The Relevance of Handedness in Cognitive Outcomes After Glioma Surgery in Adults: A Retrospective Study

Gliomas necessitate a balanced surgical approach to maximize resection while preserving cognitive function. Postoperative cognitive decline is a common concern, especially in language and memory domains. While factors like age and education are known to influence outcomes, the role of handedness remains inconsistently documented despite its known association with cerebral language organization. This study aims to investigate the impact of handedness on cognitive outcomes in adult glioma patients by comparing non-right-handed (nRH) individuals to a matched cohort of right-handed (RH) patients.

This retrospective, single-center study analyzed 35 nRH patients who underwent glioma surgery. The cohort was divided into groups with left-sided and right-sided lesions. A subset of 15 nRH patients was paired with lesion-matched RH counterparts. Neurocognitive status, including language, memory, and executive functions, was assessed at four time points: pre-operatively, immediately post-surgery, and at 1-3 and 4-6 months follow-up.

In nRH patients with left-sided lesions, a transient decline in language and memory functions was observed post-surgery, with most functions recovering by the 4-6 months follow-up. The most significant finding was that nRH patients with left-sided lesions performed significantly better on verbal fluency tasks than their matched RH counterparts, both at baseline and during the recovery phase. No significant differences were found between nRH and RH patients with right-sided lesions, indicating that this advantage is specific to language networks in the left hemisphere.

This study demonstrates that handedness is a critical factor influencing cognitive outcomes after glioma surgery. The superior performance of nRH patients in verbal fluency tasks suggests a neuroplastic advantage, likely a contralateral compensatory mechanism, which aids in language recovery. These findings suggest that handedness should be considered a prognostic factor in surgical planning, potentially allowing for a more aggressive resection of tumors in the left hemisphere of nRH patients due to their robust potential for language recovery.