Speech motor profiles in primary progressive aphasia (Staiger et al., 2023)

Purpose: Previous research on motor speech disorders (MSDs) in primary progressive aphasia (PPA) has largely focused on patients with the nonfluent/agrammatic variant of PPA (nfvPPA), with few systematic descriptions of MSDs in variants other than nfvPPA. There has also been an emphasis on studying apraxia of speech, whereas less is known about dysarthria or other forms of MSDs. This study aimed to examine the qualitative and quantitative characteristics of MSDs in a prospective sample of individuals with PPA independent of subtype. Method: We included 38 participants with a root diagnosis of PPA according to current consensus criteria, including one case with primary progressive apraxia of speech. Speech tasks comprised various speech modalities and levels of complexity. Expert raters used a novel protocol for auditory speech analyses covering all major dimensions of speech. Results: Of the participants, 47.4% presented with some form of MSD. Individual speech motor profiles varied widely with respect to the different speech dimensions. Besides apraxia of speech, we observed different dysarthria syndromes, special forms of MSDs (e.g., neurogenic stuttering), and mixed forms. Degrees of severity ranged from mild to severe. We also observed MSDs in patients whose speech and language profiles were incompatible with nfvPPA. Conclusions: The results confirm that MSDs are common in PPA and can manifest in different syndromes. The findings emphasize that future studies of MSDs in PPA should be extended to all clinical variants and should take into account the qualitative characteristics of motor speech dysfunction across speech dimensions. Supplemental Material S1. Diagnostic features of the nonfluent variant (nfvPPA), the semantic variant (svPPA) and the logopenic variant (lvPPA) of primary progressive aphasia following the consensus criteria formulated by Gorno-Tempini et al. (2011). Supplemental Material S2. Definition of auditory speech characteristics (features). Supplemental Material S3. Auditory speech characteristics of the different motor speech syndromes. Supplemental Material S4. Severity levels of the 10 speech scales among speakers without motor speech disorders (MSDs). BREATH = speech breathing; PL = pitch/loudness; VOQ = voice quality; VOS = voice stability; SP = sound production; RES = nasal resonance; RATE = articulation rate; FLU = speech fluency; MOD = prosodic modulation; BEHAV = speech behaviour. A score of 0.00 represents most severe impairment; a severity level of > 3.33 indicates no/equivocal speech impairment. Supplemental Material S5. Severity levels of the 36 speech features among speakers without motor speech disorders (MSDs). Shown separately with respect to the speech domains (i) speech breathing (BREATH), pitch & loudness (PL), voice quality (VOQ), and voice stability (VOS); (ii) sound production (SP) and nasal resonance (RES); (iii) articulation rate (RATE), speech fluency (FLU), prosodic modulation (MOD), and speech behaviour (BEHAV). A score of 0.00 represents most severe impairment; a severity level of > 3.33 indicates no/equivocal speech impairment. Staiger, A., Schroeter, M. L., Ziegler, W., Pino, D., Regenbrecht, F., Schölderle, T., Rieger, T., Riedl, L., Müller-Sarnowski, F., & Diehl-Schmid, J. (2023). Speech motor profiles in primary progressive aphasia. American Journal of Speech-Language Pathology. Advance online publication. https://doi.org/10.1044/2023_AJSLP-22-00319</p