Beyond motor: clinical manifestations of right hemisphere gliomas - a systematic review

Right-hemisphere gliomas have traditionally been regarded as less eloquent than left-sided lesions, influencing surgical decision-making and anesthetic approach. However, these tumors produce diverse non-motor manifestations affecting cognition, behavior, and socio-emotional functioning with important consequences for quality of life. This review aimed to characterize these manifestations and their implications for functional eloquence.

Following PRISMA guidelines, PubMed, Scopus, and Embase were searched using predefined terms for right-hemisphere gliomas and their manifestations. Eligible studies included patients with supratentorial right-hemisphere gliomas reporting motor and/or non-motor clinical manifestations. Studies were excluded if the clinical presentation was incompletely described or if glioma pathology lacked histopathological confirmation. Extracted data included tumor location, histopathology, clinical manifestations, neuropsychological assessments, and functional outcomes.

A total of 372 patients from 88 studies were included. Median age was 42 years (range, 11-87), with slight male predominance (49% vs. 48% female). Preoperative non-motor manifestations were common and heterogeneous, most frequently compromising cognition and executive performance (43%), followed by vision and visuospatial deficits (28.4%) and language deficits (24%). Postoperatively, the most common deficits involved language (46%), followed by vision and visuospatial deficits (40%), and cognition and executive dysfunction (23.1%). Analyses relating extent of resection to postoperative deficits were considered exploratory because reporting of extent of resection and postoperative outcome assessment were incomplete and heterogeneous.

Right-hemisphere gliomas carry a substantial and under-recognized burden of non-motor manifestations that challenge conventional definitions of functional eloquence and support the expansion of functional assessment and surgical planning encompassing right-hemisphere cognitive and behavioral networks.