Definition of Progressive Supranuclear Palsy

Progressive supranuclear palsy (PSP) is a rare neurodegenerative disorder. The core clinical features are ocular motor dysfunction (slow vertical saccades, vertical gaze palsy), postural instability, parkinsonism and cognitive dysfunction (frontal/behavioural impairment, speech/language disorder, corticobasal syndrome). According to the predominant clinical features, several subtypes have been defined (e.g. Richardson’s syndrome, PSP with predominant parkinsonism, PSP with progressive gait freezing, PSP with predominant frontal presentation…). The estimated prevalence ranges from 1.1–6.4/100,000. The pathological hallmark is the accumulation of microtubule-associated protein tau aggregates, predominantly involving isoforms with four microtubule-binding repeats in neurons, oligodendrocytes and astrocytes. Some symptomatic treatments are available while neuroprotection or disease-modification remain unmet treatment needs.