Distinguishing Mental From Physical Fatigue in Patients With Low-Grade Glioma

Fatigue is a common consequence of low-grade gliomas (LGG), but its specific nature has not been extensively studied. In particular, it remains unclear if the prevalence and determinants of mental fatigue differ from those of physical fatigue. Therefore, this study aimed to examine (1) whether the prevalence and severity of mental fatigue differ from physical fatigue in patients with LGG; (2) the specific determinants of mental and physical fatigue, including cognitive impairments, affective symptoms and radiological abnormalities.

A total of 148 patients with LGG were included and assessed with the Dutch Multifactor Fatigue Scale (DMFS; mental and physical fatigue) and the Hospital Anxiety and Depression Scale (HADS; affective symptoms). Neuropsychological tests were administered to measure cognitive impairments, particularly in basic and complex information processing speed.

Severe mental fatigue affected 38% of patients, a significantly different prevalence than that of severe physical fatigue (22%), with an overlap of 15%. Patients with severe mental fatigue had significantly lower scores on a divided attention task, compared to patients with non-severe mental fatigue. In a hierarchical linear prediction model with demographical, radiological and psychological variables, different sets of determinants were found for mental fatigue (anxiety and depression) and physical fatigue (depression, educational level and tumor volume).

Mental fatigue can be distinguished from physical fatigue in patients with LGG, characterized by a high prevalence and unique determinants. Therefore, mental fatigue should be considered as a distinct construct and presumably requires a different (neuro)psychological therapeutic approach compared to physical fatigue.