Subjective Report, Objective Neurocognitive Performance, and "Invisible Symptoms" in Multiple Sclerosis.

BACKGROUND: Self- and informant-report measures are often useful in predicting objective cognitive performance; however, the relationship between these reports and mood, anxiety, and fatigue requires further examination. Additionally, it remains unclear as to how these factors might be associated with objective neurocognitive performance. METHODS: Eighty-six persons with multiple sclerosis (PwMS; F = 65, M = 21) completed a comprehensive neuropsychological battery that included objective neurocognitive measures, subjective reports of neurocognitive function with the Multiple Sclerosis Neuropsychological Screening Questionnaire (MSNQ) Self-Report (MSNQ-S) and Informant-Report (MSNQ-I), and self-report measures of anxiety, depression, and fatigue. Hierarchical linear regressions were conducted with depression, anxiety, the interaction between depression and anxiety, cognitive fatigue, and physical fatigue as predictors. Outcome variables included the MSNQ-S, MSNQ-I, each of five neurocognitive composites, and global intraindividual variability (IIV). RESULTS: Although greater cognitive fatigue was associated with greater reported cognitive dysfunction, it was not associated with objective neurocognitive impairment. Greater depression predicted poorer performance on measures of processing speed and verbal memory, though the effects became non-significant once accounting for anxiety. The interaction between depression and anxiety predicted greater neurocognitive IIV; those with high levels of depression and anxiety demonstrated greater dispersion of scores. CONCLUSIONS: Cognitive fatigue may skew one's perception of their cognition, though it is not associated with objective impairment. However, co-occurring depression and anxiety were associated with greater variability which is a marker of poorer neurocognitive integrity. Our findings highlight the importance of accounting for depression, anxiety, and cognitive fatigue in PwMS, given that they are all potentially modifiable factors.