PNFA accounts for only about 20% of all people with FTD. Unlike semantic dementia where the person maintains the ability to speak but loses the meaning of the word, people with PNFA have difficulty producing language fluently even though they still know the meaning of the words they are trying to say. The person may talk slowly, having trouble saying the words, and have great trouble with the telephone, talking within groups of people or understanding complex sentences. In recent years it has become apparent that many patients with PNFA go on to develop severe Parkinsonian symptoms that overlap with progressive supranuclear palsy [1] (PSP) and corticobasal degeneration [2] (CBD) such as an inability to move the eyes side-to-side, muscle rigidity in the arms and legs, falls, and weakness in the muscles around the throat.
Links:
[1] http://memory.ucsf.edu/education/diseases/psp
[2] http://memory.ucsf.edu/education/diseases/cbd