Word count matters: Features of written language production in progressive apraxia of speech with and without agrammatism.

Introduction: Apraxia of speech (AOS) is a motor speech disorder characterized by sound distortions, substitutions, deletions, and additions; slow speech rate; abnormal prosody; and/or segmentation between words and syllables. AOS can result from neurodegeneration, in which case it can be accompanied by the primary agrammatic aphasia (PAA), which when presenting together are called AOS+PAA. AOS can also be the sole manifestation of neurodegeneration, termed primary progressive AOS (PPAOS).

Longitudinal assessment of white matter alterations in progressive supranuclear palsy variants using diffusion tractography.

Introduction: White matter (WM) tract degeneration is a characteristic feature of progressive supranuclear palsy (PSP), with longitudinal changes observed in PSP-Richardson's syndrome (PSP-RS). Little, however, is known about the other PSP variants. We assessed cross-sectional and longitudinal WM degeneration across PSP variants using diffusion tractography.

White matter hyperintensities and TDP-43 pathology in Alzheimer's disease.

Introduction: Greater white matter hyperintensities (WMHs) on magnetic resonance imaging (MRI) are seen with transactive response DNA-binding protein 43 (TDP-43) pathology in frontotemporal lobar degeneration (FTLD-TDP). WMH associations with TDP-43 pathology in Alzheimer's disease (AD-TDP) remain unclear.

Methods: A total of 157 participants from Mayo Clinic Rochester with autopsy-confirmed AD, known TDP-43 status, and antemortem fluid-attenuated inversion recovery (FLAIR) MRI were included.

Functional connectivity abnormalities in clinical variants of progressive supranuclear palsy.

Progressive supranuclear palsy (PSP) can present with different clinical variants which show distinct, but partially overlapping, patterns of neurodegeneration and tau deposition in a network of regions including cerebellar dentate, superior cerebellar peduncle, midbrain, thalamus, basal ganglia, and frontal lobe. We sought to determine whether disruptions in functional connectivity within this PSP network measured using resting-state functional MRI (rs-fMRI) differed between PSP-Richardson's syndrome (PSP-RS) and the cortical and subcortical clinical variants of PSP. Structural MRI and rs-fMRI scans were collected for 36 PSP-RS, 25 PSP-cortical and 34 PSP-subcortical participants who met the Movement Disorder Society PSP clinical criteria.