• normal pressure hydrocephalus
• chronic hydrocephalus

In their paper in this issue (pp 9–12), Bret et al¹ question the concept of normal pressure hydrocephalus (NPH) and propose renaming the condition chronic hydrocephalus. The original description of the condition is usually attributed to Hakim and Adams,² although, as Bret and colleagues point out, the condition was probably described earlier. The original description was of a constellation of clinical symptoms and signs of symptomatic hydrocephalus without overt evidence of raised intracranial pressure rather than a defined pathophysiology. …