p = 0.003). After 2 years on natalizumab, 17 patients (32.7%) demonstrated clinically significant improvement (increase from baseline > 1 SD) in GCS. Results were similar regardless of whether patients had previously received MS therapy. CONCLUSIONS:Patients treated with natalizumab demonstrated significant improvement in cognitive function, measured by NeuroTrax GCS, over 2 years of treatment.