Main clinical findings and their frequency in cortical-subcortical areas tested in awake brain mapping for diffuse...

The main objective of awake surgery for brain gliomas is to achieve maximum tumor removal while safeguarding cognitive functions. This approach offers a unique chance to gain deeper insights into brain function. This study aims to detail the clinical findings and their relationship, frequency and probability of occurring in cortical and subcortical anatomical structures at both hemispheres.

This series represents our initial series of 51 consecutive diffuse low-grade gliomas (DLGG) treated with awake surgery.

The surgeries were evenly distributed between the left hemisphere (LH, n = 26 - all right-handed) and the right hemisphere (RH, n = 25 - one left-handed and one ambidextrous). In the LH, the main clinical findings during cortical mapping were positive motor responses (51 times; 33.3 % of clinical findings), followed by speech arrest (26; 16.9 %) and semantic paraphasia (19; 12.4 %). For LH subcortical responses: semantic paraphasia (36; 36.7 %), anomia (16; 16.3 %) and speech perseveration (13; 13.2 %). In the RH the main clinical findings during cortical mapping were positive motor responses (46; 38 % of clinical findings), negative motor responses (21; 17.3 %) and speech arrest (18; 14.8 %). For RH subcortical responses: negative motor responses (9; 21.9 %), positive motor responses (7; 17 %), and semantic paraphasia (5; 11.1 %). The cortical anatomical structures with the highest average functional findings per exposure were the precentral gyrus (average of 2.1 findings per evaluation), vPMC (ventral premotor cortex) (1.5) and postcentral gyrus (1.2); and in the subcortical area: IFOF (Inferior Fronto-Occipital Fasciculus) (1.2), corticospinal tract (1.0) and somatic sensory fibers (1.0).

The clinical findings in each hemisphere are extremely important information for all neuro-oncological approaches. We highlight the brain regions most likely to have intraoperative findings. We emphasize the importance of functional findings in the RH, which, in addition to motor function, sensitivity, eye movement, visual alteration, social cognition, spatial awareness, and attention, also includes significant language findings.