Prosodic and phonetic subtypes of primary progressive apraxia of speech

• Published in: Brain and language Vol. 184; pp. 54 - 65
• Main Authors: Utianski, Rene L., Duffy, Joseph R., Clark, Heather M., Strand, Edythe A., Botha, Hugo, Schwarz, Christopher G., Machulda, Mary M., Senjem, Matthew L., Spychalla, Anthony J., Jack, Clifford R., Petersen, Ronald C., Lowe, Val J., Whitwell, Jennifer L., Josephs, Keith A.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 01.09.2018; Academic Press
• Subjects: Aged; Aphasia, Primary Progressive - classification; Aphasia, Primary Progressive - diagnosis; Aphasia, Primary Progressive - diagnostic imaging; Apraxia; Apraxias - classification; Apraxias - diagnosis; Apraxias - diagnostic imaging; Brain - diagnostic imaging; Diffusion tensor imaging; Female; Humans; Magnetic resonance imaging; Magnetic Resonance Imaging - methods; Male; Middle Aged; Neuroimaging; Neuroimaging - methods; Phonetics; Positron-Emission Tomography; Primary progressive aphasia; Primary progressive apraxia of speech; Prosody; Speech - physiology; Positron-emission tomography; Primary progressive apraxia of speech; Magnetic resonance imaging; Primary progressive aphasia; Diffusion tensor imaging
• ISSN: 0093-934X; 1090-2155; 1090-2155
• DOI: 10.1016/j.bandl.2018.06.004

•Phonetic PPAOS is characterized predominantly by distorted sound substitutions.•Prosodic PPAOS is characterized predominantly by slow, segmented speech.•The predominant clinical characteristics of PPAOS can be quantified reliably.•PPAOS subtypes are associated with distinct imaging patterns on MRI, DTI, and FDG-PET. Primary progressive apraxia of speech (PPAOS) is a clinical syndrome in which apraxia of speech is the initial indication of neurodegenerative disease. Prior studies of PPAOS have identified hypometabolism, grey matter atrophy, and white matter tract degeneration in the frontal gyri, precentral cortex, and supplementary motor area (SMA). Recent clinical observations suggest two distinct subtypes of PPAOS may exist. Phonetic PPAOS is characterized predominantly by distorted sound substitutions. Prosodic PPAOS is characterized predominantly by slow, segmented speech. Demographic, clinical, and neuroimaging data (MRI, DTI, and FDG-PET) were analyzed to validate these subtypes and explore anatomic correlates. The Phonetic subtype demonstrated bilateral involvement of the SMA, precentral gyrus, and cerebellar crus. The Prosodic subtype demonstrated more focal involvement in the SMA and right superior cerebellar peduncle. The findings provide converging evidence that differences in the reliably determined predominant clinical characteristics of AOS are associated with distinct imaging patterns, independent of severity.