Purpose: Of the three currently recognized variants of primary progressive aphasia, behavioral differentiation between the nonfluent/agrammatic (nfvPPA) and logopenic (lvPPA) variants is particularly difficult. The challenge includes uncertainty regarding diagnosis of apraxia of speech, which is subsumed within criteria for variant classification.…

Some syllables are louder, longer and stronger than other syllables at the lexical level. These prominent prosodic characteristics of certain syllables are captured by suprasegmental features including fundamental frequency, duration and intensity. A language like English uses fundamental frequency, duration and intensity to distinguish stressed…