Progressive supranuclear palsy: progression and survival

Progressive supranuclear palsy (PSP) is a progressive neurodegenerative disorder characterized by postural instability and falls, vertical supranuclear gaze palsy, parkinsonism with poor levodopa response, pseudobulbar palsy, and frontal release signs. The natural history of the disease has been previously described. However, the time frame of appearance of clinical milestones and how these symptoms may relate to survival in PSP are unknown. The primary objective was to determine the prevalence of symptoms at different stages of PSP and to estimate the time of appearance of clinical symptoms characteristic of the disease. Second, we determined the association between clinical symptoms and survival. We prospectively studied 35 PSP patients during assessments scheduled every 6 months for up to 2 years. We estimated symptoms prevalence and the association between symptoms and survival. The median age of onset was 65.9 years (IQR 60.6-70.0), and the median time from onset to first assessment was 3.0 years (IQR 2.4-3.9). The most commonly reported symptoms at baseline were: motor (100%) followed by cognitive/behavioral (89%), systemic and bulbar (80%), and sleep disturbances (60%). Slowness of movement, falls, neck stiffness and difficulty looking up/down had high prevalence from baseline, while balance and gait impairment were less common at baseline but increased in prevalence over time. The presence of sleep disturbances, and possibly hallucinations, was associated with increased death risk. Improved recognition of the clinical spectrum and milestones of PSP advances knowledge of the disease, helps earlier diagnosis, and allows prognostic predictions.