Table 7.

Problems that may emerge during disease course of patients initially presenting with PPAOS, with survival estimates.

Dysarthria  • Evident in minority (<30%) of patients at 2-4 years post symptom onset  • May not be evident in majority of patients until 5-6 years post symptom onset  • Dysarthria type most often spastic, hypokinetic, or mixed spastic-hypokinetic

Aphasia  • Emerges in 40-50% of patients by about 5 years post symptom onset  • Prevalence increases after 5 years but onset can be delayed until 10+ years  • Onset may be later in disease course in those with Prosodic subtype of AOS

Dysphagia  • Typically does not develop until after dysarthria has emerged

Emerging broader neurodegenerative syndrome  • Commonly evolves to PSP and/or CBS after 5+ years disease duration but may meet criteria before 5 years in substantial minority  • Uncommonly evolves to ALS

Survival  • Estimated survival ~ 9 years post-symptom onset for PPAOS  • Estimated survival ~ 7-8 years post-symptom onset for AOS+PAA and PAA