Standardizing Normal Pressure Hydrocephalus Diagnosis: The Interdisciplinary Lausanne's Protocol

Introduction: Idiopathic normal pressure hydrocephalus (iNPH) is a reversible neurological condition characterized by gait disorders, cognitive impairment, and urinary incontinence with ventriculomegaly at brain imaging. Due to the diagnostic complexity, we developed a structured multidisciplinary protocol to improve iNPH diagnosis. We present here the results of the first year after its implementation. Methods: A multidisciplinary team involving neurosurgeons, physical therapists, neuropsychologists, and neurologists at the Lausanne University Hospitals (Switzerland) organized a diagnostic path with the following steps: first neurological assessment at the Leenaards Memory Center, neuropsychological assessment, CSF tap test with physiotherapeutic evaluation before and 24 h after the CSF tap-test, post-CSF tap test interdisciplinary consultation with a neurosurgeon and a neurologist, and an interdisciplinary board. In case of neurosurgical treatment, interdisciplinary consultations took place at 6 weeks, 6 and 12 months. Results: This retrospective analysis included 86 patients (mean age: 76.26 ± 9.08 years; 32.6% female) evaluated between June 2024 and May 2025. Gait disorders were the most common complaint (94.2% of the patients) followed by cognitive (75.6%) and urinary (60.5%) complaints. After initial investigations, the Board evaluated 44 candidates and recommended ventriculoperitoneal shunting for 27 patients. So far, 16 patients have been operated. A total of 92% reported gait improvement at 6 weeks postoperative control. Patients above 80 years of age reported more often gait improvement than patients below 80 years. Conclusion: The Lausanne's protocol demonstrates a feasible, structured, simplified, and efficient diagnostic pathway for iNPH, especially for the oldest patients.