P01.11.A Perioperative executive functioning in patients with low-grade gliomas near the Frontal Aslant Tract

Abstract

Background A tract potentially involved in important executive cognitive processes is the Frontal Aslant Tract (FAT). In particular the right FAT has been associated with executive functioning (EF). In neurosurgery, it remains unclear if patients with tumors near the FAT demonstrate EF impairments after resection. This study investigated whether low grade gliomas (LGG) that affect the core white matter and/or structural integrity of the FAT predict preoperative and 3 months postoperative EF, when controlled for tumor volume and the integrity of other nearby tracts (SLF II and SLF III). Material and Methods Data was analyzed from patients with frontal and parietal LGG who underwent surgery between 2010-2021. Probabilistic tractography was performed prior to surgery to generate preoperative tracts of the FAT, SLF II and SLF III. The core of the FAT was defined as the white matter between the seed and the target region. Average mean diffusivity for each tract was taken as a measure of structural integrity. EF was assessed one day before and 3 months post-surgery with the following tests: Stroop test, symbol digit coding test (SDC), shifting attention test (SAT), and letter fluency test (LF). We performed linear mixed models and linear regression analyses to investigate the relationship between presurgical tumor overlap with the core of the FAT and FAT integrity with pre- and postsurgical executive test performances. Results Seventy-five patients were included (left tumor N=39, right tumor N=36). Mean pre-surgical Z-scores were within 0.5 standard deviation from a healthy control group for all tests, but with substantial variance between patients (Z-score range:-3.59 to 2.4). The results demonstrated that core overlap of the right FAT predicted preoperative performance on the SAT (p<.01, β= -.473), Stroop (p<.01, β= -.519), and SDC (p<.01, β= -.519). Right or left core overlap did not significantly predict performance three months after surgery. FAT integrity did not predict preoperative EF performance, whereas it did predict SAT performance at three months post-surgical (p<.01, β= -.694) when controlled for SLF II, III integrity and tumor volume. Conclusion Although patients with frontal or parietal LGG showed no dysfunction on tests of EF before surgery on group level, they demonstrated large variability between patients. Tumor overlap with the core of the right FAT predicted worse presurgical EF performances, but not short-term post-surgical performances. Right FAT integrity predicted short-term post-surgical performance on cognitive flexibility. These results are in line with previous findings that the right FAT is involved in EF and indicate that preoperative FAT integrity might predict which patients will perform worse after surgery.