Degenerative pathologies on cortical biopsy, dopaminergic depletion, and shunt efficacy in iNPH

Abstract

INTRODUCTION Coexisting degenerative pathologies may influence the efficacy of ventriculoperitoneal (VP) shunting in idiopathic normal pressure hydrocephalus (iNPH). METHODS We evaluated 58 iNPH patients who underwent VP shunting with cortical biopsy assessing pathologies including amyloid beta (A beta). Concordance between biopsy-identified Alzheimer's pathology and amyloid positron emission tomography (PET) and the influence of magnetic resonance imaging-based iNPH indices, dopamine transporter (DAT) imaging, and biopsy pathologies on postoperative outcomes were examined. RESULTS A beta pathology was found in 23 patients (39.7%) and showed high concordance with amyloid PET (95.2%). Although A beta positivity was associated with poorer 1-year cognitive outcome, and cognitive improvement reached significance only in A beta-negative patients, both A beta-positive and A beta-negative groups exhibited functional improvement after surgery. Lower anterior striatal DAT uptake was paradoxically associated with better postoperative outcomes, particularly in A beta-positive individuals. DISCUSSION Cortical biopsy provides information concordant with amyloid PET, and biopsy-confirmed Alzheimer's pathology and dopaminergic status influence shunt efficacy. VP shunting remains beneficial in iNPH even with degenerative comorbidities.