ABSTRACT NUMBER: ESOC2026A1968 NEUROPSYCHOLOGICAL DEFICITS IN UNILATERAL POSTERIOR CEREBRAL ARTERY STROKE INVOLVING THE HIPPOCAMPUS

Abstract Background and aims To determine the neuropsychological consequences of posterior cerebral artery (PCA) stroke with hippocampal involvement, focusing on hemispheric lateralization. Methods In this retrospective observational study, neuropsychological data of 78 patients with PCA stroke with hippocampal involvement, collected within the first days after the event, were analysed. Data include clinical behaviour observation, clinical tests without given norms, as well as standardized test batteries. Cognitive function data assessed in at least 20 patients were evaluated and dichotomised according to z-values as “impaired” for z ≤ -1.3, which covers the lowest 10% of normal distribution and „unimpaired“ for z > -1.3. Results When compared to right-hemispheric PCA stroke (RH, N=32), left-hemispheric PCA stroke (LH, N=46) was associated with markedly higher rates of subjective memory dysfunction (9.4% vs. 73.9%; p<0.001) and significant deficits in episodic memory (9.4% vs. 41.3%; p=.002), language production (0% vs. 45.7%; p<.001) and comprehension (0% vs. 19.6%; p=.009). Standardized testing confirmed a significantly higher frequency of impairments in verbal comprehension, naming, fluency, recall, recognition, and visual recall among left PCA stroke patients (see Figure). Logistic regression identified hemispheric lateralisation as the principal predictor of cognitive dysfunction, with no additional effect of thalamic involvement. Conclusions Left PCA stroke involving the hippocampus is strongly associated with memory and language dysfunction, underscoring hemispheric lateralisation as a key determinant of cognitive outcome. These findings highlight the need for targeted neuropsychological assessment and tailored rehabilitation strategies in this group of patients. Conflict of interest All authors: nothing to disclose Figure 1 - belongs to Conclusions