Objectives A subset of idiopathic Normal Pressure Hydrocephalus (NPH) patients respond to VP shunt insertion temporarily. Adjustable anti-gravity devices are designed to control position-induced CSF drainage changes; we aim to assess to effect of using these devices to achieve controlled overdrainage in temporary shunt responders.

Design A single-centre retrospective study of patients undergoing VP shunt valve revision from an adjustable differential pressure valve with fixed anti-siphon (ProGAV +Shuntassistant) to a system incorporating an adjustable anti-siphon valve (ProGAV +ProSA) (April 2013-April 2018).

Subjects 21 patients diagnosed with temporary shunt-responsive NPH who improved on high volume shunt reservoir tap (10M: 11F). Mean age at first VP shunt insertion was 74.5±7.87 years.

Methods Medical records were retrospectively reviewed for demographics, interventions and clinical outcomes.

Results Mean duration until revision with a ProSA valve was 31.5±16.8 months (mean ±SD). Mean follow up was 31.4±15.9 months. Of 20 patients with sufficient follow-up, 12 made objective improvements in walking and/or neuropsychological test outcome. 15 patients made subjective improvements in mobility or cognitive impairment.

Conclusions VP shunting with adjustable differential pressure valves and fixed antigravity devices may not drain sufficient CSF for optimum management of low pressure hydrocephalus. Addition of adjustable anti-gravity devices at lower shunt settings in temporary shunt responders may improve outcome.