The epidemiology of progressive supranuclear palsy (Steele-Richardson-Olszewski syndrome).

Progressive supranuclear palsy (PSP, also known as Steele-Richardson-Olszewski syndrome) is relatively uncommon. Studies to date have found a crude population prevalence for PSP of between 1.39 and 4.9 cases per 100,000. An increased awareness of the condition, together with recently formulated clinical diagnostic criteria, should facilitate future descriptive epidemiological studies.Possible aetiological influences both genetic (tau polymorphisms) and environmental (herbal tea and tropical fruit consumption in the French West Indies) have recently been postulated. Future studies into both disease prevalence and aetiology would benefit from a multi-centre approach.