J Neurosurg. 2026 Apr 24:1-14. doi: 10.3171/2025.12.JNS251883. Online ahead of print.
ABSTRACT
OBJECTIVE: The aim of this study was to evaluate associations between the corpus callosum angle (CCA), corpus callosum splenial angle (CCSA), and resistance to CSF outflow (Rout) with neuropsychological performance in patients who had suspected idiopathic normal pressure hydrocephalus (iNPH), and to assess their predictive value for diagnosis and postoperative cognitive outcomes following ventriculoperitoneal shunt placement.
METHODS: This prospective observational study included 74 patients (39 male, mean age 73.6 years) who were evaluated for iNPH between 2019 and 2022 at a single institution. All patients underwent MRI-based measurement of the CCA and CCSA, the Katzman test for Rout, and a comprehensive neuropsychological battery. Patients were grouped by CCA size (< 90°, 91°-109°, and > 110°), CCSA size (< 60°, 61°-79°, and > 80°), and Rout (≥ 12 mm Hg and < 12 mm Hg). Group comparisons were performed using nonparametric tests, and logistic regression was applied to identify neuropsychological predictors of elevated Rout.
RESULTS: Lower CCA values were associated with trends toward poorer performance in imitation apraxia, visual gnosis, and Mini-Mental State Examination (MMSE) scores, although none reached statistical significance after correction for multiple comparisons. Elevated Rout (≥ 12 mm Hg) was significantly associated with better MMSE scores (adjusted p = 0.029), while other domains, including symbolic apraxia, rhythm reproduction, and confrontation naming, showed consistent trends but without statistical significance after correction. A logistic regression model that incorporated MMSE and rhythm reproduction predicted elevated Rout with 93.5% sensitivity and an area under the curve of 0.86. Postoperative cognitive improvements were modest and variable; however, long-term follow-up revealed sustained functional gains in selected patients, particularly those with elevated Rout and preserved preoperative cognitive function.
CONCLUSIONS: CCA and Rout were independently associated with distinct cognitive profiles in patients with suspected iNPH. In particular, Rout demonstrated predictive value for preserved global cognition. Integrating anatomical, physiological, and neuropsychological markers might enhance diagnostic accuracy and improve patient selection for ventriculoperitoneal shunt placement.
PMID:42030562 | DOI:10.3171/2025.12.JNS251883
