Primary progressive aphasia (PPA), also known as Mesulam's Syndrome, is a gradually appearing and gradually worsening disorder of speech that occurs without any major change in other cognitive functions for a period of at least two years. There are three main variants of PPA:

• Progressive nonfluent aphasia
• Logopenic progressive aphasia, and
• Semantic dementia

References

• Mesulam, MM (2001) "Primary progressive aphasia" Ann Neurol. 49(4):425-32.
• Gorno-Tempini ML, Dronkers NF, Rankin KP, Ogar JM, Phengrasamy L, Rosen HJ, Johnson JK, Weiner MW, Miller BL. (2004) "Cognition and anatomy in three variants of primary progressive aphasia." Ann Neurol. 55(3):335-46.

Neurology | Cognitive disorders