2. Summary of key characteristics of iNPH randomised controlled trials.

Study	Study design	Location	Blinding	Participants	CSF testing entry criteria	Radiological criteria	Number randomised/shunted	Intervention	Published in medical literature
Tisell 2011	1‐arm, cross‐over RCT	Single centre, Sweden	Double (participant & assessor)	Symptomatic iNPH > 60 years with Binswanger's	Negative CSFTT and LIS	Evans index > 0.3, Binswanger's disease*	14/14	VP shunt	Full
Toma 2016	1‐arm, cross‐over RCT	Single centre, UK	Double (participant & assessor)	Symptomatic iNPH > 60 years	Positive ELD	Evans index > 0.3	15/15	VP shunt	Partial
Kazui 2015	1‐arm, cross‐over RCT	Multicentre, Japan	Not blinded	Symptomatic iNPH > 60 years	Normal CSF opening pressure	Evans index > 0.3 and high‐convexity and medial subarachnoid space tightness	93/88	LP shunt	Full
Luciano 2023	1‐arm, cross‐over RCT	Multicentre: USA, Canada, Sweden	Double (participant & assessor)	Symptomatic iNPH > 60 years	Positive CSFTT or ELD	Evans index > 0.3	18/18	VP shunt	Full

Abbreviations: CSF: cerebrospinal fluid; CSFTT: CSF tap‐test; ELD: external lumbar drain; iNPH: idiopathic normal pressure hydrocephalus; LIS: lumbar infusion study; LP: lumboperitoneal; RCT: randomised controlled trial; VP: ventriculoperitoneal

*Binswanger's disease defined by a score of 2 to 3 on Wahlund scale.