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Semantic and logopenic primary progressive aphasia differ in pitch variation during a motor speech task
Author(s) -
Pressman Peter S.,
Lemieux Eric,
Matthewson Gordon,
O'Neill Chris,
Ross Elliott D.
Publication year - 2020
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1002/alz.043377
Subject(s) - primary progressive aphasia , audiology , disinhibition , variation (astronomy) , psychology , frontotemporal dementia , medicine , neuroscience , disease , dementia , pathology , physics , astrophysics
Abstract Background Semantic variant primary progressive aphasia (svPPA) is an uncommon neurodegenerative disease associated with selective atrophy of the dominant temporal lobe. Previous observations of left hemisphere damage suggest that prosodic expression (mediated predominantly by the right hemisphere and dorsal processing streams) is often preserved and may even be enhanced as a release phenomenon in some aphasic syndromes. We predicted left temporal injury would be associated with increased pitch variation, thereby distinguishing it from other PPA syndromes such as the logopenic variant of primary progressive aphasia (lvPPA). Method 8 patients with svPPA and 10 patients with lvPPA repeated the syllable "Pa" as part of a motor speech evaluation. We compared the coefficient of variation of fundamental frequency, perceived as vocal pitch, using a separate variances two‐way t‐test. To better understand what may drive differences in pitch variation, we also correlated pitch variation with disinhibition measures on the Neuropsychiatric Symptoms Inventory Questionnaire (NPI‐Q) and the Frontal Assessment Battery (FAB). Result Compared to 10 patients with lvPPA (M 4.5, SD 1.6), patients with svPPA (M 14.0, SD 10.3) displayed more variation of fundamental frequency (T = 2.6, p = 0.02). There was no correlation with either the NPIQ or FAB disinhibition measures. Conclusion Pitch variation during simple motor speech tasks may serve as an additional diagnostic feature to distinguish between subtypes of PPA. The temporal atrophy associated with svPPA may release hyperprosodic performances on a simple motor speech task, through a mechanism beyond behavioral disinhibition as assessed in either the NPI‐Q or the FAB. Further research is needed to better understand the neural underpinnings of prosodic differences between PPA subtypes.