Perioperative Changes in Episodic Memory in Patients Undergoing Brain Tumor Surgery: A Longitudinal Study of Clinical Determinants

Background/Objectives: Episodic memory impairment is common in patients with intracranial tumors and has significant implications for clinical management. Memory is often treated as a unitary construct, and parameter-specific patterns and perioperative changes remain poorly understood. This study aimed to examine different memory parameters, their temporal dynamics, and clinical predictors of impairment. Methods: This observational study included 76 patients undergoing resection of supratentorial tumors, assessed preoperatively and at one week and three months postoperatively. Episodic memory was evaluated using a standardized word-list learning paradigm, yielding measures of immediate recall, delayed recall, and recognition. Performance was classified using age-adjusted z-scores, and relevant intraindividual changes were examined. Risk factors for impairment were analyzed using logistic regression. Results: Long-term memory measures were more frequently impaired than immediate recall across all time points. Impairment rates increased markedly one week after surgery to as high as 46.5% but returned to baseline levels at three months; however, individual trajectories were heterogeneous. Preoperative impairment was associated with lower functional status. Postoperative memory deficits were strongly associated with preoperative impairment, with older age being additionally associated with transient deficits. Conclusions: Memory impairment after brain tumor surgery is dynamic and parameter-specific, with long-term memory particularly vulnerable. Predictor findings are exploratory given limited event numbers and substantial cohort heterogeneity. Although deficits are often transient, high interindividual variability exists, underscoring the need for individualized risk stratification and neuropsychological care. Increased attention should be paid to the vulnerable acute postoperative period, as intact short-term memory may mask impairments.