Figure 1.
Early presenting syndromes associated with PSP pathology. PSP clinical syndromes are first divided into the typical PSP syndrome and the atypical PSP syndromes. The typical PSP syndrome, or PSP-S, is also sometimes referred to as Richardson’s syndrome (PSP-RS) and is the most common presenting syndrome. The atypical PSP syndromes include PSP presenting as the corticobasal syndrome (PSP-CBS), as Parkinson’s disease-like (PSP-P), with progressive akinesia/gait freezing (PSP-PAGF), with cerebellar ataxia (PSP-C), as the behavioural variant of frontotemporal dementia (PSP-bvFTD) and with apraxia of speech with or without aphasia (PSP-AOS). Of note, PSP-AOS is sometimes incorrectly referred to as PSP-PNFA for non-fluent aphasia.