Normal pressure hydrocephalus or progressive supranuclear palsy? A clinicopathological case series.

Idiopathic normal pressure hydrocephalus (iNPH) is a poorly understood condition, which typically presents with the triad of balance impairment, urinary incontinence and subacute cognitive decline, while brain imaging shows a marked enlargement of the cerebral ventricles. Few patients with iNPH have come to post-mortem. We identified four patients from the Queen Square Brain Bank archival collection, who had received a diagnosis of iNPH during life, and reviewed their clinical, radiological and pathological characteristics. At post mortem examination, one patient had Parkinson's disease (PD) while the other three had progressive supranuclear palsy (PSP). All four had presented with pure akinesia with gait freezing, accompanied by unsteadiness and falls. An awareness that PSP or PD can mimic the clinical symptoms of iNPH may help to avoid invasive and futile cerebrospinal fluid shunting procedures.