Long lasting pure freezing of gait preceding progressive supranuclear palsy: a clinicopathological study.

Primary progressive freezing of gait (PPFG) is the term used to designate an uncommon condition featuring freezing of gait with frequent falls, without bradykinesia, rigidity or tremor, and unresponsive to levodopa. There are very few pathological reports of patients with PPFG in the literature. We report on 2 patients (one with pathological confirmation) diagnosed initially as PPFG and evolving into clinically defined progressive supranuclear palsy (PSP) more than 10 years after onset of symptoms. These 2 cases suggest that PPFG can represent the initial manifestation of a neurodegenerative disease, such as PSP, rather than a differentiated nosological entity.