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. 2018 Sep:184:54-65.
doi: 10.1016/j.bandl.2018.06.004. Epub 2018 Jul 4.

Prosodic and phonetic subtypes of primary progressive apraxia of speech

Rene L Utianski  1 , Joseph R Duffy  2 , Heather M Clark  2 , Edythe A Strand  2 , Hugo Botha  3 , Christopher G Schwarz  4 , Mary M Machulda  5 , Matthew L Senjem  4 , Anthony J Spychalla  4 , Clifford R Jack Jr  4 , Ronald C Petersen  3 , Val J Lowe  6 , Jennifer L Whitwell  4 , Keith A Josephs  3
Affiliations

Prosodic and phonetic subtypes of primary progressive apraxia of speech

Rene L Utianski et al. Brain Lang. 2018 Sep.

Erratum in

Abstract

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.

Keywords: Diffusion tensor imaging; Magnetic resonance imaging; Positron-emission tomography; Primary progressive aphasia; Primary progressive apraxia of speech.

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Figures

Figure 1.
Figure 1.
Flowchart of participant inclusion/ exclusion; patients included in the current study are noted by the shaded box.
Figure 2.
Figure 2.
Areas of greater atrophy in the PPAOS groups compared to their respective controls, resulting from MRI analyses (uncorrected, p < .001). Results are displayed on a semitransparent 3D brain render, made using MRICroGL.
Figure 3.
Figure 3.
Regions of reduced white matter tract integrity (measured by DTI fractional anisotropy) in PPAOS subgroups, compared to their respective controls (FWE corrected, p < .05). Results are displayed on a semitransparent 3D brain render, made using MRICroGL. Affected areas are shown in blue for Phonetic and yellow for Prosodic.
Figure 4.
Figure 4.
Areas of hypometabolism on FDG-PET in PPAOS subgroups, compared to their respective controls (FDR, p < .05). Results are displayed on a semitransparent 3D brain render, made using MRICroGL.
See this image and copyright information in PMC

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