Normal pressure hydrocephalus: current concepts in diagnosis and management focused on clinical decision

Purpose: This continuing education column aims to review and present a pragmatic approach to the diagnosis and treatment of normal-pressure hydrocephalus (NPH). It includes an overview of epidemiology, clinical features, and radiologic findings, as well as the appropriate diagnostic tests to determine accuracy and assess a patient’s likelihood of shunt responsiveness. Finally, recent advances in shunt technology, surgical techniques, and clinical outcomes are discussed. Current Concepts: Idiopathic NPH (iNPH) is a potentially reversible syndrome characterized by enlarged cerebral ventricles (ventriculomegaly), gait apraxia, cognitive impairment, and urinary incontinence without an identifiable cause. The prevalence of iNPH is higher than previously recognized. In addition to ventriculomegaly, which is a nonspecific finding associated with various conditions, disproportionately enlarged subarachnoid spaces with high-convexity tight sulci and enlarged sylvian fis-sures are now part of the diagnostic criteria for iNPH. Physiologically based tests, such as the tap test, continuous external lum-bar drainage of cerebrospinal fluid (CSF) with gait assessment before and after CSF removal, or CSF infusion testing to measure CSF outflow resistance, can reliably identify patients most likely to respond to shunt surgery. Biomarkers from CSF and neu-roimaging may also provide valuable information for predicting treatment responsiveness. When properly selected, patients have a 70% to 90% chance of benefiting from CSF diversion surgery. Discussion and Conclusion: A substantial proportion of patients can achieve improvement with CSF diversion procedures; however, surgical treatment is not universally successful, and long-term outcomes remain inconclusive despite initial gains. Further research is needed to refine diagnostic accuracy and to explore potential nonsurgical treatment strategies.