Homburg

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• Neurocognitive effects of CSF biomarkers in idiopathic normal pressure hydrocephalus patients undergoing VP shunt placement
• The authors reply
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Neurochirurgische Klinik Universitätsklinikum des Saarlandes Kirrberger Straße 66421 Homburg/Saar www.uniklinikum-saarland.de

Prof. Dr. med. Joachim OERTEL Direktor Tel.: 06841/16-24400 Fax: 06841/16-24480 joachim.oertel@uks.eu

Hannah Spielmann

Magomed Lepshokov

Anna Prajsnar-Borak

Joachim Oertel

In a Prospective observational cohort study Spielmann et al. investigates the association between cerebrospinal fluid (CSF) biomarkers (Tau, Phospho-tau, Aβ42/Aβ40 ratio) and neurocognitive outcomes following ventriculoperitoneal (VP) shunt surgery in patients with idiopathic normal pressure hydrocephalus (iNPH). 80 patients were assessed with neuropsychological tests before and after lumbar puncture, and at 6 weeks and 3 months postoperatively.

• Prospective design with repeated neurocognitive assessments.
• Relevant biomarker panel (Tau, P-Tau, Aβ42/Aβ40) with potential prognostic value.
• Use of sensitive cognitive tests beyond MMSE (e.g., DemTect, TMT A & B).
• Suggests personalized treatment strategies based on CSF biomarker profiles.

• No control group or randomization → limits causal inference.
• Short follow-up (3 months); long-term cognitive evolution not assessed.
• Confounding factors (age, comorbidities, baseline cognitive function) not clearly controlled.
• No multivariate analysis or statistical power calculations provided.
• MMSE used despite low sensitivity in detecting iNPH-related changes.
• Biomarker thresholds not standardized or validated.
• Functional and quality-of-life outcomes not reported.

• The beta-amyloid ratio (Aβ42/Aβ40) is associated with better cognitive outcomes after shunt surgery.
• No significant improvement observed in MMSE, but specific domains (executive function, psychomotor speed) showed gains.
• Suggests Aβ42/Aβ40 as a possible biomarker for patient selection, but external validation is needed.

This study adds to growing evidence that CSF biomarkers, particularly the Aβ42/Aβ40 ratio, may help predict neurocognitive recovery after shunting in iNPH. However, methodological limitations reduce the strength of the conclusions. Larger, multicenter trials with longitudinal follow-up and controlled design are required to confirm its clinical utility.

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