P01.08.b mental fatigue in patients with low-grade glioma: associations with neurocognitive functioning and tumor characteristics

Abstract BACKGROUND Fatigue is a frequent consequence of low-grade glioma (LGG), but the causes are still barely understood. Specifically mental fatigue might be related to cognitive impairment such as mental slowness and decreased attention. Also, patients with greater tumor volumes or tumors in certain locations (such as the frontal cortex) might have more cognitive impairments and experience more fatigue. The aim of the present study was twofold: (1) to examine the relationship between mental fatigue and information processing speed and complex attention and (2) to investigate the associations between mental fatigue and tumor volume and location in patients with LGG. MATERIAL AND METHODS 124 patients with LGG (IDH mutated astrocytoma and oligodendroglioma grade 2 and 3) were included before the start of proton therapy. Different facets of fatigue, including mental fatigue, were measured after surgery, with a multidimensional fatigue scale, the Dutch Multifactor Fatigue Scale (DMFS). The Vienna Test System was used to examine simple information processing speed, response inhibition, and divided attention. Tumor location and tumor volume (radiation target volume) were scored on the pre-radiotherapy MRI scan. Descriptive statistics, Spearman’s correlations, and between group comparisons were performed. RESULTS 41% of patients with LGG reported severe mental fatigue. No significant differences were found in mean performance on simple information processing speed, response inhibition and divided attention between severely mental fatigued patients and non-severely mental fatigued patients. However, the percentage of patients with impaired divided attention was significantly higher in the severely mental fatigued group (39%) compared to the non-severely mental fatigued group (16.2%), χ2 = 7.6, p < 0.05. No significant relationships were found between mental fatigue and tumor volume and location. Also, tumor location was not related to neurocognitive functioning, but larger tumor volume was significantly associated with poorer performance on divided attention (r = -0.19, p < 0.05). CONCLUSION A high rate of mental fatigue was found in patients with LGG. Furthermore, a relationship between impaired divided attention and severe mental fatigue was found. This implies that patients may develop mental fatigue due to increased cognitive efforts to compensate for attentional deficits. This might be especially important in patients with larger tumors, considering the relationship between tumor volume and divided attention. The results stress the importance of neuropsychological assessment in this patient group before the start of adjuvant treatment, to timely offer individual rehabilitation.